Determination of paraquat and diquat preconcentrated with N doped TiO2nanotubessolid phase extraction cartridge prior to capillary electrophoresis

Abstract

This paper describes a new method for rapid and sensitive determination of paraquat (PQ) and diquat (DQ) by solid phase extraction with N doped TiO₂ nanotubes cartridge prior to capillary electrophoresis. Several factors that would affect the extraction efficiency were optimized and the optimal conditions were as followed: sample volume, 500 mL; sample pH, pH 9.0; eluant, 1 mol L⁻¹ HCl/methanol: 70/30 (v/v); eluant volume, 3 mL; sample flow rate, 2.5 mL min⁻¹. Under the optimal conditions, the linear ranges and detection limits were 2.5–100 μgL⁻¹, 5–50 μg L⁻¹ and 1.95 μg L⁻¹, 2.59 μg L⁻¹ for PQ and DQ, respectively. The proposed method was successfully applied to the analysis of PQ and DQ in several environmental water samples, and the spiked recoveries were over the range of 84.15–95.38%. These results indicated that N doped TiO₂ nanotubes had better enrichment ability for PQ and DQ as a novel SPE adsorbent material, and maybe have good application prospect for monitoring other pollutants in the environment.