Industrial grade ammonium metatungstate is ammonium metatungstate of very high purity. The determination of bismuth (Bi) in AMT may be feasible by coprecipitation-hydride generation-atomic fluorescence spectrometry.
A Method for the Determination of Bismuth in AMT by Coprecipitation-hydride Generation-atomic Fluorescence Spectrometry
1. Instrument
AFS-830 dual channel atomic fluorescence spectrometer; bismuth high intensity hollow cathode lamp.
2. Reagents
(1) Standard stock solution: 1,000 μg/mL;
(2) Bismuth standard solution: 100ng/mL;
(3) Reducing agent: 20g/L KBH-5g/L KOH mixed solution, which is freshly prepared just before use;
(4) Masking agent: 200 g/L tartaric acid solution;
(5) Coprecipitation agent: 20g/L LaCl3 solution;
(6) Base solution (50 g/L): Weigh 12.50g of ammonium metatungstate (99.995%), dissolve it in a certain amount of aqueous ammonia, stand and dilute with water in a 250mL volumetric flask;
(7) HCl (1+1): Guaranteed reagent (GR);
(8) Deionized water.
3. Experimental Procedures
(1) Weigh 0.125g (accurate to 0.0001g) sample in a 50mL beaker, add a small amount of water, the appropriate amount of coprecipitator and KOH, heated at low temperature for 15min, filter, wash precipitate and beaker twice with KOH solution and then wash twice with water.
(2) Do coprecipitation twice. After the precipitate is dissolved in HCl solution, pour it into a 25mL volumetric flask, add in 5.0mL HCl (1+1), 2mL tartaric acid solution, and dilute to mark with water, then shake to prepare the solution to be tested., finally test the prepared solution on relative machines.
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