Two sensitive fluorescence methods for the determination of cobaltous in food and hair samples

摘要

F1uorescence reactions among Co(Il), with two new 8-sulfonamidoquinoline derivatives, 5-(4-chlorophenylazo)-8-(benzene namido)quinoline (CPBSQ), and 5-(3-fluo-4-chlorophenylazo)-8-((FCPBSQ), and H_2O_2 were investigated. CPBSQ or FCPBSQ reacted with cobalt(II) in the presence of H_2O_2, and basic medium forming a chelate, which exhibited intensive fluorescence in ultraviolet region. The fluorescence intensities were proportional to the concentration of cobalt(Il) over the range of 0.l-l00 and 0.5-200 μg/l with the detection limits of 0.05 and 0.l0 μg/l for CPBSQ and FCPBSQ systems, respectively. A range of metal ions, including Cu(Il) and Ni(II) did not interfere with the determinations for both systems. The methods, which are high sensitive and more selective, have been successfu1ly applied to the determination of trace amount of cobalt in food and hair samples.