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

✍ Scribed by S. W. Head

Publisher
John Wiley and Sons
Year
1964
Tongue
English
Weight
456 KB
Volume
15
Category
Article
ISSN
0022-5142

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✦ Synopsis

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.

' Allethrin 90% ' analysed at 87.5%. The sample was distilled and the middle fraction b.p. 16z0j6p collected ; this analysed at 94.9% allethrin by the rapid D.N.P. method.

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