Browsing by Author "Hsieh, YZ"

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Analysis of chitin oligosaccharides by capillary electrophoresis with laser-induced fluorescence
(2002-12-06)
Wang, CY
;
Hsieh, YZ
;
應用化學系
;
Department of Applied Chemistry
A method, using capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection for analyzing chitin oligosaccharides is described. Chitin oligosaccharides were derivatized with 9-aminopyrene-1,4,6-trisulfonate (APTS) via reductive amination at 37 degreesC for 16 h (optimized conditions). The APTS-chitin oligosaccharides were analyzed using either an acidic citric acid-phosphate buffer or an alkaline borate buffer. The effects of buffer types, buffer pH values, and buffer concentrations on the separation were examined. The analytes were successfully separated by using a pH 4.6 citric acid-phosphate within 19 min. The APTS-derivatized chitin monosaccharide (D-glucosamine) migrated first. The analytes were also completely separated by using a pH 9.0 borate buffer within 24 min. Moreover, the specificity of enzyme digestion on chitin polysaccharides using the optimized APTS labeling procedure and the CE-LIF method was demonstrated. (C) 2002 Elsevier Science B.V. All rights reserved.
Analysis of chlorophenoxy acid herbicides by cyclodextrin-modified capillary electrophoresis
(1996-09-20)
Hsieh, YZ
;
Huang, HY
;
交大名義發表
;
應用化學系
;
National Chiao Tung University
In this study, we developed a capillary electrophoresis method involving cyclodextrins to separate seven chlorophenoxy acid herbicides and their enantiomers. The cavity size and the concentration of cyclodextrins heavily influenced the migration time of individual herbicides. The peak resolution also varied with different concentration ratios of cyclodextrins. Adding 4 mM alpha-cyclodextrin and 1 mM beta-cyclodextrin in the buffer was found to produce the optimum experimental condition. The herbicides examined in this study could be successfully separated within 7 min; meanwhile, the two pairs of enantiomers could also be completely resolved. The calibration lines' correlation coefficients for the separation conditions were all above 0.996. The dynamic range of the analysis of seven herbicides was at least two orders, from 1 ppm to 100 ppm. Analyzing the seven herbicides by capillary electrophoresis posed the advantages of a high resolution, high separation efficiency and good reproducibility. By combining with a C-18 disk preconcentration method, the herbicides' detection limits in the environmental water were below 1 ppb.
Analysis of petroleum distillates from fire debris using supercritical fluid extraction with a two-level orthogonal array experimental design
(2002-08-01)
Huang, CT
;
Hsieh, YZ
;
應用化學系
;
Department of Applied Chemistry
A supercritical fluid extraction (SFE) method was developed in the present study as an effective sample pretreatment technique of petroleum distillates from fire debris. Three petroleum distillates were used as target analytes, including 95 unleaded gasoline, kerosene, and premium diesel. An orthogonal array (L16) experimental design was adopted to separately evaluate primary SFE experimental factors. The SFE efficiencies of petroleum distillates at various extraction conditions were examined and the optimized SFE conditions were identified. Experimental results demonstrated that the optimized SFE method not only provided an effective extraction method for the spiked sample, but also successfully recovered residues of petroleum distillates from fire debris.
Analysis of prostaglandins by micellar electrokinetic capillary chromatography
(1997-02-14)
Hsieh, YZ
;
Kuo, KL
;
應用化學系
;
Department of Applied Chemistry
This paper presents a rapid and reliable micellar electrokinetic capillary chromatography (MEKC) method to separate major prostaglandins and thromboxane B-2. The running buffer was modified with sodium dodecyl sulfate (SDS). The effects of the SDS concentration on the migration behavior of analytes was also examined. Moreover, the influences of electrolyte concentration and capillary temperature on the separation were investigated. In optimum conditions, seven major prostaglandins and thromboxane B-2 could be separated within 8 min. The relative standard deviations of the migration times (reproducibility) of the analytes were less than 0.82%.
Analysis of prostaglandins by micellar electrokinetic capillary chromatography
(1997-02-14)
Hsieh, YZ
;
Kuo, KL
;
交大名義發表
;
應用化學系
;
National Chiao Tung University
This paper presents a rapid and reliable micellar electrokinetic capillary chromatography (MEKC) method to separate major prostaglandins and thromboxane B-2. The running buffer was modified with sodium dodecyl sulfate (SDS). The effects of the SDS concentration on the migration behavior of analytes was also examined. Moreover, the influences of electrolyte concentration and capillary temperature on the separation were investigated. In optimum conditions, seven major prostaglandins and thromboxane B-2 could be separated within 8 min. The relative standard deviations of the migration times (reproducibility) of the analytes were less than 0.82%.
Analysis of Puerariae radix and its medicinal preparations by capillary electrophoresis
(1998-04-03)
Wang, CY
;
Huang, HY
;
Kuo, KL
;
Hsieh, YZ
;
應用化學系
This study presents a high-performance capillary electrophoresis (CE) method to analyze five constituents of Puerariae radix, an important crude herb used in Chinese medicine. Puerarin, daidzin, daidzein, genistein and biochanin A are the bioactive constituents of Puerariae radix. Herein, those analytes were successfully separated within 6 min using a pH 10.1 borax-NaOH buffer. The effects of pH value and concentration of the running buffer on the separation of the fie analytes were also examined. The relative standard deviations of the analytes' migration times were less than 0.38% under the optimized separation conditions. Notably, the correlation coefficients of the analytes' linear calibration graphs exceeded 0.998. Moreover, the amounts of the five constituents in three different Puerariae radix samples were determined by the CE method with a relatively simple extraction procedure. (C) 1998 Elsevier Science B.V.
CMOS chip as luminescent sensor for biochemical reactions
(2003-06-01)
Lu, U
;
Hu, BCP
;
Shih, YC
;
Yang, YS
;
Wu, CY
We describe a novel biochemical sensing method and its potential new biosensing applications. A light-sensitive complementary metal oxide semiconductor (CMOS) chip prepared through a standard 0.5-mum CMOS process was developed for measuring biochemical reactions. A light producing enzymatic reaction catalyzed by horseradish peroxidase (HRP) was designed as a platform reaction to determine the concentration of hydrogen. peroxide (H2O2) by the CMOS chip with a standard semiconductor parameter analyzer (HP4145). The kinetics of enzymatic reaction were determined and compared with a standard and sophisticated fluorometer (Hitachi F-4500) in a biochemical laboratory. Similar results were obtained by both instruments. Using glucose oxidase as an example, we further demonstrated that the HRP platform can be used to determine other H2O2 producing reactions with the CMOS system. The result points to an important application of the CMOS chip in biological measurements and in diagnosis of various health factors.
Determination of cinnamaldehyde, cinnamic acid, paeoniflorin, glycyrrhizin and [6]-gingerol in the traditional Chinese medicinal preparation Kuei-chih-tang by cyclodextrin-modified micellar electrokinetic chromatography
(1997-05-30)
Huang, HY
;
Kuo, KL
;
Hsieh, YZ
;
應用化學系
;
Department of Applied Chemistry
This study presents a cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) technique with a multi-wavelength detection method to determine specific components in Kuei-chih-tang. Kuei-chih-tang, a Chinese medicinal preparation, is composed of five crude herbs, i.e., Cinnamomi ramulus, Paeoniae radix, Glycyrrhizae radix, Zingiberis rhizoma and Zizyphi fructus. The effects of SDS and gamma-cyclodextrin on the analytes' migration behavior were examined. The selected components were successfully separated within 10 min using a pH 10.0 borax-NaOH buffer containing 20 mM SDS and 2 mM gamma-cyclodextrin. The correlation coefficients of the linear calibration graphs for the analytes exceeded 0.993. Moreover, the optimized CD-MEKC method was employed to analyze four different Kuei-chih-tang samples. (C) 1997 Elsevier Science B.V.
Determination of metabolites of benzene, toluene, ethylbenzene, and xylene by beta-cyclodextrin modified capillary electrophoresis
(2003-01-01)
Wang, CY
;
Huang, CT
;
Hsieh, YZ
;
應用化學系
;
Department of Applied Chemistry
A beta-cycloclextrin modified capillary electrophoresis method for determining the metabolites of benzene, toluene, ethyl benzene, and xylene (BTEX) is described. Creatinine and uric acid were also examined as reference compounds. By employing a 20 mM, pH 10.0 borax-NaOH buffer containing 7-mM of beta-CD, ten analytes could be successfully separated within 10 min on a 50 pm capillary at an electric potential of 25 kV. The effects of pH and the concentration of beta-CD on the separation of the ten analytes are discussed. Under optimized separation conditions, the relative standard deviations for the migration times of the analytes were less than 0.93% and the correlation coefficients of the analyte linear calibration graphs exceeded 0.998 in the range from 1 to 300 mug/mL. Analyses of BTEX metabolites in urine samples from both occupationally exposed and non-exposed subjects are shown herein. BTEX metabolites were determined in the urine sample of a gas station attendant.
Determination of preservatives in food products by cyclodextrin-modified capillary electrophoresis with multiwavelength detection
(1997-04-25)
Kuo, KL
;
Hsieh, YZ
;
應用化學系
;
Department of Applied Chemistry
A high-performance capillary electrophoretic method with multiwavelength detection was developed to analyze frequently used preservatives. The effects of alpha-cyclodextrin and beta-cyclodextrin on migration behaviours of nine preservatives were investigated. The preservatives were successfully separated within 9 min using a borax-NaOH buffer (pH 10.0) modified with 2 mM alpha-cyclodextrin. In optimized separation conditions, the reproducibilities of the migration times of the preservatives were satisfactory (R.S.D. values <0.99%). The correlation coefficients of the linear calibration graphs for the preservatives, ranging between 5 and 500 mu g ml(-1), exceeded 0.991. By employing this reliable capillary electrophoresis method, preservatives in three different food products were determined.
Determination of puerarin, daidzein, paeoniflorin, cinnamic acid, glycyrrhizin, ephedrine, and [6]-gingerol in Ge-gen-tang by micellar electrokinetic chromatography
(1997-09-30)
Huang, HY
;
Hsieh, YZ
;
應用化學系
;
Department of Applied Chemistry
This paper presents a micellar electrokinetic chromatography (MEKC) method with diode-array detection to analyze for seven major components in the traditional Chinese medicinal preparation of Ge-gen-tang. Those analytes were successfully separated within 9 min using a pH 9.0 berate buffer containing 20 mM Sodium dodecyl sulfate at 30 degrees C. Experimental results indicated that the relative standard deviations of the analytes' migration times were <0.43% and the correlation coefficients of the analytes' linear calibration graphs exceeded 0.996. The quantities of the seven components in four different Ge-gen-tang samples were determined by the MEKC method coupled with a relatively simple extraction method. (C) 1997 Elsevier Science B.V.
Determination of saikosaponins by micellar electrokinetic capillary chromatography
(1997-01-24)
Hsieh, YZ
;
Huang, HY
;
應用化學系
;
Department of Applied Chemistry
In this study, we examine the feasibility of determining saikosaponins a, b1, b2, c and d, i.e., the bioactive components in Bupleuri Radix, using the micellar electrokinetic capillary chromatography technique. Results obtained from using different anion surfactants, bile salt or sodium dodecyl sulfate (SDS), are also compared. By using bile salt as a pseudostationary phase, the baseline separation of saikosaponins is observed; however, the detection limit is unfavorable. Whereas the baseline resolution of saikosaponins is achieved after adding gamma-cyclodextrin in the SDS running buffer. In addition, another separating method is developed with the mixed micellar system of SDS and Brij 35 containing gamma-cyclodextrin. The contents of saikosaponins in traditional Chinese medicinal prescriptions, such as Sheau Chair Hwu Tang, Bupleuri Radix plant and Chair Hwu San are analyzed by one of the above methods. The entire separation can be completed within 9 min by these methods. The R.S.D. values of the migration times are all below 1%. Moreover, the detection limits of saikosaponins vary from 7 to 33 mu g/ml.
Determination of saikosaponins by micellar electrokinetic capillary chromatography
(1997-01-24)
Hsieh, YZ
;
Huang, HY
;
交大名義發表
;
應用化學系
;
National Chiao Tung University
In this study, we examine the feasibility of determining saikosaponins a, b1, b2, c and d, i.e., the bioactive components in Bupleuri Radix, using the micellar electrokinetic capillary chromatography technique. Results obtained from using different anion surfactants, bile salt or sodium dodecyl sulfate (SDS), are also compared. By using bile salt as a pseudostationary phase, the baseline separation of saikosaponins is observed; however, the detection limit is unfavorable. Whereas the baseline resolution of saikosaponins is achieved after adding gamma-cyclodextrin in the SDS running buffer. In addition, another separating method is developed with the mixed micellar system of SDS and Brij 35 containing gamma-cyclodextrin. The contents of saikosaponins in traditional Chinese medicinal prescriptions, such as Sheau Chair Hwu Tang, Bupleuri Radix plant and Chair Hwu San are analyzed by one of the above methods. The entire separation can be completed within 9 min by these methods. The R.S.D. values of the migration times are all below 1%. Moreover, the detection limits of saikosaponins vary from 7 to 33 mu g/ml.
Effects of analyte-matrix interactions on supercritical fluid extraction efficiencies of polycyclic aromatic hydrocarbons
(1997-04-21)
Hsieh, YZ
;
Chang, AC
;
交大名義發表
;
應用化學系
;
National Chiao Tung University
The effects of different variables for analyte-matrix interactions on supercritical fluid extraction (SFE) efficiencies of polycyclic aromatic hydrocarbons (PAHs) were investigated. The results indicated that the main factors for describing a matrix, e.g., the chemical properties of the matrix surface, surface area, and pore size, could significantly influence the analyte-matrix interactions. The polarizability of an analyte was demonstrated to be yet another significant factor for influencing analyte-matrix interactions. Either elevating the temperature or adding modifiers could also increase the SFE recoveries. The underlying mechanisms of these variables are discussed.
Fabrication of microfluidic devices using dry film photoresist for microchip capillary electrophoresis
(2006-04-14)
Tsai, YC
;
Jen, HP
;
Lin, KW
;
Hsieh, YZ
;
應用化學系
An inexpensive, disposable microfluidic device was fabricated from a dry film photoresist using a combination of photolithographic and hot roll lamination techniques. A microfluidic flow pattern was prefabricated in a dry film photoresist tape using traditional photolithographic methods. This tape became bonded to a poly(methyl methacrylate) (PMMA) sheet with prepouched holes when passed through a hot roll laminator. A copper working electrode and platinum decoupler was readily incorporated within this microchip. The integrated microchip device was then fixed in a laboratory-built Plexiglas holder prior to its use in microchip capillary electrophoresis. The performance of this device with amperometric detection for the separation of dopamine and catechol was examined. The separation was complete within 50 s at an applied potential of 200 V/cm. The relative standard deviations (RSD) of analyte migration times were less than 0.71%, and the theoretical plate numbers for dopamine and catechol were 3.2 x 10(4) and 4.1 x 10(4), respectively, based on a 65 min separation channel. (c) 2005 Elsevier B.V. All rights reserved.
High-performance capillary electrophoretic analysis of synthetic food colorants
(1998-03-01)
Kuo, KL
;
Huang, HY
;
Hsieh, YZ
;
應用化學系
;
Department of Applied Chemistry
A high-performance capillary electrophoresis method with diode-array detection has been developed for analysis of synthetic food colorants. The influence of buffer composition on the separation of the food colorants was examined, as were the effects of alpha-, beta- and gamma-cyclodextrins on analyte migration behavior. Eight food colorants were completely separated within 10 min using pH 9.5 borax - NaOH buffer containing 5 mM beta-cyclodextrin. Experimental results indicate that the relative standard deviations of analyte migration times were < 0.88% under the optimized separation condition. Correlation coefficients of the linear calibration plots of the analytes exceeded 0.998. The method was suitable for determination of the quantities of synthetic food colorants in ice cream bars and fruit soda drinks.
On-line preconcentration and determination of ketamine and norketamine by micellar electrokinetic chromatography - Complementary method to gas chromatography/mass spectrometry
(2006-04-14)
Jen, HP
;
Tsai, YC
;
Su, HL
;
Hsieh, YZ
;
應用化學系
We have investigated a rapid, simple, and highly efficient on-line preconcentration method using in micellar electrokinetic chromatography (MEKC) for the analysis of abused drugs. Ketamine is an anesthetic that has been abused as a hallucinogen. We applied the sample sweeping technique first to ketamine and its major metabolite, norketamine, and separated the analytes with MEKC. Several of the sweeping MEKC parameters to effect successful separations, such as the concentration of sodium dodecyl sulfate (SIDS), the injection time, and the applied voltage were optimized. The improvements in the number of theoretical plates under the different separation conditions are presented clearly in a three-dimensional representation. The limits of detection were 2.8, 3.4, and 3.3 ng/mL for ketamine, norketamine, and ketamine-D-4, respectively. The enrichment factor for each compound was within the range of 540-800. Experimental results are in agreement with those of analysis conducted by gas chromatography/mass spectroscopy (GC/MS). Therefore, we believe that sweeping, combined with MEKC, represents a suitable complementary method to GC/MS for use in clinical and forensic analyses of ketamine and norketamine. (c) 2005 Elsevier B.V. All rights reserved.
Optimization of the headspace solid-phase microextraction for determination of glycol ethers by orthogonal array designs
(2002-11-15)
Huang, CT
;
Su, YY
;
Hsieh, YZ
;
應用化學系
;
Department of Applied Chemistry
A headspace solid-phase microextraction (HS-SPME), in conjunction with gas chromatography-flame ionization detection for use in the determination of six frequently used glycol ethers at the mug/l level is described. A 75 mum Carboxen-polydimethylsiloxane fiber was used to extract the analytes from an aqueous solution. Experimental HS-SPME parameters such as extraction temperature, extraction time, salt concentration and sample volume, were investigated and optimized by orthogonal array experimental designs. The relative standard deviations for the reproducibility of the optimized HS-SPME method varied from 1.48 to 7.59%. The correlation coefficients of the calibration curves exceeded 0.998 in the mug/l range of concentration with at least two orders of magnitude. The method detection limits for glycol ethers in deionized water were in the range of 0.26 to 3.42 mug/l. The optimized method was also applied to the analysis of glycol ethers in urine and blood samples with the method detection limits ranged from 1.74 to 23.2 mug/l. (C) 2002 Elsevier Science B.V. All rights reserved.
Restriction mapping of genes by capillary electrophoresis with laser-induced fluorescence detection
(1997-04-01)
Peck, K
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Wung, SL
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Chang, GS
;
Yen, JJY
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Hsieh, YZ
Restriction mapping is one of the essential steps in gene analysis and molecular biology studies, Slab gel electrophoresis is the traditional way to separate DNA fragments for restriction mapping, However, slab gel electrophoresis does not provide sufficient resolution as required in many mapping applications, and the use of radioisotopes in traditional mapping methods creates health hazards, In the present study, capillary electrophoresis coupled with laser-induced fluorescence detection and a modified partial digestion mapping procedure was developed to map DNA fragments. By using capillary electrophoresis, a restriction map of a genomic lambda phage clone of human interleukin 5 receptor a chain (IL5R alpha) gene was constructed, The IL5R alpha gene was analyzed to have five XbaI enzyme cutting sites at locations 1370, 2290, 2950, 5430, and 9330, The system was further characterized by using pBluescript SK(+) phagemid DNA as a model, Using a sequence-derived map as a reference, the pBluescript SK(+) restriction map constructed by capillary electrophoresis had an accuracy greater than 90%.
Separation of retinoids by micellar electrokinetic capillary chromatography
(1997-02-14)
Hsieh, YZ
;
Kuo, KL
;
交大名義發表
;
應用化學系
;
National Chiao Tung University
In this study, we have developed a micellar electrokinetic capillary chromatography (MEKC) method with diode-array detection to separate five important retinoids, including retinol, retinal, retinoic acid, retinyl acetate and retinyl palmitate. These very hydrophobic retinoids are successfully separated with phosphate buffer containing sodium deoxycholate (SDC) and Brij 35 as the micellar pseudostationary phase. The effects of SDC and Brij 35 concentration on the migration behavior of the five retinoids are also discussed. The relative standard deviations of the migration times of the retinoids are less than 1.9% in the optimized separation condition. Moreover, a direct extraction method without saponification is employed to extract retinyl esters in pharmaceutical products. The ranges of recoveries are 95%-99% for retinyl esters with less than 2% relative standard deviations. Therefore, retinyl esters in pharmaceutical products can be determined by combining the direct extraction and the MEKC methods.