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Cheng-Huang Lin

4 papers in the library · 91 citations · publishing 2003-2008

Papers

A general approach to the screening and confirmation of tryptamines and phenethylamines by mass spectral fragmentation.

Talanta January 15, 2008 Bo-Hong Chen, Ju-Tsung Liu, Wen-Xiong Chen et al. 32 citations

Mass spectrometry methods—GC-EI/MS, LC-ESI/MS, and MALDI/TOFMS—were compared for analyzing 13 tryptamine and phenethylamine compounds, including AMT, DMT, 5-MeO-AMT, DET, DPT, DBT, DIPT, 5-MeO-DMT, 5-MeO-DIPT, methamphetamine, 3,4-MDA, 3,4-MDMA, and MBDB. Parent ions were difficult to obtain by GC/MS, but protonated molecular ions were clearly observed by ESI/MS and MALDI/TOFMS. Two major characteristic fragmentations occurred: alpha-cleavage (producing [3-vinylindole]+) and beta-cleavage (producing [CH2N(+)R(N1)R(N2)]). With ESI, alpha-cleavage was the major process; with MALDI, beta-cleavage dominated. The ionization efficiency and fragments from either cleavage depended on the degree of alkylation of the side chain nitrogen.

Identification of 2,5-dimethoxy-4-ethylthiophenethylamine and its metabolites in the urine of rats by gas chromatography-mass spectrometry.

Journal of chromatography. B, Analytical technologies in the biomedical and life sciences December 25, 2003 Li-Chan Lin, Ju-Tsung Liu, Shiu-Huey Chou et al. 29 citations

A gas chromatography-mass spectrometry method identified four metabolites of the psychoactive compound 2C-T-2 in rat urine after a single 20 mg/kg dose. The metabolites included 2-(4-ethylthio-2,5-dimethoxyphenyl)-ethanol, 4-ethylthio-2,5-dimethoxyphenyl acetic acid, and two isomeric acetamido metabolites. Based on these findings, a metabolic pathway for 2C-T-2 in rats is proposed.

The bioactivity of 2,5-dimethoxy-4-ethylthiophenethylamine (2C-T-2) and its detection in rat urine by capillary electrophoresis combined with an on-line sample concentration technique.

Journal of chromatography. B, Analytical technologies in the biomedical and life sciences November 25, 2004 Yu-Chih Chiu, Shiu-Huey Chou, Ju-Tsung Liu et al. 18 citations

Oral administration of 2,5-dimethoxy-4-ethylthiophenethylamine (2C-T-2) to mice decreased nitric oxide (NO) production by T and B lymphocytes in the spleen and T cells in the thymus, suggesting the drug may weaken immune defense functions. In rats, the parent drug was detected in urine using capillary electrophoresis with UV absorbance. Without sample concentration, detection limits were 4.5 and 5.0 μg/mL; with stacking and sweeping-micellar electrokinetic chromatography, limits improved to 19.2 and 9.1 ng/mL. After intra-peritoneal injection of 20 μg/g body weight in three male rats, 2.9 μg/mL and 0.25 μg/mL of 2C-T-2 were found in first- and second-day urine fractions.

Comparison of the separation of nine tryptamine standards based on gas chromatography, high performance liquid chromatography and capillary electrophoresis methods.

Journal of chromatography. A February 15, 2008 Man-Juing Wang, Ju-Tsung Liu, Hung-Ming Chen et al. 12 citations

Nine tryptamines were compared using GC, HPLC, and CE separation techniques. GC/MS and LC/UV-absorption detection limits ranged from 0.5 to 15 µg/mL and 0.3 to 1.0 µg/mL, respectively. CZE/UV-absorption gave detection limits of 0.5–1 µg/mL, while sweeping-MEKC improved detection dramatically to 2–10 ng/mL. Migration times ranged from 11 to 15 minutes by GC, 8 to 23 minutes by HPLC, and 20 to 26 minutes by sweeping-MEKC. The migration order of DMT, DET, DPT, and DBT follows molecular weight, while the order for AMT, 5-MeO-AMT, DIPT, and 5-methoxy-tryptamines can be altered by changing separation conditions.