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Dušan Uhrín - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Scotch Whisky by 1H NMR and chemometrics yields insight into its complex chemistry.
Food chemistry, 2019Co-Authors: William Kew, Ian Goodall, Dušan UhrínAbstract:Scotch Whisky has been analysed as a complex mixture in its raw form using high resolution Nuclear Magnetic Resonance (NMR) and previously developed water and ethanol suppression techniques. This has allowed for the positive identification of 25 compounds in Scotch Whisky by means of comparison to reference standards, spike-in experiments, and advanced 1D and 2D NMR experiments. Quantification of compounds was hindered by signal overlap, though peak alignment strategies were largely successful. Statistical total correlation spectroscopy (STOCSY) yielded information on signals arising from the same compound or compounds of similar origin. Statistical analysis of the spectra was performed using Independent and Principal Components Analysis (ICA, PCA) as well as Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA). Several Whisky production parameters were successfully modelled, including blend or malt status, use of peated malt, alcohol strength, generic authentication and maturation wood type, whilst age and geographical origin could not be modelled.
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Complementary Ionization Techniques for the Analysis of Scotch Whisky by High Resolution Mass Spectrometry
Analytical chemistry, 2018Co-Authors: William Kew, Ian Goodall, C. Logan Mackay, David J. Clarke, Dušan UhrínAbstract:Fourier transform mass spectrometry (FTMS) is widely used to characterize the chemical complexity of mixtures, such as natural organic matter (NOM), petroleum, and agri-food products (including Scotch Whisky). Although electrospray ionization (ESI) is by far the most widely used ionization source in these studies, other ionization techniques are available and may offer complementary information. In a recent study, we found matrix free laser desorption/ionization (LDI) to be effective for the analysis of Suwannee river fulvic acid (SRFA), and to provide complementary chemical insights. In this study, LDI along with atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI) were compared to ESI for the analysis of Scotch Whisky. High mass accuracy (54 ppb, mean) allowed for the assignment of 86% of peaks, with 3993 unique molecular formulas identified from four representative samples analyzed. All four ionization techniques, performed in negative mode, identified thousan...
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Advanced Solvent Signal Suppression for the Acquisition of 1D and 2D NMR Spectra of Scotch Whisky
Magnetic Resonance in Chemistry, 2017Co-Authors: Nicholle G. A. Bell, Ian Goodall, Dušan UhrínAbstract:A simple and robust solvent suppression technique that enables acquisition of high quality 1D 1H NMR spectra of alcoholic beverages on cryoprobe instruments was developed and applied to acquire NMR spectra of Scotch Whisky. The method uses three channels to suppress signals of water and ethanol, including those of 13C satellites of ethanol. It is executed in automation allowing high throughput investigations of alcoholic beverages. Based on the well-established 1D NOESY solvent suppression technique, this method suppresses the solvent at the beginning of the pulse sequence, producing pure phase signals minimally affected by the relaxation. The developed solvent suppression procedure was integrated into several homo- and heterocorrelated 2D NMR experiments, including 2D COSY, 2D TOCSY, 2D band-selective TOCSY, 2D J-resolved spectroscopy, 2D 1H, 13C HSQC, 2D 1H, 13C HSQC-TOCSY and 2D 1H, 13C HMBC. A 1D chemical-shift-selective TOCSY experiments was also modified. The wealth of information obtained by these experiments will assist in NMR structure elucidation of Scotch Whisky congeners and generally the composition of alcoholic beverages at the molecular level.
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Advanced solvent signal suppression for the acquisition of 1D and 2D NMR spectra of Scotch Whisky.
Magnetic resonance in chemistry : MRC, 2017Co-Authors: William Kew, Nicholle G. A. Bell, Ian Goodall, Dušan UhrínAbstract:A simple and robust solvent suppression technique that enables acquisition of high-quality 1D 1 H nuclear magnetic resonance (NMR) spectra of alcoholic beverages on cryoprobe instruments was developed and applied to acquire NMR spectra of Scotch Whisky. The method uses 3 channels to suppress signals of water and ethanol, including those of 13 C satellites of ethanol. It is executed in automation allowing high throughput investigations of alcoholic beverages. On the basis of the well-established 1D nuclear Overhauser spectroscopy (NOESY) solvent suppression technique, this method suppresses the solvent at the beginning of the pulse sequence, producing pure phase signals minimally affected by the relaxation. The developed solvent suppression procedure was integrated into several homocorrelated and heterocorrelated 2D NMR experiments, including 2D correlation spectroscopy (COSY), 2D total correlation spectroscopy (TOCSY), 2D band-selective TOCSY, 2D J-resolved spectroscopy, 2D 1 H, 13 C heteronuclear single-quantum correlation spectroscopy (HSQC), 2D 1 H, 13 C HSQC-TOCSY, and 2D 1 H, 13 C heteronuclear multiple-bond correlation spectroscopy (HMBC). A 1D chemical-shift-selective TOCSY experiments was also modified. The wealth of information obtained by these experiments will assist in NMR structure elucidation of Scotch Whisky congeners and generally the composition of alcoholic beverages at the molecular level.
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Chemical Diversity and Complexity of Scotch Whisky as Revealed by High-Resolution Mass Spectrometry
Journal of The American Society for Mass Spectrometry, 2017Co-Authors: Ian Goodall, David Clarke, Dušan UhrínAbstract:Scotch Whisky is an important product, both culturally and economically. Chemically, Scotch Whisky is a complex mixture, which comprises thousands of compounds, the nature of which are largely unknown. Here, we present a thorough overview of the chemistry of Scotch Whisky as observed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Eighty-five whiskies, representing the majority of Scotch Whisky produced and sold, were analyzed by untargeted high-resolution mass spectrometry. Thousands of chemical formulae were assigned for each sample based on parts-per-billion mass accuracy of FT-ICR MS spectra. For the first time, isotopic fine structure analysis was used to confirm the assignment of high molecular weight CHOS species in Scotch Whisky. The assigned spectra were compared using a number of visualization techniques, including van Krevelen diagrams, double bond equivalence (DBE) plots, as well as heteroatomic compound class distributions. Additionally, multivariate analysis, including PCA and OPLS-DA, was used to interpret the data, with key compounds identified for discriminating between types of Whisky (blend or malt) or maturation wood type. FT-ICR MS analysis of Scotch Whisky was shown to be of significant potential in further understanding of the complexity of mature spirit drinks and as a tool for investigating the chemistry of the maturation processes. Graphical Abstract ᅟ
Ian Goodall - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Scotch Whisky by 1H NMR and chemometrics yields insight into its complex chemistry.
Food chemistry, 2019Co-Authors: William Kew, Ian Goodall, Dušan UhrínAbstract:Scotch Whisky has been analysed as a complex mixture in its raw form using high resolution Nuclear Magnetic Resonance (NMR) and previously developed water and ethanol suppression techniques. This has allowed for the positive identification of 25 compounds in Scotch Whisky by means of comparison to reference standards, spike-in experiments, and advanced 1D and 2D NMR experiments. Quantification of compounds was hindered by signal overlap, though peak alignment strategies were largely successful. Statistical total correlation spectroscopy (STOCSY) yielded information on signals arising from the same compound or compounds of similar origin. Statistical analysis of the spectra was performed using Independent and Principal Components Analysis (ICA, PCA) as well as Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA). Several Whisky production parameters were successfully modelled, including blend or malt status, use of peated malt, alcohol strength, generic authentication and maturation wood type, whilst age and geographical origin could not be modelled.
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Rapid Scotch Whisky Analysis and Authentication using Desorption Atmospheric Pressure Chemical Ionisation Mass Spectrometry.
Scientific reports, 2019Co-Authors: B. L. Smith, Ian Goodall, David M Hughes, Abraham K. Badu-tawiah, Rebecca Eccles, Simon MaherAbstract:Whisky, as a high value product, is often adulterated, with adverse economic effects for both producers and consumers as well as potential public health impacts. Here we report the use of DAPCI-MS to analyse and chemically profile both genuine and counterfeit Whisky samples employing a novel ‘direct from the bottle’ methodology with zero sample pre-treatment, zero solvent requirement and almost no sample usage. 25 samples have been analysed from a collection of blended Scotch Whisky (n = 15) and known counterfeit Whisky products (n = 10). Principal component analysis has been applied to dimensionally reduce the data and discriminate between sample groups. Additional chemometric modelling, a partial least squares regression, has correctly classified samples with 92% success rate. DAPCI-MS shows promise for simple, fast and accurate counterfeit detection with potential for generic aroma profiling and process quality monitoring applications.
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Complementary Ionization Techniques for the Analysis of Scotch Whisky by High Resolution Mass Spectrometry
Analytical chemistry, 2018Co-Authors: William Kew, Ian Goodall, C. Logan Mackay, David J. Clarke, Dušan UhrínAbstract:Fourier transform mass spectrometry (FTMS) is widely used to characterize the chemical complexity of mixtures, such as natural organic matter (NOM), petroleum, and agri-food products (including Scotch Whisky). Although electrospray ionization (ESI) is by far the most widely used ionization source in these studies, other ionization techniques are available and may offer complementary information. In a recent study, we found matrix free laser desorption/ionization (LDI) to be effective for the analysis of Suwannee river fulvic acid (SRFA), and to provide complementary chemical insights. In this study, LDI along with atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI) were compared to ESI for the analysis of Scotch Whisky. High mass accuracy (54 ppb, mean) allowed for the assignment of 86% of peaks, with 3993 unique molecular formulas identified from four representative samples analyzed. All four ionization techniques, performed in negative mode, identified thousan...
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A novel approach to assess the quality and authenticity of Scotch Whisky based on gas chromatography coupled to high resolution mass spectrometry.
Analytica chimica acta, 2018Co-Authors: Michal Stupak, Ian Goodall, Monika Tomaniova, Jana Pulkrabova, Jana HajslovaAbstract:Abstract Whisky is one of the most popular spirit drinks in the world. Unfortunately, this highly valued commodity is vulnerable to fraud. To detect fraudulent practices and document quality parameters, a number of laboratory tests based on various principles including chromatography and spectroscopy have been developed. In most cases, the analytical methods are based on targeted screening strategies. Non-targeted screening (metabolomics fingerprinting) of (semi)volatile substances was used in our study. Following the pre-concentration of these compounds, either by solid phase microextraction (SPME) or by ethyl acetate extraction, gas chromatography (GC) coupled to tandem mass spectrometry (Q-TOF mass analyser) was employed. Unsupervised principal component analysis (PCA) and supervised partial least squares discriminant analysis (PLS–DA) were used for evaluation of data obtained by analysis of a unique set of 171 authentic Whisky samples provided by the Scotch Whisky Research Institute. Very good separation of malt whiskies according to the type of cask in which they were matured (bourbon versus bourbon and wine) was achieved, and significant ´markers' for bourbon and wine cask maturation, such as N-(3-methylbutyl) acetamide and 5-oxooxolane-2-carboxylic acid, were identified. Subsequently, the unique sample set was used to construct a statistical model for distinguishing malt and blended whiskies. In the final phase, 20 fake samples were analysed and the data processed in the same way. Some differences could be observed in the (semi)volatile profiles of authentic and fake samples. Employing the statistical model developed by PLS-DA for this purpose, marker compounds that positively distinguish fake samples were identified.
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Complementary Ionization Techniques for the Analysis of Scotch Whisky by High Resolution Mass Spectrometry
2018Co-Authors: William Kew, Ian Goodall, David J. Clarke, Logan C. Mackay, Dušan UhrínAbstract:Fourier transform mass spectrometry (FTMS) is widely used to characterize the chemical complexity of mixtures, such as natural organic matter (NOM), petroleum, and agri-food products (including Scotch Whisky). Although electrospray ionization (ESI) is by far the most widely used ionization source in these studies, other ionization techniques are available and may offer complementary information. In a recent study, we found matrix free laser desorption/ionization (LDI) to be effective for the analysis of Suwannee river fulvic acid (SRFA), and to provide complementary chemical insights. In this study, LDI along with atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI) were compared to ESI for the analysis of Scotch Whisky. High mass accuracy (54 ppb, mean) allowed for the assignment of 86% of peaks, with 3993 unique molecular formulas identified from four representative samples analyzed. All four ionization techniques, performed in negative mode, identified thousands of formulas. Many were unique to each ionization source, while 699 formulas were common to all techniques. Ions were identified in both deprotonated and radical anion forms. Our study highlights the importance of a multi-ionization source approach; we recommend that analysis of complex mixtures, especially novel ones, should not be limited solely to ESI
Frances R. Jack - One of the best experts on this subject based on the ideXlab platform.
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Selecting new distilling yeasts for improved fermentation and for sustainability
2012Co-Authors: Graeme M. Walker, James M. Brosnan, Thomas A. Bringhurst, Frances R. JackAbstract:Yeast is essential for the production of all distilled spirits and as such has provided much interest at previous Worldwide Distilled Spirits Conferences (Walker 2010a). The strain of yeast employed in potable spirit fermentations is crucially important not only for yielding high levels of ethanol, but also for production of minor yeast metabolites which collectively contribute to the development of spirit flavour (Watson 1981). Distillers must therefore pay careful attention to the type of yeast used to ensure consistency of fermentation performance in terms of both of these parameters (Watson 1984). Walker (1998) has provided a fundamental and detailed review of the physiology and biochemistry of yeast and Campbell (2003) concisely summarised yeast and fermentation aspects with regard to Scotch Whisky production. Watson (1984) has highlighted a number of yeast characteristics that are important in determining the efficiency of fermentation. These include carbohydrate utilisation, rate of fermentation, alcohol tolerance and culture stability. Scotch Whisky distillers are strongly interested in extending this list of desirable yeast attributes. Over the last decade or so, there has been a high level of interest in new distilling yeasts, and there has been much research into new strains and different types of yeast by distillers, yeast scientists in academia and yeast manufacturers. This expansion of research has become more important now that distillers are increasingly seeking initiatives that fulfil the sustainability requirements of the industry. With the emergence of a rising awareness of environmental issues, such as global warming and climate change, distillers now have to take a longer term perspective on issues that will impact on the sustainability of their respective industries. These present challenges for distillers to meet through initiatives to reduce demands for energy, use less water and improve the utilisation of co-products. This means that Scotch Whisky distillers will have to think ‘out of the box’ (Ingledew 2009) when considering new yeasts. As a result distillers’ expectations for their yeast supplies are changing, with a greater requirement for efficient fermentation performance under more highly stressful conditions. Hence, it is essential to stimulate research into developing new yeast strains that will be capable of fulfilling these objectives.
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Sensory and Chemical Analysis of ‘Shackleton's’ Mackinlay Scotch Whisky
Journal of the Institute of Brewing, 2011Co-Authors: James Pryde, Frances R. Jack, Gordon M. Steele, John M. Conner, Mark Lancaster, Lizzie Meek, Craig Owen, Richard Paterson, Fiona Strang, Jacqui WoodsAbstract:J. Inst. Brew. 117(2), 156–165, 2011 Three cases of Mackinlay’s Rare Highland Malt Whisky were excavated from the ice under Sir Ernest Shackleton’s 1907 expedition base camp hut at Cape Royds in Antarctica in January 2010. The majority of the bottles were in a pristine state of preservation and three were returned to Scotland in January 2011 for the first sensory and organoleptic analysis of a Scotch malt Whisky distilled in the late 1890s. Sensory analysis and the higher alcohol and maturation congener profiles describe a lightly peated malt Whisky matured in American white oak sherry or wine casks. Analysis of process related compounds together with combined gas chromatography (GC) mass spectrometry and GC-olfactometry analysis of fermentation related congeners show a distinctly ‘modern’ style of malt Whisky. While Scotch malt Whisky at the end of the 19th century was generally regarded as heavily peated and harsh in character, Charles Mackinlay & Co. Distillers were producing a malt Whisky with an altogether more subtle character at their Glen Mhor distillery near Inverness. The sensory and chemical analysis of this unique Whisky artefact significantly changes our understanding of the quality and character of Scotch malt Whisky produced by our distilling forefathers.
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Development of guidelines for the preparation and handling of sensory samples in the Scotch Whisky industry
Journal of the Institute of Brewing, 2003Co-Authors: Frances R. JackAbstract:Sensory panels are used widely in the Scotch Whisky industry in a range of applications. Sensory data can play a key role in monitoring product quality or advancing flavour understanding. Therefore, the quality of this data must be high. Standard procedures for sensory evaluation outline requirements for experimental design, selection and training of panellists, and sensory room design. However, there are certain aspects of sample preparation and handling, specific to the assessment of Whisky, which are not covered by these standards. This paper describes a programme of research aimed at examining these factors and their potential impact on sample condition. The results of this study have been collated, to produce guidelines for the preparation and handling of sensory samples in the Scotch Whisky industry. Following these guidelines should aid in the optimisation of sensory data quality.
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modelling the sensory characteristics of Scotch Whisky using neural networks a novel tool for generic protection
Food Quality and Preference, 2002Co-Authors: Frances R. Jack, Gordon M. SteeleAbstract:Scotch Whisky is tightly defined by UK and EC legislation. It is vital to monitor products to ensure that they conform to this legislation. Sensory evaluation is an important aspect of generic authenticity. This involves appraisals by a highly trained Whisky panel, in order to determine whether or not sensory attributes are consistent with those expected of a Scotch Whisky. However, this approach is subject to bias due to personal preferences, and a more objective method of evaluation is required. This research describes the development of a neural network model, based on sensory profile data from 144 Scotch whiskies and Non-Scotch products, and its application as a tool for classifying products in terms of whether or not they have the sensory characteristics expected of a Scotch Whisky. The improved performance of this approach is demonstrated for a range of Scotch whiskies, whiskies of other origins and non-Whisky spirit drinks.
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Modelling the sensory characteristics of Scotch Whisky using neural networks—a novel tool for generic protection
Food Quality and Preference, 2002Co-Authors: Frances R. Jack, Gordon M. SteeleAbstract:Scotch Whisky is tightly defined by UK and EC legislation. It is vital to monitor products to ensure that they conform to this legislation. Sensory evaluation is an important aspect of generic authenticity. This involves appraisals by a highly trained Whisky panel, in order to determine whether or not sensory attributes are consistent with those expected of a Scotch Whisky. However, this approach is subject to bias due to personal preferences, and a more objective method of evaluation is required. This research describes the development of a neural network model, based on sensory profile data from 144 Scotch whiskies and Non-Scotch products, and its application as a tool for classifying products in terms of whether or not they have the sensory characteristics expected of a Scotch Whisky. The improved performance of this approach is demonstrated for a range of Scotch whiskies, whiskies of other origins and non-Whisky spirit drinks.
Michael T Hannan - One of the best experts on this subject based on the ideXlab platform.
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oppositional identities and resource partitioning distillery ownership in Scotch Whisky 1826 2009
Organization Science, 2014Co-Authors: David G Mckendrick, Michael T HannanAbstract:We build on recent theory and research on the role of categories in resource partitioning. We analyze Scotch Whisky making between 1826 and 2009—a case that seemed initially to fail to conform to the pattern of the beer industry now treated as prototypical. On close examination (both qualitative and quantitative), we find that high concentration in the center of the market is not sufficient to generate a partition. Rather, we see a long delay between the heightening of concentration in the industry and the emergence of a cluster of peripheral producers that claim an identity in opposition to the dominant generalists. We explain the source of the delay as a function of the nature of the audience, which until recently did not regard conglomerate or foreign ownership of distilleries as an impediment to producing authentic Whisky. Only when critics started to question how ownership of distilleries related to authenticity did the revival of the traditional form of ownership begin to occur. By analyzing entries...
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Oppositional Identities and Resource Partitioning: Distillery Ownership in Scotch Whisky, 1826–2009
Organization Science, 2014Co-Authors: David G Mckendrick, Michael T HannanAbstract:We build on recent theory and research on the role of categories in resource partitioning. We analyze Scotch Whisky making between 1826 and 2009—a case that seemed initially to fail to conform to the pattern of the beer industry now treated as prototypical. On close examination (both qualitative and quantitative), we find that high concentration in the center of the market is not sufficient to generate a partition. Rather, we see a long delay between the heightening of concentration in the industry and the emergence of a cluster of peripheral producers that claim an identity in opposition to the dominant generalists. We explain the source of the delay as a function of the nature of the audience, which until recently did not regard conglomerate or foreign ownership of distilleries as an impediment to producing authentic Whisky. Only when critics started to question how ownership of distilleries related to authenticity did the revival of the traditional form of ownership begin to occur. By analyzing entries of focused firms in the recent period, we find that widespread ownership of distilleries of diversified corporations (but not foreign ownership) supported the formation of more traditional types of Whisky distillers. But endurance of identity-based resource partitioning might require development of a collective identity and collective strategy by producers. In the case we studied, each focused producer has an idiosyncratic identity, which may be insufficient to cause audiences to agree on a code that excludes the mainstream producers from membership in the new category and thereby maintain a partitioned market.
William Kew - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Scotch Whisky by 1H NMR and chemometrics yields insight into its complex chemistry.
Food chemistry, 2019Co-Authors: William Kew, Ian Goodall, Dušan UhrínAbstract:Scotch Whisky has been analysed as a complex mixture in its raw form using high resolution Nuclear Magnetic Resonance (NMR) and previously developed water and ethanol suppression techniques. This has allowed for the positive identification of 25 compounds in Scotch Whisky by means of comparison to reference standards, spike-in experiments, and advanced 1D and 2D NMR experiments. Quantification of compounds was hindered by signal overlap, though peak alignment strategies were largely successful. Statistical total correlation spectroscopy (STOCSY) yielded information on signals arising from the same compound or compounds of similar origin. Statistical analysis of the spectra was performed using Independent and Principal Components Analysis (ICA, PCA) as well as Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA). Several Whisky production parameters were successfully modelled, including blend or malt status, use of peated malt, alcohol strength, generic authentication and maturation wood type, whilst age and geographical origin could not be modelled.
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Complementary Ionization Techniques for the Analysis of Scotch Whisky by High Resolution Mass Spectrometry
Analytical chemistry, 2018Co-Authors: William Kew, Ian Goodall, C. Logan Mackay, David J. Clarke, Dušan UhrínAbstract:Fourier transform mass spectrometry (FTMS) is widely used to characterize the chemical complexity of mixtures, such as natural organic matter (NOM), petroleum, and agri-food products (including Scotch Whisky). Although electrospray ionization (ESI) is by far the most widely used ionization source in these studies, other ionization techniques are available and may offer complementary information. In a recent study, we found matrix free laser desorption/ionization (LDI) to be effective for the analysis of Suwannee river fulvic acid (SRFA), and to provide complementary chemical insights. In this study, LDI along with atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI) were compared to ESI for the analysis of Scotch Whisky. High mass accuracy (54 ppb, mean) allowed for the assignment of 86% of peaks, with 3993 unique molecular formulas identified from four representative samples analyzed. All four ionization techniques, performed in negative mode, identified thousan...
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Complementary Ionization Techniques for the Analysis of Scotch Whisky by High Resolution Mass Spectrometry
2018Co-Authors: William Kew, Ian Goodall, David J. Clarke, Logan C. Mackay, Dušan UhrínAbstract:Fourier transform mass spectrometry (FTMS) is widely used to characterize the chemical complexity of mixtures, such as natural organic matter (NOM), petroleum, and agri-food products (including Scotch Whisky). Although electrospray ionization (ESI) is by far the most widely used ionization source in these studies, other ionization techniques are available and may offer complementary information. In a recent study, we found matrix free laser desorption/ionization (LDI) to be effective for the analysis of Suwannee river fulvic acid (SRFA), and to provide complementary chemical insights. In this study, LDI along with atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI) were compared to ESI for the analysis of Scotch Whisky. High mass accuracy (54 ppb, mean) allowed for the assignment of 86% of peaks, with 3993 unique molecular formulas identified from four representative samples analyzed. All four ionization techniques, performed in negative mode, identified thousands of formulas. Many were unique to each ionization source, while 699 formulas were common to all techniques. Ions were identified in both deprotonated and radical anion forms. Our study highlights the importance of a multi-ionization source approach; we recommend that analysis of complex mixtures, especially novel ones, should not be limited solely to ESI
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Advanced solvent signal suppression for the acquisition of 1D and 2D NMR spectra of Scotch Whisky.
Magnetic resonance in chemistry : MRC, 2017Co-Authors: William Kew, Nicholle G. A. Bell, Ian Goodall, Dušan UhrínAbstract:A simple and robust solvent suppression technique that enables acquisition of high-quality 1D 1 H nuclear magnetic resonance (NMR) spectra of alcoholic beverages on cryoprobe instruments was developed and applied to acquire NMR spectra of Scotch Whisky. The method uses 3 channels to suppress signals of water and ethanol, including those of 13 C satellites of ethanol. It is executed in automation allowing high throughput investigations of alcoholic beverages. On the basis of the well-established 1D nuclear Overhauser spectroscopy (NOESY) solvent suppression technique, this method suppresses the solvent at the beginning of the pulse sequence, producing pure phase signals minimally affected by the relaxation. The developed solvent suppression procedure was integrated into several homocorrelated and heterocorrelated 2D NMR experiments, including 2D correlation spectroscopy (COSY), 2D total correlation spectroscopy (TOCSY), 2D band-selective TOCSY, 2D J-resolved spectroscopy, 2D 1 H, 13 C heteronuclear single-quantum correlation spectroscopy (HSQC), 2D 1 H, 13 C HSQC-TOCSY, and 2D 1 H, 13 C heteronuclear multiple-bond correlation spectroscopy (HMBC). A 1D chemical-shift-selective TOCSY experiments was also modified. The wealth of information obtained by these experiments will assist in NMR structure elucidation of Scotch Whisky congeners and generally the composition of alcoholic beverages at the molecular level.