“…Spectrophotometric methods occupy a special position due to their simplicity and inexpensive instrumentation with reasonable sensitivity. A literature survey reveals that many reagents have been employed for determination of Mo(VI) ions at trace levels such as 2,3,4-trihydroxy acetophenone phenylhydrozone, 17 thionine, 18 6-(5-chloro-2-hydroxy-4-sulfophenylazo)-5-hydroxy-1naphthalenesulfonicacid, 19 7,8-dihydroxy-4-methylcoumarin, 20 gallacetophenone phenylhydrazone, 11 resacetophenone p-hydroxybenzoylhydrazone, 21 thiocyanate, 22 and triphenyltetrazolium. 23 However, most of them have reported low sensitivity with molar absorptivity less than 4 Â 10 4 L mol À1 cm À1 and in some instances do not have the necessary selectivity which requires an extraction step prior to the analysis.…”