Direct Analysis Mass Spectrometry

McEwan, Murray J.

doi:10.1007/978-1-4899-7588-1_8

Cited by 16 publications

(14 citation statements)

References 214 publications

(213 reference statements)

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“…SIFT‐MS 13,14 is a real‐time analytical technique for direct, comprehensive gas and headspace analysis, usually with sub‐ppbV limits of quantitation (LOQs) 15–17 . Data obtained by SIFT‐MS instruments compare well with an accepted chromatographic method for environmental VOC analysis 18 …”

Section: Methodsmentioning

confidence: 99%

“…Rapid switching between the reagent ions provides high selectivity in the absence of chromatographic pre‐separation or high‐resolution mass spectrometric detection. The key benefit of the additional ions is not primarily in the number of reagents ions, but in the multiple reaction mechanisms that provide additional independent measurements of each compound, delivering unparalleled selectivity and detection of an extremely broad range of compounds in real time 10,14,16 …”

Section: Methodsmentioning

confidence: 99%

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An evaluation of selected ion flow tube mass spectrometry for rapid instrumental determination of paper type, origin and sensory attributes

Langford¹,

Bruyn²,

Padayachee³

2020

Packag Technol Sci

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As the food and pharmaceutical industries move toward more sustainable forms of packaging, paper is experiencing somewhat of a comeback as a packaging material. However, by its very nature paper is rich in volatiles—both with and without significant olfactory impact. Human sensory analysis has long been the benchmark for determining that a product is fit for consumer application. However, sensory analysis is limited in its application due to the high per‐sample cost. Selected ion flow tube mass spectrometry (SIFT‐MS) is an instrumental approach that has potential to rapidly screen paper samples for both sensory and chemical composition attributes in a single broad‐spectrum and sensitive analysis of volatiles. In this study, a combined approach utilizing SIFT‐MS sample analysis with multivariate statistical data processing is evaluated for its ability to distinguish between samples of different paper composition (in particular, virgin, recycled, or mixed fibres), mill of origin (manufacturing mill), sensory odour intensity rating, and sensory odour note. Paper samples from four mills were analysed using instrumental and sensory methods, together with one pulp sample. The key discriminating volatiles varied depending on the classification model but typically included hydrogen sulfide, ethanol, acetone, hexanal, dimethyl sulfide, and formaldehyde. The pulp sample generally exhibited significantly higher concentrations of volatiles—especially methanol and hydrogen sulfide. Because it was so different, it was eliminated from certain models—in particular, for determination of the mill of origin. Chemical analysis with multivariate statistical processing exhibited near‐perfect classification of the fibre type and the mill of origin. Evaluation of instrumental prediction of odour intensity rating and odour note used multivariate statistical analysis to correlate sensory and instrumental results. It was found that concentration data provided superior classification of odour intensity rating and odour note than did odour activity values (compound concentrations divided by their human odour detection thresholds [ODTs]). This result is tentatively attributed to significant uncertainties introduced by literature ODTs and the method's limit of quantitation being higher than the ODT for several compounds. When using SIFT‐MS concentration data—when coupled with multivariate statistical data processing—this preliminary study demonstrates potential for rapid, instrumental determination of the odour intensity rating and odour note traditionally determined using human sensory analysis.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

An evaluation of selected ion flow tube mass spectrometry for rapid instrumental determination of paper type, origin and sensory attributes

Langford¹,

Bruyn²,

Padayachee³

2020

Packag Technol Sci

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“…Since the late 2000s, direct mass spectrometry (DMS) techniques have become more mainstream in environmental monitoring [8] and identification of odors in food sciences [9]. DMS methods can analyze odor in real-time and can be deployed at site.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Efficacy of SIFT-MS for Speciation of Wastewater Treatment Plant Odors in Parallel with Human Sensory Analysis

Langford¹,

Billiau²,

McEwan

2020

Environments

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Odors from wastewater treatment plants (WWTPs) have frequently been attributed primarily to hydrogen sulfide (H2S). Low-to-medium cost hydrogen sulfide sensors have been utilized as odor indicators. However, other odorous species are usually present that may have lower odor thresholds than hydrogen sulfide. Hydrogen sulfide is not always present in odorous environments and the correlation of hydrogen sulfide to odor at a treatment facility is inconsistent. Such factors determine hydrogen sulfide an inconsistent indicator and more sophisticated measurement techniques are required to accurately predict odor intensity from complex gaseous mixes. In this paper, the performance of a direct mass spectrometric technique, selected ion flow tube mass spectrometry (SIFT-MS), is evaluated for analysis of odors from diverse sources at a modern WWTP. The soft chemical ionization employed in SIFT-MS provides detection and quantification of a wide range of potential odorants to below, or close to, the human odor detection threshold (ODT). The results presented demonstrate that methyl mercaptan is almost always a more significant odorant at this WWTP than hydrogen sulfide and confirm that the relative abundances of these odorants vary significantly. Parallel SIFT-MS chemical analysis and human sensory analysis (olfactometry) was conducted in this study. Good agreement was observed for samples of moderate to strong “sewage” or “chemical” character. However, in samples that were otherwise low in odor intensity, sensory analysis did not attribute “sewage” odor notes as the predominant odor character. Chemicals attributed with this odor character were present significantly above the ODTs in the mixed samples and were detected by SIFT-MS. A weak correlation was obtained between total odor activity values measured using SIFT-MS and the odor concentration (in odor units per cubic meter) determined using dilution olfactometry. The complexity of the wastewater matrix and complexity of human odor recognition from mixed samples is thought to be the underlying cause of less-than-ideal correlation, perturbing both olfactometry and SIFT-MS analyses.

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“…With these opportunities in view, this article provides the first comprehensive review of the emerging applications of SIFT‐MS in the food industry, although we note that the SIFT‐MS technique has been the subject of numerous general and breath analysis review articles. Like APCI‐MS and PTR‐MS, SIFT‐MS offers advantages over GC/MS in three main areas, viz :…”

Section: Introductionmentioning

confidence: 99%

“…In this article, we focus on the SIFT‐MS technique and its benefits for odorant analysis, then illustrate its research and industrial applications from the literature, before concluding with some comments on emerging industry trends for SIFT‐MS. It should be emphasized that many of these flavour applications have also been investigated using APCI‐MS and PTR‐MS, but review of that literature lies outside the scope of this review.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive odorant analysis for on‐line applications using selected ion flow tube mass spectrometry (SIFT‐MS)

Langford¹,

Padayachee²,

McEwan

et al. 2019

Flavour & Fragrance J

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Selected ion flow tube mass spectrometry (SIFT‐MS) is a direct mass spectrometry technique developed for volatile organic compound (VOC) analysis. In this comprehensive review of the SIFT‐MS flavour literature, its flexibility and utility are evident. SIFT‐MS has found wide application in the analysis of formation and release of odorants in fruits, vegetables, nuts, and seeds – including flavour and sensory optimization during cooking. Dairy products and poultry, red meat, and seafood also comprise a significant number of studies across processing, sensory, and shelf‐life studies. Edible oils, initially investigated for flavour and oxidative status, have recently been very successfully classified according to origin using a combined chemometrics and SIFT‐MS approach. Other recent developments – across different food groups – have been growth in applications to packaging (including meats in modified atmosphere packaging), and correlations of SIFT‐MS data with various types of sensory testing. The continuing growth of food odorant publications indicates that the SIFT‐MS technique has a significant role to play in understanding and managing favourable and unfavourable aroma formation in both academia and industry.

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Direct Analysis Mass Spectrometry

Cited by 16 publications

References 214 publications

An evaluation of selected ion flow tube mass spectrometry for rapid instrumental determination of paper type, origin and sensory attributes

An evaluation of selected ion flow tube mass spectrometry for rapid instrumental determination of paper type, origin and sensory attributes

Evaluation of the Efficacy of SIFT-MS for Speciation of Wastewater Treatment Plant Odors in Parallel with Human Sensory Analysis

Comprehensive odorant analysis for on‐line applications using selected ion flow tube mass spectrometry (SIFT‐MS)

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