Acknowledgements
This work was supported by TRF grant (no: TRG5680045)
supported by the Thailand Research Fund, Faculty of Science,
Prince of Songkla University. Partial support was also provided by
Department of Applied Science, Trace Analysis and Biosensor
Research Center (TAB-RC), the Center for Innovation in Chemistry
(PERCH-CIC) and the Higher Education Research Promotion and
National Research University Project of Thailand, the Commission
of Higher Education. We also give gratefully thanks to the Drug
Control Division, Food and Drug Administration Thailand for the
methamphetamine samples (Yaba).