Optimisation of headspace solid phase microextraction for gas chromatography time-of-flight mass spectrometry analysis of pit latrine key odorants

Abstract

Solid phase microextraction (SPME) fibre type and main experimental factors and their interactions for optimisation of a headspace solid phase microextraction-gas chromatography time-of-flight mass spectrometry (HS-SPME/GC-ToFMS) for the determination of four key odorants; butyric acid, dimethyl trisulphide, p-cresol and indole, in pit latrine faecal sludge were identified. Carboxen-polydimethylsiloxane (CAR/PDMS) was the SPME fibre that gave best extraction efficiency for all the odorants of interest in this study. All the factors and their interactions were statistically insignificant at α = 0.05 on the total peak areas of DMTS. The main effects; extraction temperature, extraction time and ionic strength were statistically significant at α = 0.05 on the total peak areas of butyric acid, p-cresol and indole. The two-way interactions of extraction temperature and extraction time, extraction temperature and ionic strength, and extraction time and ionic strength were also statistically significant at α = 0.05 on the total peak areas of butyric acid, p-cresol and indole. The sample pH and the interactions of sample pH and ionic strength were statistically significant at α = 0.05 for indole only.