Spectrofluorimetric determination of tetracycline and anhydrotetracycline in serum and urine.

A spectrofluorimetric method, involving alkaline degradation and formation of a magnesium complex, is described for the determination of tetracycline (TC) and anhydrotetracycline (ATC) in their mixed solution. Tetracycline is degraded and determined in alkaline solution. This treatment of ATC produces almost no fluorescence, but a fluorescent magnesium complex forms at pH 7.5. Several synthetic samples of TC and ATC, with TC:ATC ratios ranging from 50:1 to 1:50, were analysed. The recoveries of TC and ATC are about 71-76 and 61-63% in serum, respectively, and are all about 100% in urine.     

Fluorimetric determination of tetracycline and anhydrotetracycline

Summary A rapid fluorimetric method employing the complexes of Al³⁺ with tetracycline (TC) and anhydrotetracycline (ATC) has been used for the measurement of the concentrations of TC and ATC in about 10^–7–10^–6 mol/l. The assay offers simplicity and rapidly compared with other methods. The recoveries in the determination of synthetic samples are in the range of 95–103% for TC and 101–120% for ATC. Several determinations of TC and ATC in serum and urine have been carried out with satisfactory results.     

Spectrofluorimetric assay for acyl CoA-cholesterol acyltransferase

A sensitive assay for acyl CoA-cholesterol acyltransferase (EC 2.3.1.26) in rat liver microsomal and mitochondrial preparations is described. The lowered cholesterol concentration in the enzyme reaction with oleoyl CoA is determined spectrofluorimetrically by using the cholesterol oxidase/peroxidase/p-hydroxyphenylpropionic acid system. The assay requires as little as 20 μg of protein in the enzyme preparation.     

Spectrofluorimetric determination of benzodiazepinooxazoles

Summary A study of fluorescence properties of Cloxazolam and Oxazolam has been carried out. pK_a-values were calculated and a spectrofluorimetric method was developed in acidic hydroalcoholic medium for the determination of the drugs. The fluorescence intensity was linear with the concentration up to at least 6.00×10^–6 mol/l for Cloxazolam and 5.17×10^–6 mol/l for Oxazolam. Detection limits obtained were 2.91×10^–8 mol/l and 4.56×10^–8 mol/l for Cloxazolam and Oxazolam, respectively. Spectrofluorimetric methods were applied to the determination of both drugs in pharmaceuticals and errors lower than 2.5% were obtained. Spectrophotometric determination methods were also developed.     

Spectrofluorimetric determination of triethylenethiophosphoramide in blood

The method is based on a reaction of the ethyleneimine group with sodium sulfide, taurine and o-phthalaldehyde to give a fluorescent product. Triethylenethiophosphoramide (thioTEPA) can be determined in the range 9.4–945 ng in 100 μl of 1-propanol with a relative standard deviation of 2.3–4.7%. The method is applied to the determination of thioTEPA in rabbit blood plasma. The use of Extrelut 3 proved to be efficient for the clean-up of thioTEPA in plasma samples.     

荧光光谱法测定药物泼尼松

肾上腺皮质激素类药物泼尼松被浓硫酸氧化产生具有荧光特性物质。本文研究了泼尼松与浓硫酸的反应及表面活性剂对体系荧光强度的影响,据此建立了一种测定泼尼松含量的新方法。本法的检出限为2.79×10-8mol.L-1,相对标准偏差为1.8%,荧光强度与泼尼松浓度在5.58×10-7~3.90×10-6mol.L-1范围内呈良好线性关系。     

Spectrofluorimetric Determination of Boron in Soil

There is increasing interest in the determination of boron in several fields,for example, boron is an essential trace element in the physiology of plants.     

Spectrofluorimetric Determination of Antimony

Abstract

A spectrofluorimetric procedure for the determination of micromolar concentrations of antimony(III) was devised based on its reduction of cerium(IV) to produce fluorescent cerium(III). The method was optimized and the reaction was fast enough in hydrochloric acid media without the need for iodide or osmium(VIII) as catalysts. Linear calibration graphs were obtained in the range 1-10 10^?6M. The standard deviation for determining 5 × 10^?6M antimony(III)(10 times) was 1.43 × 10^?7M and the relative error was -3.4 %. The method was applied to the determination of antimony(III) in its mixture with antimony(V), total antimony was later determined after reduction with mercury metal in deoxygenated solutions. The affect several reducing agents on the determination of antimony-was also examined.     

荧光分光光度法测定中药中总蒽醌含量

在丙酮溶液中,蒽醌有较强的荧光性质,据此建立了中药中蒽醌的荧光测定新方法,其荧光强度与蒽醌含量在0．4～50μg／mL范围内呈良好的线性关系。     

Spectrofluorimetric Determination of Fenoterol in Pharmaceuticals

A highly sensitive spectrofluorimetric method was developed for the determination of fenoterol HBr in pharmaceutical preparations. The method is based on the nitrosation of fenoterol followed by reaction with 2‐cyanoacetamide in the presence of ammonia and measuring the produced fluorescence at 380 nm after excitation at 338 nm. All the variables affecting the reaction conditions were carefully studied and optimized. Linear calibration graph was obtained in the range of 0.064–0.64 μg.mL^?1 with a correlation coefficient of 0.9999 and a relative standard deviation of 0.83%. The method was applied to dosage forms and the results obtained agreed well with those obtained by the official method. A proposal of the reaction pathway was suggested.     

Spectrofluorimetric flow-injection determination of cyanide

The spectrofluorimetric determination of cyanide (0.1–20 μg ml^?1) with pyridoxal and pyridoxal-5-phosphate by a normal flow-injection method and a stopped-flow procedure is reported. The large number of interfering species in the normal method is significantly decreased by the use of the stopped-flow method. The relative standard deviation is <2%.     

Spectrofluorimetric Determination of Indenolol in Biological Fluids

Abstract

A simple sensitive and highly reproducible fluorimetric method for the routine determination of indenolol in biological fluids and in dosage forms has been developed.     

Spectrofluorimetric determination of 1,4-thienodiazepines

The fluorescence characteristics of four 1,4-thienodiazepines in aqueous and methanolic solutions and the effect of pH on fluorescence intensity are described. The pK_a values are calculated. Fluorimetric methods with limits of detection between 3 and 38 ng ml^?1 were developed, and applied for determinations of one drug in tablets, and the others in serum after extraction with a Sep-Pak C₁₈ cartridge.     

Spectrofluorimetric determination of formaldehyde in maple syrup

A quick and simple method was developed for determination of formaldehyde in maple syrup. In this method, formaldehyde reacts with Fluoral P to form a complex which is chemically extracted by isobutanol and determined by spectrofluorimetry. Performance, as gauged by the limits of detection (0.16 mg/kg) and quantitation (0.21 mg/kg), recovery (>79%), and variability (1.9-16.1%, depending on fortification level and class of syrup) were superior to the current official AOAC standard method.     

UV spectrophotometric flow-injection assay of tetracycline antibiotics retained on Sephadex QAE A-25 in drug formulations

A flow injection analysis system with solid phase spectrophotometric transduction has been developed for the assay of tetracycline (TC), doxycicline (DTC), oxycicline (OTC) and chlortetracycline (CTC). The packing material of the flow-through cell consists of Sephadex QAE A-25 resin on which tetracyclines are temporarily retained. The carrier itself acts as the desorbing solution. The measurements of the intrinsic absorbance of tetracyclines (1000 μl of sample volume) were made at 380 nm (TC, DTC and OTC) and 387 nm (CTC). The detection limits were found to be 0.069 (TC and OTC), 0.081 (DTC) and 0.121 (CTC) μg ml⁻¹ and the linear dynamic range extended between 0.5 and 12 (TC, DTC and OTC) and 1–20 μg ml⁻¹ (CTC). The relative standard deviations (n=10) ranged between 0.7 and 1.2%. A study of the potentially interfering species was carried out. Using the proposed method, tetracyclines were satisfactorily determined without any interference from excipients in pharmaceutical preparations.     

Spectrofluorimetric determination of clioquinol in pharmaceutical preparations

Summary The absorption spectrum of the nitrate radical (NO₃) in aqueous solution and the kinetic of the reactions with Cl^– and OH^– have been determined using laser-spectrometric techniques. The maximum absorption was found at 635 nm with a decadic absorption coefficient of =(530±110) l/mol·cm. At 298 K rate constants of k₁=(1.0±0.2)·10⁷ l/mol·s for the reaction with chloride and of k₂=(8.2±0.9)·10⁷ l/mol·s for the reaction with hydroxide were obtained.