U.S. flag

An official website of the United States government, Department of Justice.

Species and Age Determination of Blow Fly Pupae Based Upon Headspace Analysis

NCJ Number
Date Published
January 2017
45 pages
This project's goal was to develop a chemical method for determining the species and age of forensically relevant pupae, i.e.. blow fly (fly) pupae, as well as to determine the effects of biotic and abiotic factors on the resulting chemical profiles.

Chemical analysis of fly pupae was conducted, with attention to chemical markers of species and age. Also studied were the effect of genetic variation, temperature, humidity, light level, and diet. Chemo metric techniques capable of identifying patterns in the data and classifying unknown samples were used for the discrimination and classification of data. The six phases of research design and methods are described. The project succeeded in developing a new method for the analysis of pupal liquid extracts by total vaporization solid phase micro extraction (TV-SPME), with gas chromatography-mass spectrometry (GC-MS) serving as the instrumentation for analysis. The TV-SPME delivery technique renders approximately an order of magnitude improvement in sensitivity over traditional liquid injection methods, This may alleviate the need for rotary evaporation, reconstitution, collection of high performance liquid chromatography fractions, and many of the other pre-concentration steps that are common in the current literature. Attempts to analyze the volatile organic compounds (VOCs) of Phaormia regina pupae via HS-SPME were unsuccessful. For useful chemical information to be obtained, the analysis had to be preceded by an extraction to separate the fatty acids, hydrocarbons, sterols, and other compounds of interest from the matrix. This led to the development for the analysis of pupal liquid extracts by TV-SPME. 8 tables, 7 figures, and 67 references

Date Published: January 1, 2017