Determination of arsenate by sorption pre-concentration on polystyrene beads packed in a microfluidic device with chemiluminescence detection.
A highly sensitive chemiluminescence (CL) method for the determination of arsenate in water based on a simple microfluidic device was developed. The method was based on sorption pre-concentration of arsenate as a form of vanadomolybdoarsenate heteropoly acid (VMoAs-HPA) ion-paired with hexadecyltrimethylammonium bromide on the surface of polystyrene beads packed in a microfluidic device monitored by chemiluminescence detection. The composition of the VMoAs-HPA complex was studied by varying the concentrations of ammonium molybdate, ammonium vanadate and sulfuric acid with a variable-size simplex optimization process, of which the optimum concentrations were 6.3 x 10(-5), 5.0 x 10(-6) and 1.0 x 10(-2) M, respectively. In this work, 1.0 x 10(-3) M ethylenediaminetetraacetic acid was added to all work solutions to remove the interferences of the other metal ions on the CL detection. The integration of sorption pre-concentration not only increased the detection sensitivity but also eliminated the interference from phosphate and chromate. The calibration plot was linear from 1.0 x 10(-7) to 5.0 x 10(-5) M As(v). The limit of detection was 8.9 x 10(-8) M As(v) (S/N = 3). The time required for one analysis run was as short as 5 min. The relative standard deviation was 5.9% (n = 9). This method was successfully applied to the determination of arsenate in mineral-, drinking- and tap-water samples.
Som-aum
Waraporn
W
Department of Chemistry, Tsinghua University, Haidian, Beijing 100084, China.
Li
Haifang
H
Liu
Jiangjiang
J
Lin
Jin-Ming
JM
D000327:Adsorption; D001149:Arsenates / Q000032:analysis*; D017022:Flow Injection Analysis / Q000379:methods; D008163:Luminescent Measurements / Q000379:methods; D046210:Microfluidic Analytical Techniques / Q000379:methods; D008863:Microspheres; D011137:Polystyrenes; D014867:Water / Q000032:analysis*
D001149:Arsenates; D011137:Polystyrenes; D014867:Water; C025657:arsenic acid