Rapid method for the determination of ‘total pyrethrins’ by spectroscopy of their 2,4‐dinitrophenylhydrazones

Abstract

A rapid method for the analysis of pyrethrum extract and pyrethrum formulations containing synergists and emulsifying agents has been developed. The pyrethrins are converted into their 2,4-dinitrophenylhydrazones and, wwithout chromatography, the optical density at 377 mp determined. The optical density is converted into pyrethrin concentration by using the value E = 28,000 for the molecular extinction coefficient of the pyrethrin dinitrophenylhydrazones.