Preconcentration and detection of ultra trace Molybdenum in Water, Biological, Food and Soft drinking Samples by Dispersive Liquid-Liquid Microextraction method

A sensitive method to determine the ultra-trace amounts of molybdenum is developed by dispersive liquid–liquid microextraction. This method is based on the reaction of molybdenum with thiocyanate in acidic media (HCl) and at present of ascorbic acid to form a red complex with the maximum absorption peak at 473 nm. In this method, the chloroform was used as an extractant solvent and cetyl trimethyl ammonium bromide (CTAB) was utilized as the disperser agent which also acts as the counter ion of Mo(V) anionic complexes. Under the optimum conditions, the calibration graph was linear over the range of 2.0-50.0 ng mL-1 of molybdenum with a detection limit of 0.2 ng mL-1. The relative standard deviations (RSDs) for 5 and 30 ng mL-1 of molybdenum were 3.1 and 1.9 % (n=10), respectively. The proposed method was successfully applied to determine the molybdenum in the nail, water, wastewater, cereal, vegetable, fruit, and soft drinking samples.