Sex Pheromones of Noctuid Moths. IX. Isolation Techniques and Quantitative Analysis for the Pheromones, with Special Reference to that of Trichoplusia ni (Lepidoptera: Noctuidae)12

Abstract

General extraction and purification steps for sex pheromones of noctuid moths are outlined as derived from the specific case of Trichoplusia ni (Hübner). These include an ether extraction, a falling-film distillation, preparative thin-layer chromatography, and preparative gas-liquid chromatography. Operating parameters are given for these procedures. Collecting only abdomen tips gave a 4-fold purification over extracting whole moths. In the case of T. ni the distillation was carried out at 100°C (0.5 mm) and 140° (0.1 mm) and resulted in a 10-fold purification. Thin-layer chromatography of the pheromones of T. ni, Autographa californica (Speyer), and Heliothis virescens (F.) all resulted in R_t's of 0.30 to 0.50 on silica gel, using benzene as the developing solvent. The retention time for the pheromone of T. ni was determined for 4 different gas-liquid chromatography columns. The time of biological activity was correlated with the electrical response of a hydrogen flame detector. Criteria for the purity of a gas chromatogram are given. A procedure for quantitative analysis for the pheromone of T. ni is given. This analysis made use of an internal standard. Apparatus and procedures are given for the collection of sub-milligram amounts from a gas chromatograph.