Molecular spectroscopy – Information rich detection for gas chromatography

Zavahir, Junaida Shezmin; Nolvachai, Yada; Marriott, Philip J.

doi:10.1016/j.trac.2017.11.014

Cited by 38 publications

(23 citation statements)

References 269 publications

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“…Moreover, analysis of BrC extracts in a nonpolar hexane solvent showed that light absorption by the nonpolar water-insoluble fraction of OC in BB emissions is comparable or even higher than that of WSOC. , Chemical composition of the nonpolar OC constituents has been traditionally investigated using gas chromatography/mass spectrometry (GC/MS). , However, their light absorption properties are rarely measured. Although the GC-UV hyphenation has been developed for half century, its applications are mainly in the UV and vacuum UV range . Our previous studies demonstrated that a combination of high performance liquid chromatography (HPLC), photodiode array (PDA) detector, and high-resolution mass spectrometry (HRMS) is a powerful platform for chemical characterization of BrC chromophores in OA. , This technique separates solvent-extractable BrC compounds into fractions with characteristic retention times, UV–vis absorption spectra, and elemental composition offering useful insights into their plausible molecular structures. , Similar techniques were employed to separate, identify, and quantify BrC chromophores in cloudwater, ambient aerosols, , and biomass burning smoke particles .…”

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“…39,40 However, their light absorption properties are rarely measured. Although the GC-UV hyphenation has been developed for half century, 41 its applications are mainly in the UV 42 and vacuum UV range. 43 Our previous studies demonstrated that a combination of high performance liquid chromatography (HPLC), photodiode array (PDA) detector, and highresolution mass spectrometry (HRMS) is a powerful platform for chemical characterization of BrC chromophores in OA.…”

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Comprehensive Molecular Characterization of Atmospheric Brown Carbon by High Resolution Mass Spectrometry with Electrospray and Atmospheric Pressure Photoionization

et al. 2018

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Light-absorbing components of atmospheric organic aerosols, which are collectively termed “brown carbon” (BrC), are ubiquitous in the atmosphere. They affect absorption of solar radiation by aerosols in the atmosphere and human health as some of them have been identified as potential toxins. Understanding the sources, formation, atmospheric evolution, and environmental effects of BrC requires molecular identification and characterization of light-absorption properties of BrC chromophores. Identification of BrC components is challenging due to the complexity of atmospheric aerosols. In this study, we employ two complementary ionization techniques, atmospheric pressure photo ionization (APPI) and electrospray ionization (ESI), to obtain broad coverage of both polar and nonpolar BrC components using high-resolution mass spectrometry (HRMS). These techniques are combined with chromatographic separation of BrC compounds with high performance liquid chromatography (HPLC), characterization of their light absorption with a photodiode array (PDA) detector, and chemical composition with HRMS. We demonstrate that this approach enables more comprehensive characterization of BrC in biomass burning organic aerosols (BBOAs) emitted from test burns of sage brush biofuel. In particular, we found that nonpolar BrC chromophores such as PAHs are only detected using positive mode APPI. Meanwhile, negative mode ESI results in detection of polar compounds such as nitroaromatics, aromatic acids, and phenols. For the BrC material examined in this study, over 40% of the solvent-extractable BrC light absorption is attributed to water insoluble, nonpolar to semipolar compounds such as PAHs and their derivatives, which require APPI for their identification. In contrast, the polar, water-soluble BrC compounds, which are detected in ESI, account for less than 30% of light absorption by BrC.

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Comprehensive Molecular Characterization of Atmospheric Brown Carbon by High Resolution Mass Spectrometry with Electrospray and Atmospheric Pressure Photoionization

et al. 2018

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“…Sulfides, thiols, mercapto esters, thiophenes, and thiazoles were identified in whisky 50 years ago. Because larger amounts of other volatiles, such as ethanol (percent order), fusel alcohols (hundred ppm order) and esters (ppm order), are present relative to sulfur volatiles (ppt to hundred ppb), sample preparation before analysis by GC, sulfur-selective detectors [ 62 ] such as a flame photometric detector (FPD), SCD, and multi-dimensional GC [ 61 , 62 , 63 , 64 , 65 ] might be helpful in the analysis of such minor volatiles. The analytical methods used to date are summarized in Table 3 .…”

Section: Chemical Analysis Of Sulfur Compoundsmentioning

confidence: 99%

A Narrative Review of Sulfur Compounds in Whisk(e)y

Wanikawa¹,

Sugimoto²

2022

Molecules

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The production process of whisky consists of malting, mashing, fermentation, distillation and maturation. Sulfur volatile compounds generated during this process have long attracted interest because they influence quality in general. More than forty compounds have been reported: they are formed during malting, fermentation, and distillation, but some may decrease in concentration during distillation and maturation. In sensory analysis, sulfur characteristics are described as sulfury, meaty, cereal, feinty, and vegetable, among others. Their contribution to overall quality depends on their concentration, with a positive contribution at low levels, but a negative contribution at high levels. Chemical analyses of sulfur volatiles have been developed by using sulfur-selective detectors and multi-dimensional gas chromatography to overcome the numerous interferences from the matrix. Formation pathways, thresholds, and contribution have not been elucidated completely; therefore, methods for integrating diverse data and knowledge, as well as novel technical innovations, will be needed to control sulfur volatiles in the future.

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“…The reported methods for analysing fatty acids mainly include infrared spectroscopy (Xu et al, 2015), silver-ion thin-layer chromatography (Albuquerque et al, 2011), gas chromatography (GC) (Li et al, 2012), GC-mass spectroscopy (Zeng et al, 2013a), multidimensional GC (Nolvachai et al, 2017), liquid chromatography (Wu et al, 2017) and capillary electrophoresis (Porto et al, 2015). GC is the most widely used technique for fatty acid analysis due to its high separation efficiency, satisfactory accuracy, convenience and relatively low cost, although it usually requires conversion of fatty acids to their fatty acid methyl esters (FAMEs) prior to separation (Zavahir et al, 2018). Polar stationary phases, such as wax types and highly polar cyanopropylsiloxane columns (BPX-70, SP-2560, CP-Sil 88 and HP-88), have been highly recommended for several years as the preferred choice for FAME analysis (Saadeh et al, 2015;Delmonte, 2016;Abramovi c et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

An improved gas chromatography‐based approach for characterisation of fatty acids in fresh basil seed oil

Tian

Guo

et al. 2021

Int J of Food Sci Tech

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An improved gas chromatography-based analytical method for the simultaneous separation of seventytwo fatty acids was developed. Twenty-six types of trans fatty acids and conjugated linoleic acids were separated and identified with this method, especially trans C18 isomers. This method was confirmed to be high throughput and have high sensitivity and a low detection limit. It was successfully applied to separate and identify fatty acids in fresh basil seed oil. The linolenic acid content (51.67 g/100 g) was highest in basil seed oil, followed by linoleic acid (20.16 g/100 g) and oleic acid (12.70 g/100 g). These unsaturated fatty acids in fresh basil seed oil were transformed into trans fatty acids, conjugated linoleic acids and saturated fatty acids after heating to a certain temperature for an adequate duration, and the formation mechanisms were characterised.

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Molecular spectroscopy – Information rich detection for gas chromatography

Cited by 38 publications

References 269 publications

Comprehensive Molecular Characterization of Atmospheric Brown Carbon by High Resolution Mass Spectrometry with Electrospray and Atmospheric Pressure Photoionization

Comprehensive Molecular Characterization of Atmospheric Brown Carbon by High Resolution Mass Spectrometry with Electrospray and Atmospheric Pressure Photoionization

A Narrative Review of Sulfur Compounds in Whisk(e)y

An improved gas chromatography‐based approach for characterisation of fatty acids in fresh basil seed oil

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