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…

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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…

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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…

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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…

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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).

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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.   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…

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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

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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.   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. 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.     1H…

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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…

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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…

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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…

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