A new thiosemicarbazone, benzildithiosemicarbazone (BDTSC), is proposed as a sensitive and selective analytical reagent for extractive spectrophotometric
determination of Cd(II). BDTSC reacts with cadmium(II) to give a yellow-colored complex in ammonium chloride–ammonium
hydroxide buffer of pH 10.5, which is easily extracted into isoamylalcohol with 1:1 composition having a maximum absorbance at wavelength
360 nm. The molar absorptivity and Sandell’s sensitivity are found to be 0.196 × 104 dm3 mol−1 cm−1 and 0.008g cm−2 of Cd(II), respectively.
The instability constant of the method has been calculated by Asmus’ method as 5.05 × 10−5 (which is in close agreement with the value obtained
by Edmonds and Birnbaum’s method) at room temperature. The interfering effect of various cations and anions has also been studied. The method
has been successfully applied for the determination of Cd(II) in several standard reference materials as well as environmental samples, medicinal
leaves and leafy vegetables.
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