Infrared Spectophotometric Determination of Allethrin

Insecticidal Activity and Structure, Some Barthrin Isomers and Their Toxicity to Houseflies in Space Sprays

“…With the latter the closeness of the relative toxicities together with the precision of their estimation does not permit a meaningful estimation of the proportion of the two fractions by this bioassay. That proportion is undoubtedly the same as in allethrin (6,12) when prepared according to the synthesis of Schechter, Green, and LaForge (17). Synerholm (18) stated that there is practically no difference in effectiveness, when tested against houseflies in the large group Peet-Grady chamber, between the piperonyl ester prepared from the dl-cis-trans acid and that from the d-trans acid.…”

“…A like calculation was made for the two pairs of isomers having the alcoholic component of the Z form. Then the proper trans and cis pairs were used in a similar equation, but with the trans-cis proportion of 80 to 20 as found in the synthetic acid by Freeman (6) with the spectrophotometric method. Thus, ratios of toxicity were obtained for 4-allethrolone dl-cistrans chrysanthemumic acid ester (1.594) and for the corresponding Z-allethrolone ester (0.279).…”

Use of Substitute Standards in Infrared Differential Spectrophotometry

“…In the differential method, employed when there is overlapping of absorption bands of major and minor components, the absorption due to the major component is essentially subtracted from the total absorption. The remaining absorption is due to the minor component (1)(2)(3)(4)(5)(6)(7)(8)(9). If, however, some of the impurity to be measured-for example, 1%-is present in the material to be used as standard, all determinations based on this standard will be 1% lower than the true value.…”