TY  - JOUR
AU  - Azizan, Kamalrul Azlan 
AU  - Baharum, Syarul Nataqain 
AU  - Ressom, Habtom W. 
AU  - Noor, Normah Mohd. 
PY  - 2012
TI  - GC-MS Analysis and PLS-DA Validation of the Trimethyl Silyl-Derivatization Techniques
JF  - American Journal of Applied Sciences
VL  - 9
IS  - 7
DO  - 10.3844/ajassp.2012.1124.1136
UR  - https://thescipub.com/abstract/ajassp.2012.1124.1136
AB  - Problem statement: Comparison and validation analysis of the conventional and power-adjusted Microwave-Assisted (MA) techniques of TMS derivatization using Gas Chromatography-Mass Spectrometry (GC-MS) and  Multivariate Analysis (MVA) of Partial Least Squares Analysis (PLS-DA). Further improvement of the conventional technique using vigorous shaking was tested and analyzed. Approach: Cross-validation and response permutation test of PLS-DA and S-plot of Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) was applied to the extracellular data of Lactococcus lactis, which was analyzed by GC-MS. The analyzed samples were firstly derivatized using Methoximination (MeOX) and N-methyl-N-trimethylsilyl fluoroacetamide (MSTFA) followed by conventional and power-adjusted Microwave-Assisted (MA) heating treatment. Results: The supervised PLS-DA applied to extracellular data failed to show the same clustering results between conventional and power-adjusted Microwave-Assisted (MA) techniques. It was suggested that the type of heating used in the derivatization techniques had affected the detection of groups of metabolites. Furthermore using the UV-scaling method, S-plot and Variable Importance for Projection (VIP), about 40 metabolites that were responsible towards the clustering and separation showed in PLS-DA score plots were successfully indicated. Conventional technique with vigorous shaking showed clear clustering according to groups compared to MA technique. Conclusion: Type of heating applied to the TMS derivatization showed effects towards the detection of metabolites where conventional technique indicated strong clustering compared to MA technique.