The determination of catechol, phenol, and hydroquinone in urine.

There have been many methods devised for the determination of urinary phenols based on calorimetric, gravimetric, and titrimetric procedures, but few of them include quantitative determinations of hydroquinone and catechol. These two phenols are produced in considerable amounts in animals exposed to benzene (1) and since we wished to study this problem further a convenient method of analysis had to be devised. The present paper describes a relatively simple method for the determination of catechol, phenol, and hydroquinone in urine. All titrations are made with a single solution and only one primary standard, potassium bromate, is required. Reagents2 M pyridine-acetate buffer. 160 ml. of pyridine and 10 ml. of glacial acetic acid diluted to 1 liter; pH 6.5. Lead acetate solution, 37.9 gm. of Pb(CH&00)2.3Hz0 per liter. Add 1 ml. of glacial acetic acid. Potassium iodate solution, saturated. Sodium hydroxide solution, 30 per cent. 0.2 I\; bromate-bromide solution. 5.568 gm. of KBr03 and 20 gm. of KBr per liter. 0.2 N sodium sulfite solution. 12.6 gm. of anhydrous Na2S03 per liter protected from air by CO2 and standardized frequently against the bromate solution. Ethyl alcohol, 95 per cent. Ether, washed with sodium hydroxide-potassium permanganate solution until alcohol and aldehyde are absent, and then distilled. Sodium bicarbonate, 10 grain tablets and powder. Hydrolysis of Phenolic Esters-Hydrolysis of the esters is carried out in the extraction tube in the inverted position, A, Fig. 1. Measure 25 ml. of centrifuged urine’ into an extraction tube and add 8 drops of concentrated sulfuric acid. Insert a rubber stopper and tip the tube in a horizontal position with the side arm up until t,he CO2 has