title: Stacking and low-temperature technique in nonaqueous capillary electrophoresis for the analysis of 3,4-methylenedioxymethamphetamine.
abstract: Low-temperature and ambient-temperature nonaqueous stacking techniques in capillary electrophoresis (CE) are described for the first time. A low-temperature bath was used to control the temperature from ambient to subzero degrees, by which a novel hyphenated method, low-temperature bath-nonaqueous capillary electrophoresis stacking (LTB-NACE stacking) is demonstrated. 3,4-Methylenedioxymethamphetamine (3,4-MDMA) was determined at a concentration of 4.7 x 10(-6) M (at a 92.1% confidence level) by normal nonaqueous capillary zone electrophoresis (NACZE) and this was improved to 2.6 x 10(-8) M and 5.0 x 10(-9) M, respectively, when the NACZE stacking and LTB-NACZE stacking techniques were applied. The content of 3,4-MDMA in an illicit drug and a suspect urine sample was readily detected. Upon application of the LTB to the separation of isomers the resolution (R) for the separation of 2,3-/3,4-MDMA was improved from 0.6 (LTB, 22 degrees C) to 1.6 (LTB, -55 degrees C) and for (+)3,4-MDMA/(-)3,4-MDMA, from 0.4 (LTB, 25 degrees C) to 1.0 (LTB, -10 degrees C).
authors.affiliation: Department of Chemistry, National Taiwan Normal University, 88 section 4, Tingchow Road, Taipei, Taiwan.
authors.forename: Chih-Hsin
authors.initials: CH
authors.lastname: Tsai
authors.forename: Ching
authors.initials: C
authors.lastname: Fang
authors.forename: Ju-Tsung
authors.initials: JT
authors.lastname: Liu
authors.forename: Cheng-Huang
authors.initials: CH
authors.lastname: Lin
mesh_terms: D015104:3,4-Methylenedioxyamphetamine / Q000032:analysis*; D019075:Electrophoresis, Capillary; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet
chemical_list: D015104:3,4-Methylenedioxyamphetamine