A novel chromogenic agent for colorimetric estimation of copper in water and pharmaceutical tablets

The current study intends to develop a novel, simple and selective colorimetric method to identify the presence of copper on the basis of a newly-synthesized Schiff base prepared from the condensation of 1,3-phthalaldehyde with 2-aminophenol. The new chromogenic agent was studied using elemental analysis, IR, NMR, MS, and UV-VIS absorption. The new chelate produces a stable colored complex with Cu(II) ions with a 1:1 composition using the continuous variation method. The colored complex exhibited a strong absorption peak at 440 nm and this phenomenon empowers copper analysis to be conducted in natural water, and pharmaceutical solutions directly via the colorimetric method. The author analyzed and optimized all the factors that tend to influence the sensitivity of the method. Such factors include pH, time, the concentration of the ligand and temperature. The process, proposed in the study, was then evaluated in terms of precision, accuracy and selectivity. The study outcomes are as follows: linear dynamic range 0.8-22 ug mL-1; limit of quantitation 0.970 ug mL-1; and limit of detection 0.293 ug mL-1.