Abstract
In-line solid phase extraction capillary electrophoresis-mass spectrometry (In-line SPE-CE/MS) has been developed for the screening of methamphetamine (MA) and amphetamine (AP) in hair. A Teflon tube packed with solid phase extractant was connected In-line to the capillary. The detection sensitivity of this method was about 100 times higher than that of common stacking methods. Since the filtrate of digested hair samples could be injected directly into the In-line SPE-CE/MS system, enzyme-based digestion techniques were investigated for the pre-treatment of hair samples. As a result, we found that hair was mostly digested with proteinase K, along with dithiothreitol, urea and TNE buffer (pH 8.0, 10 mM Tris, 100 mM NaCl, 1 mM EDTA) at 55℃ in an hour. Finally, hair samples spiked with MA and AP were analyzed by the developed In-line SPE-CE/MS method. The limits of quantification were 0.08 ng/sample for MA and 0.18 ng/sample for AP. In-line SPE-CE/MS is useful for the screening of MA in hair because MA in a single 1-cm hair strand is detectable at the concentration of 1.6 ng/mg hair.
