Kumar, A; Dass, R; Chaudhary, R
A simple and rapid extractive spectrophotometric method for micro determination of molybdenum using thiocyanate as a complexing agent has been worked out for industrial, environmental and soil samples. The Mo(v)-thiocyanate complex is extracted into 2,2'-dipyridyl in chloroform. The vermilion colour of the extract is measured at lambda(max) 505 nm against a similarly prepared reagent blank. The 1 : 4 (Mo : SCN) complex is found to be stable for more than one hour in the extract and obeys Beer's law over the concentration range of 0-11 mu g Mo ml(-1). The molar absorptivity and Sandell's sensitivity of the proposed method are found to he 1.24 x 10(4) dm(3) mol(-1) cm(-1) and 0.007.5 mu g Mo cm(-2), respectively. A large number of cations, anions and complexing agents of major analytical importance such as Re(VII), Cr(III,VI), Cu(II), Zr(IV), Mn(II), Ni(II), Fe(II,III), W(VI), U(VI), V(V) and platinum metals, sulphate, chloride, fluoride, bicarbonate, phosphate. tartrate and EDTA do not interfere. Only oxalate, acetate, hydrogen peroxide, tin, cobalt, bismuth, titanium. osmium and ruthenium interfered in the procedure. The method has been applied satisfactorily for the determination of molybdenum in varieties of samples.