SOP for STANDARD WORKING PROCEDURE FOR ESTIMATION OF SODIUM

PRINCIPLE:

          When a solution containing of sodium is introduced in the flame, the intensity of

           the transmitted   radiation  will  decrease  in   proportion  to  the  extent  of   the

           concentration of this element  in solution. A Hollow Cathode lamp made of the

           element to be determined provided the source of radiation

Limit of Detection:    0.1 mg/L        

REAGENTS:

1. Potassium Chloride Solution: Dissolve 40 g of potassium chloride in distilled water and make up to 1 Lit.

2.   Stock Sodium Solution: Use 1000 mg/L of Sodium Standard Solution as a stock   sodium solution.

3. Standard Sodium Solution: Take appropriate aliquots of the stock sodium solution in a series of 100 ml volumetric flasks to give a range of standard solutions in the working range (0.1, 0.2, 0.3, 0.4, and 0.5 mg/L). Add 10 ml of potassium chloride solution and dilute to 100 ml to have about 2000 µg / L of potassium to suppress ionization while working in air acetylene flame.

PROCEDURE:

Preparation of Sample Solution:  To 100 ml sample in beaker add 5 ml of

concentrated HNO₃  and evaporate to dryness. Repeat this operation once again

by adding concentrated nitric acid. Dissolve the residue in minimum volume of

concentrated HCl. Boil to dissolve, dilute to 50 ml with distilled water, filter and

make up to 100 ml in a volumetric flask.

Preparation of Blank solution: Prepare appropriate blank solutions using same

reagents and same volume of distilled.

Analysis: Operate the instrument as per SOP . Aspirate the blank solution to set auto zero. Aspirate series of standards and then aspirate the sample solution. Read the concentration in mg/L of Sodium directly

REFERENCE: IS 3025 (Part 45): 1993