A simple method for preparation of high specific activity128I

The preparation of high specific activity¹²⁸I by neutron activation of KIO₃ is described. The¹²⁸I^– produced in a Szilard-Chalmers process is eluted with a water-isopropylamine mixture which dissolves only KI but not KIO₃.     

Simple potentiometric method for determination of specific activity of carrier-free125I with the aid of ion-selective membrane electrode

A simple potentiometric method for determination of specific activity of carrier-free¹²⁵I (NaI) has been elaborated. The method is based on the measurement of tracer amounts of iodide present in the¹²⁵I preparate, by using an ion-selective membrane electrode. The method presented is suitable in practice for rapid estimation of specific activity of carrier-free¹²⁵I preparation in cases where the knowledge of its numerical value is necessary.     

A simple method for a determination

The a term is a primary parameter that is used to indicate the deviation of the epithermal neutron distribution in the k ₀-standardization method of neutron activation analysis, k ₀-NAA. The calculation of a using a mathematical procedure is a challenge for some researchers. The calculation of a by the "bare-triple monitor" method is possible using the dedicated commercial software KAYZERO^®/SOLCOI^®. However, when this software is not available in the laboratory it is possible to carry out the calculation of a applying a simple iterative linear regression using any spreadsheets. This approach is described in this paper. The experimental data used in the example were obtained by the irradiation of a set of suitable monitors in the NAA #1 irradiation channel of the HANARO research reactor (KAERI, Korea). The results obtained by this iterative linear regression method agree well with the results calculated by the validated mathematical method.     

Immobilized enzymes - A simple calorimetric method for the determination of the catalytic activity

The results communicated in this paper show that rapid and reliable information about the activity of immobilized enzymes follows from calorimetric measurements. The study was done using spherical and plain carriers as well as different enzymes (urease, glucose-oxidase, invertase). The enzyme thermistor developed by Danielsson et al. was used as a measuring system. This measuring system was applied to investigate the activity of enzyme carrier complexes produced by the sol-gel technique. The influence of processing parameters could be pointed out at complexes of different forms (xerogel, gel on ceramic carrier, thin gel layers on foil, etc.). With the described calorimetric method, a fast and reliable technique for comparative determination of the activity of immobilized enzymes is available. A special advantage of this method is its variability in carriers and the generally applicable thermal measuring principle. Therefore, it seems useful for the development of new immobilization techniques.     

On the heterogeneity of125I-labelled proteins used as tracers in radioimmunoassay

The distribution of mono- poly- and unlabelled protein molecules in the radiolabelling mixture was calculated from probability point of view as a function of the radioiodine/protein ratio.     

A simple spectrophotometric method for the determination of minoxidil

A simple and sensitive method for the determination of minoxidil using 3-methyl-2-benzothiazolinone hydrazone (MBTH) and Fe(III) as the coloring agent is described. The method is sensitive to permit the determination of 0.5–4.5 μg ml⁻¹ of minoxidil at 500 nm. The accuracy and precision of the method were checked by high-performance liquid chromatography.     

A simple colorimetric method for the determination of ammonia in seawater

A method is proposed for the determination of trace amounts of ammonia in seawater. After calcium and magnesium have been chelated with CDTA, the blue colour obtained with hypochlorite and thymol-acetone is measured at 630 nm. The sensitivity is 1.3 ng NH₄⁺-N/cm².     

A specific method for the determination of polar allyl compounds

Summary A new quantitative method for the determination of allyl chloride was elaborated. The first part of the paper deals with some problems of the reaction mechanisms of allyl compounds with a solution of phloroglucinol in a hydrochloric acid medium. The second part of the work is concerned with the structure of the coloured product of condensation.Based on these informations a selective quantitative micromethod for the determination of allyl chloride was worked out. In this process the determination is not influenced by vinyl, propenyl and other similar derivates. The limit of possibility of the quantitative determination is 20 g.The author investigates also some problems of taking samples from the atmosphere. After the sucking through of a certain quantity of air this air is capable to eluate the matter which has been already caught in the absorptive solution if there was no chemical reaction after the absorption. This means, however, that we are not able to determine deliberately the quantity of the taken air; this quantity is to be determined in an experimental way.

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Zusammenfassung Eine neue quantitative Methode für die Bestimmung von Allylchlorid wurde ausgearbeitet. Im ersten Teil der Arbeit werden einige Probleme des Mechanismus der Reaktion von Allylverbindungen mit einer Lösung von Phloroglucin im Salzsäuremedium behandelt. Im weiteren wird die Struktur des farbigen Produkts der Kondensation bestimmt.An Hand dieser Erkenntnisse wurde eine selektive quantitative Mikromethode für die Bestimmung des Allylchlorids aufgestellt. Dabei haben Vinyl-, Propenyl- und andere verwandte Derivate keinen Einfluß auf die Bestimmung. Die Grenze der Möglichkeit einer quantitativen Bestimmung liegt bei 20 g.Der Autor befaßt sich in seiner Arbeit auch mit einigen Problemen der Probenentnahme aus der Atmosphäre. Nachdem eine gewisse Menge Luft durchgesaugt worden ist, kann die Luft den in der Absorptionslösung einmal bereits festgehaltenen Stoff eluieren, falls es nach der Absorption zu keiner chemischen Reaktion kommt. Dies bedeutet jedoch, daß wir das maximale Quantum der entnommenen Luft nicht nach Belieben bestimmen können, sondern daß es experimentell festgelegt werden muß.

     

A new method for the production of a magnetic immunosorbent used in radioimmunoassay and immunoradiometric assay

A method has been developed enabling the direct coupling of first or second antibody to finely dispersed magnetite (Fe₃O₄). The immunosorbent thus produced was applied in various radioimmunoassay systems (T3, T4, TSH, Cortisol) for the separation of bound and free antigens. The elimination of the need for precoating the magnetic particles with a polymer has several advantages. One of them lies in the ease of one-step production of the immunosorbent and other is the high antibody/magnetite ratio. The influence of the concentration of the immunosorbent and detergent (TWEEN 20 or TRITON X-100) on the assay parameters (Bo, NSB, etc.) has been systematically investigated and the optimum concentration of the magnetizable particles and detergent has been determined. The reliability of magnetic separation has been validated by comparing it with the conventional PEG separation method.This work was performed in the scope of the Coordinated Research ProgrammeAntibodies Immobilized on Magnetic Particles for Radioimmunoassay and Immunoradiometric Assay (No6 487CF) organized and supported by the International Atomic Energy Agency, Vienna. The authors express their thanks to the Agency for supporting this work.     

A simple visual method for the determination of phosphorus in environmental waters

Summary The visual method proposed here for the determination of phosphate ion in environmental water samples does not need any instrument. The highly sensitive method is based on the observation of the blue color produced as the result of ion association of phosphomolybdate and malachite green in acidic medium. Down to 10 ppb of phosphate-phosphorus can be determined by addition of 1 ml of reagent solution to 4 ml of sample in a test tube. The method has been effectively used for the determination of phosphate ion which is a nutrient for phytoplakton in brackish lakes and rivers.

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Einfaches visuelles Verfahren zur Phosphorbestimmung in Umwelt-Gewässern

     

A simple HPLC method for the determination of apigenin in mouse tissues

The flavone apigenin occurs in many leafy vegetables and fruits. It has been reported to have cancer chemopreventive efficacy in rodents. An HPLC method described previously for the determination of tricin, the dimethoxy cogener of apigenin, was modified and validated for measurement of apigenin in mouse tissues. Separation was carried out on a Hypersil-BDS C(18) column (4.6 x 250 mm) with an isocratic mobile phase of 55% methanol in 0.1 m ammonium acetate, pH 5.10, containing 0.27 mm disodium ethylenediamine tetraacetic acid. UV detection was at 336 nm, without interference from endogenous tissue compounds. The assay was linear in the range 25-400 ng/mL, 0.25-4 microg/mL and 2.5-40 microg/mL, with r(2) > 0.99 in all cases, for mouse plasma, liver and intestinal mucosa, respectively. Apigenin in mouse plasma, liver and intestinal mucosa was efficiently extracted with 0.1 m acetic acid in acetone. The assay recovery at low, medium and high concentrations was between 94.6 and 131.7% for all biomatrices, with a relative standard deviation of <10%. The lower limit of quantification for plasma was 25 ng/mL with a relative standard deviation of <15%. The method was used to measure the steady-phase apigenin levels in tissues of mice receiving apigenin in their diet.     

一种定量分析金属镀层中特定元素含量的简单方法

用光学的方法（如常见的X射线荧光分析法、发射光谱分析法^[1]等）分析固体样品中特定元素及其含量是常见的分析方法。相对于化学方法，它们的分析过程简单、迅速。笔者在分析样品中遇到了一些比较特殊的分析要求，例如在金属外镀了另外的合金，要求分析在镀层中特定元素的浓度。一种直接的方法是用X射线荧光做定量分析，可以给出镀层的元素含量。但X荧光定量分析需要特定的标样，对使用者存在一定的不便之处，而且设备也较贵。本研究采用普通的原子光谱分析法结合简单的数学推导，解决了上述问题。本方法也可以应用于普通的光学原子发射光谱分析。     

A simple and rapid chemical method for the determination of cephalosporins

A simple and rapid chemical assay for cephalosporins is described. It is a simple modification of the colorimetric determination of penicillins in which the narrow spectrum beta-lactamase (penicillinase) is replaced by a broad spectrum beta-lactamase (cephalosporinase) produced by Enterobacter cloacae. The method can be used for assay of fermentation broths as well as for pure cephalosporins.     

A simple spectrophotometric method for determination of isoxsuprine hydrochloride in pharmaceuticals

A spectrophotometric method has been developed for the determination of isoxsuprine hydrochloride and its dosage forms, based on its coupling reaction with diazotized sulphanilic acid. The yellow chromophore has an absorption maximum at 440 nm. Beer's law holds over the range 0.8-8 mu/ml in the final solution.