Extractive direct and derivative spectrophotometric determination of nickel (II) in medicinal leaves,Soil,and Alloy samples by using Pyridoxal-3-thiosemicarbazone (PDT)

Nickel(ii) reacts with 3-hydroxy-5-(hydroxymethyl)-2-methylpyridine-4-carbaldehyde thiosemicarbazone or pyridoxal-3-thiosemicarbazone (pdt) and forms a yellow colored complex,which was extracted into isobutanol from sodium acetate and acetic acid buffer at ph 6.0. the absorbance value of the ni(ii)-pdt complex was measured at different intervals of time at 430 nm,to ascertain the time stability of the complex. the extraction of the complex into the solvent was instantaneous and stable for more than 5hrs. the system obeyed beer's law in the concentration range of 0.35-3.53 μg/ml of nickel(ii),with an excellent linearity and a correlation coefficient of 0.999. the molar absorptivity and sandell's sensitivity of the extracted species were found to be 1.6 x 104 l mol-1 cm-1 and 3.6 x 10-3 μg/cm2 at 430 nm,respectively. hence,a detailed study of the extraction of nickel(ii) with pdt has been undertaken with a view to developing a rapid sensitive extractive direct and derivative spectrophotometric method for the determination of nickel(ii) when present alone or in the presence of diverse ions which are usually associated with nickel(ii) in medicinal leaves,soil and leafy vegetable oils. various standard alloy samples (cm 247 lc,in 718,bcs 233,266,253 and 251) have been tested for the determination of nickel for the purpose of validation of the present method. the results of the proposed method are comparable with those from atomic absorption spectrometry and were found to be in good agreement.