Study On Filter Fiber Coated With Phenyl Fluorone For Enricichmwet And Determination Of Molybdenum Indium Germanium And Gallium By GFAAS

The enrichment of trace amount of Molybdenum, Indium, Germanium and Gallium was realized with a filter fiber coated with phenyl fluorone based on its property of forming stable complexes with these metal cations in acidic solution.The preparation of filter fiber coated with phenyl fluorone was investigated in the perspectives of concentration of phenyl fluorone and the soak time. The optimized result was obtained with 1.00 g of filter fiber soaked in 20.00mL phenyl fluorone of 10 mg/mL for 3 hours, acidified with 1:10 (V/V) HC1 afterwards. The process automation of separation, pre-concentration using the fibre column was established.For Molybdenum, its static and dynamic behavior of pre-concentration with the filter fiber column was examined using GFAAS. When the pH of pregnant solution was equal to 2, Molybdenum was quantitatively enriched while the solution flowed through the column at a rate of less than 2.0 mL/min. Then it was desorbed from the column completely by 2.00 mL ammonia of 3 % at the rate of 1.0mL/min. Molybdenum in the eluent was determined directly without matrix modifiers since this method possessed the merit of high selectivity and less matrix interferences, generating a detection limit of 0.00755ng/mL, recovery between 92.0~103.0% and RSD in the range of 0.97 ~ 4.8%. Measured values of Molybdenum in national standard samples GSS-5 and GSR-1 using the above-mentioned method were in good agreement with recommended values.The filter fiber column coated with phenyl fluorone was extended to pre-concentrate trace amount of Indium. The optimized enrichment condition wasachieved when the pregnant solution at pH = 5 flowed through the filter fiber column at the rate of less than 2.0 mL/min., then 8mL HNO3 of 5.00mol/L was implemented as an eluent. With a general graphite tube coated with Tungsten and Silver as matrix modifier, sensitivity was enhanced with GFAAS. The method was validated by determination of trace Indium in water, artificial Zinc, and Aluminium samples. The detection limit was 0.32 ng/mL, the recovery was in the range of 95.0~101%, RSD was between 1.8~7.0%.The filter fiber coated with phenyl fluorone was utilized to pre-concentrate trace amount of Germanium determined by GFAAS. The conditions of measurement, enrichment and eluent were explored. The filter was soaked in pregnant solution containing trace amount of Germanium (pH=2) for 60 minutes at 60℃, then, the fiber was filtered and washed. A clear solution was attained after the fiber was treated with 5mL HNO3 (98%) using a microwave digester. With pyrolytic graphite tube coated with Tungsten and Lanthanum as a matrix modifier, Germanium in the solution was measured using GFAAS resulting in satisfactory results. The detection limit was 0.20ng/mL, the recovery was in the range of 95.2—101%, RSD was between 2.3—11.8%. Germanium in national standard reference samples GSS-6 and GSR-5 were employed for the method validation yielding a good agreement with recommended values.The filter fibre coated with phenyl fluorone was employed to absorb the trace amount of Gallium in 0.01mol/L HNO3, then desorbed by 5.00mL HC1 of 6mol/L. GFAAS was performed to determine Gallium, giving detection limit of 0.00555 ng/mL, recovery in the range of 96.0—102% and RSD between 0.53 — 2.0%. Applied the masking agent of NaF, the results of determination of artificial Aluminum, Magnesium and Calcium samples were satisfactory.