Biochemical Studies of Toxic Agents

The determination ofthe so-called 'ethereal sulphate content' of urine is a simple analytical procedure, and there are many reports in the literature which show that the administration of phenols to experimental animals is followed by an increased excretion ofethereal sulphates in the urine. On the other hand, because of the difficulties which have usually been encountered, relatively few ethereal sulphates have been separated from urine. For many phenols, therefore, the belief that they are converted to arylsulphuric acids in the body is based solely on the observation that when administered to animals they give rise to an increase in the ethereal sulphate content of the urine. In the free state many arylsulphuric acids are unstable substances, and those which have been isolated from urine have usually been separated in the form of their alkali-metal salts. The separation of such salts from urine is not easily accomplished, however. In the course of investigations designed to find an alternative method of isolating arylsulphuric acids, Laughland & Young (1942) obtained evidence that these compounds can be separated from urine in the form of their salts with organic bases. At the same time, Barton & Young (1943) developed a simple method of preparing salts of this type, and in a study of the salts formed by a series of arylsulphuric acids with various organic bases they found that p-toluidine consistently yielded crystalline derivatives with properties well suited to the characterization ofthe arylsulphuric acids they were studying. Later work by Laughland & Young (1944) showed that the p-bromoaniline salts of a number of arylsulphuric acids have a low solubility in water. One outcome of these investigations was that other workers were led to employ organic bases in the separation and characterization of urinary steroid sulphates (cf. Klyne & Marrian, 1945; Klyne, Schachter & Marrian, 1948; Paterson & Klyne, 1948).