SOP for STANDARD WORKING PROCEDURE FOR ESTIMATION OF NICKEL

PRINCIPLE:

            The Nickel content of the sample is determined by Pre-Concentrate aspirating the sample into the flame of and Atomic Absorption Spectrophotometer. The Absorbance is measured at 232 nm using a Nickel Hollow Cathode Lamp.

Limit of Detection: 0.01 mg/L

REAGENTS

1. Hydrochloric Acid – Concentrated

2. Nitric Acid : Concentrated

3. Nitric Acid : (1:499)

4. Nickel Stock Solution: Merck 1000 mg/L NIST Certified Reference Material or weight 1.0 gm of pure metal and dissolved it in conc. HNO₃ heating to affect complete dissolution. Allow to cool and transfer each solution quantitatively to a 1000 ml volumetric flask, dilute to the mark with water and mix. (1 ml of standard solution contain 1 mg of Ni)

PROCEDURE

Preparation of Standard Solution: Prepare a reagent blank and a series of 100 ml standards containing 0.1, 0.2, 0.3, 0.4 and 0.5 mg/L of Nickel by diluting a suitable volume of the standard solution with dilute nitric acid.

Sample Preparation: To 1000 ml well-mixed sample to the evaporation dish and add 3 ml nitric acid. Heat and evaporate to 20 ml (do not boil). Cool and add 3 ml nitric acid and heat until digestion is complete, Add 2 ml HCl (1:1 v/v) and heat gently to dissolve the residue. Wash the evaporation dish for 3 to 4 times with water and filter. Wash the filter and discard. Dilute the filtrate & make up 100 ml volume with water. (10 times concentrate the sample)

Analysis: Operate the instrument as per SOP. Aspirate nitric acid (1:499) as blank. Then aspirate series of standards and then aspirate the sample solution. Read the concentration in mg/L of Nickel directly.

(Apply the dilution factor 0.1 because the sample is concentrate 10 times)

REFERENCE: IS 13428: 1998