High-speed liquid chromatography employing an ultraviolet photometric detector has been applied to the simultaneous determination of hippuric and m-methylhippuric acids in urine. Reversed-phase partition chromatography is carried out on a ,tBondapak C18 column with methanol-water as the eluent system. This method obviates the necessity for isolation or reaction of these acids before assay. The ...

The biological monitoring for exposure to toluene is based on the measurement of urinary hippuric acid concentration (HA-U). In occupational health, workers exposed to toluene are examined for HA-U, because collection of urine samples is easy. The HA-U of some designers in a great household electrical products corporation who did not use toluene occupationally showed relatively high values. Fro...

ABSTRACr It is not known whether urinary excretion of hippuric acid (HA) or orthocresol (0-Cr) is to be preferred for the biological monitoring of workers with occupational exposure to toluene. To study this, 42 printing trade workers with more than 10 years' exposure to a mixture of organic solvents including toluene (0-20 ppm) and 43 control subjects matched by age, smoking habits, and living...

1. The fate of (-)-quinic acid has been investigated in 22 species of animals including man. 2. In man and three species of Old World monkeys, i.e. rhesus monkey, baboon and green monkey, oral quinic acid was extensively aromatized (20-60%) and excreted in the urine as hippuric acid, which was determined fluorimetrically. 3. In three species of New World monkeys, i.e. squirrel monkey, spider mo...

In 1963 Umberger and Fiorese (1) introduced a colorimetric method for HA,1 based on the color reaction of HA, dissolved in anhydrous pyridine, with BSC. Therefore, for applying their method to determine HA in urine, HA must first be extracted from the urine. We found that HA dissolved in water-pyridine (1:1, by vol) produces a red-orange color when BSC is added at room temperature. The absorpti...

The problem of the origin of the glycine available for hippuric acid synthesis after the administration of benzoic acid or its salts has been studied by many investigators with varying results. It should be borne in mind, in this connection, that all species of animals do not react similarly in response to the ingestion of benzoic acid. Thus the organisms of man (l), the rabbit (2), the goat (3...

Two experiments were conducted to examine the effect of benzoic acid in the diet of lactating sows on urinary pH and nutrient digestibility. In the first experiment, three levels of benzoic acid in the diet were tested (0.5, 1.0, and 2.0%), while in the second experiment only one dietary level of benzoic acid (0.5%) was used. In the second experiment, the urinary excretion of benzoic acid and h...