Sodium Dodecyl Sulfate VS

Sodium Dodecyl Sulphate VS; C₁₂H₂₅NaO₄S = 288.4

For a 0.001m solution Dissolve 0.2884 g of sodium dodecyl sulfate, calculated with reference to the substance dried at 105° for 2 hours, in sufficient water to produce 1000 mL.

Ascertain its exact concentration in the following manner. To 50 mL add 15 mL of chloroform, 10 mL of 1m sulfuric acid and 1 mL of a solution containing 0.003% w/v of each of dimethyl yellow and oracet blue 2R in chloroform and titrate with 0.004m benzethonium chloride VS, shaking vigorously and allowing the layers to separate after each addition, until the chloroform layer acquires a permanent clear green colour. Each mL of 0.004m benzethonium chloride VS is equivalent to 1.154 mg of C₁₂H₂₅NaO₄S.