Exploration of Extraction and Separation Techniques for Routine Trace Analysis of Organic Compounds in Water: Dispersive Liquid-Liquid Microextraction vs Liquid-Liquid Extraction

Abstract

Dispersive liquid-liquid microextraction (DLLME) was compared to liquid-liquid extraction (LLE) in terms of the methods’ abilities to analyze samples and ultimately to provide information to an analyst. A simple method of relative quantification by compound class approximation was introduced and its validity tested, while the merits of comprehensive gas chromatography – time-of-flight mass spectrometry (GC×GC-TOFMS) were exhibited on multiple sets of locally obtained environmental water samples. 20 classes of compounds were effectively identified by the DLLME-GC×GC-TOFMS protocol proposed. The limits of detection (LOD) of the protocol ranged between 17 and 377 times lower than the conventional protocol designed for targeted total extractable hydrocarbon (TEH) and total petroleum hydrocarbon (TPH) analysis, with LODs of selected compounds between 0.08 and 1.0 µg/L. Relative quantification shows promising results and was used for quantification of non-targeted analytes within real samples. This quantification method will be used to inform future work to be implemented in industrial environmental analysis.

Keywords

• Non-targeted analysis
• microextraction
• comprehensive two-dimensional gas chromatography
• water
• hydrocarbons
• organic contaminants