Analysis of Volatile Methylsiloxanes in Water using a Small-scale Liquid-liquid Extraction Method followed by Gas Chromatography-mass Spectrometry (LLE-GC-MS)

Abstract

Volatile methylsiloxanes (VMS) are ubiquitous anthropogenic pollutants that have been under scrutiny for their potential toxicity and environmental persistence. The aim of this work was to develop and validate a fast and reliable methodology to determine seven VMSs (D3, D4, D5, D6, L3, L4 and L5) in water matrices, based on a small-scale liquid-liquid extraction (LLE) assisted by ultrasounds and using a low volume of organic solvents. VMSs were quantified by gas chromatography-mass spectrometry (GC-MS). This methodology was successfully validated, showing low detection limits and a good precision (most of the relative standard deviations values below 15%) and accuracy (53-108%). Wastewater samples were analyzed and D5 and D6 were the dominant compounds in influent streams, with similar concentrations to those found in literature (up to 7 µg L-1). Most effluent samples presented VMSs levels below the limits of detection, with only D5 reaching up to 0.05 µg L-1.

Keywords

• volatile methylsiloxanes
• wastewater
• gas chromatography – mass spectrometry