This paper describes a novel method in which solvent microextraction（SME） is followed by on-line back-extraction-field amplified sample injection（OLBE-FASI） in capillary zone electrophoresis（CZE）.The water-immis...This paper describes a novel method in which solvent microextraction（SME） is followed by on-line back-extraction-field amplified sample injection（OLBE-FASI） in capillary zone electrophoresis（CZE）.The water-immiscible solution sample, sealed with water plug in the sample vial,was used for direct electroinjection. The water plug with moderate content of organic solvent,low-conductivity,and the presence of a small（amount） of H+ provided the highest sensitivity for analyzing positively chargeable compounds,such as cocaine and thebaine.The linear range was 0.040—4,0.040—2 μg/mL,with the square of the correlation coefficient(r2)>0.997,respectively.Detection limits were in the range of 5—10 ng/mL.展开更多
A method of on\|line ultrasensitive chemiluminescence detection with capillary electrophoresis for Co(Ⅱ) is reported. Using our newly developed capillary electrophoresis with chemiluminescence detection system and no...A method of on\|line ultrasensitive chemiluminescence detection with capillary electrophoresis for Co(Ⅱ) is reported. Using our newly developed capillary electrophoresis with chemiluminescence detection system and novel mixing mode of the reagents, the effects of field\|amplified sample injection on detection limits of metal ions were studied in detail. The sub\|fmol/L level(0.13 fmol/L, 1.6 ymol) detection of cobalt ions in ultradilute solution was performed. The separation of fmol/L level Co(Ⅱ) and trace amounts of Ni(Ⅱ) was performed successfully.展开更多
The field-amplified sample injection behavior of cationic tripropylamine(TPA) and anionic proline(Pro) at a positive voltage in capillary electrophoresis with tris(2,2′-bipyridyl)ruthenium(Ⅱ) electrochemiluminescenc...The field-amplified sample injection behavior of cationic tripropylamine(TPA) and anionic proline(Pro) at a positive voltage in capillary electrophoresis with tris(2,2′-bipyridyl)ruthenium(Ⅱ) electrochemiluminescence(ECL) detection system was studied. In the case of TPA, where the sample solution was prepared in pure water, ECL sensitivity can be improved by 100 times compared to conventional electroinjection method when a positive voltage was applied. Under the same positive voltage condition, anionic Pro prepared in electrolyte solution can also be injected and concentrated in the column when a water plug was injected before sample introduction. The sensitivity and efficiency were enhanced by 10 and 46 times, respectively. The behavior of cationic TPA can be explained by conventional field amplified sample injection(FASI)theory. When the ratio of resistivities of sample matrix to that of separation buffer is less than 1(γ1), the conventional FASI theory can also be used to explain the improved sensitivity and theoretical plates of Pro. The sensitivity, plate, velocity(v ep), amplified factor(v ep/v 0 ep) and peak variance(σ 2) of Pro reach maximum at optimized water plug length and buffer concentration of the sample matrix.展开更多
A novel method for fast determination of ethylendiamine （EDA） in Aminophylline Tablets has been developed by small-sized capillary electrophoresis with amperometric detection （small-CE-AD） coupled with field-ampli...A novel method for fast determination of ethylendiamine （EDA） in Aminophylline Tablets has been developed by small-sized capillary electrophoresis with amperometric detection （small-CE-AD） coupled with field-amplified sample injection （FASI）. Under the optimum conditions, EDA and four aliphatic diamine homologs （1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane and 1,6-diaminohexane） could be well separated within 6 min at a separation voltage of 2.0 kV in an acetate buffer solution of pH 3.8 with low limit of detection （LOD） of 1.3 × 10^-11 g/mL for EDA （S/N=3）. The proposed method has been successfully applied to direct deter- mination of EDA content in different batches of Aminophylline Tablets. The method does not require off-line preconcentration and derivatization steps, which should find wide application fields including pharmaceuticals as an alternative to conventional and microchip CE approaches.展开更多
文摘This paper describes a novel method in which solvent microextraction（SME） is followed by on-line back-extraction-field amplified sample injection（OLBE-FASI） in capillary zone electrophoresis（CZE）.The water-immiscible solution sample, sealed with water plug in the sample vial,was used for direct electroinjection. The water plug with moderate content of organic solvent,low-conductivity,and the presence of a small（amount） of H+ provided the highest sensitivity for analyzing positively chargeable compounds,such as cocaine and thebaine.The linear range was 0.040—4,0.040—2 μg/mL,with the square of the correlation coefficient(r2)>0.997,respectively.Detection limits were in the range of 5—10 ng/mL.
文摘A method of on\|line ultrasensitive chemiluminescence detection with capillary electrophoresis for Co(Ⅱ) is reported. Using our newly developed capillary electrophoresis with chemiluminescence detection system and novel mixing mode of the reagents, the effects of field\|amplified sample injection on detection limits of metal ions were studied in detail. The sub\|fmol/L level(0.13 fmol/L, 1.6 ymol) detection of cobalt ions in ultradilute solution was performed. The separation of fmol/L level Co(Ⅱ) and trace amounts of Ni(Ⅱ) was performed successfully.
文摘The field-amplified sample injection behavior of cationic tripropylamine(TPA) and anionic proline(Pro) at a positive voltage in capillary electrophoresis with tris(2,2′-bipyridyl)ruthenium(Ⅱ) electrochemiluminescence(ECL) detection system was studied. In the case of TPA, where the sample solution was prepared in pure water, ECL sensitivity can be improved by 100 times compared to conventional electroinjection method when a positive voltage was applied. Under the same positive voltage condition, anionic Pro prepared in electrolyte solution can also be injected and concentrated in the column when a water plug was injected before sample introduction. The sensitivity and efficiency were enhanced by 10 and 46 times, respectively. The behavior of cationic TPA can be explained by conventional field amplified sample injection(FASI)theory. When the ratio of resistivities of sample matrix to that of separation buffer is less than 1(γ1), the conventional FASI theory can also be used to explain the improved sensitivity and theoretical plates of Pro. The sensitivity, plate, velocity(v ep), amplified factor(v ep/v 0 ep) and peak variance(σ 2) of Pro reach maximum at optimized water plug length and buffer concentration of the sample matrix.
基金This work was financially supported by the National Natural Science Foundation of China （No. 21205042）, the Special Funds for the Development of Major Scien- tific Instruments and Equipment （No. 2011YQ15007205）, and the Fundamental Research Funds for the Central Universities.
文摘A novel method for fast determination of ethylendiamine （EDA） in Aminophylline Tablets has been developed by small-sized capillary electrophoresis with amperometric detection （small-CE-AD） coupled with field-amplified sample injection （FASI）. Under the optimum conditions, EDA and four aliphatic diamine homologs （1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane and 1,6-diaminohexane） could be well separated within 6 min at a separation voltage of 2.0 kV in an acetate buffer solution of pH 3.8 with low limit of detection （LOD） of 1.3 × 10^-11 g/mL for EDA （S/N=3）. The proposed method has been successfully applied to direct deter- mination of EDA content in different batches of Aminophylline Tablets. The method does not require off-line preconcentration and derivatization steps, which should find wide application fields including pharmaceuticals as an alternative to conventional and microchip CE approaches.
