An Observation concerning the Bratton-marshall Diazo Reaction in Sulfonamide-free Urine.

I N 1939, Bi’atton and Marsimall (1) described a niethod for the quantitative ammalysis of sulfoimamides by coupling their diazonium salts with N-(1-naphthyl)-etimylenediamine to form an azo dye. Since then, the procedure has been used extensively for the determination of sulfonamide compounds jim blood ammd urine (2). Recently an occasion arose for the qualitative identification of sulfonamide compounds in urine. The sample was acidified with trichloi’oacetic acid and subjected to time usual coupling reaction. A bright pink color was takell a evidence of the presemmce of sulfonamides. However, a control um’ine run at time same time gave time same positive reaetioim. Time test was repeated with a number of urine samples from people who Imad not taken sulfa drugs recently, and positive reactions were obtained in all instances. These findilmgs were verified in 2 other laboratories employing the same procedure with different samples. A search of the literature revealed no ref ereimee to the fact that aim azo dye is formed witim this method in urine from people who have not ingested sulfa drugs. Absorption curves were ruim for time azo dye formed in sulfonamidefree urine and for a sulfadiazine solution, using time Beckman DK-2 recording spectrol)ilotonleter. A urine blank put timrougim time sanme re-