Fluorescence Quenching of o-Methoxyl Tetraphenylporphyrin for Determination of Trace Cadmium in Waste Water

摘要

A fluorescence spectrophotometry based on o-methoxyl tetraphenylporphyrin (0-OCH3TPP) for analysis of trace amount of cadmium ion in environmental waste water with a high sensitivity and high selectivity has been discussed in this paper. When the optimal concentration of the porphyrin was fixed as 5.0×10~(-5)moI/L and the optimal pH value was adjusted to 8.81 using Tris-HCl-tetrahydrofuran buffer solution, the fluorescence extinction value was proportional to the logarithmic value of Cd2+ concentration with the range of 5.0×10~(-8)to 1.0×10~(-6) mol/L, and the correlation coefficient was 0.9974 (n=10). The detection limit for Cd~(2+) could be evaluated to be 4.07×10~(-8)mol/L. In addition, no obvious interferences from some common metal ions were observed. Also, the presented fluorescence spectrophotometry possessed a very nice reproducibility and stability with a recovery rate of 98.20%～102.00%, indicating that it was of feasibility for determination of trace amount of Cd~(2+) in environmental waste water.