摘要:

The ion channel sensor is reviewed. The concept and sensing principle of this kind of sensor are briefly discussed. The fabrication of the sensing membrane and the application of the ion channel sensor in electroanalytical chemistry are evaluated. The future developing direction is also anticipated.

ISSN:0003-2719    

DOI:10.1080/00032719908542896

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

By electrochemical adsorption of glucose oxidase (GO) on a polypyrrole (PPy) nanotubular layer, a glucose biosensor has been fabricated. PPy microtubules can be synthesized by oxidative polymerization of the pyrrole monomer within the pores of a polycarbonate template. The activities of immobilized GO are investigated and the electrochemical properties are characterized by comparison of the GO electrode constructed by electropolymerization and doping.

ISSN:0003-2719    

DOI:10.1080/00032719908542897

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Simultaneous determination of D- and L-lactic acids was achieved using an apparatus containing two enzyme reactors and an octadecylsilica column placed between the two reactors in tandem in a single flow line. The enzymes used for the D-lactic acid assay were D-lactate dehydrogenase and glutamic-pyruvic transaminase, and for the L-lactic acid assay, L-lactate dehydrogenase and glutamic-pyruvic transaminase. The optimal concentrations of L-glutamic acid and NAD+in the carrier were determined. Of the buffers examined for use as a carrier medium, Tris buffer was found to be the most favorable. Under these optimal conditions, NADH due to D-lactic acid and that due to L-lactic acid could be observed separately in this apparatus. The calibration curve for D-lactic acid was linear in the range of 20 – 1000 μM, and that for L-lactic acid was 2 – 250 μM. This method was applied to analyze D- and L-lactic acids in several beverages that contained lactic acid bacteria. The D- and L-lactic acid content determined by the present method agreed with that determined by a commercially available test-kit method.

ISSN:0003-2719    

DOI:10.1080/00032719908542898

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A method to detect three anabolic steroids (boldenone, nandrolone and mesterolone) is presented. The anabolic steroids are isolated from equine plasma and urine by extraction with diethyl ether and C18Sep-Pak cartridge adsorption, respectively. The extracts obtained were derivatized with trifluoroacetyl anhydride and analyzed by GC/SIM/MS. The selected ion monitoring (SIM) mode was applied to increase the sensitivity and, when possible, the higher m/z ions were selected to improve identification. Stability of derivatives was good and compounds having hydroxy and conjugated ketone groups produced trifluoroacetyl ester derivatives that were also stable. Repeatability of the chromatographic analysis was evaluated on the basis of area repeatability, and the coefficient of variation obtained was lower than 4.4. The detection limit was 1 and 5 ng/ml for all the anabolic steroids studied in equine plasma and urine, respectively.

ISSN:0003-2719    

DOI:10.1080/00032719908542899

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A determination method of proteins with the limit of determination at nanogram levels is proposed by using a common spectrofluorometer to detect intensity of resonance light-scattering (RLS). Proteins, including bovine serum albumin (BSA), human serum albumin (HSA), pepsin (Pep), α-chymotrypsin (Chy), lysozyme (Lys) and cellulase (Cel), can combine with quercetin (QT) in the pH range 4.10∼4.35, and produce an enhanced RLS signal at 400.0 and 470.0 nm. Optimization conditions for the protein-QT interaction were tested. Depending on the concentration of QT, different proteins in the range 0∼4.5 μg ml−can be determined with the limit of determination at nanogram levels.

ISSN:0003-2719    

DOI:10.1080/00032719908542900

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

It is shown that the urine from workers exposed to mercury vapor contains practically only inorganic mercury (II), which can be easily determined by flow injection cold vapor atomic absorption spectrometry after adding only HNO3to the urine at room temperature. If organic mercury is suspected to be present, the sample is treated with KMnO4/H2SO4at 80°C - 100°C and total mercury is determined. On using HNO3only, 30 - 40 urine samples/h can be easily processed. The method presents good accuracy, precision and high sensitivity, achieving a limit of detection and a limit of quantification (L.O.Q), respectively, of 0.12 mg/L and 0.4 mg/L Hg (II) in the final dilution, using 1.0 mL urine. Urine reference SRM - NIST as well as samples from workers exposed to mercury vapor were analyzed by the proposed methodology.

ISSN:0003-2719    

DOI:10.1080/00032719908542901

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A multi-center study in the U.S. and China involving a total of 393 healthy subjects and 203 lung cancer patients was conducted to investigate the utility of DR-70™ immunoassay to detect lung cancer. Interference to DR-70™ test due to different disease states and blood collection procedures were also investigated. Benign and non-cancer diseases that can give rise to elevated DR-70™ levels included pneumonia, lung infection, burns, trauma due to surgery, arthritis, renal failure, sepsis etc. The study also showed that most consistent DR-70™ test results were obtained when blood was collected in vacutainers containing SST gel and clot activator. It is important that the DR-70™ test not be performed on samples of patients suffering from the aforementioned diseases. As these non-cancer disease states and improper blood collection procedures may lead to false positive results.

ISSN:0003-2719    

DOI:10.1080/00032719908542902

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A rapid, sensitive and stability indicating method for the determination of sparfloxacin (SPAR) by RP - HPLC has been developed on a Merck RP - Select B (5 μm; 12.5 cm x 4.0 mm) column using a mobile phase of water: acetonitrile: triethylamine (80 : 20 : 0.2 v/v) pH of which was adjusted to 2.6 with orthrophosphoric acid. The flow rate was 1 ml / min. and the detection was carried out at 304 nm using Waters 486 variable wavelength detector. The retention time forSPARwas 7.2 min. Linearity range was from 8 - 1000 ppm. The method showed good precision and accuracy when applied to two brands of tablets containingSPAR. In alkaline mediaSPARis stable where as it undergoes degradation in acidic and oxidising conditions generating different degradation products the nature of which is required to be established. The proposed method nicely separates the degraded products fromSPARand hence can be used as stability indicating method for the assay ofSPAR.

ISSN:0003-2719    

DOI:10.1080/00032719908542903

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Two two-component mixtures have been assayed using both Vierordt's method and ratio-spectra zero-crossing derivative spectrophotometric methods. Such mixtures are hydrochlorothiazide-spironolactone and hydrochlorothiazide-ramipril. These selected applications illustrate the relative ease and simplicity offered by ratio - spectra zero - crossing derivative spectrophotometry for the assay of two component mixtures with spectral interferences from matrix formulations.

ISSN:0003-2719    

DOI:10.1080/00032719908542904

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The use of multivariate spectrophotometric calibration is reported for the analysis of tablets containing the antibiotics sulfamethoxazole and trimethoprim, and a combination of the former two drugs with the analgesic phenazopyridine. The resolution of these mixtures has been accomplished without prior separation, derivatisation or use of nonaqueous solvents, with the aid of partial least-squares (PLS-1) regression analysis of electronic absorption spectral data. The analytes have been simultaneously determined with high accuracy and precision, and with no interference from tablet excipients.

ISSN:0003-2719    

DOI:10.1080/00032719908542905

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor