title: Determination of malachite green in fish water samples by cloud-point extraction coupled to cation-selective exhaustive injection and sweeping-MEKC.
abstract: We have employed a high-sensitivity off-line coupled with on-line preconcentration method, cloud-point extraction (CPE)/cation-selective exhaustive injection (CSEI) and sweeping-MEKC, for the analysis of malachite green. The variables that affect CPE were investigated. The optimal conditions were 250 g/L of Triton X-100, 10% of Na(2)SO(4) (w/v), heat-assisted at 60 degrees C for 20 min. We monitored the effects of several of the CSEI-sweeping-MEKC parameters - including the type of BGE, the concentrations of SDS, the injection length of the high-conductivity buffer, and the injection time of the sample - to optimize the separation process. The optimal BGE was 50 mM citric acid (pH 2.2) containing 100 mM SDS. In addition, electrokinetic injection of the sample at 15 kV for 800 s provided both high separation efficiency and enhanced sweeping sensitivity. The sensitivity enhancement for malachite green was 1.9 x 10(4) relative to CZE; the coefficients of determination exceeded 0.9928. The LOD, based on an S/N of 3:1, of CSEI-sweeping-MEKC was 0.87 ng/mL; in contrast, when using off-line CPE/CSEI-sweeping-MEKC the sensitivity increased to 69.6 pg/mL. This proposed method was successfully applied to determine trace amounts of malachite green in fish water samples.
authors.affiliation: College of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063, P R China. luoxubiao@126.com
authors.forename: Xubiao
authors.initials: X
authors.lastname: Luo
authors.forename: Xin
authors.initials: X
authors.lastname: Jiang
authors.forename: Xinman
authors.initials: X
authors.lastname: Tu
authors.forename: Shenglian
authors.initials: S
authors.lastname: Luo
authors.forename: Liushui
authors.initials: L
authors.lastname: Yan
authors.forename: Bo
authors.initials: B
authors.lastname: Chen
mesh_terms: D000818:Animals; D002412:Cations / Q000737:chemistry; D005591:Chemical Fractionation / Q000379:methods*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D019343:Citric Acid / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D005399:Fishes; D005618:Fresh Water / Q000737:chemistry*; D015203:Reproducibility of Results; D012394:Rosaniline Dyes / Q000032:analysis*; D012680:Sensitivity and Specificity; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry; D013696:Temperature
chemical_list: D002412:Cations; D012394:Rosaniline Dyes; D013431:Sulfates; D013501:Surface-Active Agents; C012036:sodium sulfate; C005095:malachite green; D019343:Citric Acid; D012967:Sodium Dodecyl Sulfate; D000431:Ethanol