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field-amplified sample injection-Capillary Electrophoresis for the Determination of Bisphenol A, α-Naphthol and β-Naphthol in Drinks and Lake Water

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CHROMATOGRAPHIA 2016年第5-6期79卷 327-333页

作者： Peng, Xiaofeng Wang, Huawen Yang, Binbin Zhan, Xin Wu, Yiwei Hubei Normal Univ Coll Chem & Chem Engn Hubei Key Lab Pollutant Anal & Reuse Technol Hubei Collaborat Innovat Ctr Rare Met Chem Huangshi 435002 Peoples R China

To improve the sensitivity of capillary electrophoresis, field-amplified sample injection (FASI) was developed to determine bisphenol A (BPA), alpha-naphthol (alpha-NAP) and beta-naphthol (beta-NAP) in drinks and lake water. Parameters (sample matrix, concentration of NaCl, water plug length, sample injection time and voltage) affecting FASI have been systematically investigated. Under optimum conditions, the sensitivity was improved 17.1-, 15.8- and 9.9- fold for BPA, alpha-NAP and beta-NAP, respectively. The detection limits of BPA, alpha-NAP and beta-NAP were 0.071, 0.038 and 0.081 mu g mL(-1) and the proposed method has been successfully applied to detect BPA, alpha-NAP and beta-NAP in drinks and lake water with recoveries of 82.0-109.3 %.

关键词： field-amplified sample injection Capillary electrophoresis Bisphenol A alpha-Naphthol beta-Naphthol Drinks Lake water

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field-amplified sample injection coupled with pseudo-isotachophoresis technique for sensitive determination of selected psychiatric drugs in human urine samples after dispersive liquid-liquid microextraction

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ANALYTICA CHIMICA ACTA 2014年第0期811卷 88-93页

作者： Dziomba, Szymon Kowalski, Piotr Slominska, Agata Baczek, Tomasz Med Acad Gdansk Dept Pharmaceut Chem PL-80416 Gdansk Poland

A field-amplified sample injection (FASI) technique was elaborated for fast and sensitive determination of selected central nervous system drugs in human urine samples. Factors affecting the sensitivity enhancement, such as background electrolyte (BGE) and the analytical matrix composition were optimized and discussed. Pseudo-isotachophoresis (p-ITP) mechanism contribution in preconcentration mechanism was discussed. All separations were performed in uncoated fused silica capillaries 50 mu m x 57 cm at 22 kV. The optimized analytical matrix was composed of 0.25 mM HCOOH in 90% (v/v) methanol, while BGE contained 45 mM TRIS/HCl (pH 2.20). The head-column injection was performed in 0.25 mM HCOOH water solution (3 s, 3.45 kPa). sample was introduced into the capillary by electrokinetic injection (70 s, 5 kV) followed by short BGE plug (3 s, 3.45 kPa). Seven psychiatric drugs (olanzapine, prochlorperazine dimaleate, trifluoperazine dihydrochloride, perphenazine, promazine hydrochloride, clomipramine hydrochloride, and chlorprothixene hydrochloride) were separated in about 6 min. The elaborated method was additionally supported with dispersive liquid-liquid microextraction (DLLME) technique which in summary with FASI provided about 8000-13,000-fold sensitivity enhancement in comparison to the capillary zone electrophoresis (CZE) method with standard hydrodynamic injection (5 s, 3.45 kPa). (C) 2013 Elsevier B.V. All rights reserved.

关键词： Capillary electrophoresis field-amplified sample injection Pseudo-isotachophoresis Dispersive liquid-liquid microextraction Human urine samples

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field-amplified sample injection and in-capillary derivatization for sensitivity improvement of the electrophoretic determination of histamine

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JOURNAL OF CHROMATOGRAPHY A 2005年第2期1100卷 230-235页

作者： Zhang, LY Sun, MX Wuhan Univ Coll Life Sci Key Lab MOE Plant Dev Biol Wuhan 430072 Peoples R China

The feasibility of the combination of field-amplified sample injection (FASI) and in-capillary derivatization was explored for improving sensitivity of histamine in capillary electrophoresis (CE). Naphthalene-2,3-dicarboxaldehyde (NDA) was used as derivatization reagent. The reagent and sample was introduced by tandem mode. The derivatization was accomplished by at-inlet mode with standing time of 1.5 min. The combination of FASI and in-capillary derivatization was successfully achieved with about 400-fold concentration sensitivity enhancement compared to pre-capillary derivatization at the same set-up. The detection limit of concentration for histamine reached 1.25 x 10(-11) M by CE and fluorescence detection with S/N = 3. Parameters affecting FASI and in-capillary derivatization process including sample matrix, buffer concentration and reagent injection amount, were investigated. (c) 2005 Elsevier B.V. All rights reserved.

关键词： capillary electrophoresis field-amplified sample injection in-capillary derivatization histamine

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field-amplified sample injection in capillary zone electrophoresis for the pharmacokinetic research of trace risperidone and its major metabolite 9-hydroxyrisperidone in beagle dogs

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JOURNAL OF SEPARATION SCIENCE 2020年第17期43卷 3555-3564页

作者： Fan, Xianyu Li, Ji Wu, Shengyuan Jiang, Jingjing Wang, Jiajing Wang, Shuowen Lou, Yuefen Fan, Guorong Shanghai Jiao Tong Univ Sch Med Shanghai Gen Hosp Dept Clin Pharm Shanghai Peoples R China Kunming Med Univ Sch Pharmaceut Sci Kunming Yunnan Peoples R China Kunming Med Univ Yunnan Key Lab Pharmacol Nat Prod Kunming Yunnan Peoples R China Tongji Univ Sch Med Lab Drug Metab & Pharmacokinet Shanghai Peoples R China Tongji Univ Sch Med Shanghai Peoples Hosp 4 Dept Pharm Shanghai Peoples R China Shanghai Ctr Drug Evaluat & Inspect Shanghai Peoples R China Shanghai Key Lab Pharmaceut Metabolite Res Shanghai Peoples R China

This article describes a method for the simultaneous quantitation of risperidone and its major metabolite, 9-hydroxyrisperidone, in beagle dog plasma by field-amplified sample injection in capillary zone electrophoresis. The separation was carried out at 25 degrees C in a 48 cm x 75 mu m fused-silica capillary with an applied voltage of 20 kV using 60 mM NaH(2)PO(4)buffer (pH 3.6). The detection wavelength was 280 nm. Clean-up and preconcentration of plasma samples were conducted by 96-well formatted liquid-liquid extraction. In this study, this stacking technique provided a sensitivity enhancement of approximately 158 to 188 fold compared with the same sample without stacking. The method was suitably validated with respect to stability, specificity, linearity, lower limit of quantitation, accuracy, precision, and extraction recovery. Calibration curves exhibited good linearity (r(2 )> 0.995) over a wide concentration range of 2.5 to 200 ng/mL for both risperidone and 9-hydroxyrisperidone. The intra- and interday precisions at the three quality control levels were less than 11.40%. The intra- and interday accuracies ranged from 87.90 to 107.17% for risperidone and from 88.43 to 105.92% for 9-hydroxyrisperidone. All validation data were within the required limits. In conclusion, the method developed was successfully applied to pharmacokinetic studies of risperidone and 9-hydroxyrisperidone in beagle dogs.

关键词： 9-hydroxyrisperidone capillary zone electrophoresis field-amplified sample injection pharmacokinetics risperidone

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field-amplified sample injection and Solid-Phase Extraction for Sensitivity Improvement of Electrophoretic Determination of Indole-3-Acetic Acid and Indole-3-Butyric Acid in Food samples

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FOOD ANALYTICAL METHODS 2018年第4期11卷 1155-1162页

作者： Zheng, Yang Peng, Xiaofeng Wu, Yiwei Hubei Normal Univ Hubei Collaborat Innovat Ctr Rare Met Chem Hubei Key Lab Pollutant Anal & Reuse Technol Inst Adv MatColl Chem & Chem Engn Huangshi 435002 Peoples R China

A sensitive method has been established by using activated carbon as an adsorbent for extraction of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) from bean sprout, tomato, potato, cucumber, and wheat grain prior to field-amplified sample injection-micellar electrokinetic capillary chromatography (FASI-MEKC) detection. Parameters affecting FASI and solid-phase extraction (SPE) were optimized in detail. Under the optimal conditions, the sensitivity of SPE-FASI-MEKC for IAA and IBA was respectively improved by 32.5 and 29.7 times as compared with the direct MEKC. The detection limits were 4.1 for IAA and 5.3 ng mL(-1) for IBA with 4.9-5.2% RSD (n = 9, C = 0.03 mu g mL(-1)). The new method has been successfully applied to detect IAA and IBA in bean sprout, tomato, potato, cucumber, and wheat grain with the recoveries of 81.7-110%.

关键词： field-amplified sample injection Indole-3-acetic acid Indole-3-butyric acid Micellar electrokinetic capillary chromatography Solid-phase extraction

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field-amplified sample injection combined with CE for the enantiodetermination of cathinones in urine samples

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JOURNAL OF SEPARATION SCIENCE 2020年第14期43卷 2914-2924页

作者： Perez-Alcaraz, Albert Borrull, Francesc Calull, Marta Aguilar, Carme Univ Rovira & Virgili Dept Analyt Chem & Organ Chem Marcelli Domingo 1 E-43007 Tarragona Spain

This work presents a capillary electrophoresis methodology for the enantiodetermination of cathinones in urine employing a liquid-liquid extraction sample pretreatment. The cathinones were enantioseparated by adding a mixture of 8 mM 2-hydroxypropyl beta-cyclodextrin and 5 mM beta-cyclodextrin to the background electrolyte, which consists of 70 mM of monosodium phosphate aqueous solution at pH 2.5. field-amplified sample injection was used as preconcentration strategy to improve the sensitivity. We studied various parameters that affect this stacking strategy, in particular, the sample solvent and its pH, the presence or absence of a low conductivity solvent plug introduced before the sample injection, the nature and volume of this plug, and the voltage and time of the electrokinetic injection of the sample. The optimum conditions were achieved by injecting a plug of isopropanol:H2O 50/50 at 50 mbar for 5 s prior to the electrokinetic injection of the sample prepared in an aqueous solution of HCl 10(-6) M. The sensitivity enhancement factors were from 562 to 601 in terms of peak area and from 444 to 472 in terms of peak height. The method was validated by analyzing spiked urine samples, obtaining a linear range of 25 to 1000 ng/mL and limits of detection ranging from 15 to 45 ng/mL.

关键词： cathinones chiral capillary electrophoresis field-amplified sample injection urine analysis

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field-amplified sample injection and in-capillary derivatization for capillary electrophoretic analysis of metal ions in local wines

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MICROCHEMICAL JOURNAL 2007年第2期86卷 209-215页

作者： Santalad, Apichai Burakham, Rodjana Srijaranai, Supalax Grudpan, Kate Khon Kaen Univ Fac Sci Dept Chem Khon Kaen 40002 Thailand Chiang Mai Univ Fac Sci Dept Chem Chiang Mai 50200 Thailand

In-capillary derivatization and field-amplified sample injection (FASI) coupled to capillary zone electrophoresis (CZE) was evaluated for the analysis of metals (Co(II), Cu(II), Ni(II), and Fe(II)) using 2-(5-Nitro-2-Pyridylazo)-5-(N-Propyl-N-Sulfopropylamino)Phenol (Nitro-PAPS) as the derivatizing agent. For FASI, the optimum conditions were water as sample solvent, 1 s hydrodynamic injection (0.1 psi) of a water plug, 5 s of electrokinetic introduction (10 W) of the sample. The in-capillary derivatization was successfully achieved with zone-passing strategy in order tandem injection of Nitro-PAPS reagent (0.5 psi, 7 s), a small water plug (0.1 psi, 1 s), and metal ion introduction (10 W, 5 s). The solution of 45 mmol L-1 borate pH 9.7 and 1.0 x 10(-5) mol L-1 Nitro-PAPS containing 20% acetonitrile was used as the running buffer. The limit of detection obtained by the proposed method was lower than those from pre-capillary derivatization about 3-28 times. The recovery of the method was comparable to pre-capillary derivatization method. In-capillary derivatization-FASI-CZE was applied to analysis of metals in wine samples. The results were compared with those obtained by CZE with pre-capillary derivatization method and atomic absorption spectrometry (AAS). (c) 2007 Elsevier B.V. All rights reserved.

关键词： capillary zone electrophoresis field-amplified sample injection in-capillary derivatization metal ions nitro-PAPS wines

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field-amplified sample injection combined with capillary electrophoresis for the simultaneous determination of five chlorophenols in water samples

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ELECTROPHORESIS 2019年第14期40卷 1771-1778页

作者： Gao, Fangfang Chen, Xiaoxia Li, Xiaobin Li, Jinhua Liu, Huitao Chen, Lingxin Yantai Univ Coll Chem & Chem Engn Yantai Peoples R China Hebei Univ Sci & Technol Hebei Res Ctr Anal & Testing Shijiazhuang Hebei Peoples R China Chinese Acad Sci Yantai Inst Coastal Zone Res Res Ctr Coastal Environm Engn & Technol CAS Key Lab Coastal Environm Proc & Ecol Remediat Yantai Peoples R China

A sensitive method of CZE-ultraviolet (UV) detection based on the on-line preconcentration strategy of field-amplified sample injection (FASI) was developed for the simultaneous determination of five kinds of chlorophenols (CPs) namely 4-chlorophenol (4-CP), 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and 2,6-dichlorophenol (2,6-DCP) in water samples. Several parameters affecting CZE and FASI conditions were systematically investigated. Under the optimal conditions, sensitivity enhancement factors for 4-CP, 2-CP, 2,4-DCP, 2,4,6-TCP, and 2,6-DCP were 9, 27, 35, 43, and 43 folds, respectively, compared with the direct CZE, and the baseline separation was achieved within 5 min. Then, the developed FASI-CZE-UV method was applied to tap and lake water samples for the five CPs determination. The LODs (S/N = 3) were 0.0018-0.019 mu g/mL and 0.0089-0.029 mu g/mL in tap water and lake water, respectively. The values of LOQs in tap water (0.006-0.0074 mu g/mL) were much lower than the maximum permissible concentrations of 2,4,6-TCP, 2,4-DCP, and 2-CP in drinking water stipulated by World Health Organization (WHO) namely 0.3, 0.04, and 0.01 mu g/mL, respectively, and thereby the method was suitable to detect the CPs according to WHO guidelines. Furthermore, the method attained high recoveries in the range of 83.0-119.0% at three spiking levels of five CPs in the two types of water samples, with relative standard deviations of 0.37-8.58%. The developed method was proved to be a simple, sensitive, highly automated, and efficient alternative to CPs determination in real water samples.

关键词： Capillary electrophoresis Chlorophenols field-amplified sample injection Water samples

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field-amplified sample injection for the determination of albumin and transferrin in human urines by MEKC

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ELECTROPHORESIS 2009年第4期30卷 668-673页

作者： Wu, Yi-Wei Liu, Jun-Feng Xiao, Tang-Xin Han, De-Yan Zhang, Hai-Li Pan, Ji-Cheng Hubei Normal Univ Coll Chem & Environm Engn Coll Life Sci Huangshi 435002 Hubei Province Peoples R China Second Hosp Huangshi Dept Clin Lab Huangshi Peoples R China

An MEKC method combining field-amplified sample injection (FASI) has been developed for the analysis of albumin (Alb) and transferrin (TRF) in human urines. Various parameters affecting FASI preconcentration were optimized systematically. Under the optimum conditions, using electrokinetic sample injection for 90 s, the sensitivity was improved 77.6- and 45.3-fold for TRF and Alb, respectively, without loss of separation efficiency when compared with hydrodynamical sample injection for 5 s (0.5 psi). The detection limits of TRF and Alb were found to be 0.31 and 0.14 mg/L, respectively. The proposed method has been successfully applied to the determination of TRF and Alb in desalted urines from patients with kidney diseases, and the recoveries of TRF and Alb were 91.1-101.7%.

关键词： Albumin field-amplified sample injection Human urine MEKC Transferrin

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Development and validation of a capillary electrophoresis method for the determination of phenothiazines in human urine in the low nanogram per milliliter concentration range using field-amplified sample injection

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ELECTROPHORESIS 2005年第12期26卷 2418-2429页

作者： Lara, FJ García-Campaña, AM Alés-Barrero, F Bosque-Sendra, JM Univ Granada Fac Sci Dept Analyt Chem E-18071 Granada Spain

A capillary zone electrophoresis (CZE) method with ultraviolet-visible detection has been established and validated for the determination of five phenothiazines: thiazinamium methylsulfate, promazine hydrochloride, chlorpromazine hydrochloride, thioridazine hydrochloride, and promethazine hydrochloride in human urine. Optimum separation was obtained on a 64.5cm x 75 mu m bubble cell capillary using a buffer containing 150 mm tris(hydroxymethyl)aminomethane and 25% acetonitrile at pH 8.2, with temperature and voltage of 25 degrees C and 20 kV, respectively. Naphazoline hydrochloride was used as an internal standard. field-amplified sample injection (FASI) has been applied to improve the sensitivity of the detection. Considering the influence of parameters affecting the on-line preconcentration (nature of preinjection plug, sample solvent composition, injection times, and injection voltage) and due to the significant interactions among them, in this paper we propose for the first time the application of a multivariate approach to carry out the study. The optimized conditions were as follows: preinjection plug of water for 7 s at 50 mbar, electrokinetic injection for 40 s at 6.2 kv, and 32 pm of H3PO4 in the sample solvent. Also, a solid-phase extraction (SPE) procedure is developed to obtain low detection limits and an adequate selectivity for urine samples. The combination of SPE and FASI-CZE-UV allows adequate linearities and recoveries, low detection limits (from 2 to 5 ng/mL), and satisfactory precisions (3.07.2% for an intermediate RSD %).

关键词： capillary zone electrophoresis field-amplified sample injection phenothiazines solid-phase extraction urine analysis

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