The Selected Ion Flow Tube Method for Workplace Analyses of Trace Gases in Air and Breath: Its Scope, Validation, and Applications

Mass Spectrometry Reviews

2004

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699

935

Selected ion flow tube mass spectrometry (SIFT-MS) is a new analytical technique for the real-time quantification of several trace gases simultaneously in air and breath. It relies on chemical ionization of the trace gas molecules in air/breath samples introduced into helium carrier gas using H(3)O(+), NO(+), and O(2) (+.) precursor ions. Reactions between the precursor ions and trace gas molecules proceed for an accurately defined time, the precursor and product ions being detected and counted by a downstream mass spectrometer, thus effecting quantification. Absolute concentrations of trace gases in single breath exhalation can be determined by SIFT-MS down to ppb levels, obviating sample collection and calibration. Illustrative examples of SIFT-MS studies include (i) analysis of gases from combustion engines, animals and their waste, and food; (ii) breath and urinary headspace studies of metabolites, ethanol metabolism, elevated acetone during ovulation, and exogenous compounds; and (iii) urinary infection and the presence of tumors, the influence of dialysis on breath ammonia, acetone, and isoprene, and acetaldehyde released by cancer cells in vitro. Flowing afterglow mass spectrometry (FA-MS) is briefly described, which allows on-line quantification of deuterium in breath water vapor.

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Section: Laboratory Airmentioning

confidence: 99%

Selected ion flow tube mass spectrometry (SIFT‐MS) for on‐line trace gas analysis

Mass Spectrometry Reviews

2004

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699

935

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“…This is now a routine aspect of all SIFT-MS analyses of breath. So, although validation studies have been carried out (Š paněl et al, 1997;Smith et al, 1998), calibration of SIFT-MS instrument for each individual compounds using prepared mixtures, which is difficult at low (ppb) concentrations, is not required when breath humidity can be measured.…”

Section: Progress In Sift-msmentioning

confidence: 99%

“…During the development of SIFT-MS we have consciously carried out pilot studies in several areas to demonstrate its potential, including exposure to toxic gases in health and safety studies (Smith et al, 1998), cell biology (Smith, Wang, & Š paněl, 2002a;, the analysis of environmental air in pollution studies, in particular the emissions from petrol and diesel combustion engines (Smith, Cheng, & Š paněl, 2002;Smith et al, 2004), the odorous emissions from animal waste (Smith, Š paněl, & Jones, 2000) and the rumen of diary cows (Dewhurst et al, 2001), and in food flavor research (Š paněl & Smith, 1999d). We have summarized these pilot studies and discussed other areas in which SIFT-MS can be valuable in our previous review .…”

Section: Other Miscellaneous Applications Of Sift-msmentioning

confidence: 99%

Progress in SIFT‐MS: Breath analysis and other applications

Mass Spectrometry Reviews

2011

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305

255

The development of selected ion flow tube mass spectrometry, SIFT-MS, is described from its inception as the modified very large SIFT instruments used to demonstrate the feasibility of SIFT-MS as an analytical technique, towards the smaller but bulky transportable instruments and finally to the current smallest Profile 3 instruments that have been located in various places, including hospitals and schools to obtain on-line breath analyses. The essential physics and engineering principles are discussed, which must be appreciated to design and construct a SIFT-MS instrument. The versatility and sensitivity of the Profile 3 instrument is illustrated by typical mass spectra obtained using the three precursor ions H(3)O(+), NO(+) and O(2)(+)·, and the need to account for differential ionic diffusion and mass discrimination in the analytical algorithms is emphasized to obtain accurate trace gas analyses. The performance of the Profile 3 instrument is illustrated by the results of several pilot studies, including (i) on-line real time quantification of several breath metabolites for cohorts of healthy adults and children, which have provided representative concentration/population distributions, and the comparative analyses of breath exhaled via the mouth and nose that identify systemic and orally-generated compounds, (ii) the enhancement of breath metabolites by drug ingestion, (iii) the identification of HCN as a marker of Pseudomonas colonization of the airways and (iv) emission of volatile compounds from urine, especially ketone bodies, and from skin. Some very recent developments are discussed, including the quantification of carbon dioxide in breath and the combination of SIFT-MS with GC and ATD, and their significance. Finally, prospects for future SIFT-MS developments are alluded to.

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“…We have developed selected ion flow tube mass spectrometry, SIFT-MS, for trace gas analysis of air with special attention given to exhaled (very humid) breath [11,12]. Using SIFT-MS we can readily measure the concentrations of the major breath metabolites, including acetone, in single exhalations on-line and in real time [11][12][13][14][15]. It is also straightforward to quantify trace gases in urine headspace using SIFT-MS [8,16].…”

Section: Introductionmentioning

confidence: 99%

Selected ion flow tube mass spectrometry of 3-hydroxybutyric acid, acetone and other ketones in the headspace of aqueous solution and urine

International Journal of Mass Spectrometry

2008

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