Abstract
A colorimetrical procedure as a simplified method for the determination of so-called Fujiwara-reaction-positive metabolites of trichloroe thylene in urine was studied. The procedure is summarized as the following. The mixture containing 2.0. ml·of urine, 2.0 ml of 50 g/dl sodium hydroxide solution and 10.0 ml·of pure pyridine is shaken, and the mixture is then immersed for 15 minutes (12∼15 minutes) in a water bath at 70°C. Being cooled by running cold water for 1 minute, the colored pyridine layer is diluted twice of five times with 1:1 pyridine-water mixture. Colorimetry should be done within 5∼15 minutes at 530 mμ against the blank, control which has been prepare similarly starting from 2.0 ml·of water. The plug of cotton wool containing a piece of dry potassium hydroxide is not necessary during the whole procedure. The range obtained with this method reaches 80 mg/l when the pyridine layer is diluted twice, and 300 mg/l when diluted five times.
