Determination of copper by the zone-merging flow injection spectrophotometry

A zone-merging flow injection spectrophotometric method has been established to determine copper with 5-(5-bromo-2-pyridyazo)-2,4-diaminotoluene(5-Br-PADAT) as the chromogenic agent and NaAc-HAc buffer solution as carrier liquid.The linear range of this method is 1.98×10~(-6)-2.98×10~(-5)(mol/L,)and the correlation coefficient is 0.9997 at 530nm.The detection limit for Cu~(2+) is 6.5ng/L.Compared with the conventional spectrophotometry,the proposed method has a lot of advantages such as high sensitivity,good repeatability,high speed,low consumption of reagents, automatic operation,and high stability of samples.In addition,it saves more reagent and controls confluent pattern more accurately than that of conventional double-route FIA system.