摘要:

In this series of papers, we are reporting on the rapid and sensitive detection of glycosides by high performance liquid phase separation methods such as high performance liquid chromatography (HPLC), capillary electrophoresis (HPCE), and capillary electrochromatography (CEC). In this report, which is the second in this series, we are describing the detection of glucosinolates via their acid hydrolysis degradation products. The rationale behind this approach is the lack of authentic standards, a fact that makes the routine analysis of glucosinolates rather difficult. Upon acid hydrolysis, glucosinolates hydrolyze, among other things, to carboxylated compounds that are reflective of the individual glucosinolates.

ISSN:1082-6076    

DOI:10.1080/10826079808000524

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Retention behavior of eleven neutral compounds in reversed phase capillary electrochromatography (RP-CEC) was investigated by using solvatochromic comparison method. The retention behavior in RP-CEC can be predicted quite well based on either multiple solvatochromic parameters of solutes or solvatochromic solvent polarity measurement ET(30) of mobile phase.

ISSN:1082-6076    

DOI:10.1080/10826079808000525

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Anions and cations in mineral water were simultaneously measured by capillary electrophoresis with a chelating agent. Ions studied were chloride, sulfate, sulfite, nitrate, nitrite, fluoride, formate, and acetate for anions, and magnesium, calcium, copper, lead and zinc for cations. They were separated in a fused-silica capillary (50 cm × 50 μm i.d.) filled with 300 mM borate buffer (pH 9.0) containing a cationic surfactant and a chelating agent as the electro-osmotic flow modifier and chelator, respectively. The method was successfully applied to the determination of ions in mineral water.

ISSN:1082-6076    

DOI:10.1080/10826079808000526

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper presents a trial and error method for determining the optimal values of k andaof the Mark-Houwink equation using polymers with different intrinsic viscosities ([η]) and molecular weight distribution (MWD) as standards. The values of k andafor polystyrene, EP-copolymer, polypropylene, polyethylene, polyvinylchloride, and polycarbonate, etc., have been determined with this method. The relative errors of the resultant [η] are below 6%, 4% or 3%. The viscosity-average molecular weight (Mv) of polystyrene standards agrees well with those of Pressure Chemical Co.; the weight- and number-average molecular weights of EP-copolymer coincide with that measured by using the low angle laser light scattering KMX-6 and the Knauer membrane osmometer, respectively. Thus, the method possesses high precision and can be applied to polymers with a wide range of molecular weight (MW) and molecular weight distribution (MWD).

ISSN:1082-6076    

DOI:10.1080/10826079808000527

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A new type of column packed with polystyrene gels which have a broad pore size distribution in a particle (henceforth referred to as the multipore column) was developed, and its performance was compared with the so-called linear column (henceforth referred to as the mixed-bed column). The chromatogram of the epoxy resin (Epikote 1009) on the multipore column showed a monomodal distribution, but the chromatogram on the mixed-bed column showed the inflection on the chromatogram at the molecular mass of about 10,000 as polystyrene equivalent. There was a big difference in the pore size distributions of gels packed in the two types of columns; the pore size distribution of the multipore column showed the trapezoid, while that of the mixed-bed column had sharp maxima for pores with a diameter of 0.08 μm. This difference in the pore size distribution may be the main reason for the inflection phenomenon, though the calibration curves of these two types of columns were almost the same. The multipore column also had the advantage of the mixed-bed column in the linearity of the calibration curve.

ISSN:1082-6076    

DOI:10.1080/10826079808000528

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Atmospheric pressure chemical ionization mass spectrometry (APCI-MS) coupled to reversed-phase high performance liquid chromatography (RP-HPLC) was used for direct analysis of intact triacylglycerols (TAGs) from hydroxy-containing plant oils. Castor bean oil,Lesquerella fendleriandLesquerella gordoniioils were separated into tri-hydroxy, di-hydroxy, mono-hydroxy, and non-hydroxy TAGs using the RP-HPLC method. The APCI-MS ionization source produced fragments representing loss of zero (protonated molecular ion), one, two, and three hydroxy groups. The primary fragments (base peaks) in the mass spectra resulted from loss of all hydroxy groups from the TAGs. Using the acetonitrile/methylene chloride solvent system, diagnostically important acetonitrile adducts were formed which allowed identification of the molecular weights of the hydroxy TAGs as well as confirmation of the number of hydroxy groups contained therein. A series of four adducts was formed: [M+23]+, [M+39]+, [M+54]+, and [M+59]+.

ISSN:1082-6076    

DOI:10.1080/10826079808000529

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

An isocratic technique was developed for the analysis of luteinizing hormone releasing hormone (LHRH) by high performance liquid chromatography (HPLC) using 210 nm UV detection, ZORBAX ODS column (4.6 mm × 15 cm), mobile phase (86% triethylamine phosphate buffer: 14% acetonitrile), and 1.5 mL/min flow rate. The coefficient of variation (C.V.) for precision and proportionality assays was lower than 5% for all concentrations studied. The detection limit of LHRH was 1 ng/mL.

ISSN:1082-6076    

DOI:10.1080/10826079808000530

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Identification of 3-hydroxykynurenine and xanthurenic acid and determination of 3-hydroxykynurenine transaminase activity using HPLC with electrochemical detection (HPLC-ED) are described using mosquito larval samples as testing materials. Results indicate that 3-hydroxykynurenine and xanthurenic acid in crude biological samples can be identified based on their electrochemical and chromatographic behaviors during HPLC-ED analysis. Xanthurenic acid is produced through transamination of 3-hydroxykynurenine, and identification of xanthurenic acid in the mosquito larval extract also leads to the detection of 3-hydroxykynurenine transaminase activity in this insect species.

ISSN:1082-6076    

DOI:10.1080/10826079808000531

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In this paper we describe the use of high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) as rapid and automated techniques for the analysis of DNA fragments generated by the polymerase chain reaction. Unlike traditional slab gel electrophoresis, these techniques allow a single-step qualitative and quantitative analysis of DNA. Furthermore, both techniques allow the detection of DNA fragments with high sensitivity in the subnanogram to microgram range. The complete automation of the instrumentation permit the unattended analysis of a great number of samples, and the direct entry of the data into a computer facilitates the processing of large numbers of PCR products. Furthermore, the HPLC technique allows the recovery with quantitative yield of pure DNA fragments suitable for other applications.

ISSN:1082-6076    

DOI:10.1080/10826079808000532

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A sensitive high-performance liquid chromatographic (HPLC) method has been developed and validated for the determination of the lactone and carboxylate forms of the novel antitumor drug irinotecan (CPT-11) and its active metabolite SN-38 in plasma. The instability of the compounds required immediate bed-side protein precipitation of plasma samples with an ice-cold mixture of methanol and acetonitrile. These methanolic extracts could be stored at −70°C for at least 3 months without degradation of the analytes. Separation of the lactone and carboxylate forms of CPT-11 and SN-38 was achieved on a C18reversed phase column with a mobile phase composed of a mixture of 0.1 M ammonium acetate, triethylamine, and acetonitrile (800:1:156, w/v/w) and 5 mM tetra-butyl ammonium phosphate. Detection was performed fluorimetrically. Within-run and between-run precision was always less than 11% in the concentration ranges of interest (1.0–100 ng/mL and 0.5–25 ng/mL, for CPT-11 and SN-38, respectively). The method was successfully implemented in a phase I clinical and pharmacokinetic trial in patients treated with a 14-days low dose continuous infusion of CPT-11.

ISSN:1082-6076    

DOI:10.1080/10826079808000533

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor