Determination Of ultra trace molybdenum in beans Samples

Molybdenume plays an important role in growth, healthiness and the prevention of tooth decay. Shortage of molybdenum in diet may lead to neurological disorders and even early death [1, 2]. The fertilizers contain molybdenum leads to increased agricultural productions. Therefore, molybdenum is very important in agriculture [3].A sensitive method to determine the ultra-trace amounts of molybdenum is developed by dispersive liquid–liquid microextraction (DLLME). This method is based on the reaction 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 chloroforme was used as extractant solvent and cetyl trimethyl ammonium bromide 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 2.8×10-8–5.2×10-7 mol L-1 (2.0-50.0 ng mL-1) of molybdenum with detection limit of 2.08×10-9 mol L-1 (0.2 ng mL-1). For determination of the molybdenum content of beans samplest (Chickpea, Green Lentil, White Beans) adequate amount of wet samples were dried in an oven at 75 ◦C for 48 h. Determined weight of the well-dried powder of each sample was transferred to a porcelain crucible and laid in ashes at 500 ◦C for 8 h in a furnace. The residues were digested with nitric acid/hydrogen peroxide until complete dissolution of the sample was obtained [4]. Finally, To 3 balloons 10 mL containing 5 ml of beans, ascorbic acid (0.004 mol L-1), hydrochloric acid (0.8 mol L-1), and thiocyanat (0.01 mol L-1) added, then distilled water to volume It was then passed to a glass-centrifugal tube with a conical end. Then, 200 microliters chloroform containing CTAB (0.03 mol L-1) was injected. After that, with speed of 3500 rpm for 5 minutes centrifugation and then transferred to quartz microsel. The absorption was measured using a Uv-visible spectrophotometer apparatus at a constant wavelength of 473 nm.