Low Part per Trillion Determination of Reactive Alkanethiols in Wastewater by in Situ Derivatization-Solid-Phase Microextraction Followed by GC/MS

Abstract

A solid-phase microextraction (SPME) procedure for the simultaneous determination of volatile alkanethiols (i.e., methane-, ethane-, propanethiol) and dihydrogen sulfide in aqueous samples as stable thioethers followed by GC/MS determination was developed. Accordingly, N-ethylmaleimide as derivatization reagent in the aqueous phase was used for the first time, improving the analyte stability and method sensitivity in comparison to the determination of free forms. Thus, pH of the aqueous medium, reaction time, and derivatization reagent concentration have been evaluated, and the main parameters affecting the SPME process (i.e., coating selection, extraction mode and time profile, extraction and desorption temperatures) optimized. At the selected derivatization and extraction conditions, the proposed method provided no matrix effect either in the derivatization reaction or in the microextraction steps. RSD values were lower than 11% and LODs from 0.74 to 5.2 ng L(-1). The developed procedure was successfully applied to different water and wastewater samples, where dihydrogen sulfide and some of the target alkanethiols were identified at low-microgram per liter concentrations.

Selective preconcentration of volatile mercaptans in small SPE cartridges: Quantitative determination of trace odor‐active polyfunctional mercaptans in wine

“…Because of this, many procedures for the quantitative determination of light mercaptans make use of derivatization strategies which are often considered more robust and accurate [23][24][25][26][27] and only in few cases selective isolations of these analytes have been developed [28][29][30]. Nevertheless, in the case of polyfunctional mercaptans the opposite is true and most of the few proposed analytical procedures are based on the selective isolation of the underivatized mercaptans [11,[31][32][33] and only some recent reports make use of derivatization procedures [34][35][36] to determine these compounds as their pentafluorobenzyl derivatives.…”

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

“…NMR spectroscopy 1 H and 13 C NMR spectra were recorded with a 500 MHz Bruker Avance (Bremen, Germany) spectrometer at 500.13 and 125.76 MHz, respectively. Chemical shifts (d) and coupling constants (J) are expressed in parts per million and hertz, respectively.…”

“…No precipitate was observed. 2,2'-Disulfanedyildibenzamide (6): 1 H NMR: d = 7.28 (td, J = 7.6, 1.0 Hz; 2H-C(5,5')), 7.44 (td, J = 7.6, 1.3 Hz; 2H-C(4,4'), 7.63 (dd, J = 7.6, 1.0 Hz; 2H-C(3,3'), 7.72 ppm (dd, J = 7.6, 1.3 Hz; 2H-C(6,6')); 13 …”

“…In this case, the derivatisation was performed in the liquid phase, and a subsequent extraction had to be performed to get this impressive sensitivity. The quantification of H 2 S, CH 3 SH, ethanethiol and propanethiol in waste water was achieved with derivatisation using Nethylmaleimide (NEM) in the liquid phase, followed by SPME of the liquid phase and GC-MS. [13] The limits of detection (LODs) were below 1 ng L…”

“…The electron-impact (EI) mass spectra of NEM 2 ÀS 2 and NEM-S-CH 3 3 were in accordance with those in the literature. [13] The PDMS fibre was used because of its high loading capacity.…”