N-ethyl-3-carbazolecarboxaldehyde-3-thiosemicarbazone: a new extractive spectrophotometric reagent for the determination of copper(II) in environmental and pharmaceutical samples.

N-ethyl-3-carbazolecarboxaldehyde-3-thio- semicarbazone (ECCT) as an new analytical reagent used for the development of a highly sensitive extractive spectrophotometric method for the determination of copper(II). The ECCT forms a greenish-yellow colored 1:1 (M:L) complex with copper(II) at pH 3.0, which is well extracted into n-butanol and shows maximum absorbance at 380 nm. The color of the complex is stable for more than forty eight hours. The system obey Beer's law in the range 0.4-3.6 with 2.243 x 10(4) l mol(-1) cm(-1), 2.83 x 10(-3) microg cm(-2) molar absorptivity and Sandell's sensitivity respectively. The regression coefficient is 0.412 with 0.99 correlation coefficient. The precision and accuracy of the method was checked by finding the relative standard deviation (0.422%). This developed method has been successfully employed for the determination of copper(II) in environmental and pharmaceutical samples. The method is evaluated by analyzing samples from the bureau of analyzed samples (BCS 233, 266, 216/1, 207 and 179) and by inter comparison of experimental values using AAS.