DETERMINATION OF TRACE COBALT, NICKEL AND CADMIUM BY ON-LINE FLOW INJECTION ANALYSIS WITH COPRECIPITATION PRECONCENTRATION FAAS
DONG Liping and FANG Zhaolun (Flow-injection Analysis Research Center,Institute of Applied Ecology, Academia Sinica,110015 Shenyang)
An efficient on-line coprecipitation system was developed for flame atomic absorption spectrometry (FAAS) using a flow injection technique. Cobalt, nickel and cadmium were coprecipitated with ammonium pyrrolidinedithiocarbamite (APDC) -Fe complex, and the precipitate was collected on a knotted reactor (KR) made of 250cm long 0. 5mm. i. d,PTFE tube without filter. The precipitate was dissolved by MIBK and directly introduced into the spectrometer. Enhancement factors were 42, 30 and 33 for Co,Ni and Cd,respectively,and the corresponding detection limits were 1, 3 and 0. 3 μg/L, respectively. The RSD were 2. 3% for 20. 0μg/L Co, 2. 0% for 100μg/L Ni, and2. 4% for 10. 0μg/L Cd. The analytical results obtained for determination of Co in standard reference bovine liver (NBS1577a) and Ni, Cd in standard reference urine (GBW09103) agreed well with the recommended values.