First derivative spectrophotometric determination of copper(II) and nickel(II) simultaneously using 1-(2-hydroxyphenyl)thiourea

A sensitive simultaneous determination of copper(II) and nickel(II) was achieved using first derivative spectrophotometry based on zero-crossingover technique. In the current method, 1-(2-hydroxyphenyl)thiourea (HPTU) was used as a chromogenic reagent. To enhance the sensitivity in the method, pyridine was used as activator, cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) were used as surfactants. Analytical parameters such as pH, reagent concentration, reaction time, etc., have been investigated. The ranges of determination for copper(II) and nickel(II) were 0.003-0.9 and 0.5-100 ng/mL, respectively. The proposed method was applied to plant samples for the determination of copper(II) and nickel(II) simultaneously.