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

Abstract

Three different procedures for the quantitative assessment of free and metal complexed volatile sulfur compounds (VSCs) and for the determination of truly free SO2 have been developed, taking advantage of a GC-sulfur chemiluminescent detector system (GC-SCD) with cryotrapping. The inertness of the inlet systems, together with the column used (SPB-1 sulfur) makes it possible to obtain a non-saturated perfectly Gaussian peak for SO2, well resolved from H2S. In the main procedure, the injection of 1 mL of the headspace of a sample prepared in complete anoxia and equilibrated at 30°C makes it possible to get highly sensitive signals for all VSCs and free SO2. Detection limits are 3, 35 and 60 ng/L for H2S, MeSH and EtSH, 13 g/L for truly free SO2 (at pH=3.4, or 0.46 g/L for molecular SO2), and better than 1 g/L for other relevant sulfur volatiles. Method precision is also satisfactory and linearity covers the whole range of occurrence of these compounds. A second procedure, not making use of the cryotrapping unit, gives also satisfactory results, although with higher detection limits (0.03, 0.25 and 0.37 µg/L for free H2S, MeSH and EtSH, respectively). For the analysis of free plus metal-complexed forms, it has been demonstrated that the headspace injection of the vapors on a 1:10 brine dilution of the sample heated at 70°C for 25 min, gives good estimates of the free + metal-complexed forms of H2S and wine mercaptans.

Quality and volatile compound analysis of shrimp heads during different temperature storage

“…However, the OAV of nitrogen- and sulphur-containing compounds (mainly trimethylamine, indole, and dimethyl trisulphide) in the samples stored at 4 °C were lower than those of samples at 20 °C. As reported, sulfur compounds could act as aroma components and precursors in reactions and produce more complex aroma compounds ( Ontañón, Vela, Hernández-Orte & Ferreira (2019) . Among these volatile compounds, 3-methylbutyraldehyde, 2-pentanone, 1-pentanol, phenylethylaldehyde, 2-undecanone, and 3-methyl-1-butanol showed greater impacts on the overall odor formation with their low olfactory threshold given fruity, winey, cocoa, and lipid aromas.…”

Investigating the Aroma of Syrah Wines from the Northern Rhone Valley Using Supercritical CO2-Dearomatized Wine as a Matrix for Reconstitution Studies

“…The analysis of highly volatile sulfur compounds was carried out using the method proposed by Ontanõń et al 18 based on automated headspace solid-phase microextraction and GC-pulsed flame photometric detection. A volume of 4.9 mL of saturated NaCl brine was placed in a 20 mL standard headspace vial and sealed.…”

A high-resolution Orbitrap Mass spectral library for trace volatile compounds in fruit wines

“…These trace compounds needed to be identified by other detectors. The aldehydes and ketones could be detected in Syrah wines 13 and model wine solution by flame ionization detector (FID) 14 , 15 . The flame photometry (FPD) was used to identify sulfur compounds in Cabernet Sauvignon wines 16 , 17 .…”