GFAAS Determination of Trace Amount of Copper in Environmental Water Samples with Cloud Point Extraction

GFAAS was applied to the determination of trace amount of copper in environmental water samples with 5-(5-iodine-2-pyridylazo)-2,4-diaminotoluene (5-I-PADAT) as complexing agent and p-octyl polyethylene glycol phenyl ether (Triton X-114) as extracting agent. The optimized conditions found were as follows:①pH of buffer solution of acetic acid and sodium acetate:5.3; ② amount of 1.0×10^-3mol·L^-1 5-I-PADAT solution:0.25 mL; ③ amount of 10 g·L^-1 Triton X-114 solution:1.0 mL; ④water bath heating time:15 min;⑤ water bath heating temperature:60℃; ⑥ amount of 0.1 mol·L^-1 HNO₃-methanol solution:70 μL. Linear relationship between values of absorbance and mass concentration of copper was obtained in the range of 1.0-14 μg·L^-1, with detection limit (3s/k) of 0.216 μg·L^-1. The proposed method was applied to the analysis of 2 environmental water samples, giving values of recovery of 102%, 100%, and values of RSD's (n=6) of 4.5%, 4.3%.