AOAC Official Method 938.11 Aluminum and Zinc in Deodorants
Gravimetric Method
First Action 1938
Final Action
A. Reagents
(a) 8-Hydroxyquinoline solution.—Dissolve 5.0 g 8-hydroxyquinoline in 12 mL CH3COOH, dilute to 100 mL with H2O, and filter if not clear. Prepare fresh solution £2 weeks.
(b) Ammonium acetate solution.—Approximately 2M. Dissolve 150–160 g NH4CH3COO in 1 L H2O and filter if not clear.
(c) Hydrochloric acid.—Approximately 2M (1 + 5).
(d) Ammonium hydroxide.—Approximately 2M. Volume of NH4OH required to neutralize 20 mL 2M HCl, (c), should be known to within ±2 mL.
B. Preparation of Test Sample
(a) Liquids.—Dilute 5 mL test sample to 250 mL with H2O in volumetric flask. If perfume oils separate, filter before taking aliquot for analysis.
(b) Creams and pastes.—Accurately weigh 2–3 g test sample into 250 mL beaker. Add 5 mL HCl (HNO3 if chlorides are to be determined) and ca 50 mL H2O, and heat until oils liquefy and separate; cool until oils solidify, and decant aqueous layer through fluted paper into 250 mL volumetric flask. Return filter to original beaker and macerate thoroughly. Repeat above extraction twice, decant as before, and finally thoroughly wash residue and paper withH2O. (It is unnecessary to return filter paper to beaker after these extractions.) Cool combined extracts to room temperature, dilute to volume with H2O, and mix.
