Synthesis of New 5-methylfuran-2-carbaxaldehyde thiosemicarbazone (5- MFAT): Selective and Sensitive Spectrophotometric Determination of Co(II) in Vegetable, Soil, water and Alloy Samples

Cobalt (II) reacts with 5-methylfuran-2-carbaxaldehyde thiosemicarbazone (5-MFAT) and forms a light yellow colored complex, which was extracted into isobutanol from sodium acetate and acetic acid buffer at pH 6.0. The absorbance value of the Co (II)–5-MFAT complex was measured at different intervals of time at 360 nm, to ascertain the time stability of the complex. The extraction of the complex into the solvent was instantaneous and stable for more than 24hrs. The system obeyed Beer’s law in the concentration range of 0.236 -2.36 μg/ml of cobalt (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 1.86 x 10 4 L mol -1 cm -1 and 3.2 x 10 -3 μg/cm 2 at 360 nm, respectively. Hence, a detailed study of the extraction of cobalt (II) with 5-MFAT has been undertaken with a view to developing a rapid selective, sensitive and extractive spectrophotometric method for the determination of cobalt (II) when present alone or in the presence of diverse ions which are usually associated with cobalt (II) in vegetable, soil, water and various standard alloy samples have been tested for the determination of cobalt (II) 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.