SPECTROPHOTOMETRIC DETERMINATION OF SOME QUINONES

A simple, sensitive and selective spectrophotometric method has been d eveloped for determination of p-benzoquinone, tetrachloro-p-benzoquino ne, 1,4-napthaquinone and menadione (vitamin K-3) The method is based on reaction of these quinones with excess piperidine in ethylalcohol. The colored products obtained display a maximum absorption at lambda = 370-510 nm, depending upon the type of quinone used, E(1cm)(1%) in th e range 72-870. The effects of time, temperature and concentration on the nature of the reaction products have been investigated. The result s obtained with an average recovery of 93.75%.