AOAC Official Method 938.15 Guaiacol in Drugs
Titrimetric Method
First Action 1938
Final Action
A. Reagent
Hydriodic acid.—Specific gravity 1.7. Boil HI 30 min under reflux with excess of hypophosphorous acid. When cool, transfer to dark, glass-stoppered bottle. Do not leave bottle unstoppered more than few minutes.
B. Apparatus
Methoxyl apparatus.—See Figure 956.07B (see 12.1.16).
C. Determination
Place aliquot of alkaline guaiacol solution (guaiacol dissolved in 1% NaOH) containing 0.03–0.06 g guaiacol in boiling flask and evaporate solution just to dryness on steam bath in air current. For solid guaiacol compounds, weigh 0.06–0.10 g and transfer directly to flask. Complete determination by method for methoxyl group, 956.07C (see 12.1.16), beginning “Add 2.5 mL melted phenol from wide-tip pipet . . .”. Boil 30 min and titrate with 0.1M Na2S2O3, 942.27 (see A.1.13). 1mL0.1M I2, 939.13 (see A.1.07), = 0.00207 g guaiacol; 0.00229 g guaiacol carbonate; 0.00404 g potassium
guaiacol sulfonate.
References: JAOAC 21, 543(1938); 22, 721(1939).
CAS-90-05-1 (guaiacol)
