Headspace solid‐phase microextraction and gas chromatographic analysis of low‐molecular‐weight sulfur volatiles with pulsed flame photometric detection and quantification by a stable isotope dilution assay

Abstract

Low-molecular-weight volatile sulfur compounds such as thiols, sulfides, disulfides as well as thioacetates cause a sulfidic off-flavor in wines even at low concentration levels. The proposed analytical method for quantification of these compounds in wine is based on headspace solid-phase microextraction, followed by gas chromatographic analysis with sulfur-specific detection using a pulsed flame photometric detector. Robust quantification was achieved via a stable isotope dilution assay using commercial and synthesized deuterated isotopic standards. The necessary chromatographic separation of analytes and isotopic standards benefits from the inverse isotope effect realized on an apolar polydimethylsiloxane stationary phase of increased film thickness. Interferences with sulfur-specific detection in wine caused by sulfur dioxide were minimized by addition of propanal. The method provides adequate validation data, with good repeatability and limits of detection and quantification. It suits the requirements of wine quality management, allowing the control of oenological treatments to counteract an eventual formation of excessively high concentration of such malodorous compounds.

The Light Struck Taste of Wines

“…On the other hand, within the family of sulfides and disulfides are found dimethyl sulfide and dimethyl disulfide, characteristic compounds for providing aromas associated with cabbage, asparagus, corn or onion flavors when present in high concentrations. They have an odor threshold around 25 μg/L and 29 μg/L, respectively [39][40][41]. The emergence of sulfur compounds related to the LST usually is also linked to a loss of fruity aromas of wines, such as ethyl and acetate esters, alcohols and fatty acids [42].…”

Gas chromatographic-sulfur chemiluminescent detector procedures for the simultaneous determination of free forms of volatile sulfur compounds including sulfur dioxide and for the determination of their metal-complexed forms

“…preconcentration strategy [28][29][30][31][32][33]. The matrix effects associated to competence towards active adsorption sites in the fiber [34] have been circumvented by dilution with brine [32], by the use of standard addition as calibration method [28] or by using deuterated isotopomers as internal standards [33]. Nevertheless, the SPME of these components can induce the formation of artifacts [35,36] and in any case requires a careful calibration of each fiber.…”

A Highly Selective and Sensitive Colorimetric Chemosensor for the Detection of Hydrogen Sulfide: A Real‐time Application in Multiple platforms

“…In recent years, with the ongoing efforts of research groups, various methods have been developed to detect H 2 S. For example, electrochemical assays (10–14), chromatography (15–17), metal‐induced sulfide precipitation (18) and optical probes are the main techniques to detect H 2 S. Among these methods, optical detection has received significant attention in recent years owing to its simplicity, high sensitivity and selectivity, and good repeatability (19–38). Chemodosimeter is the most common optical approach in which the chemical probe is incorporated with an H 2 S selective irreversible responsive unit and optical response modulator.…”