A New Sensitive and Selective Photometric Method of Determination of Trace Amount Molybdenum with 4-Hydroxy-Coumarinthiol

Chemistry Department, Jadavpur University, Calcutta.-700 032 Manuscript received 3 June 1980, revised 19 December 1980, accepted 9 June 1981 A new photometric method for the determination of molybdenum (VI) with 4- hydroxy-coumarinthiol is reported in this paper. The reagent forms a stable intensely coloured violet complex extracted in chloroform. The complex extracted from 1 M HCI absorbs maximum at 560 nm and has the molar absorptivity 1.2 x 104 1.mole-1 cm-1. The system conforms to Beer's law from 0.5 to 12 ppm with optimum range 1-7 ppm at 560 nm. The Sandell's sensitivity of the reaction is 0.00812 \(\mu\)g cm-2 Mo(VI). 7.5 times excess of Cu(II), V(V), W(VI) is tolerated and all other ions do not interfere. The stepwise and overall stability constants of the 1 : 2 complex have been determined by spectrophotometric methods