Based on our previous report on N-alkylpyridinium isotope quaternization （NAPIQ） for the analysis of alcoholic and α,β-unsaturated ketone compounds, we have further applied NAPIQ method in the screening of hair lipids in drug abusers. Relative isotopic quantification was used for comparison of fatty alcohols between normal and drug abuse group, The NAPIQ strategy was proven to be a high-throughput method in the metabolic comparison studies of different group samples. The attached N-cationic pyridinium significantly improved the detection sensitivity for these fatty alcohols in matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometric （MALDI-FTMS） analysis. The experimental results showed that the levels of fatty alcohols in the hair of heroin abuse group decreased significantly compared with the normal groups, which may be the results of the inducing of peroxidation enzyme. NAPIQ was proven to be an effective and alternative method in the research of fatty alcoholic metabolism for drug abuse monitoring.
Pd-catalyzed oxidative coupling reaction was of great importance in the aromatic C--H activation and the for-mation of new C-O and C--C bonds. Sanford has pioneered practical, directed C-H activation reactions em-ploying Pd（OAc）2 as catalyst since 2004. However, until now, the speculated reactive Pd（Ⅳ） transient intermedi-ates in these reactions have not been isolated or directly detected from reaction solution. Electrospray ionization tandem mass spectrometry （ESI-MS/MS） was used to intercept and characterize the reactive Pd（Ⅳ） transient inter-mediates in the solutions of Pd（OAc）2-catalyzed oxidative coupling reactions. In this study, the Pd（IV） transient in-termediates were detected from the solution of Pd（OAc）2-catalyzed oxidative coupling reactions by ESI-MS and the MS/MS of the intercepted Pd（IV） transient intermediate in reaction system was the same with the synthesized au-thentic Pd（Ⅳ） complex. Our ESI-MS（/MS） studies confirmed the presence of Pd（Ⅳ） reaction transient intermedi-ates. Most interestingly, the MS/MS of Pd（Ⅳ） transient intermediates showed the reductive elimination reactivity to Pd（Ⅱ） complexes with new C-O bond formation into product in gas phase, which was consistent with the proposed reactivity of the Pd（Ⅳ） transient intermediates in solution.
Wei Zhu Haoyang Wang Haihui Peng Guosheng Liu Yinlong Guo
