Fluorospectrophotometric Determination of Trace Amounts of Co and Ni in Water

A fluorescence reagent, 5,10,15,20-tetra(4-aminophenyl)-porphyrin (TAPP) was synthesized. Fluorescence quenching effect was observed when TAPP was reacted with Co(Ⅱ) or Ni(Ⅱ). The use of TAPP as a fluorescence probe in the determination of trace amounts of Co and Ni was studied. In a Tris-HCl buffer medium of pH 7.2, Co(Ⅱ) and Ni(Ⅱ) were reacted with TAPP in the presence of SDS, the magnitude of decrease in fluorescence intensity, ΔF, of the reaction was obtained by taking the difference between values of emission fluorescence intensity of the blank solution (F0) and the sample solution (Fs) measured at (λem) 516 nm, with (λex) at 392 nm. Linear relationships between values of ΔF and concentration of Co(Ⅱ) and Ni(Ⅱ) were found to be same in the range of 2.0×10-7-1.0×10-5mol·L-1, with their detection limits (3S/N)of 2.0×10-8mol·L-1 and 4.0×10-8mol·L-1 respectively. Values of recovery found in the analysis of samples of natural water and waste water, were in the range of 97.0 %-108.5 % for Co(Ⅱ) and 97.0%-106.5% for Ni(Ⅱ).