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pH: This parameter measures the acidity and alkalinity of liquid shampoo. An excess of acidity harms the scalp and that of alkalinity reduces the effectiveness of shampoo. Mild acids can improve its conditioning effect. The IS specifies that the pH range should be within 4 to 9.
Foam height: This parameter checks the lather-producing ability of a shampoo. For this, the volume of foam is determined. The minimum limit of 2 per cent solution of shampoo is 150 mm.
Active detergents: This parameter determines the limit for anionic detergent content which consists of negatively charged hydrophylic or water-loving detergents, used for their foaming property and low price. The IS specifies the limit as 5 per cent.
Non-volatile alcohol soluble matter: The test for this parameter determines the chloride content, the thickening agent that helps in maintai- ning viscosity in shampoos. The IS sets the minimum limit at 10 per cent.