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Determination Of Cobalt (II) In Various Environmental Samples With 3,5-Dibromosalicylaldehyde Thiosemicarbazone Using Spectrophotometry Coupled With Flow-Injection Technique

P.Chiranjeevi, K.Suvardhan, K.Suresh Kumar, D.Rekha, S.Ramanaiah

The present paper describes a facile, rapid and economical flow-injection method for the determination of cobalt(II) in various environmental samples. The method is based on the formation of green colored complex between cobalt(II) and 3,5-dibromosalicylaldehyde thiosemicarbazone (3,5-DBSTSC) at pH 4.0 ± 0.2. The absorbance of the complex was measured spectrophotometrically at 431 nm. The influence of various parameters such as pH, flow-rate of samples, volume of the sample and length of reaction coil were investigated. Beer’s law was obeyed over the range of 0.6-12 μg ml-1. The molar absorptivity and Sandell’s sensitivity were 1.387×104 l mol-1cm-1 and 0.004125 μg cm-2 respectively. Detection limits for cobalt(II) was found to be 0.0155 μg ml-1. The detailed study of various interferences made the method more selective. The method was successfully applied to the determination of cobalt(II) in various environmental samples. The performance of proposed method was evaluated in terms of Student’s t-test and Variance ratio f-test which indicates the significance of proposed method over reported method. Recoveries obtained revealed that the proposed procedure shows good accuracy at 95 % confidence level.