An adaptive breath sampler for use with human subjects with an impaired respiratory function

M. Basanta, T. Koimtzis, D. Singh, I. Wilson, C. L P Thomas

    Research output: Contribution to journalArticlepeer-review

    Abstract

    An adaptive sampler for collecting 2.5 dm3 samples of exhaled air from human subjects with an impaired respiratory function is described. Pressure in the upper respiratory tract is continuously monitored and the data used to control an automated system to collect select portions of the expired breathing cycle onto a mixed bed Tenax™ and Carbotrap™ adsorbent trap for analysis by GC-MS. The sampling approach is intended for use in metabolomic profiling of volatiles in human breath at concentrations greater than μg m-3. The importance of experimental reproducibility in metabolomic data is emphasised and consequently a high purity air supply is used to maintain a stable exogenous volatile organic compound profile at concentrations in the range 5 to 30 μg m-3. The results of a 90 day stability study showed that exogenous VOCs were maintained at significantly lower levels (40 times lower for isopropyl alcohol) and with significantly higher reproducibility (80 times lower standard deviation for isopropyl alcohol) than would have been be the case if ambient air had been used. The sampling system was evaluated with healthy controls alongside subjects with chronic obstructive pulmonary disease. Subjects were able to breathe normally with control subjects observed to breathe at a rate of 9 to 17 breaths per minute, compared to 16 to 30 breaths per minute for subjects with COPD. This study presents, for the first time, observations and estimates of intra-subject breath sample reproducibility from human subjects. These reproducibility studies indicated that VOCs in exhaled breath exhibit a variety of dynamic behaviours, with some species recovered with a RSD
    Original languageEnglish
    Pages (from-to)153-163
    Number of pages10
    JournalAnalyst
    Volume132
    Issue number2
    DOIs
    Publication statusPublished - 2007

    Keywords

    • instrumentation: Breath Tests
    • Equipment Design
    • Exhalation
    • methods: Gas Chromatography-Mass Spectrometry
    • Humans
    • diagnosis: Respiratory Tract Diseases
    • instrumentation: Specimen Handling

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