Electromagnetic induction-assisted heating as a new method for on-line cloud point extraction of cadmium from water samples

摘要

We report on a novel method for on-line cloud point extraction (CPE) for preconcentration of cadmium ions. It is based on electromagnetic induction-assisted heating (EMIH) of iron particles in a packed bed contained in a quartz tube that acts as an on-line CPE enrichment column. The cadmium complex of l-(2-pyridylazo)-2-naphthol is quantitatively retained by the column under the cloud point temperature with the help of EMIH. The column was then eluted with alcoholic borax buffer at room temperature and on-line coupled to FAAS. Under optimum conditions, the limit of detection (3 sb/b) and limit of quantification (10 s_b/b) are 0.21 μg L~(-1) and 0.70 μg L~(-1) of Cd(II), respectively, and the relative standard deviation is 3.8 % (for n=8; at 20 ngmL~(-1)). An enhancement factor of 76 is typically achieved. The correlation coefficient of the calibration graph using the present method was 0.9986. The method was successfully applied to determine Cd(II) in water samples