Method for quantitative determination of the four known juvenile hormones in insect tissue using gas chromatography—mass spectroscopy

Abstract A rapid, specific, and sensitive method is described for the extraction, purification, and quantitative determination of the three known juvenile hormones in insect tissue, using combined gas chromatography—mass spectroscopy (GC—MS) in the electron impact mode with selected ion-monitoring (SIM) for detection. A fourth, new, naturally occuring juvenile hormone was detected (and subsequently identified by other means) in this way. After initial extraction of biological material, a fast and efficient purification sequence utilizing non-aqueous reversed-phase and alumina mini-column chromatography achieves quickly a 10 3 –10 4 purification factor. Derivatization for analysis by acid-catalyzed methan-d 3 -olysis of the 10,11-epoxide moiety, followed by liquid chromatography separation of the resultant 11-methoxy-d 3 -10-hydroxy (methoxyhydrin) derivatives, completes the sample work-up. The methoxyhydrins are then directly analyzed by GC—MS (SIM). A tritium-labeled analogue is added during the extraction as an internal standard, which allows determination of recovery for each sample and simultaneously assures quantitative accuracy. Recoveries are 75–80%, and detection limits of 10–40 pg per gram of tissue are normally achievable.