SOP for ESTIMATION OF BERYLLIUM

REAGENT:

1. Stock beryllium solution: Dissolve 9.837 g beryllium sulfate tetra hydrate (BeSO4. 4H2O) purity 0.999, in 100 ml distilled water. Filter if necessary and dilute to 500 ml (1 ml = 1 mg Be)
2. Standard beryllium solution: Dilute 5 ml stock beryllium solution with distilled water to 1000 ml in volumetric flask (1 ml = 5 mg Be)
3. EDTA Reagent: Add 30 ml distilled water and a drop of an alcoholic solution of methyl red (50 mg/100 ml) to 2.5 g EDTA neutralize with ammonium hydroxide cool and dilute to 100 ml.
4. Aluminium buffer Reagent: Transfer 500 g ammonium acetate to 1 lit distilled water in a 2 lit beaker. Add 80 ml concentrated glacial acetic acid and stir till completely dissolved. Filter if necessary. Dissolve 1 g aurintricarboxylic acid triammonium salt (aluminon) in 50 ml distilled water and add to the buffer solution in the 2 lit beaker. Dissolve 3 g benzolic acid in 20 ml methyl alcohol and add to buffer solution. While stirring. Dilute mixture to 2 lit. Transfer 10 g gelatin to 250 ml distilled water in a 400 ml beaker. Place beaker until gelatin is dissolved completely. Pour warm gelatin into 1000 ml volumetric flask containing 500 ml distilled water. Cool to room temperature dilute to the mark and mix. Transfer gelatin solution and buffer solution to a 4 lit chemical resistant dark glass bottle. Mix and store in a cool dark place. The reagent is stable for at least one month.

PROCEDURE:

Sample treatment: If organic matter is present and total beryllium is desired digest sample with nitric acid and sulfuric acid. If only dissolved beryllium is desired filter the sample through 0.45 mm membrane filter.

Pipette 0, 0.1, 0.5, 1, 2, 3 & 4 ml standard beryllium solution to a series of 100 ml of volumetric flask. Transfer 50 ml or less sample containing less than 200 mg Be to a 100 ml volumetric flask. Add 2 ml EDTA reagent to each flask and dilute if with distilled water to approximately 75 ml. Add 15 ml aluminon buffer reagent dilute to 100 ml with distilled water mix thoroughly let it stand away from light for 20 min. filter if necessary. Read absorbance at 515 nm.

CALCULATION:

                                            mg Be (in 100 ml final volume)

                    mg Be /Lit = -------------------------------------------

                                               ml of sample

REFERENCE:  APHA – 3500 Be D. Aluminon method