On-line thermal desorption-gas chromatography of intact insects for pheromone analysis

By using a thermodesorption system (TDS) together with a programmable tempe rature vaporizer (PTV) injector, we confirmed the composition of the sex ph eromone of Adoxophyes orana (Lepidoptera: Tortricidae) and Campylomma verba sci (Heteroptera: Miridae) from a single insect per analysis. Intact female s and males or pheromone glands were placed in the oven part of the TDS, wh ich was subsequently heated. The compounds released were transferred to the PTV, which was cooled to -150 degrees C. Injection was on a dual-column GC by heating the PTV rapidly to 250 degrees C. The major sex pheromone compo unds of A. orana were found only in the pheromone gland of females. Male an d female C. verbasci showed fingerprint-identical chromatograms, except for the two sex pheromone compounds, which were present only in females. No di stinct differences were found in compounds released from female and male Ly gocoris pabulinus (Heteroptera: Miridae). The advantages of this rapid meth od are the high sensitivity and the low degree of degradation and contamina tion. This technique was effective in analyzing small insects by gas chroma tography-mass spectrometry (GC-MS) without prior manipulation, such as solv ent extraction or distillation.