Analysis of faeces from stick insects and of their food plant Psidium guajava L.

The objective of this study was to see whether there were any differences in chemical constituents between the faeces of the stick insects, Hepteropteryx dilata, and the leaves of the plants Psidium guajava L. which the insects used for their food. Various extraction techniques, namely, Soxhlet, supercritical fluid extraction and purge and trap technique were used for the initial extraction of the chemical constituents. After initial extraction, the sample solutions underwent further purification by solid phase extraction (SPE) using magnesium silicate as the packing material. The treated samples were then injected onto either a high resolution capillary column (PTE-5™ or SPB-5) gas chromatograph (GC) with a flame ionisation detector or the high performance liquid chromatograph (HPLC) using a reversed phase C-18 column and detection by photodiode array detector. The compounds were identified with the help of gas chromatography coupled with a mass spectrometer. [Continues.]