摘要:

The Indole-3-acetic acid (IAA), ester-and amide-linked IAA in peach seeds were determined by a kinetic method based on the measurement of the Indole-α-pyrone derivative of the free acid. The free acid concentration was 355 ng/g of fresh weight, the concentrations for the ester-and amide-conjugated IAA were 877 and 1785 ng/g of fresh weight, respectively. The relative standard deviation was always less than 15%.

ISSN:0003-2719    

DOI:10.1080/00032718808066510

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A spectrophotometric method for the determination of cystine with o-phthalaldehyde (OPA) in the absence of thiol is described. When cystine is heated at 60[ddot]C for 30 min in a low excess of OPA (pH 9.5), a very stable derivative with 1:2 stoichiometry (cystine:OPA) and an absorption maximum at 335 nm (E = 4600) is formed. At pH < 1 the derivative is protonated (protonation constants: log K1= 5.88 and log K2= 3.70 at I = 0.1 and 20[ddot]C) and another absorption band at 440 nm (E = 3800) appears, which allows the determination of cystine in the presence of other amino acids.

ISSN:0003-2719    

DOI:10.1080/00032718808066511

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A high performance liquid chromatographic procedure is presented for the determination of ergotamine tartarate and cyclizine hydrochloride in pharmaceutical tablets. An aliquot of the sample is dissolved in methanol containing ethyl p-hydroxybenzoate as an internal standard and chromatographed on a 5 üm, C18, Hibar pre-packed, Lichrospher (250 mm × 4.0 mm i.d.), column using a mobile phase of 0.01 M ammonium acetate in acetonitrile: water: triethylamine (35:64:1) solution, the pH was adjusted to 3.7 with glacial acetic acid. The method was tested for linearity, recovery, and specificity and was found to be fast, sensitive, accurate and reproducible with a total elution time of six min.

ISSN:0003-2719    

DOI:10.1080/00032718808066512

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Two different UV-spectrophotometric modes, zero-order and first-derivative, have been applied for direct quantitation of aztreonam in bulk form and in some of its pharmaceutical formulations. Direct UV-measurement of aqueous solutions of the drug at about 285 nm exhibits significant linearity at a concentration range 1–5 mg/100 ml with a relative standard deviation ± 0.4%. The first-derivative (d'A) spectrophotometric measurements of the drug at 300 nm show results with relative standard deviation ± 0.6%. Drug assay gives percentage contents of 100.29 ± 0.95 and 99.16 ± 0.80 by applying zero-order spectrophotometry and 98.95 ± 0.52 and 98.70 ± 1.31 by adopting derivative spectrophotometry for aztreonam in 0.5-g and 1.0-g vials, respectively. The reproducibility and accuracy of both described methods have been assessed by applying the standard addition technique of the pure drug to each pharmaceutical formulation. The percentages of the mean recoveries of added drug were 100.28 ± 1.61 and 100.17 ± 0.90 for zero-order measurements and 100.02 ± 1.82 and 99.65 ± 1.05 for first-derivative spectrophotometry in case of 0.5-g and 1.0-g injectable samples, respectively.

ISSN:0003-2719    

DOI:10.1080/00032718808066513

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This paper describes a new high-pressure liquid chromatographic method used for quantitation of bumetanide in urine and plasma. Compared to previously reported methods, this assay offers the advantages of increased sensitivity, shortened sample preparation time and decreased instrumentation requirements. After addition of the 4-benzyl derivative of bumetanide as the internal standard, both urine and plasma underwent a single extraction with ethyl acetate at an acidic pH. The organic extract was separated, evaporated to dryness, reconstituted with methanol, and chromatographed using a reversed-phase C-18 radial compression cartridge with fluorescence detection. Sensitivity limits are approximately 1 ng of bumetanide per mL of plasma, with a coefficient of variation for identical samples never exceeding 6%. The method lends itself to pharmacokinetic and pharmacodynamic studies of bumetanide in humans following single therapeutic doses.

ISSN:0003-2719    

DOI:10.1080/00032718808066514

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A method is described for the quantitative analysis of acitretin and its isomer metabolite, or of isotretinoin and its principal metabolites, in human plasma. Following a simple extraction, the compounds are determined by reversed-phase high-performance liquid chromatography (HPLC) and detection at 350nm. This method was applied to plasma specimens collected from healthy volunteers and patients receiving single or multiple dose administrations of these compounds.

ISSN:0003-2719    

DOI:10.1080/00032718808066515

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The coupling of dual phase gas diffusion flow injection analysis with mass spectrometry has been shown to be feasible. This combined technique offers a high degree of selectivity and sensitivity. This technique was developed to determine whether volatile mixed arsenic selenium hydrides are formed in dual phase gas diffusion flow injection analysis hydride generation.

ISSN:0003-2719    

DOI:10.1080/00032718808066516

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

An improved zone sampling method where a small volume mixing device is placed before the fraction loop has been developed. In this method the samples are dispersed by the gradient chamber (device) and its dispersion profile of the injected samples is exponential. Therefore, the fraction difference caused by a lug of the fraction timing is small and consequently the optimization of system is very easy. The method was applied to the predilution of the samples in clinical flow injection analysis.

ISSN:0003-2719    

DOI:10.1080/00032718808066517

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The calibration response of a diquat bis(tetra-4-chlorophenylborate) (DQT. 2T4C1PB) based ISE for DQT was stable for 55 days. The ISE calibration slope and minimum detectable activity a(min) of DQT were in the ranges (S.D. in parentheses) 30(0.6) to 28(1.7) mV/log a (DQT) and 4(3) × 10−9M to 3(0.2) × 10−6M, respectively.

ISSN:0003-2719    

DOI:10.1080/00032718808066518

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The acetylcholine (ACh) receptor protein isolated fromTorpedoelectric organ was incorporated into asolectin liposomes and immobilized noncovalently on the surface of a Planar Interdigitated Capacitive sensor to produce an ACh receptor-based biosensor. Capacitance of the biosensor, which was stable in buffered saline, increased rapidly when ACh was added. The response was dosedependent and specific for ACh, and the biosensor did not respond to six other neurotransmitters. Impure receptor preparations containing ACh esterase produced a smaller signal in response to ACh but showed enhanced response after inhibition of ACh esterase with diisopropylfluorophosphate.

ISSN:0003-2719    

DOI:10.1080/00032718808066519

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor