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In the industrial practice Howard mould count (Howard, 1911) is used for the estimation of mould contamination of foods. It was developed originally for the investigation of mould contamination of tomato purée. It is also used nowadays for quality control purposes for other food products as well. Recently this constitutes the basis of the acceptance of the finished products in international trade. This technique demands experts with a lot of practice and morphological proficiency. The investigation makes use of eyes and so the tiredness of the investigator can cause uncertainties.The possibility of other methods for the determination of mould contamination of tomato purée was investigated to replace the Howard method. The NIR technique — as a rapid, non-destructive, reagentless and accurate method — was anticipated as a suitable method for the mentioned purpose. Canned tomato purée had been allowed to become mouldy then the sample was blended with non-mouldy samples in different ratio, so a series of tomato purées containing known amounts of mouldy purée was prepared. Howard mould counts and ergosterol content — another mould contamination relating value — was used as reference for NIR calibration.At quantitative investigation better results were obtained using ergosterol values. The best correlation coefficient (R=0.93) and the smallest standard error of calibration (SEC=0.008 mg g−1 ergosterol) was achieved with triangular smoothing and second derivation of the spectra. At qualitative investigation Polar Qualification System (PQS) was used. Clusters between samples with low and high ergosterol levels could be separated.

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Abstract  

Detailed results are presented in this paper for all analytical quality control samples distributed by the IAEA including a new animal muscle intercomparison material of very low chromium content, and an attempt is made to draw some conclusions regarding likely sources of analytical error.

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Abstract  

A quartz pyrohydrolysis apparatus designed for the safe handling of pyrophoric carbide nuclear fuel samples while separating C1 and F trace impurities for quality control analysis is described. It has several advantages over the commonly used pyrohydrolysis apparatus. Performance of the apparatus during routine analysis of a large number of nuclear fuel samples has been found to be quite satisfactory.

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The laboratory for INAA in Delft processes several thousands of samples per year for multielement determinations in a variety of matrices. Samples are measured on different spectrometers (using well-type and coaxial detectors), by different persons and using many different analytical protocols. All these results should be consistent with each other with respect to the degree of accuracy, i.e., the combination of trueness and precision. A rigorous internal quality control program has been implemented with automatic on-line evaluation. Annually an additional evaluation of the internal quality control results is carried out using statistical techniques. The Naji-plot approach has proven to be an important graphical tool since it provides direct insight in both trueness and precision. It is demonstrated that the degree of accuracy of the results obtained under the large variety of operational parameters is under constant improvement.

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Thermoplastic polymers quality control

DSC baseline optimisation for heat of fusion measurements

Journal of Thermal Analysis and Calorimetry
Authors: R. Castelli, M. Deplano, and P. M. Rota

A technique is proposed for improving the accuracy of the heat of fusion of semicrystalline polymers by DSC. The results of three commercially available instruments are compared.

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The thermal to epithermal neutron flux ratio (f) and the deviation of the epithermal neutron spectrum from the 1/E shape (α) are essential parameters for the correct application of k 0-standardized neutron activation analysis. Several methods are applied for the determination of f and α. They are based on Cd-covered multi-monitor or on bare-irradiations methods. The recently developed and characterized synthetic multi-element standards (SMELS) were designed as a validation tool for the proper implementation of the k 0-NAA method in a laboratory. In particular, SMELS Type III contains Au and Zr, thus allowing the direct determination of f and α. It could, therefore, replace the traditional flux monitors. Furthermore, it could be used as a quality control material to monitor the stability of the irradiation facility and the detector. This paper presents the accuracy of the f and α determination and the feasibility of quality control using SMELS for irradiation channel Y4 of the BR1 reactor.

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Summary

The stems of Uncaria rhynchophylla (Miq.) ex Havil have a long history of use in traditional Chinese medicine to treat diseases and improve health. There is evident evidence that alkaloids constituents are mainly responsible for the beneficial effects of this plant medicine. The amounts of the major bioactive alkaloids in this plant vary widely with species, habitat, and as such, and establishment of a high-performance liquid chromatography (HPLC) fingerprint for quality control of this herbal medicine is of particular importance. The most alkaloids are used for medicine treatment and research. On the basis of the chromatographic data, a consistent HPLC fingerprint pattern containing 15 common peaks was obtained. Among these common peaks, four were identified as rhynchophylline, isorhynchophylline, corynoxeine, and isocorynoxeine. On the basis of this HPLC fingerprint and principal-components analysis, the quality of fifteen samples from different producing areas of China was objectively assessed. To summarize, the data described in this study offer valuable information for quality control and proper use of U. rhynchophylla (Miq.) ex Havil.

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Quality Control (QC) of radiopharmaceuticals is important, providing products of high standards. The current study refers to an enzymic radioiodination method applied to the labeling of antibodies used in nuclear medicine and to the respective QC procedures. Readily available materials such as125I, polyclonal immunoglobulin G (IgG) and a collection of simple chromatographic techniques helped establish a QC protocol suitable for the radiochemical evaluation of radioiodinated biomolecules. A high pre-purification radiolabeling yield (90%) for total protein was detected by paper electrophoresis (PE) and size exclusion chromatography (SEC), but only the inclusion of SDS-PAGE confirmed the existence of “self-iodination” of lactoperoxidase (LPO) and revealed the true radiolabeling yield for125I-IgG (79%).

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Abstract  

The 90YCl3 radionuclide precursor (solution of 90Y3+ in diluted HCl) of high purity and high specific activity is already commercially produced and successfully used in nuclear medicine. At the Nuclear Physics Institute ASCR, the 90YCl3 radionuclide precursor is prepared using extraction 90Sr/90Y generator (technology of centrifuge extractors with di-2-ethylhexylphosphoric acid, D2EHPA).1 Its radionuclidic, radiochemical, and chemical purity were examined and specified. The procedure developed for labeling of DOTA-Tyr3-octreotide (DOTATOC) with carrier-free 86/90Y by Rösch 2 at the Institute of Nuclear Chemistry of the University Mainz was optimized and modified in our Department of Radiopharmaceuticals at NPI ASCR as standard labeling test (SLT) for analytical purposes. The SLT as a method for 90YCl3 radionuclide precursor quality control determining its labeling efficiency using ITLC SG chromatography is described and proposed thereinafter. The labeling-efficiency of the tested batches of our product reached more than 95%.

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A simple and accurate reversed phase high-performance liquid chromatography (HPLC) method has been developed for the estimation of uniformity of dosage units, and delivered dose uniformity tests of fluticasone propionate and salmeterol xinafoate in samples obtained during the fine particle mass determination, using C8 Luna (2) 100A 100 × 4.6 mm, 5 micrometer particle size in gradient mode, with mobile phase comprising of buffer solution: 0.6% trifluoroacetic acid solution in water-tetrahydrofurane (8:2 v/v) and acetonitrile-methanol (1:1 v/v) in the ratio of 60:40 v/v. The flow rate was 1.5 mL min−1, and the detection was monitored by ultraviolet (UV) detector at 239 nm and 250 nm. Linearity was observed in the concentration range of 0.025–4.8 μg mL−1 for salmeterol xinafoate and 0.04–32.5 μg mL−1 for fluticasone propionate (R 2 > 0.999). The recovery in the range from 98.2% to 102.7% and relative standard deviation (RSD) ≤ 2.2% demonstrated accuracy and high precision of the method. The quantification limit at an injection volume of 40 μL was 0.04 μg mL−1 for fluticasone propionate and 0.025 μg mL−1 for salmeterol xinafoate. The developed and validated method can be successfully applied for simultaneous quality control of dry powder inhalation products containing salmeterol xinafoate and fluticasone propionate in pharmaceutical industry.

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