A Study on the Variability of Fresh Diesel from Service Station in Kota Bharu Using GC-MS and PCA

The variability of the diesel population in Kota Bharu was investigated in this paper. Discrimination of diesel samples was performed by gas chromatography-mass spectrometry (GC-MS). Subsequent statistical analyses of these data were performed including principal component analysis. A data set containing 41 peaks from extracted ion chromatograms normalized to n-22 was used and diesel sample distribution pattern was visualized in the score plot. The results show that GC-MS analyses were able to discriminate different fresh diesel samples into a few groups. Among the diesel samples collected from service station on the same day, Petronas diesels were significant different from Caltex, Mobil, Esso and most of Shell samples. Diesel samples collected from a selected service station over a time scale of weeks varied significantly by GC-MS. Care must be exercised when interpreting data showing similarities or differences in GC-MS profile as to the source where the sample could have come from.