Direct Determination of Trace Copper(II) in Seawater by Flow Injection Catalytic Photometry

It is found that the copper can catalyze the fading reaction of neutral red reduced by hydrogen peroxide using the alanine as a sensitizer in NH4Cl-NH3 H2O medium(pH=8.0).Based on this method,a new flow injection catalytic photometric method was proposed for determination of trace copper in seawater.Beers law is obeyed in the concentration range of 2.0～32.0 μg/L of copper.The relative standard deviation of 1.3% was obtained by injecting 10.00 μg/L copper of standard solution(n=14).The detection limit calculated from three times of the average background noise was 0.12 μg/L.The recoveries of sea samples were between 97.2% and 105.2%.