摘要:

The redox reactions for a solid supported BLM electrode containing vinyl-ferrocene as an electron mediator in glyceryldioleate dissolved in squalene with a Teflon coated wire (Pt or SS) as a solid support have been investigated using cyclic voltammetry. The results have shown that (i) ferrocene can be very easily immobilized on the surface of a metallic electrode by the new supported BLM (s-BLM) system. This demonstrates that the s-BLM system offers a novel approach to the electrode modification by simple way of immobilization of compounds within BLM, and (ii) ferrocene in a bilayer lipid membrane increases about two orders of magnitude a potassium cyanide ion sensitivity of the platinum electrode.

ISSN:0003-2719    

DOI:10.1080/00032719308019867

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A novel method of eliminating interferences which arise from electrochemically active substances is described. The sample solutions are passed through a platinum tube electrode inserted into the sample flow line, where they are subjected to DC pre-electrolysis before delivery to a detector cell containing an enzyme electrode. This method was specifically developed to avoid the interference of monoamines and ascorbic acid when brain extracellular fluid is analysed for glutamate, glucose or lactate using an amperometric enzyme flow-cell. HPLC analysis of the reaction products showed that the pre-oxidation treatment efficiently removes the principal interferents, but leaves unaffected the analyte of interest.

ISSN:0003-2719    

DOI:10.1080/00032719308019868

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A modified method for a qualitative and quantitative analysis of theophylline in small blood serum volume (40 μl) was developed. According to this method, blood serum samples containing theobromine, as internal standard and caffeine from coffee consumption of the patients are centrifuged with acetonitrile to precepitate proteins. These serum samples are evaporated in a water bath at 45°C under stream of nitrogen to remove organic solvents. Then the samples were treated by solid—phase liquid extraction using C18Bond Elut cartridges preconditioned with methanol and water. The Chromatographic Separation was achieved on a Lichrosorb RP-18 10 μm ODS, 250×4 mm I.D. using methanol: 0.05M ammonium acetate (42:58) at a pH 7.0. The eluted components are detected at 272 nm. The retention time is 3.03 min for theobromine and 3.76 min for theophylline. Theophylline is quantitated by comparing theophylline peak areas with that of known quantities of the internal standard. The peak areas were found to be linearly related to theophylline concentrations providing a quantitative means of assaying theophylline in biological samples. The absolute detection limit is 0.501 ng and the linearity is observed up to 120.0 ng per 20 μl injection.

ISSN:0003-2719    

DOI:10.1080/00032719308019869

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A high performance liquid chromatography method with uv detection was developed for the quantitation of pseudoephedrine in human plasma in the presence of guaifenesin. The method involved a sample preparation technique based on solid phase extraction, followed by evaporation, reconstitution in water and injection into the HPLC system. The HPLC system consisted of a C8 column and a 70:30 V/V 0.03M sodium heptane sulfonate : acetonitrile as the mobile phase, ultraviolet detector at 220 nm and (±)α-(methylaminomethyl) benzyl alcohol (MAMBA) as the internal standard. The concentration-response relationship for pseudoephedrine was found to be linear over a concentration range of 25 ng/ml to 450 ng/ml, with a lower limit of detection of 20 ng/ml and a lower limit of quantitation of 25 ng/ml. The coefficient of variation for inter-day ranged from 5.7% to 10.5% with a mean of 8.3% over the concentration range of 70–450 ng/ml. The coefficient of variation for intra-day ranged from 1.1% to 5.1% with a mean of 4.4% over the same concentration range. The mean percent recovery of pseudoephedrine from plasma was 90%. In addition, this method was specific in the presence of guaifenesin.

ISSN:0003-2719    

DOI:10.1080/00032719308019870

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The cross-linked amylose is a semisynthetic polysaccharide realised by cross-linking amylose with epichlorohydrin, generating an insoluble three-dimensional structure based on polyglucose chains linked by α-1, 4-glucosidic bonds.

ISSN:0003-2719    

DOI:10.1080/00032719308019871

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Fluvoxamine was reacted with chloranil in aqueous ethanolic medium buffered at pH 9 to yield a complex with maximum absorption at 347 nm. The estimated molar absorptivity and stability constant of the complex were (1.30 ± 0.03) × 104L mol−1cm−1and (1.7 ± 0.5) × 104L mol−1respectively. Absorbance at (δmax) was linearly related to concentration of fluvoaxamine over the range 2 to 25 μg ml−1with a detection limit of 0.4 μg ml−1. The slopes of log-log plots of initial concentrations of fluvoxamine or chloranil vs. initial rate of color development were both unity. When the reaction was applied to commercial tablets (Faverin ρ −50) labeled to contain 50 mg of fluvoxamine maleate per tablet, the mean percentage found was 100.4 ± 1.0. Recovery experiments after standard additions and analysis of variance (ANOVA) were carried out to investigate the accuracy and precision of the proposed method. Reversed-phase high-performance liquid chromatography, (RP-HPLC), using μ-Bondapak C18(30 cm × 3.9 mm, i.d.) column, mobile phase consisting of 80% V/V-CH3CN + 20% v/v CH3COONa (0.01 M) buffer (adjusted to pH 3.5 with CH3COOH) and ultraviolet light detection was adopted for the quantitation of the commercial tablets. The results obtained by the RP-HPLC method were compared with those obtained by the proposed one.

ISSN:0003-2719    

DOI:10.1080/00032719308019872

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Simple spectrophotometric methods are described for the determination of diclofenac sodium in pharmaceutical preparations. The methods are based on the oxidation of the drug using reagents viz. ceric ammonium sulphate, dibromodimethylhydantoin, N-bromosuccinimide, and potassium bromate to yield coloured products with maximum absorbance at 450, 385, 385 and 495 nm and linear calibration graphs in the range of 2–16, 40–400, 50–500 and 50–600 μg.ml−1respectively. The methods are statistically validated and found to be accurate, sensitive and reproducible.

ISSN:0003-2719    

DOI:10.1080/00032719308019873

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Antihistamines, namely terfenadine and chlorphenoxamine hydrochloride, react with cobalt and toxiocyanate ions to give ternary complexes. These complexes are readily extractable in benzene to give a blue colour with maximum absorption at 625nm. which can be used for Quantitative spectrophotometric analysis. The mean recoveries for authentic samples of terfenadine and chlorphenoxamine hydrochloride were 99.9 ± 0.3 S.E. and 99.9 ± 0.3 respectively (P = 0.05). Alternatively, determination of cobalt content of the benzene extract via atomic absorption spectroscopy provides an indirect method for the determination of these antihistamines. The mean recoveries were 99.33 ± 0.3 and 99.19 ± 0.3 respectively. Both methods were applied to the analysis of pharmaceutical preparations, the results obtained agreed well with those obtained by official methods.

ISSN:0003-2719    

DOI:10.1080/00032719308019874

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The aim of this research was to standardize an high performance liquid chromatographic method for the determination of steroid hormones contained in commercially available pharmaceutical preparations. A Merck LiChrospher®100 RP–18 (5 μm) in LiChroCART®(125-4) column, a rotative valve injector (20 μL loop), ambient temperature, a mobile phase consisting of water-methanol and UV detection at 254nm and 212nm make possible the quantitative determination of dexamethasone acetate, prednisone, ethynylestradiol and norgestrel contained in pharmaceutical preparations.

ISSN:0003-2719    

DOI:10.1080/00032719308019875

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A method based on reversed-phase HPLC with UV detection is described for the determination of the impurity aminopropiophenone in phenylpropanolamine bulk drugs and compressed tablets. The only sample preparation necessary for the analysis is its dilution with the mobile phase. The practical detection limit is 30 ppm. The method has been applied for the analysis of commercial samples.

ISSN:0003-2719    

DOI:10.1080/00032719308019876

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor