Determination of the release rate of aldehyde pheromones from insect lures by cold trapping and direct bioluminescence analysis.

A rapid and sensitive procedure for measuring the release rate of aldehyde pheromones from insect lures has been developed. Using cold traps to condense aldehydes released into an airstream, the amount of pheromone in the aqueous condensate could be directly analyzed using a luminescence assay based on the response of bacterial luciferase to long chain aldehydes. A high recovery (approximately 70%) of aldehyde pheromone in the cold trap was obtained even when amounts as low as 10 ng were released into the airstream. Trapping times as low as 5 min can be used and analysis requires only a few seconds after temperature equilibration of the sample. This approach was applied to measure the release rate of 11-tetradecenal from different spruce budworm lures as well as to demonstrate that the release of aldehyde from a lure containing [14C]-cis-9-hexadecenal correlated closely to the release rate of radioactive material.