Flow-injection spectrophotometric determination of micro copper in seawater

With diphenyl carbazide (DPC) as coloring agent, NaCl solution as reaction medium, and hexadecylpyridinium bromide (CPB) and OP emulsifier as sensitizing agent, a novel method for the determination of micro Cu²⁺ in seawater by flow-injection spectrophotometry was developed. The experimental conditions of flow-injection analysis were optimized, and the detection wavelength was 500 nm. Under optimum conditions, the detection limit of the method was 0.003 mg/L. The peak height showed good linearity with the concentration of Cu²⁺ in the range of 0.005-0.050 mg/L. The linear equation was H(mV)=0.6161+0.1752×10-3 ρ(mg/L) with r = 0.9988. The relative standard deviation was 1.0% (n=11) for determination of 0.020 mg/L Cu²⁺ in the standard solution. The interferences of other coexisting elements could be effectively eliminated with masking agent. The proposed method had been applied to the determination of trace Cu²⁺ in simulated seawater and actual seawater. The results were in good agreement with those obtained by graphite furnace atomic absorption spectrophotometry (GF-AAS).