Detection of volatile organic compounds in breath using thermal desorption electrospray ionization-ion mobility-mass spectrometry

A thermal desorption unit has been interfaced to an electrospray ionization-ion mobility-time-of-flight mass spectrometer. The interface was evaluated using a mixture of six model volatile organic compounds which showed detection limits of <1 ng sample loaded onto a thermal desorption tube packed with Tenax, equivalent to sampled concentrations of 4 μg L−1. Thermal desorption profiles were observed for all of the compounds, and ion mobility-mass spectrometry separations were used to resolve the probe compound responses from each other. The combination of temperature programmed thermal desorption and ion mobility improved the response of selected species against background ions. Analysis of breath samples resulted in the identification of breath metabolites, based on ion mobility and accurate mass measurement using siloxane peaks identified during the analysis as internal lockmasses

Comparison of metabolomic profiles obtained using chemical ionization and electron ionization mass spectrometry in exhaled breath

The exhaled breath is rich in a wide range of volatile organic compounds with the potential to provide readily accessible biomarkers for metabolic activity in the body as a result of normal or abnormal/disease processes. Exhaled breath samples from five healthy volunteers have been analyzed by thermal desorption GC–MS using electron impact and chemical ionization. A total of eight compounds: 2-propenoic acid; 2-methyl, methyl ester; toluene; hexanal; 1,4-cyclohexadiene, 1-methyl-4-(1methlethyl); phenol; nonanal; dodecane and indole, have been evaluated to establish differences in selectivity and sensitivity using these two mechanisms of ionization. The combination of both electron impact and chemical ionization profiles could prove valuable when prospecting for breath-derived biomarkers as they result in complementary information that aids the identification of unknown components

Towards a metabolomic approach to respiratory disease in childhood: Feasibility and acceptability of a novel breath-sampling procedure and initial breath analysis data

Asthma diagnosis and treatment is based mainly on presence of symptoms and response to treatment. This carries the risk of misdiagnosis and under- or overtreatment. The focus in asthma management has shifted to the underlying chronic airway inflammation. We are developing a novel approach in which breath samples are analysed for volatile organic compounds (VOCs) that alone or in combination may be used as biomarkers for airway inflammation. The aims of the current study are (1) to determine the feasibility and acceptability of the sampling procedures for children aged 8-16 years, and (2) to collect preliminary data on potential candidate markers. [Taken from Introduction and Objectives