Determination of thiol compounds by automated headspace solid‐phase microextraction with in‐fiber derivatization

Abstract

In this article, headspace solid-phase microextraction (HS-SPME) analysis of thiol compounds with both solid and aqueous samples was investigated using N-phenylmaleimide as an in-fiber derivatization reagent. The derivatives were analyzed using GC-MS. The HS-SPME method was executed on an automatic sampler and optimized by studying a variety of factors such as the selection of the fiber, extraction time, temperature, agitation speed, etc. Method validation was carried out by spiking known amounts of thiol compounds into the sample and calculating the concentration by standard addition. The relative standard deviations (RSD) for the majority of the thiols were less than 10%. The developed method resulted in a limit of detection (LOD) in the low microgram per liter for most of the thiols analyzed, which was about one order of magnitude lower than the HS-SPME without derivatization. Finally, the overall method was successfully applied for the determination of thiols in yellow onion, green onion and garlic.

Quantification of Hydrogen Sulfide and Methanethiol and the Study of Their Scavenging by Biocides of the Isothiazolone Family

“…In the water phase, the reaction was never complete and a better reproducibility was obtained by using the minor peak of NEMÀ SH instead of that of (NEM) 2 ÀS. Wang et al [14] determined thiols in liquids, but also in solid samples, by using N-phenylmaleimide as an in-fibre derivatisation reagent. The fibre was first exposed to the headspace of the reagent, and then to the headspace of the analyte.…”

Chemoselective reactions and their applications in metabolite isolation and analysis.

“…Such chemoseletive (CS) reagents are usually chemically modified to suit a particular analytical technique, e.g. fluorescent detection [119,120], colorimetric assays [121][122][123], capillary electrophoresis [124], electrochemical detection [125], SALDI-MS [126] and chromatographic methods coupled with mass spectrometry(GC-MS [127], LC-MS [128]). These are designed to covalently modify (i.e., tag) glutathione for detection and quantification using UV absorption studies.…”

Reduced Organic Sulfur: Analyisis and Interaction with Mercury in the Aquatic Environment

“…Thiol analysis involves separation using chromatography and electrophoresis followed by detection using electrochemical methods, fluorescence and postcolumn derivatization UV-Vis detection (Vairavamurthy and Mopper 1990;Owens and LaCourse 1997;Kabzinski 1998;Wang et al 1998;Tang et al 2003;Zhang et al 2004;Gong et al 2005;Petrlova et al 2006;Wang et al 2006). Some electrochemical methods have μM detection limits, but they suffer from oxide formations at the tip of the electrode used (usually gold) and adsorption of sulfur to the electrode surface (Owens and LaCourse 1997;Wang et al 1998;Gong et al 2005;Petrlova et al 2006).…”

“…These include separation techniques (chromatography and electrophoresis) followed by electrochemical, fluorescence and postcolumn derivatization UV-Vis detection methods Vairavamurthy and Mopper 1990;Owens and LaCourse 1997;Kabzinski 1998;Wang et al 1998;Tang et al 2003;Zhang et al 2004;Gong et al 2005;Petrlova et al 2006;Wang et al 2006). Electrochemical methods, having detection limits at μM levels, are on the basis of thiol oxidization on the surface of working electrode and therefore inducing the catalytic response with the complexes of metal ions in the electrolyte.…”

“…The representative methods for thiol analysis are summarized in Table 2.1. Solid phase extraction (SPE) (Huang et al 2010), solid phase micro extraction (SPME) (Mestres et al 1999;Hill and Smith 2000;Mestres et al 2000;Mestres et al 2002;Turkmen et al 2004;Berijani et al 2006;Wang et al 2006) and affinity chromatography have been used for the analysis of biological samples. Lyophilization (Thing et al 2010) and rotary evaporation were commonly used techniques for aquatic sample analysis (Zhang et al 2004).…”