Flow injection chemiluminescence determination of femtogram-level cobalt in egg yolk, fish tissue and human serum

Femtogram-level cobalt was determined based on its significantly catalyzed effect on lurninol-dissolved oxygen chemiluminescence (CL) reaction in the flow system. The increment of CL signal was proportional to the concentration of cobalt, giving linear range from 10 fg ml(-1) to 50 pg ml(-1) (r(2) = 0.9992) with a detection limit 4 fg ml(-1) (3 sigma). At a flow rate of 2.0 ml min(-1), a typical analytical procedure for cobalt, including sampling and washing, could be performed in 0.5 min with a relative standard deviation of less than 3.0%. The proposed method has been successfully applied for the determination of cobalt in egg yolk, fish tissue and human serum, agreed well with radioimmunoassay. (c) 2004 Elsevier Ltd. All rights reserved.