Determination of Assay for Hexadecyl Trimethyl Ammonium Chloride

1.1 Reagents and solutions

a. Anhydrous Ethanol: Analytically pure

b. Calcium Carbonate: Analytically pure

c. Fluorescent Yellow Ethanol solution: 1g/L

d. Silver Nitrate standard solution: c(AgNO₃) = 0.1mol/L

1.2 Analysis Steps 

Weigh 0.35g (accurate to 0.0002g) sample into 50mL Ethanol, add 25mL pure water, 0.1g Calcium Carbonate and 8 drops Fluorescent Yellow Ethanol solution. Titrate by 0.1mol/L AgNO₃ standard solution. The solution turn to pink red, as the titration end point.

1.3 Result calculation

   Calculate the Assay X of  Hexadecyltrimethylammonium Chloride in sample according to following formula:

   In formula:

         V: The consumed volume of Silver Nitrate standard solution in titration, mL;

         c: Molar concentration of Silver Nitrate standard solution, mol/L;

         m: Mass of measured sample, g;

         320 - molar mass of Hexadecyltrimethyl ammonium Chloride

1.4 Allowable difference

The difference between the two parallel determination results should not exceed 0.5%, taking the arithmetic mean as the determination result.