Comparison between Liquid-Liquid Extraction and Solid Phase Extraction for Toxaphene in Underground Water Samples

Toxaphene is a broad-spectrum organochlorine insecticide, which was one of the most widely used pesticides worldwide. It was listed as an organic contaminant in the Stockholm Convention on Persistent Organic Pollutants (2001) and the Groundwater Pollution Survey Specification of the China Geological Survey (2006), respectively, because of persistence and adverse effects on humans and the ecosystem. In this study, three methods of extraction of toxaphene from ground water samples were compared using liquid-liquid extraction, a solid phase extraction cartridge and solid phase extraction disc. The analytical conditions were optimized detailed for GDX-502 solid phase extraction (SPE) cartridge lab-filled because of its excellent character. The research results show that GDX-502 SPE cartridge packed in the lab has the highest recoveries (92.3%-98.5%) in three SPE cartridges such as GDX-502, commercial LC-C₁₈ and ENVITM-C₁₈, and is also better than a solid phase extraction disc (92.8%-96.8%) & liquid-liquid extraction (80.3%-88.5%). The extraction time of the SPE disc only needs 20-30 min for single extraction, and less than 40-50 min of GDX-502 SPE cartridge, 200 min of LC-C₁₈ and ENVITM-C₁₈. The GDX-502 SPE processes 12 samples as a batch which is more than 6 for the SPE disc. The SPE disc has the highest analytical cost and the GDX-502 SPE is cheaper than the SPE disc. The SPE is considered environmentally friendly because its solvent amounts are less than those for liquid-liquid extraction. Finally, the GDX-502 solid-phase extraction cartridge has more advantages in terms of extraction efficiency, throughput, cost and environmental protection.