Determination of atropine sulfate-Non-aqueous titrimetric method

Scope of application:

Determination of atropine sulfate ((C 17H23NO3) 2 H2SO4) by nonaqueous titration.

This method is suitable for the determination of atropine sulfate.

Method principle:

Accurately weigh the sample, add glacial acetic acid and acetic anhydride to dissolve, add 1-2 drops of crystal violet indicator, and titrate with perchloric acid titration solution until the solution is pure blue.

Reagent:

1. water (freshly boiled and left at room temperature)

2. glacial acetic acid

3. Acetic anhydride

4. Crystal violet indicator

5. Perchloric acid titration solution (0. 1 mol/L)

6. Benchmark potassium hydrogen phthalate

Instruments and equipment:

Sample preparation:

1. perchloric acid titration solution (0. 1 mole/liter)

Preparation: Take 750 ml anhydrous glacial acetic acid (calculated by water content, add 5.22 ml acetic anhydride per 1g water), add 8.5 ml perchloric acid (70-72%), shake well, let cool, add a proper amount of anhydrous glacial acetic acid to make it 1000mL, shake well and stand for 24 hours. If the sample is easy to acetylate, the water content of this solution must be determined by moisture determination method, and then the water content of this solution should be adjusted to 0.0 1%~0.2% with water and acetic anhydride.

Calibration: Take about 0. 16g of benchmark potassium hydrogen phthalate dried to constant weight at 105℃, accurately weigh it, add 20mL of anhydrous glacial acetic acid to dissolve it, add 1 drop of crystal violet indicator, slowly titrate it to blue with this solution, and correct the titration result with blank test. Every 1mL perchloric acid titration solution (0. 1mol/L) is equivalent to 20.42mg of potassium hydrogen phthalate. According to the consumption of the solution and the amount of potassium hydrogen phthalate, the concentration of the solution is calculated.

2. Benchmark potassium hydrogen phthalate

Storage: put it in a brown glass bottle and keep it sealed.

Operating steps:

Take 0.5g of this product, accurately weigh it, add glacial acetic acid and acetic anhydride 10mL to dissolve it, and titrate with perchloric acid titration solution (0. 1mol/L) until the solution is pure blue. The titration results were corrected by blank test. Every 1mL perchloric acid titration solution (0. 1mol/L) is equivalent to 67.68mg (0.68mg).

Note 1: "accurate weighing" means that the weighing should be accurate to one thousandth of the weighed weight, and "accurate weighing" means that the accuracy of measuring the volume should meet the accuracy requirements of the volume pipette in the national standard.

Note 2: Take 2-5g samples for "moisture determination", spread them in a flat weighing bottle dried to constant weight, with the thickness not exceeding 5mm and the loose samples not exceeding 10mm, accurately weigh them, open the bottle cap, dry them at 100~ 105℃ for 5 hours, then cover the bottle cap and move them into a dryer. According to the lost weight, calculate the water content (%) in the sample.

References: China Pharmacopoeia, edited by National Pharmacopoeia Committee, Chemical Industry Press, 2005, pp. 735-736.