title: Determination of 3,5,6-trichloro-2-pyridinol, phoxim and chlorpyrifos-methyl in water samples using a new pretreatment method coupled with high-performance liquid chromatography.
abstract: A novel low-density solvent-based vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction with the solidification of floating organic droplet method coupled with high-performance liquid chromatography was developed for the determination of 3,5,6-trichloro-2-pyridinol, phoxim and chlorpyrifos-methyl in water samples. In this method, the addition of a surfactant could enhance the speed of the mass transfer from the sample solution into the extraction solvent. The extraction solvent could be dispersed into the aqueous by the vortex process. The main parameters affecting the extraction efficiency were investigated and the optimum conditions were established as follows: 80 μL 1-undecanol as extraction solvent, 0.2 mmol/L of Triton X-114 selected as the surfactant, the vortex time was fixed at 60 s with the vortex agitator set at 3000 rpm, the concentration of acetic acid in sample solution was 0.4% v/v and 1.0 g addition of NaCl. Under the optimum conditions, the enrichment factors were from 172 to 186 for the three analytes. The linear ranges were from 0.5 to 500 μg/L with a coefficient of determination (r(2) ) of between 0.9991 and 0.9995. Limits of detections were varied between 0.05 and 0.12 μg/L. The relative standard deviations (n = 6) ranged from 0.26 to 2.62%.
authors.affiliation: Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing, China.
authors.forename: Guilong
authors.initials: G
authors.lastname: Peng
authors.affiliation: Mathematics and Physics, Armed Police College, Chengdu, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: He
authors.affiliation: National Centre for International Research of Low Carbon and Green Buildings, Chongqing University, Chongqing, China.
authors.forename: Daniel
authors.initials: D
authors.lastname: Mmereki
authors.affiliation: Key Laboratory on Luminescence and Real-Time Analysis (Southwest University), Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing, China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zhou
authors.affiliation: Key Laboratory on Luminescence and Real-Time Analysis (Southwest University), Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing, China.
authors.forename: Junhua
authors.initials: J
authors.lastname: Chen
authors.affiliation: Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Tang
keywords: Chlorpyrifos-methyl; High-performance liquid chromatography; Liquid-liquid microextraction; Phoxim; Surfactant-enhanced emulsification