AOAC Official Method 939.16 Mandelic Acid in Drugs
First Action 1939
Final Action
A. Qualitative Tests
(Applicable to free acid.)
See Microchemical Tests, Table 962.21B (see 18.10.02).
B. Determination
(a) Tablets.—Weigh amount of powdered test sample containing 0.4–0.5 g mandelic acid and transfer to separator containing 10 mL H2O. Acidify with HCl (1 + 3) and add 2 mL excess. Extract with six 20 mL portions CHCl3–ether (2 + 1); wash each portion in second separator with 2 mL H2O, and pass solution through cotton plug, previously saturated with solvent, into 250 mL beaker. Wash outer surface of separator stem with few mL solvent and add to main portion. Test for complete extraction with 15 mL additional solvent and evaporate in separate beaker. Wash any residue thus obtained into beaker containing main extract with few mL solvent. Evaporate to dryness at £40°C with aid of air current. Dissolve residue in 25mL CO2-free H2O, 936.16B(a) (see A.1.12), and titrate with 0.1M NaOH, using phenolphthalein. 1 mL 0.1M NaOH = 0.01522 g mandelic acid (C6H5CHOHCOOH); 0.01692 g ammonium mandelate, 0.01741 g sodium mandelate, 0.01712 g calcium mandelate, and 0.01633 g magnesium mandelate.
After titration, mandelic acid may be re-extracted and extract used for mp determinations or qualitative tests.
(b) Liquid preparations.—Measure 1 mL test sample, or aliquot of dilution containing 0.4–0.5 g mandelic acid, into separator and acidify with HCl (1 + 3). Proceed as in (a).
Reference: JAOAC 22, 757(1939).
CAS-90-64-2 (mandelic acid)
