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Abstract: Background: Isoprene in human breath is said to be related to cholesterol metabolism, and the possibility of the correlations with some clinical parameters has been studied. However, at this stage, no clear benefit of breath isoprene has been reported for clinical diagnosis. In this work, isoprene and acetone concentrations were measured in the breath of healthy and obese subjects using a needle-type extraction device for subsequent analysis in gas chromatography–mass spectrometry (GC-MS) to investigate the possibility of these compounds as an indicator of possible diseases. Methods: After measuring intraday and interday variations of isoprene and acetone concentrations in breath samples of healthy subjects, their concentrations were also determined in 80 healthy and 17 obese subjects. In addition, correlation between these breath concentrations and the blood tests result was studied for these healthy and obese subjects. Results: The results indicated successful determination of breath isoprene and acetone in this work, however, no clear correlation was observed between these measured values and the blood test results. Conclusions: Breath isoprene concentration may not be a useful indicator for obesity or hypercholesterolemia. [Copyright &y& Elsevier]

Highlights: [•] Very volatile organic compounds were extracted by a novel extraction needle. [•] Extracted VVOCs were stored in the extraction needle at room temperature for 3 days. [•] The effects of sample moisture on the determination of VVOCs were investigated. [•] The developed extraction needle was applied to the determination of breath VVOCs. [ABSTRACT FROM AUTHOR]

Abstract: A new approach to the determination of human breath acetone with particle-packed sample preparation needle was developed. The extraction needle was packed with a copolymer of methacrylic acid and ethylene glycol dimethacrylate as the extraction medium. For the analysis of breath sample, exhaled breath was collected in a sampling bag, and 50mL of the breath sample was extracted with the needle-type sample preparation device followed by analysis using gas chromatography–mass spectrometry (GC–MS). After the optimization of several basic extraction conditions for standard acetone samples, breath acetone concentration taken from controlled type-2 diabetic patients was determined. Furthermore, time variations of breath and urine acetone of four healthy individuals under fasting conditions were measured. Urine sample was collected in glass vial, and urine acetone concentration was also determined with the extraction needle by analyzing the corresponding headspace gas. The results demonstrated that the particle-packed extraction needle showed an excellent extraction performance for acetone in both breath and urine headspace samples, and that there is a clear correlation between the concentration of breath acetone and HbA1c level of controlled type-2 diabetic patients. The breath acetone level in controlled diabetic patients was in the range between 0.19 and 0.66ppmv, where its concentration in medically untreated type-2 patient was 0.92 and 1.20ppmv. The breath acetone concentration in healthy male was increased to 5.66ppmv under the 24h of fasting test, and a high correlation between the breath and urine acetone concentration was also observed. On the basis of the above results, the potential applications of the proposed method to the diagnosis of diabetes and/or ketoacidosis were suggested. [Copyright &y& Elsevier]