Determination of Volatile Sulfur Compounds in Beverage and Coffee Samples by Purge-and-Trap On-Line Coupling with a Gas Chromatography-Flame Photometric Detector

Abstract

A sensitive and fast analytical method using purge-and-trap on-line coupling with gas chromatography was developed for the determination of trace volatile sulfur compounds including dimethyl sulfide (DMS), ethyl-methyl sulfide (EMS), and dimethyl disulfide (DMDS) in beverage and coffee samples. The analytes were purged for 12 min from the sample by high purity nitrogen at a flow rate of 35 KPa and preconcentrated in the cooled fused-silica capillary trap at −75 °C. The NaCl content in the samples was maintained at 10%. The volatile sulfur compounds were separated with an Agilent-6890 gas chromatograph by a suitable temperature program and detected by means of a flame photometric detector (FPD). The detection limits were 80 ng L−1 for DMS, 80 ng L−1 for EMS, and 100 ng L−1 for DMDS, respectively. This method was successfully applied to the determination of volatile sulfur compounds in different beverage and coffee samples.