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Standard analytical Procedure of Sodium Chloride

Standard analytical Procedure of Sodium Chloride

Content

99.0 per cent to 100.5 per cent (dried substance).

CHARACTERS

Appearance

White or almost white, crystalline powder or colourless crystals or white or almost white pearls.

Solubility

Freely soluble in water, practically insoluble in anhydrous ethanol.

IDENTIFICATION

A. It gives the reactions of chlorides.

B. It gives the reactions of sodium.

TESTS

If the substance is in the form of pearls crush before use.

Solution S

Dissolve 20.0 g in carbon dioxide-free water R prepared from distilled water R and dilute to 100.0 mL with the same solvent.

Appearance of solution

Solution S is clear and colourless.

Acidity or alkalinity

To 20 mL of solution S add 0.1 mL of bromothymol blue solution R1. Not more than 0.5 mL of 0.01 M hydrochloric acid or 0.01 M sodium hydroxide is required to change the colour of the indicator Bromides.

A. Dissolve in 2 mL of water R a quantity of the substance to be examined equivalent to about 3 mg of bromide (Br–) or use 2 mL of the prescribed solution. Acidify with dilute nitric acid R and add 0.4 mL of silver nitrate solution R1. Shake and allow to stand. A curdled, pale yellow precipitate is formed. Centrifuge and wash the precipitate with three quantities, each of 1 mL, of water R. Carry out this operation rapidly in subdued light disregarding the fact that the supernatant solution may not become perfectly clear. Suspend the precipitate obtained in 2 mL of water R and add 1.5 mL of ammonia R. The precipitate dissolves with difficulty.

B. Introduce into a small test-tube a quantity of the substance to be examined equivalent to about 5 mg of bromide (Br–) or the prescribed quantity. Add 0.25 mL of water R, about 75 mg of lead dioxide R, 0.25 mL of acetic acid R and shake gently. Dry the inside of the upper part of the test-tube with a piece of filter paper and allow to stand for 5 min. Prepare a strip of suitable filter paper of appropriate size. Impregnate it by capillarity, by dipping the tip in a drop of decolorised fuchsin solution R and introduce the impregnated part immediately into the tube. Starting from the tip, a violet colour appears within 10 s that is clearly distinguishable from the red colour of fuchsin, which may be visible on a small area at the top of the impregnated part of the paper strip.)

Maximum 100 ppm.

To 0.5 mL of solution S add 4.0 mL of water R, 2.0 mL of phenol red solution R2 and 1.0 mL of a 0.1 g/L solution of chloramine R and mix immediately. After exactly 2 min, add 0.15 mL of 0.1 M sodium thiosulfate, mix and dilute to 10.0 mL with water R. The absorbance (2.2.25) of the solution measured at 590 nm, using water R as the compensation liquid, is not greater than that of a standard prepared at the same time and in the same manner, using 5.0 mL of a 3.0 mg/L solution of potassium bromide R. Iodides.

A. Dissolve a quantity of the substance to be examined equivalent to about 4 mg of iodide (I–) in 2 mL of water R or use 2 mL of the prescribed solution. Acidify with dilute nitric acid R and add 0.4 mL of silver nitrate solution R1. Shake and allow standing. A curdled, pale-yellow precipitate is formed. Centrifuge and wash with three quantities, each of 1 mL, of water R. Carry out this operation rapidly in subdued light disregarding the fact that the supernatant solution may not become perfectly clear. Suspend the precipitate in 2 mL of water R and add 1.5 mL of ammonia R. The precipitate does not dissolve.

B. To 0.2 mL of a solution of the substance to be examined containing about 5 mg of iodide (I–) per milli liter, or to 0.2 mL of the prescribed solution, add 0.5 mL of dilute sulfuric acid R, 0.1 mL of potassium dichromate solution R, 2 mL of water R and 2 mL of chloroform R. Shake for a few seconds and allow to stand. The chloroform layer is colored violet or violet-red.)

Moisten 5 g by the drop wise addition of a freshly prepared mixture of 0.15 mL of sodium nitrite solution R, 2 mL of 0.5 M sulfuric acid , 25 mL of iodide-free starch solution R and 25 mL of water R. After 5 min, examine in daylight. The mixture shows no blue colour.

Nitrites To a mixture of 0.1 mL of nitrobenzene R and 0.2 mL of sulfuric acid R, add a quantity of the powdered substance equivalent to about 1 mg of nitrate (NO3–) or the prescribed quantity. Allow to stand for 5 min. Cool in iced water and add slowly and with mixing 5 mL of water R, then 5 mL of strong sodium hydroxide solution R. Add 5 mL of acetone R. Shake and allow to stand. The upper layer is coloured deep violet.

To 10 mL of solution S add 10 mL of water R. The absorbance is not greater than 0.01 at 354 nm.
Phosphates (To 100 mL of the solution prepared and, if necessary, neutralised as prescribed add 4 mL of sulfomolybdic reagent R3. Shake and add 0.1 mL of stannous chloride solution R1. Prepare a standard in the same manner using 2 mL of phosphate standard solution (5 ppm PO4) R and 98 mL of water R. After 10 min, compare the colours using 20 mL of each solution.

Any colour in the test solution is not more intense than that in the standard).
Maximum 25 ppm.

Dilute 2 mL of solution S to 100 mL with water R.

Sulfates: (All solutions used for this test must be prepared with distilled water R.

Add 3 mL of a 250 g/L solution of barium chloride R to 4.5 mL of sulfate standard solution (10 ppm SO4) R1. Shake and allow to stand for 1 min. To 2.5 mL of this suspension, add 15 mL of the solution to be examined and 0.5 mL of acetic acid R. Prepare a standard in the same manner using 15 mL of sulfate standard solution (10 ppm SO4) R instead of the solution to be examined.

After 5 min, any opalescence in the test solution is not more intense than that in the standard. )

Maximum 200 ppm.

Dilute 7.5 mL of solution S to 30 mL with distilled water R.
Barium (Solutions of barium salts yield a white precipitate with the addition of 2 N sulfuric acid. This precipitate is insoluble in hydrochloric acid and in nitric acid.)

To 5 mL of solution S add 5 mL of distilled water R and 2 mL of dilute sulfuric acid R. After 2 h, any opalescence in the solution is not more intense than that in a mixture of 5 mL of solution S and 7 mL of distilled water R.

Iron (Dissolve the prescribed quantity of the substance to be examined in water R and dilute to 10 mL with the same solvent or use 10 mL of the prescribed solution. Add 2 mL of a 200 g/L solution of citric acid R and 0.1 mL of thioglycollic acid R. Mix, make alkaline with ammonia R and dilute to 20 mL with water R. Prepare a standard in the same manner, using 10 mL of iron standard solution (1 ppm Fe) R.
After 5 min, any pink colour in the test solution is not more intense than that in the standard.)
Maximum 2 ppm, determined on solution S.
Prepare the standard using a mixture of 4 mL of iron standard solution (1 ppm Fe) R and 6 mL of water R.

Potassium (To 10 mL of the prescribed solution add 2 mL of a freshly prepared 10 g/L solution of sodium tetraphenylborate R. Prepare a standard in the same manner using a mixture of 5 mL of potassium standard solution (20 ppm K) R and 5 mL of water R. After 5 min, any opalescence in the test solution is not more intense than that in the standard. )

Maximum 500 ppm, if intended for use in the manufacture of parenteral preparations or haemodialysis, haemofiltration or peritoneal dialysis solutions.

Flame photometer
Test solution: Dissolve 1.00 g in water R and dilute to 100.0 mL with the same solvent.
Reference solutions Dissolve 1.144 g of potassium chloride R, previously dried at 100-105 °C for 3 h, in water R and dilute to 1000.0 mL with the same solvent (600 µg of K per millilitre). Dilute as required.

Heavy metals (The methods described below require the use of thioacetamide reagent R. As an alternative, sodium sulfide solution R1 (0.1 mL) is usually suitable. Since tests prescribed in monographs have been developed using thioacetamide reagent R, if sodium sulfide solution R1 is used instead, it is necessary to include also for methods A, B and H a monitor solution, prepared from the quantity of the substance to be examined prescribed for the test, to which has been added the volume of lead standard solution prescribed for preparation of the reference solution. The test is invalid if the monitor solution is not at least as intense as the reference solution)
Maximum 5 ppm.
12 mL of solution S complies with test A. Prepare the reference solution using lead standard solution (1 ppm Pb) R.

Loss on drying

Maximum 0.5 per cent, determined on 1.000 g by drying in an oven at 105 °C for 2 h.

Bacterial endotoxins

Less than 5 IU/g, if intended for use in the manufacture of parenteral preparations without a further appropriate procedure for removal of bacterial endotoxins.

ASSAY

Dissolve 50.0 mg in water R and dilute to 50 mL with the same solvent. Titrate with 0.1 M silver nitrate determining the end-point potentiometrically. 1 mL of 0.1 M silver nitrate is equivalent to 5.844 mg of NaCl.

STORAGE

In an airtight container, protected from light.

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