The Determination of Copper in Wastewater by Flow Injectionspectrophotometry:Based on the Oxidation of Cu(II) to Iodide Ion

A simple and reliable copper determination method is proposed,that combined with the rapid and reproducible flow injection technology without any complicated pre-treatments and additional masking agents.The theory of the proposed method is based on bivalence copper's feeble oxidation action to iodide ion.In the research,chemicals and flow injection variables have been optimized,respectively,and the effects of potassium thiocyanate,amylum and temperature are studied in detail.Experimental results indicate that the proposed method possesses excellent selectivity and anti-interference capacity.The proposed method provides a linearity range over 10 mg·L-1 to 200 mg·L-1,and the following is linearity equation(A= 4.51(Cu2+,mg·L-1) – 29.622,r2 = 0.999).The detection limit estimated(S/N = 3) is 0.5 mg·L-1.The relative standard deviation(RSD) calculated from 15 times repeated injection is 1.10%(Cu2+,100 mg·L-1).The method is applied triumphantly to the analysis of different wastewater samples,and the results obtained with the proposed method are comparable with that of obtained by the reference method.The recovery percent is between 97.65%~104.0% in the determination of real and spiked wastewater samples with the proposed method.