Micro-determination and separation of molybdenum using a liquid ion exchanger

Abstract

A sensitive and selective method for the micro-determination of Mo(VI) has been developed, involving selective extraction of the yellow Mo(VI)-N-phenylbenzohydroxamic acid-SCN^– complex with a liquid ion exchanger, Aliquat 336, from a medium of 2–5 M hydrochloric acid. The molar absorptivity of the complex is 7.2 × 10⁴ l mol^–1 cm^–1 at 350 nm and the colour system obeys Beer's law in the range 0.34–10 p.p.m. of Mo(VI). The extracted metal can be quantitatively back-extracted with 0.3 M ammonia solution, thus rendering the method applicable for the concentration, determination and separation of Mo(VI) in samples containing very low levels of the metal. Molybdenum has been determined in standard steel samples and in a plant sample.