An exploratory comparative study of volatile compounds in exhaled breath and emitted by skin using selected ion flow tube mass spectrometry

Abstract

Selected ion flow tube mass spectrometry (SIFT-MS) has been used to carry out a pilot parallel study on five volunteers to determine changes occurring in several trace compounds present in exhaled breath and emitted from skin into a collection bag surrounding part of the arm, before and after ingesting 75 g of glucose in the fasting state. SIFT-MS enabled real-time quantification of ammonia, methanol, ethanol, propanol, formaldehyde, acetaldehyde, isoprene and acetone. Following glucose ingestion, blood glucose and trace compound levels were measured every 30 min for 2 h. All the above compounds, except formaldehyde, were detected at the expected levels in exhaled breath of all volunteers; all the above compounds, except isoprene, were detected in the collection bag. Ammonia, methanol and ethanol were present at lower levels in the bag than in the breath. The aldehydes were present at higher levels in the bag than in breath. The blood glucose increased to a peak about 1 h post-ingestion, but this change was not obviously correlated with temporal changes in any of the compounds in breath or emitted by skin, except for acetone. The decrease in breath acetone was closely mirrored by skin-emitted acetone in three volunteers. Breath and skin acetone also clearly change with blood glucose and further work may ultimately enable inferences to be drawn of the blood glucose concentration from skin or breath measurements in type 1 diabetes.

High throughput volatile fatty acid skin metabolite profiling by thermal desorption secondary electrospray ionisation mass spectrometry

“…Mass spectral "fingerprints" obtained in-vivo from skin with desorption electrospray ionisation (DESI) [33], secondary electrospray ionisation (SESI) [34][35] and extractive electrospray ionisation (EESI) [36] are exciting and promising developments. Selected ion flow tube mass spectrometry (SIFT-MS) has provided real-time information for acetone emanating from skin [37] and proton transfer reaction mass spectrometry (PTR-MS) has been applied to monitoring of lipid peroxidation products and the fatty acid composition of skin [38]. All these methods enable fast, selective and sensitive analysis of the area of a participant's skin presented to the instrument.…”

Background levels and diurnal variations of hydrogen cyanide in breath and emitted from skin

“…Detection of volatile compounds emitted from skin is even more demanding since their concentrations tend to be still lower than in breath, and the collection of skin gas is challenging. Despite this, a number of volatile compounds have been quantified in skin emission using SIFT-MS [20], gas chromatography coupled to flame-thermoionic and flame ionization detectors [21,22], laser-based photoacoustic detection and proton transfer reaction mass spectrometry (PTR-MS) [23]. The emission of hydrogen cyanide from skin has, however, to the best of our knowledge, not yet been documented.…”

Acetone Concentration in Gas Emanating from Tails of Diabetic Rats

“…10 It has also been reported that concentrations of acetone in both skin gas and exhaled air increased according to the length of fasting periods; 11 researchers also demonstrated that there is a good relationship between skin and exhaled air acetone concentration. 1,11 From these results, we can see that the skin gas acetone concentration reflects that of exhaled air.…”