Hydrogen Sulfide Measurement by Headspace-gas Chromatography-mass Spectrometry (HS-GC-MS): Application to Gaseous Samples and Gas Dissolved in Muscle

Abstract

The aim of our study was to present a new headspace-gas chromatography-mass spectrometry (HS-GC-MS) method applicable to the routine determination of hydrogen sulfide (H(2)S) concentrations in biological and gaseous samples. The primary analytical drawback of the GC/MS methods for H(2)S measurement discussed in the literature was the absence of a specific H(2)S internal standard required to perform quantification. Although a deuterated hydrogen sulfide (D(2)S) standard is currently available, this standard is not often used because this standard is expensive and is only available in the gas phase. As an alternative approach, D(2)S can be generated in situ by reacting deuterated chloride with sodium sulfide; however, this technique can lead to low recovery yield and potential isotopic fractionation. Therefore, N(2)O was chosen for use as an internal standard. This method allows precise measurements of H(2)S concentrations in biological and gaseous samples. Therefore, a full validation using accuracy profile based on the β-expectation tolerance interval is presented. Finally, this method was applied to quantify H(2)S in an actual case of H(2)S fatal intoxication.

Postmortem Internal Gas Reservoir Monitoring Using GC×GC-HRTOF-MS

“…Vials were inverted and stored at +4 • C prior to analysis. Preliminary studies were conducted on gases and have assured sample stability over a minimum period of two months while refrigerated [5].…”

“…Whole body postmortem computed tomography (PMCT) is often used as the imaging technique in postmortem examination. It allows the visualization of internal characteristics of the body and can serve to detect the precise localization of gas reservoirs present inside the body and further allow their collection [1][2][3][4][5]. Routinely, the occurrence and the distribution of postmortem gases are used in medicolegal laboratories, often to provide information about the cause of death [5,6].…”

“…Routinely, the occurrence and the distribution of postmortem gases are used in medicolegal laboratories, often to provide information about the cause of death [5,6]. However, the full chemical composition of these reservoirs has never been analyzed [5]. This lack of chemical profiling could lead to the misinterpretation of the origin of these gases.…”

“…For example, the chemical profile of this gas could potentially discriminate between putrefactive gas buildup and the occurrence of a gas embolism [6]. In 2015, Varlet et al demonstrated the possibility to chemically differentiate alteration gases and gas embolisms using gaseous compositions (e.g., O 2 , N 2 , CO 2 , CH 4 , and H 2 S) [5]. In order to obtain more information regarding the cause of death or the postmortem interval (PMI), a complete screening of the volatile organic compounds (VOCs) present in these gas reservoirs would be extremely valuable.…”

“…For the present study, internal gases were sampled under laser guidance and assisted by postmortem multi-detector computed tomography (MDCT) following an established procedure [4,5,20]. Solid-phase microextraction (SPME) was applied to concentrate and to introduce the VOCs into the chromatographic system.…”