Determination of copper and zinc by application of the linear regression method of multiwavelength data

In a buffer medium of HAc-NaAc at pH4.5, copper and zinc react with diphenyl thiocarbazone to form colour complexes. The maximum absorptions of the two complexes occur at 542nm and 535nm, and Cu, Zn interfere mutually with determination. In this paper, the linear regression analysis for multiwavelength data was applied to the simultaneous spectrophotometric determination of Cu and Zn. The absorbance at 11 wavelengths was measured in the range of 530 to 550 nm, and the data were treat with a simple calulator. The method has been used for simultaneous determination of Cu and Zn in plants sample with satisfactory results. The relatve standard deviation of five determination for samples are basically less than 10%.