The Chemical Fingerprint of Beer from a Single Experiment with Minimum Sample Preparation – A Rapid Quantitive Analysis by 1H NMR Spectroscopy

NMR Spectroscopy is the premier tool utilized by chemists to obtain detailed chemical information on molecular structure and is used extensively in molecular structure verification, chemical purity analysis, and complex mixture analysis. We have developed a quantitative NMR analysis that yields a chemical fingerprint that brewers can utilize to follow detailed variations in the chemistry observed in the various stages of the brewing process (malting, mashing, boiling, fermentation, ageing, and blending). The analysis observes all molecules in the beer at the same time and each molecular component (acids, alcohols, amino acids, malt-oligosaccharides) yields a unique spectral fingerprint pattern that is related to the structure of the molecule. Though the spectrum consists of a large number of overlapped individual fingerprints it is possible to identify and quantify individual components because many components have signals that appear at unique and specific points in the spectrum. The quantitative analysis is performed by comparing the area under the individual molecule signals to that of an internal standard (Maleic Acid 99%). Molecular components are quantified on a weight/volume basis in mg/L (parts-per million). Ethanol is also quantified on a %volume/volume basis.

The technique is not only applicable to the brewing process but is also being utilized to gain detailed chemical understanding of cider-making process, as well as the production of wine, mead, sake, spirits, and kombucha. Our laboratory has been developing this method with the help of a number of breweries following changes in batches of standard beers (Kolsch, Stout, Scots Ale, Barley Wine) as the brewing process is tweaked and changed over the course of 2 years. We have looked not just at finished beers but have studied dextrin solubility and chemistry of wort made from different malts, the effect of temperature on sour mashing, the effect of wild yeast and bacteria on various aspects of beer chemistry, as well as troubleshooting of “out of sensory target range” beers. The analysis requires very little sample preparation, has a large (orders of magnitude) linear concentration range of applicability and observes a large number of components in a single test that does not require constant re-calibration with expensive standards.

A poster was presented on this topic at the World Brewing Congress held August 1-17 in Denver Colorado – the poster can be downloaded here.

Beer Analysis by NMR – PDF Flyer for Craft Brewing Conference – Philadelphia

The Flyer for the PNA Beer Analysis can be found at this DropBox Link.

References to 1H qNMR Applied to Fruit Juices and Alcoholic Beverages

qNMR

“Validation of quantitative NMR”, F Malz, H Jancke, J Pharm Biomed Anal,  38, 813–823, (2005)

“Quantitative 1H NMR spectroscopy”, S K Bharti, R Roy, Trends in Anal Chem, 35, 5-26 (2012)

“NMR-based plant metabolomics: where do we stand, where do we go?”  H-K Kim, Y-H Choi, R Verpoorte Trends Biotech, 29(6), 267 (2011).

“Universal quantitative NMR analysis of complex natural samples”, C Simmler, J G Napolitano, J B McAlpine, S-N Chen and G F Pauli, Current Opinion Biotech, 25, 51–59 (2014)

“Quantitative 1H NMR: Development and Potential of a Method for Natural Products Analysis” G F Pauli, B U Jaki, D C Lankin, J. Nat. Prod., 68, 133-149 (2005)

Juices

“High-Field Proton NMR Studies of Apple Juices”, P S Belton, I Delgadillo, A M Gil, P Roma, F Casuscelli, I J Colquhoun, M J Dennis M Spraul, Mag Res Chem, 35, S52-S60 (1997)

“Quantitative determination of (-)-epicatechin in cider apple juices by 1H NMR”, I Berregi , J I Santos , G del Campo , J I Miranda, Talanta 61 (2003) 139-145

“Use of the 1H Nuclear Magnetic Resonance Spectra Signals from Polyphenols and Acids for Chemometric Characterization of Cider Apple Juices”, G del Campo, J. I Santos, N Iturriza, I Berregi, A Munduate, J Agric Food Chem, 54, 3095−3100 (2006)

“Untargeted NMR-Based Methodology in the Study of Fruit Metabolites”, A P Sobolev, L Mannina, N Proietti, S Carradori, M Daglia, A M Giusti, R Antiochia and D Capitani, Molecules, 20, 4088-4108 (2015)

“Quantitative determination of formic acid in apple juices by 1H NMR spectrometry”, I Berregi, G del Campo, R Caracena, J I Miranda, Talanta, 72, 1049–1053 (2007)

“Tracking the degradation of fresh orange juice and discrimination of orange varieties: An example of NMR in coordination with chemometrics analyses”, C R de Oliveira, R L Carneiro, A G Ferreira, Food Chem, 164, 446–453 (2014)

“Quantitation determination of chlorogenic acid in cider apple juices by 1H NMR spectrometry”, I Berregi, J I Santos, G del Campo, J I Miranda, J M Aizpurua, Anal Chim Acta, 486, 269–274 (2003)

“NMR-based multi parametric quality control of fruit juices: SGF profiling”, M Spraul, B Schuetz, P Rinke, S Koswig, E Humpfer, H Schaefer, Nutrients, 1, 148 (2009)

“Evolving window zone selection method followed by independent component analysis as useful chemometric tools to discriminate between grapefruit juice, orange juice and blends”, M Cuny, G Le Gall, I J Colquhoun, M Lees, D N Rutledge, Anal Chim Acta, 597, 203 (2007)

“Fast NMR juice identification based on sugars and other plant metabolites from fruits”, M Balan, A Nicolescu, C Deleanu, C Stavarache, M Ciobanu, Rev Roum Chim, 58(2-3), 175-182 (2013)

 

Adjuncts – Hops, Malt, Honey

“Detection of honey adulteration by sugar syrups using one-dimensional and two-dimensional high-resolution nuclear magnetic resonance”, D Bertelli, M Lolli, G Papotti, L Bortolotti, G Serra, M Plessi, J Agric Food Chem, 58, 8495 (2010)

“Identification of components of Brazilian honey by H NMR and classification of its botanical origin by chemometric methods”, E F Boffo, L A Tavares, A C T Tobias, M M C Ferreira, A G Ferreira, LWT – Food Sci Tech, 49, 55-63 (2012)

“Fast and global authenticity screening of honey using 1H-NMR profiling”, M Spiteri, E Jamin, F Thomas, A Rebours, M Lees, K M Rogers, D N Rutledge, Food Chem, 189, 60-66 (2015)

“Characterization of Markers of Botanical Origin and Other Compounds Extracted from Unifloral Honeys”, E Schievano, E Morelato, C Facchin, S Mammi, J Agric Food Chem, 61(8), 1747-1755 (2013)

“NMR Characterization of Saccharides in Italian Honeys of Different Floral Sources”, R Consonni, L R Cagliani, C Cogliati, J Agric Food Chem, 60(18), 4526-4534 (2012)

“An improved NMR method for the quantification of alpha-acids in hops and hop products”, A C Hoek, A C Hermans-Lokkerbol, R Verpoorte, Phytochem Anal, 12(1), 53-57 (2001)

“Characterization of reduced iso-α-acids derived from hops (Humulus lupulus) by NMR”, L I Nord, S B Sørensen, J Ø Duus, Magn Reson Chem, 41(9), 660-670 (2003)

 

Cider

“Cider, hard and sweet: history, traditions, and making your own”, Ben Watson, 2nd ed, Countryman Press, 2009

“Cider making, using & enjoying sweet and hard cider”, Annie Proulx & Lew Nichols, 3rd Ed, Storey Publishing, 2003

“The new cider maker’s handbook: a comprehensive guide for craft producers”, Claude Jolicoeur, Chelsea Green Publishing, 2013

“Quantitative analysis of malic and citric acids in fruit juices using proton nuclear magnetic resonance spectroscopy”, G del Campo, I Berregi, R Caracena, J I Santos, Anal Chim Acta, 556, 462–468 (2006)

“Quantitative determination of lactic and acetic acids in cider by 1H NMR spectrometry”, A Zuriarrain, J Zuriarrain, A I Puertas, M T Dueñas, I Berregi, Food Control, 52, 49–53 (2015)

“Glycerol metabolism in Lactobacillus collinoides: production of 3-hydroxypropionaldehyde, a precursor of acrolein”, Nicolas Sauvageot , Kamila Gouffi, Jean-Marie Laplace, Yanick Auffray, Int J Food Microbiol 55, 167–170, (2000)

“Glycerol metabolism and bitterness producing lactic acid bacteria in cidermaking”, G Garai-Ibabe, I Ibarburu , I Berregi , O Claisse , A Lonvaud-Funel , A Irastorza , MT Dueñas, Int J Food Microbiol, 121, 253–261, (2008)

“Quantitative determination of ethanol in cider by 1H NMR spectrometry”, A Zuriarrain, J Zuriarrain , M Villar ,I Berregi, Food Control, 50, 758-762, (2015)

 

Wine

“Application of One- and Two-Dimensional NMR Spectroscopy for the Characterization of Protected Designation of Origin Lambrusco Wines of Modena”, G Papotti, D Bertelli, R Graziosi, M Silvestri, L Bertacchini, C Durante, and M Plessi, J Agric Food Chem, 61, 1741-1746 (2013)

“NMR metabolite fingerprinting in grape derived products: An overview”, C Fotakis, K Kokkotou, P Zoumpoulakis, M Zervou, Food Res Int, 54, 1184–1194 (2013)

“NMR spectroscopy evaluation of direct relationship between soils and molecular composition of red wines from Aglianico grapes”, P Mazzei, N Francesca, G Moschetti , A Piccolo, Analytica Chimica Acta 673 (2010) 167–172

“NMR investigation of acrolein stability in hydroalcoholic solution as a foundation for the valid HS-SPME/GC–MS quantification of the unsaturated aldehyde in beverages”, M Kächele, Y B Monakhova, T Kuballa, D W Lachenmeier, Anal Chim Acta, 820, 112–118 (2014)

“Wine science in the metabolomics era”, M E Alañón, M S Pérez-Coello, M L Marina, Trends Anal Chem, 74, 1–20 (2015)

“Amino acid uptake by wild and commercial yeasts in single fermentations and co-fermentations”, N Barrajón-Simancas, E Giese, M Arévalo-Villena, J Úbeda , A Briones, Food Chem, 127, 441–446 (2011)

“Chemical Profile of White Wines Produced from ‘Greco bianco’ Grape Variety in Different Italian Areas by Nuclear Magnetic Resonance (NMR) and Conventional Physicochemical Analyses”, M Caruso, F Galgano, M A C Morelli, L Viggiani, L Lencioni, B Giussani, F Favati, J Agric Food Chem, 60, 7-15 (2012)

“Metabolomic by 1H NMR Spectroscopy Differentiates “Fiano Di Avellino” White Wines Obtained with Different Yeast Strains”, P Mazzei, R Spaccini, N Francesca, G Moschetti, A Piccolo, J Agric Food Chem, 61, 10816-10822 (2013)

“An exploratory chemometric study of 1H NMR spectra of table wines”, F H Larsen, F van den Berg, S B Engelsen, J. Chemometrics, 20, 198-208 (2006)

“Sensory attributes of wine influenced by variety and berry shading discriminated by NMR metabolomics”, S Rochfort , V Ezernieks , S E P Bastian , M O Downey. Food Chem, 121, 1296–1304 (2010)

“Metabolic Influence of Botrytis cinerea Infection in Champagne Base Wine”, Y-S Hong, C Cilindre, G Liger-Belair, P Jeandet, N Hertkorn, P Schmitt-Kopplin, J Agric Food Chem, 59, 7237-7245 (2011)

“A Thorough Study on the Use of Quantitative 1H NMR in Rioja Red Wine Fermentation Processes”, E Lopez-Rituerto, S Cabredo, M Lopez, A Avenoza, J H Busto, J M Peregrina, J Agric Food Chem, 57, 2112–2118 (2009)

“Comparison of Gas Chromatography-Coupled Time-of-Flight Mass Spectrometry and 1H Nuclear Magnetic Resonance Spectroscopy Metabolite Identification in White Wines from a Sensory Study Investigating Wine Body”, K Skogerson, R Runnebaum, G Wohlgemuth, J De ROPP, H Heymann, O Fiehn, J Agric Food Chem, 57(15), 6899-6907 (2009)

“Metabolomic Characterization of Malolactic Fermentation and Fermentative Behaviors of Wine Yeasts in Grape Wine” H-S Son, G-S Hwang, W-M Park, Y-S Hong, AND C-H Lee, J Agric Food Chem, 57(11), 4801-4809 (2009)

 “1H nuclear magnetic resonance-based metabolomic characterization of wines by grape varieties and production areas”, H-S Son, K-M Kim, F Van den Berg, G-S Hwang , W-M Park, C-H Lee, J Agric Food Chem, 56, 8007 (2008)

“Metabolomic studies on geographical grapes and their wines using 1H NMR analysis coupled with multivariate statistics”, H-S Son, G-S Hwang, KM Kim, H-J Ahn, W-M Park, F Van Den Berg, J Agric Food Chem, 57, 1481 (2009)

“Use of modern nuclear magnetic resonance spectroscopy in wine analysis: determination of minor compounds”, I J Kosir, J Kidric, Anal Chim Acta, 458, 77 (2002)

“Chemometric classification of Apulian and Slovenian wines using 1H NMR and ICP-OES together with HPICE data”, M A Brescia, I J Kosir, V Caldarola, J Kidric, A Sacco, J Agric Food Chem, 51, 21 (2003)

“Characterization of wines by nuclear magnetic resonance: a work study on wines from the Basilicata region in Italy”, L Viggiani, M A C Morelli, J Agric Food Chem, 56, 8273 (2008)

“Classification of wines based on combination of 1H NMR spectroscopy and principal component analysis”, Y-Y Du, G-Y Bai, X Zhang, M-L Liu, Chin J Chem, 25, 930 (2007)

1H NMR-based metabonomics for the classification of Greek wines according to variety, region, and vintage. Comparison with HPLC data”, M Anastasiadi, A Zira, P Magiatis, S A Haroutounian, A L Skaltsounis, E Mikros, J Agric Food Chem, 57, 11067 (2009)

1H NMR and chemometrics to characterize mature grape berries in four wine- growing areas in Bordeaux, France, G E Pereira, J P Gaudillere, C Van Leeuwen, G Hilbert, O Lavialle, M Maucourt, J Agric Food Chem, 53, 6382 (2005)

 “1H NMR-based metabolomic approach for understanding the fermentation behaviors of wine yeast strains”, H-S Son, G-S Hwang, KM Kim, E-Y Kim, F van den Berg, W-M Park, Anal Chem, 81, 1137 (2009)

“Generalized 2D-correlation NMR analysis of a wine fermentation”, G M Kirwan, S Clark, N W Barnett, J O Niere, M J Adams, Anal Chim Acta, 629, 128 (2008)

Time course of the evolution of malic and lactic acids in the alcoholic and malolactic fermentation of grape must by quantitative 1H NMR (qHNMR) spectroscopy”, A Avenoz, J H Busto, N Canal, J M Peregrina, J Agric Food Chem, 54, 4715 (2006)

“NMR-based metabolomics in wine science”, Y-S Hong, Magn Reson Chem, 49, S13 (2011)

“High- resolution NMR and diffusion-ordered spectroscopy of port wine”, M Nilsson, I F Duarte, C Almeida, I Delgadillo, B J Goodfellow, A M Gil, J Agric Food Chem, 52, 3736 (2004)

 “Quantitative NMR spectroscopy of binary liquid mixtures (aldehyde + alcohol) Part I: Acetaldehyde + (methanol or ethanol or 1-propanol)”, S Jaubert, G Maurer, J Chem Thermo 68, 332–342 (2014)

 

Beer

“Beer metabolomics: molecular details of the brewing process and the differential effects of late and dry hoppinng on yeast purine metabolism”, A R Spevacek, K H Benson, C W Bamforth, C M Slupsky, J. Inst. Brew., 122 21-28 (2016)

“Composition of beer by 1H NMR spectroscopy: effects of brewing site and date of production”, C Almeida, I F Duarte, A Barros, J Rodrigues, M Spraul, A M Gil, J Agric Food Chem, 54, 700 (2006)

“Multivariate analysis of NMR and FTIR data as a potential tool for the quality control of beer “, I F Duarte, A Barros, C Almeida, M Spraul, A M Gil, J Agric Food Chem, 52, 1031 (2004)

“High-Resolution Nuclear Magnetic Resonance Spectroscopy and Multivariate Analysis for the Characterization of Beer”, Ä I Duarte, A Barros, P S Belton, R Righelato, M Spraul, E Humpfer, A M Gil, J Agric Food Chem, 50, 2475−2481 (2002)

“Quantification of organic acids in beer by nuclear magnetic resonance (NMR)-based methods”, J E A Rodrigues , G L  Erny , A S  Barros , V I  Esteves , T Brandão , A A  Ferreira , E  Cabrita , A M  Gil,  Anal Chim Acta, 674, 166–175 (2010)

“NMR methods for beer characterization and quality control”, J E Rodrigues, A M Gil, Magn Reson Chem, 49, S37–S45 (2011)

“Quality control of beer using high-resolution nuclear magnetic resonance spectroscopy and multivariate analysis”, D W Lachenmeier, W Frank, E Humpfer, H Schafer, S Keller, M Mortter · M Spraul, Eur Food Res Technol, 220, 215–221 (2005)

“Probing beer aging chemistry by nuclear magnetic resonance and multivariate analysis”, J A Rodrigues, A S Barros, B Carvalho, T Brandão, A M Gil,  Anal Chim Acta, 702, 178–187 (2011)

“Quantification of Organic and Amino Acids in Beer by 1H NMR Spectroscopy”, L I Nord, P Vaag, J Ø Duus, Anal Chem, 76 (16), 4790–4798 (2004)

Application of Quantitative Nuclear Magnetic Resonance Spectroscopy to Biological Acidification of Barley Mashes”, A Dicaprio, J C Edwards, J Inst Brewing, 120(3), 207-211 (2014)

 

Beer Dextrins

“Separation and NMR structural characterisation of singly branched a-dextrins which differ in the location of the branch point”, A Jodelet, N M Rigby, I J Colquhoun, Carb Res, 312, 139-151 (1998)

1H NMR spectroscopy for profiling complex carbohydrate mixtures in non-fractionated beer”  B O Petersen , M Nilsson , M Bøjstrup , O Hindsgaul , S Meier, Food Chem, 150, 65–72 (2014)

“Development of brewing science in (and since) the late 19th century: Molecular profiles of 110–130 year old beers”, A Walther, D Ravasio, F Qin, J Wendlan , S Meier,  Food Chem, 183, 227–234 (2015)

Structural determination of some new oligosaccharides and analysis of the branching pattern of isomaltooligosaccharides from beer”, E Vinogradov, K Bock, Carb Res, 309, 57-64 (1998)

“NMR characterization of chemically synthesized branched a-dextrin model compounds”, B O Petersen, M S Motawie, B Lindberg Møller, O Hindsgaul, S Meier, Carb Res, 403, 149–156 (2105)

 

Sake

“NMR-Based Metabolic Profiling of Rice Wines by F2-Selective Total Correlation Spectra”, M Koda, K Furihata, F Wei, T Miyakawa, M Tanokura, J Agric Food Chem, 60(19), 4818–4825 (2012)

 

Vinegar

“Traditional balsamic vinegar and balsamic vinegar of Modena analyzed by nuclear magnetic resonance spectroscopy coupled with multivariate data analysis”, G Papotti, D Bertelli, R Graziosia, A Maietti, P Tedeschi, A Marchetti, M Plessi, LWT – Food Sci Tech, 60(2), 1017-1024 (2015)

Identification and quantification of the main organic components of vinegars by high resolution 1H NMR spectroscopy”, A. Caligiani , D. Acquotti , G. Palla , V. Bocchi, Anal Chim Acta, 585,110–119 (2007)

1H NMR studies on Italian balsamic and traditional balsamic vinegars”, R Consonni, A Gatti, J Agric Food Chem, 52, 3446 (2004)

“NMR and chemometric methods: a powerful combination for characterization of Balsamic and Traditional Balsamic Vinegar of Modena”, R Consonni, L R Cagliani, F Benevelli, M Spraul, E Humpfer, M Stocchero, Anal Chim Acta, 611, 31 (2008)

 

Spirits

“NMR metabolite profiling of Greek grape marc spirits” C Fotakis , D Christodouleas , K Kokkotou , M Zervou , P Zoumpoulakis , P Moulos , M Liouni , A Calokerinos, Food Chem, 138, 1837–1846 (2013)

“NMR metabolic fingerprinting and chemometrics driven authentication of Greek grape marc spirits”, C Fotakis, M Zervou, Food Chem, 196, 760-768 (2016)

“Rapid Determination of Total Thujone in Absinthe Using 1H NMR Spectroscopy”, Y B Monakhova , T Kuballa, and D W Lachenmeier, Int J Spectroscopy, 2011, Article ID 171684, 5 pages (2011)

“Solute Effects on the Interaction between Water and Ethanol in Aged Whiskey”, A Nose, M Hojo, M Suzuki, T Ueda, J Agric Food Chem, 52(17), 5359–5365 (2004)

“Hydrogen Bonding in Alcoholic Beverages (Distilled Spirits) and Water−Ethanol Mixtures”, A Nose, T Hamasaki, M Hojo, R Kato, K Uehara, T Ueda, J Agric Food Chem, 5(18), 7074–7081 (2005)

“Structurability: A Collective Measure of the Structural Differences in Vodkas”, N Hu, D Wu, K Cross, S Burikov, T Dolenko, S Patsaeva, D W Schaefer, J Agric Food Chem, 58(12), 7394–7401 (2010)

“Rapid Quantification of Ethyl Carbamate in Spirits Using NMR Spectroscopy and Chemometrics”, Y B Monakhova, T Kuballa, Dirk W Lachenmeier, ISRN Anal Chem, 2012, Article ID 989174, 5 pages (2012)

“Authenticity of the Traditional Cypriot Spirit “Zivania” on the Basis of 1H NMR Spectroscopy Diagnostic Parameters and Statistical Analysis”, P Petrakis, I Touris, M Liouni, M Zervou, I Kyrikou, R Kokkinofta, C R Theocharis, T M Mavromoustakos, J Agric Food Chem, 53(13), 5293–5303 (2005)

“Investigation into the structural composition of hydroalcoholic solutions as basis for the development of multiple suppression pulse sequences for NMR measurement of alcoholic beverages”, Y B Monakhova, S P Mushtakova, T Kuballa, D W Lachenmeier, Magn Reson Chem, 52, 755-759 (2014)

“Quantitative 1H NMR Analysis of Egg Yolk, Alcohol, and Total Sugar Content in Egg Liqueurs”, M Hohmann, V Koospal, C Bauer-Christoph, N Christoph, H Wachter, B Diehl, U Holzgrabe, J Agric Food Chem, 63(16), 4112–4119 (2015)

Quantitative 1H NMR Analysis of “Off-the-Shelf” Commercial Kombucha Beverages for Ethanol, Organic Acids and Residual Sugars Analysis

Over the past few years our analytical NMR service has been developing a detailed chemical fingerprint analysis of alcoholic beverages by quantitative 1H NMR (qHNMR). Beyond the typical analyses of beer, wine, port, hard cider, sake and spirits, we have been looking at other fermented beverages such as kombucha, kefir, kvass, mead, ginger beer and perry. As well as the final fermented beverages we have been actively investigating the various starting materials such as malt wort, apple juice, honey, grape juice, fruit juices, and tea. The NMR analysis can provide a rapid quantitative analysis without any sample preparation based on the molar ratio of integration value of unique molecular fingerprint peaks with the integrated signal of an internal standard. In our case we typically use maleic acid as an internal standard as it’s singlet signal peak appears in a non-overlapping are of the spectrum to the chemistry we are interested in following.

The information that can be derived from the NMR experiment covers a wide dynamic range of component molecule concentrations from 10-100,000 ppm. The analysis observes all fully dissolved chemical constituents and the spectral response is linear with regard to all chemical types. As a primary analytical method the chemist can utilize the well understood literature on the NMR chemical shifts and couplings that allow first principles analysis of each molecular fingerprint to identify and quantify the presence of targeted and non-targeted molecules in the complex mixture. The analysis provides quantitative information on the following chemical components: ethanol, higher (C3,C4,C5) alcohols, methanol, glycerol, organic acids (lactic, acetic, succinic, pyruvic, pyruvic hydrate, citric, malic, tartaric, quinic), free amino acids (alanine, isoleucine, valine, tyrosine, phenylalanine), carbohydrates (sucrose, glucose, fructose, sorbitol, xylose, galacuronic acid, maltose, 1,6- and 1,4-dextrin chemistry, maltotriose, lactose), polyphenols. It can also provide information on yeast metabolism products such as 2,3-butandiol (directly from Enterobacter or from the action of saccharomyces on diacetal which is a well-known beer flavor deviation), 1,3-propandiol (from yeast action on glycerol after carbohydrates have been entirely fermented from the beverage).

In recent years kombucha has been found to contain more than 0.5% v/v ethanol which would technically lead the product to be classified as alcoholic beverages and bring the product under scrutiny and taxation by the Alcohol and Tobacco Tax and Trade Bureau which federally regulates the alcoholic beverage industry. Kombucha is a sweetened black or green tea that has been inoculated with a symbiotic culture of bacteria and yeast (SCOBY) which ferments the sugars in the drink solution in bith the manufacturing process and in the sealed bottle shipped out to stores. The drink is sold under the premise that the SCOBY provides a probiotic culture to the consumer which means that in many Kombuch products the activity of the culture is not arrested by pasteurization or by addition of sorbate. Thus, the kombucha is bottled with active yeast and bacteria present in a high sugar containing tea drink. Fermentation is then thought to occur while the product sits on shelves and leads to >0.5% ABV when the drink is purchased or consumed. We have utilized 1H NMR to obtain quantitative ethanol concentrations on a number of kombucha beverages bought off the shelf at grocery stores. The samples we analyzed represent the entire dataset of kombuchas that we purchased and they represent the products of 5 different manufacturers. We also aged two of the products at room temperature for 7 months and analyzed them to observe the effect of long term aging on kombucha products.

Experimental: 1H NMR spectra were acquired on a Varian Mercury-300MVX spectrometer operating at a resonance frequency of 299.67 MHz and equipped with a Varian 5mm ATB PFG probe. The experiments are performed under quantitative conditions utilizing a 10 ms (p/3 tip angle) pulse with an 8 second acquisition time and a 7 second relaxation delay. 64 transients were acquired over a spectral window of 8 kHz at a controlled temperature of 27oC. Water suppression was achieved by pre-saturation and this can affect the quantitation of glucose in the samples under these conditions.

Sample preparation: Samples were purchased “off the shelf” at local grocery stores and were analyzed the same day that they were purchased. Samples were prepared by 1) degassing the samples by repeated vortex agitation, 2) samples are equilibrated at 27oC before pipetting to allow a mass to volume conversion to be utilized to calculate the %ABV utilizing an ethanol density value of 0.7816 kg/L, 3) pipetting 175ml of kombucha beverage into a 5mm NMR tube, 4) adding 100ml of a 100mg/ml solution of maleic acid (99.5% – Sigma Aldrich) in D2O (99.8%D), and 5) addition of 375ml of D2O (99.8%D – Cambridge Isotopes Laboratories). The final samples were thoroughly mixed using a vortex mixer.

Two of the kombucha samples were purchased in duplicate and not opened immediately but stored at room temperature for 7 months before being analyzed. These stored samples were compared with the same samples that were opened and analyzed immediately after purchase.

Calculations: Component concentrations were calculated on a mg/L basis based on a knowledge of the concentration of maleic acid internal standard present in the sample (10mg) using the following equation:

Component Concentration (C) in mg/L = 0.995 x 10 x ((IC/NC)/(IMA/NMA)) x (MC/MMA) x (1,000,000/175)

Where 10 mg is the mass of maleic acid used as the internal standard, IC = integral of the component peak, NC = number of protons represented in the component peak, IMA = integral of maleic acid internal standard, NMA = number of protons represented in the maleic acid integral (2), Mc = molecular weight of the component, MMA = molecular weight of maleic acid (116.1 amu). Other aspects of the equation are – 175ml of sample must be adjusted to 1 liter (1,000,000 ml), and the whole must be multiplied by 0.995 as the maleic acid can only be guaranteed to be 99.5% pure. The ethanol content is calculated based on a weight per volume basis (mg/L) and then a calculation is performed to convert this weight/volume concentration to a volume/volume basis using a density value of 0.7816 kg/L to convert the weight of ethanol to the volume of ethanol.

Results: Figures 1-7 show the 1H NMR spectra of the 7 kombucha samples purchased and analyzed immediately. All 7 samples were found to contain ethanol and only one of them was found to contain less than 0.5%. Figure 8 shows a stacked plot comparison of the chemistry observed in a kombucha that was aged for 7 months at room temperature compared to the sample when it was initially purchased. The alcohol content rose from 1.23 %ABV to 4.25 %ABV and it can be seen that all sugars in the original drink have been consumed by the SCOBY to produce this increased alcohol content. The acetic acid content of the aged drinks also increased but it is obvious that the conversion of ethanol to acetic acid by acetobacter present in the SCOBY does not offset the overall production of ethanol. The component concentrations of ethanol, sugars and organic acids in each of the kombucha beverages analyzed are provided in Table I.

Table I: Concentration of Chemical Components of Kombucha Beverages

Kombucha Sample
Component #1 #1 Aged #2 #2 Aged #3 #4 #5 #6 #7
Lactic Acid (mg/L) 64 68 131 210 461 124 1809 24 248
Succinic Acid (mg/L) 74 97 116 277 142 134 110 64 131
Acetic Acid (mg/L) 3056 5637 2746 3333 387 2806 2051 3719 444
Malic Acid (mg/L) 175 190 175 190 185 515 0 0 99
Ethanol (mg/L) 10625 12640 9580 33245 11631 10938 8114 3866 10218
Ethanol (v/v) 1.36 1.62 1.23 4.25 1.49 1.40 1.04 0.49 1.31
Sucrose (mg/L) 0 0 4141 0 12261 11790 2021 27723 11386
Glucose (mg/L) 24017 24507 24460 0 15379 15645 22776 31450 20328
Fructose (mg/L) 31786 9433 23725 0 16634 18173 30155 30791 17437
Sorbate (mg/L) 0 0 0 0 0 0 0 0 0
Citrate (mg/L) 0 0 1592 1582 0 4416 0 0 0

Kombucha1_NMR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 1: Kombucha #1 – 1H NMR spectrum – component peaks utilized in calculations indicated.

Kombucha2_NMR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 2: Kombucha #2 – 1H NMR spectrum – component peaks utilized in calculations indicated.

Kombucha3_NMR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 3: Kombucha #3 – 1H NMR spectrum – component peaks utilized in calculations indicated.

Kombucha4_NMR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 4: Kombucha #4 – 1H NMR spectrum – component peaks utilized in calculations indicated.

Kombucha5_NMR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 5: Kombucha #5 – 1H NMR spectrum – component peaks utilized in calculations indicated.

Kombucha6_NMR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 6: Kombucha #6 – 1H NMR spectrum – component peaks utilized in calculations indicated.

Kombucha7_NMR

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 7: Kombucha #7 – 1H NMR spectrum – component peaks utilized in calculations indicated.

Kombucha8_NMR

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 8: Kombucha #2 – Comparison of original analyzed “fresh kombucha” with same purchase date bottle aged at room temperature for 7 months – 1H NMR spectrum – sugar peaks are consumed by the yeast to produce higher alcohol in the aged sample.

 

References:

Alcohol in Kombucha News Articles:

http://www.cnn.com/2015/12/09/health/kombucha-tea-alcohol-content/index.html – visited 12-13-15

http://www.wsj.com/articles/battle-brews-over-kombucha-teas-1447116607 – Visited 12-13-15

Kombucha Product Information:

Kombucha Brewers International – http://kombuchabrewers.org/ – visited 12-13-15

1H qNMR:

“Universal quantitative NMR analysis of complex natural samples”, G C Simmler, J Napolitano, J B McAlpine, S-N Chen and G F Pauli, Current Opinion in Biotechnology 2014, 25:51–59

“Quantitative H NMR spectroscopy”, S K Bharti, R Roy, Trends in Analytical Chemistry, Vol. 35, 2012

“Validation of quantitative NMR”, F Malz , H Jancke, Journal of Pharmaceutical and Biomedical Analysis 38 (2005) 813–823

1H qNMR Applied to Alcoholic and Non-Alcoholic Beverages

“Quantitative determination of ethanol in cider by 1H NMR spectrometry”, A Zuriarrain , J Zuriarrain , M Villar ,I Berregi, Food Control 50 (2015) 758-762

“Quantitative determination of lactic and acetic acids in cider by 1H NMR spectrometry”, A Zuriarrain, J Zuriarrain, A I Puertas, M Dueñas, I Berregi

“Identification and quantification of the main organic components of vinegars by high resolution 1H NMR” spectroscopy, A Caligiani , D Acquotti , G Palla , V Bocchi, Analytica Chimica Acta 585 (2007) 110–119

“NMR-based metabolomics in wine science”, Y-S Hong, Magn. Reson. Chem. 2011,49, S13–S21

1H NMR-based metabolomic characterization during green tea (Camellia sinensis) fermentation”, J-E Lee , B-J Lee , J-O Chung , H-J Shin , S-J Lee , C-H Lee ⁎, Y-S Hong, Food Research International 44 (2011) 597–604

“NMR methods for beer characterization and quality control”, J E Rodrigues, A M Gil, Magn. Reson. Chem. 2011, 49, S37–S45

“Metabolomic profiling of Cheonggukjang during fermentation by 1H NMR spectrometry and principal components analysis”, H-K Choi, J-H Yoon , Y-S Kim , D Y Kwon, Process Biochemistry 42 (2007) 263–266

“Quantification of organic acids in beer by nuclear magnetic resonance (NMR)-based methods”, J E A Rodrigues , G L Erny , A S Barros , V I Esteves , T Brandão , A A Ferreira , E Cabrita , A M Gil, Analytica Chimica Acta 674 (2010) 166–175

“Monitoring a commercial fermentation with proton nuclear magnetic resonance spectroscopy with the aid of chemometrics”, S Clark , N W Barnett , M Adams , I B Cook , G A Dyson , G Johnston, Analytica Chimica Acta 563 (2006) 338–345

“Quality control of beer using high-resolution nuclear magnetic resonance spectroscopy and multivariate analysis”, D W Lachenmeier, W Frank, E Humpfer, H Schafer, S Keller, M Mortter, Manfred Spraul, Eur. Food Res. Technol. (2005) 220:215–221

1H NMR spectroscopy for profiling complex carbohydrate mixtures in non-fractionated beer”, B O. Petersen , M Nilsson , M Bøjstrup , O Hindsgaul , S Meier, Food Chemistry 150 (2014) 65–72.

“Regulatory Control of Energy Drinks Using 1H NMR Spectroscopy”, Y B Monakhova, T Kuballa, H Reusch, K Wegert G Winkler, D W Lachenmeier, Lebensmittelchemie 66, 129–168 (2012)

“Qualitative and Quantitative Control of Honeys Using NMR Spectroscopy and Chemometrics”, M Ohmenhaeuser, Y B Monakhova, T Kuballa, D W Lachenmeier, ISRN Analytical Chemistry Volume 2013, Article ID 825318, “Qualitative and Quantitative Control of Carbonated Cola Beverages Using 1H NMR Spectroscopy” P Maes, Y B Monakhova, and D W Lachenmeier, T Kuballa, H Reusch, J. Agric. Food Chem. 2012, 60, 2778−2784

A PDF Version of this Article can be found here – Kombucha NMR.pdf

Process NMR Associates quantitatively analyzes the component chemistry of craft beverages for consumers or manufacturers – for more information contact John Edwards at +1 (203) 241-0143

PANIC NMR Validation Group – Website, Meetings and Organization

Validation of NMR: No Need to PANIC – Workshop held February 13, 2015, La Jolla, CA, U.S.A

In conjunction with the 3rd PANIC conference in La Jolla, California, a 1-day NMR validation workshop was held that attracted approximately 80 interested participants. The agenda of the meeting is provided at this link (http://www.nmrvalidation.org/index.php/events/event-review) and registered participants can now download the presentations presented at the meeting. At the meeting it was decided to proceed with the idea of founding an organization dedicated to the development of validate NMR methods for use throughout all industry sectors.

Organizational Scope:

NMR spectroscopy provides a means to evaluate material with high compound and high material specificity. Information as to the chemical structure, stereochemistry, quantity, material composition, and material identity is encoded in the NMR spectrum. The high reproducibility of NMR spectroscopy from instrument to instrument and lab to lab makes NMR an excellent tool for material validation. Approaches to utilizing NMR as a material validation tool include using (1) targeted approaches, the identification and quantification of specific components, and (2) non-targeted approaches, the use of chemometric methods to evaluate the spectrum as a whole. Efforts to increase the number and the speed of validated NMR methods are underway. This promises to move NMR technology from R&D to a mainstream analytical tool for production leading to high quality product assessment.

Quantitative NMR spectroscopy (qNMR) provides the most universally applicable form of direct purity determination without the need for reference materials of analytes or the calculation of response factors, with the only requirement being the exhibition of suitable NMR spectral properties. Due to recent advances in the technical development of NMR instruments, such as acquisition electronics and probe design, detection limits of components in liquid mixtures have been improved into the lower ppm range (approx. 5–10 ppm amount of substance).

The development of validated procedures and qualified standards will give users the tools to routinely exploit qNMR and enable them to speed up analytical method development, with the added advantage of reducing the time and financial burden of multiple analytical testing.

Over the last few years a number of efforts have been made to include NMR in routine testing and analysis – especially in regulated fields such as those operating under GMP or GLP guidelines. Unfortunately it has been observed that approval authorities, standard method organizations, and auditors prefer to take analytical routes derived from classical chromatographic methods. Since NMR represents a direct comparison analysis method such decisions clearly fail to take advantage of the benefits that NMR can provide.

The PANIC validation group proposes to become a driving force in getting NMR methods validated, publicized, and supported by documentation and qualified standards. The organization will also provide a mechanism for repeatability/reproducibility assessment of NMR methods as well as the round-robin accreditation of NMR labs. We aim to proactively promote the technology and improve its acceptance by the analytical community across all industry sectors.

What we want:

  • Identify a network of NMR people concerned with validation that can ultimately assist each other through the validation process.
  • Harmonize the terminology and a standard approach for NMR validations.
  • Position the guidelines produced by consensus of the NMR community so that accreditation agencies can use this process.

It is expected that there will be an annual 1-day meeting in conjunction with future PANIC conferences. A website has been been created as an organizational repository. The website can be found here: http://www.nmrvalidation.org/index.php and details of future events and, eventually, contact information will be provided.

1H qNMR of Alcoholic Cider – Analysis of Small Molecule and Residual Sugar Chemistry

1H quantitative NMR (qNMR) has been utilized to assess the the small molecule and carbohydrate chemistry of a number of home-brewed and commercial alcoholic ciders. A quantitative chemistry distribution of the products of the various fermentations that occur in cider making. Malolactic fermentation as well as fermentation by saccharomyces and wild yeasts occur in the cider making process which traditionally occurred without the intentional addition of yeast by the manufacturer. The distribution of small molecules produced by the yeast and bacterial metabolomes at work in the process can yield information of the sensory perception of ciders produced in different ways. An investigation of the residual sugar chemistry of commercial ciders gives some indication of the process of sweetening commercial cider products with sugar additions after fermentation is complete. These typical commercial ciders are very different in chemistry distribution compared to very dry cider styles such as those found in the Basque region of Spain where fermentation is taken to the extreme resulting in complete conversion of sugars to alcohol but also glycerols to 1,3 propandiol. Finally it was decided to determine how much quantitative chemistry information could be obtained from benchtop NMR systems operating in the 60 MHz range. These benchtop NMR systems have a price and cost-of-ownership that would allow small laboratories of manufacturers to think about their use in QA and QC roles.

1H qNMR analysis of molecular components in hard cider – targeted and non-targeted quantitative chemical analysis

PNA to Present 4 Topics at the 2015 ACS North East Regional Meeting

John Edwards of Process NMR Associates will be presenting 4 papers at the 2015 ACS Northeast Regional Meeting that will be held in Ithaca, NY, June 10-13, 2015.

ABSTRACT ID: 2283171
ABSTRACT TITLE: 1H qNMR of Alcoholic Cider – Analysis of Small Molecule and Residual Sugar Chemistry (final paper number: 43)
SESSION: Food Chemistry
SESSION TIME: 5:00 PM – 9:00 PM
PRESENTATION FORMAT: Poster
DAY & TIME OF PRESENTATION: Wednesday, June, 10, 2015, 5:00 PM – 9:00 PM
ROOM & LOCATION: Emerson Suites – Campus Center

ABSTRACT ID: 2283063
ABSTRACT TITLE: Nutritional Supplement and Diesel Fuel Application Development for Benchtop NMR Systems Operating at 42, 60, and 80 MHz – Equivalency with Supercon NMR (final paper number: 336)
SESSION: Analytical Chemistry
SESSION TIME: 9:00 AM – 11:30 AM
PRESENTATION FORMAT: Oral
DAY & TIME OF PRESENTATION: Friday, June, 12, 2015 from 9:45 AM – 10:05 AM
ROOM & LOCATION: 222 – Williams Hall

ABSTRACT ID: 2283105
ABSTRACT TITLE: Survey of Low Field NMR Spectrometer Platforms for Successful Screening of Sexual Enhancement and Weight Loss Supplements for Adulteration with Drugs and Drug Analogs (final paper number: 386)
SESSION: Medicinal Chemistry
SESSION TIME: 1:00 PM – 3:20 PM
PRESENTATION FORMAT: Oral
DAY & TIME OF PRESENTATION: Friday, June, 12, 2015 from 2:20 PM – 2:40 PM
ROOM & LOCATION: 302 – Williams Hall

ABSTRACT ID: 2283153
ABSTRACT TITLE: From Mash to Bottle: Chemistry of the Beer Brewing Process and NMR-based Quality Control (final paper number: 284)
SESSION: Food Chemistry
SESSION TIME: 1:30 PM – 3:10 PM
PRESENTATION FORMAT: Oral
DAY & TIME OF PRESENTATION: Thursday, June, 11, 2015 from 1:35 PM – 1:55 PM
ROOM & LOCATION: 202 – Williams Hall

Essential Oil Analysis – Comparison of 1H NMR from Benchtop and Supercon NMR Systems

1H NMR shows excellent promise to be utilized in the quality control and authentication of essential oils. In order to ascertain if benchtop NMR systems reveal adequate “1H spectral fingerprints” for this purpose we have run several hundred essential oils at 300 MHz (Varian Mercury-300 MVX by 1H, 13C, COSY, HETCOR, DEPT)  as well as at 82.3 MHz (Picospin 80), 60 MHz (Aspect-60), and 42.5 MHz (Magritek Spinsolve). The results plainly show that the spectrometers all yield similar proton line-widths with the difference in field strength leading to different levels of spectral dispersion and resolution. Though each spectrum is different it can plainly be seen that they all contain the same information with varying degrees of overlap. Chemometric and database comparative methods are being developed to allow identification of various essential oils as well as screening and quantifying different levels of adulteration. The figures below show examples from 6 different essential oils showing spectra obtained from all 4 spectrometers and plotted in the normalized chemical shift scale (ppm) as well as the absolute frequency scale (Hz).EO1 EO2 EO3 EO4 EO5 EO6 EO7 EO8 EO9 EO10 EO11 EO12

Polyalphaolefin Hydrogenation – Residual Olefin Analysis – 1H NMR versus Bromine Number

1H NMR is an excellent tool for monitoring the residual olefin content of polymers after hydrogenation reactions. The fact that the olefin fall in a unique region of the spectrum means that it is a straightforward measurement to quantify the %H present as olefin or to correlate that olefin content with other analyses such as bromine number. Here is an example of a polyalphaolefin residual olefin analysis. The olefin proton content (%H) was plotted against bromine number values obtained on each of the samples. A linear correlation was obtain but two different correlations were observed that were dependent on the viscosity index of the polyalphaolefin being analyzed. Figure 1 shows the 1H NMR spectra obtained on neat samples on a Picospin-80 spectrometer operating at 82.3 MHz. The methyl and methlene protons of the polymer backbone are plainly seen and the olefin and alpha-olefin protons are observed.

1H NMR - Polyalphaolefins - Residual Olefin Analysis

Figure 1: 1H NMR – Polyalphaolefins – Residual Olefin Analysis

 

Figure 2 shows the linear correlation between %H olefin and bromine number with the two correlations caused by different VI grade being indicated. The analysis shows that for the two viscosity grades the grade can be identified from the linear correlation that the data falls onto and the %H olefins content can directly yield the bromine number. This NMR method provides an alternative to the following ASTM standards:                                                            D1159 Test Method for Bromine Numbers of Petroleum Distillates and Commercial Aliphatic Olefins by Electrometric Titration                                      D1491 Test Method for Test for Bromine Index of Aromatic Hydrocarbons by Potentiometric Titration                                                                         D1492  Standard Test Method for Bromine Index of Aromatic Hydrocarbons by Coulometric Titration                                                                             D2710 Test Method for Bromine Index of Petroleum Hydrocarbons by Electrometric Titration                                                                                      D5776 Test Method for Bromine Index of Aromatic Hydrocarbons by Electrometric Titration

Correlation of Olefin Content obtained by 1H NMR with Bromine Number in Polyalphaolefins

Figure 2: Correlation of Olefin Content obtained by 1H NMR with Bromine Number in Polyalphaolefins

NMR Detection of Tomato Paste Spoilage in 1000 Liter Metal Lined Totes

Poster to be Presented at the 56th ENC, Asilomar CA, April 2015

NMR Detection of Tomato Paste Spoilage in 1,000 L, Metal Lined Totes
Michele Martin1; Paul Giammatteo2; Michael McCarthy1; Matthew Augustine1
1University of California, Davis, Davis, California; 2Process NMR Associates, Danbury, CT
Abstract
Low field nuclear magnetic resonance (NMR) is used as a non-invasive method for detecting spoiled tomato paste. It is shown that the 1H T1 and T2 relaxation times change as tomato paste spoils due to changes in viscosity and/or changes in the concentration of paramagnetic compounds. With the goal of developing a spoilage detector that can be used in a tomato processing facility, a γBo = 19.5 MHz single-sided handheld NMR instrument is used. Due to the dominance of diffusion on relaxation measurements made with the single sided instrument, the slope of the amplitude of a spin echo for three different delay times is used to provide a viscosity dependent parameter that permits the differentiation between pristine and spoiled tomatoes.One-Sided NMR - Non-Invasive Analysis of  Tomato Paste

One-Sided NMR – Non-Invasive Analysis of Tomato Paste

 

Residual Catalytic Cracker – Heavy Petroleum Feedstream Properties from 1H NMR at 43 MHz

Back in October we presented a talk at Gulf Coast Conference that concerned the prediction of the chemical and physical properties of heavy petroleum feeds being converted to higher value product in a residual catalytic cracker (RCC). Over the years we have analyzed these materials by 300 and 60 MHz NMR and obtained good PLS-regression models that can adequately predict properties for real-time process control and optimization in a petroleum refinery. With the advent of a large number of new benchtop NMR systems we have been convincing ourselves that these types of analyses can be performed by systems such as the Magritek Spinsolve 43 MHz. We ran a series of samples that had been sitting around our lab for 15 years by dissolving them at about 50 volume% in a 50/50 CDCl3/CS2 solvent system. For each sample we had laboratory test data for a number of chemical and physical properties of interest to process engineers. We regressed the lab data variability against the variability in the Magritek 43MHz 1H NMR spectra and obtained cross-validated PLS models. The presentation material is given here at this link – Gulf Conference Presentation – 43 MHz RCC Feedstream Regression Models

Benchtop NMR Systems – Sensitivity with Complex Pharmaceutical Molecules

PNA has been conducting a number of studies into the adulteration of male enhancement herbal suplements with PDE5 inhibitors such as viagra, cialis and a wide number of analogs (Mw approximately 475 amu). Standard materials for the analogs are quite expensive so in th eprocess of developing ID and purity methods on our NMR systems we ran the 1H NMR on our 300, 60, and 43 MHz NMR systems at a concentration of 5mg/ml which equates to 0.01 Molar. This PDF of the NMR data demonstrates the sensitivity and resolution obtainable on these bench-top 5mm NMR systems. They can readily look at samples at these concentrations. They can readily be utilized as screening tools or as quantitation and identification analyzers.

The PDF file containing the Varian 300, Aspect-60, and Magritek 43 MHz data can be found here: NMR Data-0.01 Molar_PDE5 Analogs 300_60_43_MHz

Beer and Cider Analysis – Example of Spectral Repeatability of Benchtop 60 MHz NMR System

Here is an example of spectral reproducibility. We are doing a lot of beer NMR at the moment on our 300 MHz NMR and for “giggles” we are running many samples through the various bench-top systems in our lab. We have been quantifying small organic acids (lactic, acetic, succinic , malic, citric, etc.) as they can give some idea of yeast activities and health during fermentation. We are also quantifying  and studying the 1,4/1,6 linkage distribution of residual dextrins. The series of superimposed spectra below consists of 28 spectra of a freeze dried beer sample (a unique Belgian Dubbel. Each spectrum was 128 pulses and took approximately 30 minutes per spectrum. So the superimposed data represents a 14 hour continuous stability test.The data was automatically processed with 16K zero-fill and autophase.It looks pretty damn good.

Zoe Belgian Dubbel - Freeze Dried - 1H qNMR analysis. 128 superimposed spectra representing a 14 hour spectral reprodcibility and stability test.

Zoe Belgian Dubbel – Freeze Dried – 1H qNMR analysis. 128 superimposed spectra representing a 14 hour spectral reprodcibility and stability test.

 

We’ve been looking at a lot of sour beers – here is a home-brewed Flemish Red aged in an oak barrel – note the high lactic and acetic content.

Flemish Red Ale - Freeze dried - 1H NMR

Flemish Red Ale – Freeze dried – 1H NMR

We’ve also been analyzing a lot of hard ciders – commercial and home-brewed varitieties of various styles – very different from one sample to another in the small molecule and sugar chemistry.

Commercial Cider Example - Freeze Dried Sample - 1H NMR Analysis at 60 MHz

Commercial Cider Example – Freeze Dried Sample – 1H NMR Analysis at 60 MHz

 

Dry Basque Cider Example - Freeze Dried Sample - 1H qNMR Analysis

Dry Basque Cider Example – Freeze Dried Sample – 1H qNMR Analysis

 

1H qNMR at 300MHz or 60 MHz can be utilized to identify and quantify small molecule chemistry in fermentations. Below is an example of a quantitative chemistry report on a series of ciders.

Table - 1H qNMR - SMall Molecule and Sugars Analysis

Table – 1H qNMR – SMall Molecule and Sugars Analysis

 

Beer and Cider Analysis is offered with similar quantitative results is offered for $100 per sample in our analytical lab.

Benchtop NMR – Screening Tool for Adulterated Herbal Supplements

Survey of Low Field NMR Spectrometer Platforms for Successful Screening of Sexual Enhancement and Weight Loss Supplements for Adulteration with Drugs and Drug Analogs

John C Edwards1, Kristie M Adams2, and Anton Bzhelyansky2

1Process NMR Associates, Danbury, CT
2United States Pharmacopeial Convention, Rockville, MD

The adulteration of dietary supplements (or natural health products) with synthetic pharmaceuticals is an area of increasing concern, which presents substantial risk to public health. Widely available in retail and via the Internet, these products are often marketed as sexual enhancement, weight loss and/or bodybuilding supplements. Unlike prescription drugs, supplements do not require premarket approval by FDA before they are made available for public consumption. In fact, the agency can only take investigational action after the adulterated product has caused harm and the adverse event has been reported via MedWatch (FDA’s online portal for voluntary reporting of adverse events associated with drugs, medical devices and dietary supplements).
Development of analytical tools for screening and identification of adulterated products in the marketplace represents a significant step forward in the fight against adulterated dietary supplements. Several organizations, including AOAC and USP, have undertaken initiatives to evaluate and recommend analytical methodologies for screening supplements for adulteration. HPLC and mass spectrometry have so far dominated the screening and quantitation studies published in the literature, with NMR spectroscopy often relegated to the status of structure elucidation tool. In this work, we investigate the ability of several-low field NMR spectrometric platforms to successfully identify and quantify the presence of adulterating drug substances in sexual enhancement and weight loss supplements purchased online and in US retail. 1H qNMR of both types of samples was performed with 300 MHz NMR to confirm the presence of adulterants such as sildenafil, tadalafil, and their structural analogues (sexual enhancement supplements) and various synthetic stimulants (weight loss supplements). We have concluded that a simple sample preparation protocol combined with straightforward 1H NMR spectroscopic analysis yields a rapid, robust and reliable screening test for adulterated supplements, presenting an attractive alternative to more labor-intensive, expensive and expertise-demanding techniques du jour.

This was presented by John Edwards at SMASH in September 2014, and at the Carolina NMR Symposium in November 2014

presentation can found here: Benchtop NMR – Herbal Supplement Adulteration Screening

43 MHz - 1H NMR - Benchtop Analysis of Contamination of herbal supplements with PDE5 inhibitors

43 MHz – 1H NMR – Benchtop Analysis of Contamination of herbal supplements with PDE5 inhibitors

300 MHz - 1H NMR - Benchtop Analysis of Contamination of herbal supplements with PDE5 inhibitors

300 MHz – 1H NMR – Benchtop Analysis of Contamination of herbal supplements with PDE5 inhibitors

1H Benchtop NMR Analysis of Physical and Chemical Properties of Diesel Fuel

1H Benchtop NMR has great potential to increase the throughput of both routine and emergency fuel sample analysis in refinery laboratories. Currently fuel samples must be passed through multiple dedicated analyzers to obtain information such as density, H-Content, aromatics, olefins, saturates, benzene,
Octane numbers, cetane index, cetane number, distillation curves, vapor pressure, flash point, pour point, freeze point, cloud point, etc. Correlation of the 1H NMR spectra of these refinery fuel samples to these primary test results will allow all parameters to be predicted in about 40 seconds from the 4 pulse spectrum of the pure fuel. Here we have a few examples obtained on some diesel fuels that were submitted to our lab for ASTM D7171 – Hydrogen Content by TD-NMR. We had density, H-content, and aromatics wt% by GC. Below are three example correlation obtained on the Picospin 80 system (that requires 32 pulses per sample due to the capillary sample size). The results were very similar for the 300, 60, and 42 MHz data obtained on the three other NMR system in our laboratory. The comparative results are shown in Table II. The results are very similar independent of the field strength of the NMR system. The data from all 4 NMR systems is provided in this section.

300 MHz 1H NMR - Diesel Fuels

300 MHz 1H NMR – Diesel Fuels

80 MHz 1H NMR - Diesel Fuels

80 MHz 1H NMR – Diesel Fuels

60 MHz 1H NMR - Diesel Fuels

60 MHz 1H NMR – Diesel Fuels

43 MHz 1H NMR - Diesel Fuels

43 MHz 1H NMR – Diesel Fuels

1H NMR and Density Correlated by PLS Regression Analysis

1H NMR and Density Correlated by PLS Regression Analysis

1H NMR andAromatic Content (Wt% GC) Correlated by PLS Regression Analysis

1H NMR andAromatic Content (Wt% GC) Correlated by PLS Regression Analysis

1H NMR and Hydrogen Content (Wt% TD-NMR ASTM D7171) Correlated by PLS Regression Analysis

Summary Table of Regression Models

Summary Table of Regression Models

Nutritional Supplement and Diesel Fuel Application Development for Benchtop NMR Systems Operating at 42, 60, and 80 MHz – Equivalency with Supercon NMR

Benchtop high-resolution NMR systems are available at a number of field strengths and probe configurations. However beyond the obvious academic instruction market for these instruments very few applications have been demonstrated across all available platforms and thus proving the general applicability of benchtop NMR technology to industrial quality control. We will present two chemometric-based applications that have been developed at 4 different field strengths utilizing Varian Mercury 300 MHz, Magritek Spinsolve 42 MHz, Aspect AI 60 MHz, and Thermo Picospin 80 MHz NMR systems. Partial-least-squares (PLS) regression correlations were obtained on all 4 platforms relating to:
1) Omega-3 fatty acid composition of samples taken from various points in a nutritional supplement manufacturing process. Excellent correlations were obtained on all 4 NMR instruments proving that NMR technology is applicable to in-lab, at-line. or on-line analysis of fish oil derived omega-3 fatty acid supplements. The 40 second NMR analysis effectively replaces a 60+ minute GC analysis.
2) Physical and chemical property determination of diesel fuels where excellent correlations were obtained between 1H NMR variability and parameters such as density, aromatic content by GC, hydrogen content by 1H TD-NMR (ASTM D7171 method), and sulfur content. Many more physical and chemical properties can be correlated to the 1H NMR spectrum allowing a single 40 second NMR experiment to predict 10-15 parameters that each require dedicated analyzers.
Finally, we will present the concept and initial results from an independent server-based NMR application software that can be utilized in conjunction with the NMR software of the current benchtop NMR systems, or alternatively as a stand-alone application platform. This software would effectively make chemometric and direct measurement NMR application ubiquitous across all NMR platforms.

A link to this presentation in PDF form is given here: PLS-Regression – 300_80_60_43 MHz NMR of Fish Oil Supplements and Diesel Fuel

From Atoms to Flavour: The Chemistry of Beer

Adam DiCaprio (ex PNA) gave an excellent Science Cafe Talk under the auspices of the ACS North Carolina Section at the Busy Bee Cafe in downtown Raleigh on December 2, 2014. CHanging gears from his previous talks he centered the discussion on malt and hop chemistry as well as an start-to-finish NMR analysis of production runs of a bottled commercial tavern ale. If you are interested in having Adam give a detailed chemistry seminar on beer at your section meetings please contact him directly at adam@process-nmr.com.

A PDF version of his talk is available here …. ACS Science Cafe Talk – Dicaprio – Busy Bee Cafe – Raleigh NC – 12-2-14

Comparison of 1H NMR Spectra Obtained at 42, 60, 82, and 300 MHz – Fish Oil Omega-3 Ethyl Ester Supplement Example

Process NMR Associates is currently developing NMR applications based on direct measurement of chemometric modeling on NMR data obtained on numerous NMR platforms. Our intention is to develop solutions that can be executed on any NMR platform. With this in mind we are currently developing a fish oil analysis application that can provide the EPA and DHA omega-3 fatty acid content of fish oil supplements manufactured by an ethyl ester esterification process. We have obtained data at 42 MHz, 60 MHz, 82 MHz and 300 MHz. The chemometric modelling yielded PLS models for all 4 field strengths that yield effectively the same result – DHA can be measured to +/- ~1.1 wt% and EPA can be measured to +/- ~2.2 wt% by a 40 second 1H NMR measurement. THe correlation is derived from a  regression of the 1H NMR variability with primary GC analysis values.

This analysis has been shown for the 300 and 60 MHz data in a previous post on this blog. The same analysis was also obtained, with similar results, on 42 and 82 MHz platforms proving that individual applications can be automated and provided at all relevant frequencies of NMR analysis whether on superconducting lab systems or permanent magnet benchtop systems.

At each field strength the relative lineshapes are pretty much the same (<1 Hz at half height). The field strength differences mean that the same spectrum is dispersed across frequency space proportionate to the magnetic field. Figure 1 below shows the frequency space spectra obtained at all 4 field strengths on the same sample.

Figure 2 shows the same spectra displayed on the usual normalized chemical shift scale (ppm). In these spectra the data is stretched in order to allow the chemical shift comparison of the data. IN effect the 42 MHz NMR is stretched by a factor of 7, the 60 MHz data by a factor of 5 and the 80.2 MHz data by a factor of 3.7. The effect of the relative size of J coupling compared to the frequency space occupied by 1 ppm is an interesting observation to see directly. In traditional NMR analysis the resolution of various peaks was always the driving force for increasing the magnetic field strength of NMR instruments. With todays powerful PC’s and advanced software information can be garnished readily from any of these spectra by way of global spectral deconvolution or multivariate statistics.It is no longer necessary to obtain baseline resolution in order to integrate a resonance and obtain quantitative information.

THough the data is more closely packed together in the low field spectra it can be acknowledged that the same information is present in all 4 spectra. Automation approaches can be developed that will allow accurate measurement of quality parameters, component quantification, or structural verification to be performed on data obtained from any of these NMR systems.

The development of readily deployable NMR benchtop systems at an affordable price point must surely lead to the development of NMR into a more widely utilized technique outside of the realms of scientific study and quality control that NMR has thus far been involved.

1H NMR at 42, 60, 82, and 300 MHz

Figure 1: Comparison of 1H NMR spectra obtained on an omega-3 fish oil supplement obtained at 42, 60, 82, and 300 MHz displayed in frequency space. These spectra show the native spectra dispersion obtained at the different magnetic field strengths of the NMR spectrometers

CHemical SHift Scale Normalization of 1H NMR spectra obtained on the same sample at 42.5, 60.3, 82.3, and 300 MHz

Chemical Shift Scale Normalization (ppm) of 1H NMR spectra obtained on the same sample at 42.5, 60.3, 82.3, and 300 MHz. In these spectra the absolute frequency of the spectrum is divided by the spectrometer frequency to obtain a normalized spectrum where the chemical shift in ppm of the various peaks in the spectrum are observed at the same position on the ppm NMR scale. In this normalized view the relative proportion of a ppm that the J couplings represent in the 1H multiplets can be plainly seen.  

 

 

 

 

From Mash to Bottle: Chemistry of the Brewing Process and NMR-Based Quality Control

Poster presented by Adam Dicapro at the 3rd Carolina NMR Symposium, Kannapolis, NC, November 6, 2014

Follow this link to download a PDF of the poster

Agilent drops a bombshell – big changes are coming for the NMR community

Agilent Technologies to Close Nuclear Magnetic Resonance Business

SANTA CLARA, Calif., Oct. 14, 2014

Agilent Technologies Inc. (NYSE: A) today announced it is exiting its Nuclear Magnetic Resonance business. Agilent entered the NMR business in 2010, with the acquisition of Varian. Since then, the business has not met growth and profitability objectives.

“Today’s announcement represents a difficult decision necessary to drive improved profitability,” said Mike McMullen, president and chief operating officer, and CEO-elect. “The NMR team has been extremely dedicated and has made many excellent contributions. However, this action is a step in ensuring that our investments are placed on higher-value life sciences, applied markets and diagnostics solutions that will continue to drive growth across the company.”

Agilent will stop taking new NMR system orders immediately, but the company will continue to meet customer commitments for orders in progress and for ongoing support contracts. Agilent will continue to provide service on all installed NMR systems.

The company expects that this decision will eliminate about 300 jobs, mostly within the next 12 months. The majority of the affected positions are located in Yarnton, U.K., and Santa Clara, California.

Today’s announcement is part of Agilent’s strategy to address the business shortfalls of its Research Products Division. In early 2013 Agilent announced its exit of the OEM and Specialty Magnet business and later the MRI business to focus resources on the core NMR portfolio. Despite these adjustments, the NMR business has continued to fall short of growth and profitability objectives.

To cover the cost of exiting this business, Agilent will take an approximate $72 million restructuring charge in the fourth quarter. It expects a $20 million to $30 million decline in revenues in fiscal year 2015 due to the NMR business closure, but a positive impact of about $10 million in operating profit in FY15.

For the fourth quarter of 2014, Agilent anticipates non-GAAP earnings per share of $0.87 to $0.91, and projects revenues to be negatively affected by currency at about $13 million, and lower NMR-related revenues by about $12 million.

Keysight has posted its investor roadshow slide deck on its website at www.investor.keysight.com. “New Agilent” will post its investor roadshow slide deck on Friday, Oct. 17, after the market closes at www.investor.agilent.com.

About NMR

Nuclear magnetic resonance (NMR) spectroscopy is an analytical chemistry technique used in quality control and research for determining the content and purity of a sample as well as its molecular structure. It is used primarily in academia and government, the pharmaceutical, biotech and chemical industries.

About Agilent Technologies
Agilent Technologies Inc. (NYSE: A) is the world’s premier measurement company and a technology leader in chemical analysis, life sciences, diagnostics, electronics and communications. The company’s 20,600 employees serve customers in more than 100 countries. Agilent had revenues of $6.8 billion in fiscal 2013. Information about Agilent is available at www.agilent.com.

On Sept. 19, 2013, Agilent announced plans to separate into two publicly traded companies through a tax-free spinoff of its electronic measurement business. The new company is named Keysight Technologies, Inc. The separation is expected to be completed in early November 2014.

Forward-Looking Statements

This news release contains forward-looking statements as defined in the Securities Exchange Act of 1934 and is subject to the safe harbors created therein. The forward-looking statements contained herein include, but are not limited to, information regarding the separation of Agilent’s electronic measurement business; future revenues, earnings and profitability; the future demand for the company’s products and services; and customer expectations. These forward-looking statements involve risks and uncertainties that could cause Agilent’s results to differ materially from management’s current expectations. Such risks and uncertainties include, but are not limited to, unforeseen changes in the strength of our customers’ businesses; unforeseen changes in the demand for current and new products, technologies, and services; customer purchasing decisions and timing, and the risk that we are not able to realize the savings expected from integration and restructuring activities.

In addition, other risks that Agilent faces include those detailed in Agilent’s filings with the Securities and Exchange Commission, including our latest Form 10-K and Form 10-Q. Forward-looking statements are based on the beliefs and assumptions of Agilent’s management and on currently available information. Agilent undertakes no responsibility to publicly update or revise any forward-looking statement.

# # #

Contact:

Michele Drake
+1 408 345 8396
michele_drake@agilent.com

Neil Rees (U.K.)
+44 186 529 1472
neil_rees@agilent.com

Investor Contact:

Alicia Rodriguez
+1 408 345 8948
alicia_rodriguez@agilent.com

Presentations at SMASH 2014

“Beer Manufacturing and Analysis by NMR”, John C. Edwards and Adam Dicaprio, Presented at the Mestrelab MNova Users, Meeting – SMASH, Atlanta, GA, September 7, 2014
Get PDF Here

“Survey of Low Field NMR Spectrometer Platforms for Successful Screening of Sexual Enhancement and Weight Loss Supplements for Adulteration with Drugs and Drug Analogs”, John C. Edwards, Kristie Adams, Anton Bzhelyansky , Presented at SMASH Conference, Atlanta, GA, September 7-10, 2014.
Get PDF Here

Presentation and Posters – Magnetic Resonance in Food Conference 2014 – Cesena Italy

“Liquid and Solid-State 27Al qNMR of an Elemin Senonian Trace Minerals Supplement for Identification, Chemical Structure, Quantitation of Active Ingredient in the Product, and Product Stability”, Boris Nemzer, John C. Edwards, presented at XII International Conference on the Applications of Magnetic Resonance in Food Science: Defining Food by Magnetic Resonance, Cesena, Italy, May 20-23, 2014.
Get PDF Here

“Liquid and Solid-State Multinuclear 13C and 11B qNMR FruitexB Fructoborate Complex Nutritional Supplement. Identification, Chemical Structure, Quantitation of Active Ingredient in Product, and Product Stability”, Boris Nemzer, John C. Edwards, presented at XII International Conference on the Applications of Magnetic Resonance in Food Science: Defining Food by Magnetic Resonance, Cesena, Italy, May 20-23, 2014.
Get PDF Here

“1H qNMR of EPA and DHA Omega-3 Fatty Acid Esters – PLS Regression Models Obtained by 60 and 300 MHz NMR – At-Line and On-Line Monitoring of a Fish Oil Nutritional Supplement Manufacturing Process”, John C. Edwards, Paul J. Giammatteo, invited oral presentation at XII International Conference on the Applications of Magnetic Resonance in Food Science: Defining Food by Magnetic Resonance, Cesena, Italy, May 20-23, 2014.

“Application of High Field and Cryogen-Free Bench-Top NMR Platforms to the Monitoring and Quantitation of PDE5 Inhibitor Adulteration of Male Sexual Enhancement Supplements”, John C. Edwards, Paul J. Giammatteo, Kristie Adams, Anton Bzhelyansky , presented at XII International Conference on the Applications of Magnetic Resonance in Food Science: Defining Food by Magnetic Resonance, Cesena, Italy, May 20-23, 2014.
Get PDF Here

Presentation and Posters at PANIC 2014

“NMR Based Authentication of Nutraceuticals, Herbal Supplements, and Food Additives: Economic- and Efficacy-Driven Adulteration of Aloe Vera, Herbal Erectile Dysfunction Supplements, and Acacia Gum”, John C. Edwards, invited presentation at the 2nd PANIC, Charlotte, NC, February 3-5, 2014.
Get PDF Here

“Development of an Automated Complex Mixture Analysis qNMR Method within Mestrelab MNova – Application to Aloe Vera and the Beer Brewing Process”, John C. Edwards, Adam J. Dicaprio, Michael A. Bernstein, presented at the 2nd PANIC, Charlotte, NC, February 3-5, 2014.
Get PDF Here

“Small Molecule Chemistry of Spontaneously Fermented Coolship Ales”, Adam J. Dicaprio, John C. Edwards, presented at the 2nd PANIC, Charlotte, NC, February 3-5, 2014.
Get PDF Here

“Liquid and Solid-State 1H, 13C, and 11B qNMR Analysis of Fruitex-B®– A Calcium Fructoborate Comple: Chemical Structure and identification, quantitative analysis and stability study”, Boris Nemzer, John C. Edwards, presented at the 2nd PANIC, Charlotte, NC, February 3-5, 2014.
Get PDF Here

John Edwards to be Guest Editor of 2 Special Issues of Magnetic Resonance in Chemistry Dedicated to Benchtop NMR

I have been invited to be a guest editor for Wiley publishing to pull together 2 special issues of Magnetic Resonance in Chemistry. I am putting out a general “call for papers” but I will harass people personally. We are looking for 10-20 papers for each issue.

The deadline for submission of the papers is June 30 so no-one has an excuse that there isn’t enough time. I do ask that you email me at the contact below to let me know that you are thinking of submitting and a title would be nice also (though I won’t hold you to it). We hope to have the review and revide papers (if necessary) by late October and then publish by December 2014.

The first will be on high resolution benchtop NMR in which I would like to include all permanent magnet systems capable of obtaining a spectrum. This is an open invitation to all the vendors and their customers of (in no particular order) Anasazi, Nanalysis, One Resonance Sensors, Magritek/ACT, Aspect, Qualion, Picospin, Resonance Systems, Oxford Instruments, Bruker, home built devices, I would also make the exception that HTS systems be included as they are also cryogen free.

Any papers on spectrometers, magnets, educational, industrial, academic applications, chemometrics, automated approaches, reaction monitoring, online/at-line utilization, 2D NMR, combined spectral/relaxation applications.

The second will be on low resolution benchtop NMR but I would like to exclude applications that have been around for decades (H content, SFC, oil content, spin finish). I would like to encourage new applications to be submitted and they should include hardware, magnets, spectrometers, probes, 1D/2D Laplace inversion (I’d love a review/overview of that software aspect), applications. Again – all vendors and all users of commercial and home grown benchtop TD-NMR systems please submit.

We’re looking for articles on FPGA spectrometers, software approaches (1D/2D Laplace, chemometrics), magnet design and construction, dedicated rheology analysis instruments, field cycling NMR, unilateral NMR, core analyzers, applications of all whether educational, academic, industrial.

The types of articles can be Reviews, Mini-Reviews, Tutorial, Historical, Spotlight, Perspective, Communication, Article, Application Note, Case Report, Spectral Assignments, Correspondence.

Here is the official word on the use of color (note you can have all the color figures you wish in the online version but the print version is restricted): two colour illustrations per submission are allowed free of charge, however further colour illustrations are allowed at the Editors discretion and where they are justified. Authors can have as much colour as they like in the online version as the restrictions are just for the print version.

Please contact me directly if you would like to make a submission of your work to either of the two issues: john@process-nmr.com

I have posted the authors instructions for special Issues that I was given on my website at:
http://www.process-nmr.com/pdfs/MRC_Submission_instrux.pdf

The MRC author guidelines can be found at:
http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291097-458Xa/homepage/ForAuthors.html

Herbal Supplement for Erectile Dysfunction Found to Contain Thio Structural Analog of Sildenafil (Viagra)

A herbal supplement marketed to alleviate erectile dysfunction was recently submitted for testing in our laboratory because it was surprisingly effective considering it should only contain the traditional herbals utilized for this problem such as Oyster, 2-Deoxy-D Glucose, Barberry, Snow Lotus, Bombyx Mori L., Ginger Root, Salfron Crocus.

Above: 1H NMR of ED Herbal Supplement – this is an extract of the powder from  the capsules into 80:20 CD3CN:D2O – Observed suspicious specific small molecule peaks – herbals are usually broad featureless complex mixture spectra. This is something in different – a specific drug material appears to have been added.Comparison with the spectrum of Viagra (Sildenafil Citrate) below shows a strong similarity between the 2 active ingredients.

We also obtained the COSY, 13C and DEPT NMR Spectra on the ED herbal supplement. These are shown below.

The analysis of the NMR data led us to find that the extractable components of the sample contained predominantly Sulfoaildenafil (thioaildenafil) which is a strutural analog of Sildenafil (Viagra) and is not approved by any health regulation agency for use in erectile dysfunction medicines or supplements. Apparently these structural analogs to Viagra are found widely in herbal supplements sold for this malady. I guess we have one more for the list that the FDA keeps on such dangerously adulterated products.

Solid-State 13C NMR of Drug API and Tablets

We have an excellent solid-state Doty Scientific Supersonic 7mm CP-MAS probe for our Varian UP-200 spectrometer. This is a nice field strength for solid-state 13C analyses as it allows for spectra at higher sensitivity than a 100 MHz but still has the advantage that 7 kHz is enough to push the aromatic MAS sidebands beyond 0 ppm so that more accurate aromaticity values can be calculated. The probe is still working after 20 years and we are using the original rotors and have never had to replace any of the capacitors. We have run approaching 20,000 experiments with this probe. Here are some of the nice spectra we have been getting recently on drug API and tablets.

Above: Solid-State 13C NMR of Rapamycin API

Above: Solid-State 13C NMR of Ranitidine HCl – Zantac Tablet