Near-infrared libraries in the pharmaceutical industry: a solution for identity confirmation

The construction of near-infrared spectral libraries as an alternative to qualitative analysis methods for identifying pharmaceutical raw materials is proposed. Various conceptual and practical aspects of library construction are assessed and discussed. The procedure is demonstrated by constructing a library including NIR spectra for 125 different raw materials using the correlation coefficient as the discriminating criterion. Compounds with very similar spectra can be identified by constructing sub-cascading libraries branching off the main one that are developed by using chemometric procedures with higher discriminating ability. The construction of sub-libraries and their performance and discriminating power in three different situations are illustrated. The proposed methodology affords the expeditious unequivocal identification of all the compounds included in a library.     

Cyclotron production and quality control of “high specific activity' radionuclides in “no-carrier-added” form for radioanalytical applications in the life sciences

Radionuclides of very high specific activity A _S(t) have great relevance for applications in the life sciences. Updated definitions of A _S are given. The real A _S(t) must be measured by analytical and radioanalytical techniques. No-carrier-added (NCA) radionuclides have A _S(NCA) sometimes close to the carrier-free (CF) value A _S(CF). The accurate knowledge of excitation functions of nuclear reactions vs. ion beam energy is mandatory to maximize A _S(NCA); the minimization of isotopic dilution factor IDF(t) has been achieved too. A range of accelerator production and radioanalytical QC methods for A _S(NCA) optimization and determination is presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

Analytical and radioanalytical quality control of purity and stability of radiopharmaceutical compound [186gRe]Re-HEDP for bone metastases pain palliation

Summary The nuclear properties of ^186gRe make it a useful agent for radionuclide therapy and imaging. The coordination compound [^186gRe]Re-HEDP has proved to be a successful bone seeking agent for palliation of metastatic bone pain. Chemical, radiochemical and radionuclidic purity of commercial radiopharmaceutical [^186gRe]Re-HEDP have been checked by means by γ- and β-spectrometries, INAA and paper radio-chromatography. The results indicate a good radionuclidic purity, with levels of contamination from the short-lived ¹⁸⁸Re well below the required specifications. After injection of the radiopharmaceutical, the radiochemical measurements conducted in vivo, on biological matrices, blood, plasma and urine, have shown that, entering the systemic circulation, ^186gRe dissociates from the bis-phosphonate complex as hydrosoluble [^186gRe]ReO₄-, and the two chemical species follow different biokinetics.     

A radioanalytical technique for measurement of beta-glucuronidase activities

Summary Phenolphthalein-glucuronide is a commonly used glucuronide conjugate for beta-glucuronidase measurements. The quantity of phenolphthalein liberated by beta-glucuronidase is measured spectrophotometrically. The detection limit of the quantity of phenolphthalein using spectrophotometry is a few μg. In this study, a new radioanalytical technique for the measurement of beta-glucuronidase was applied which is 10⁶times more sensitive than the spectrophotometric technique. Radioiodinated phenolphthalein-glucuronide and phenyl-N-glucuronide were used in this study in which the beta-glucuronidase levels of some tissue samples were measured.     

Quantitation and identity confirmation of residues of quinolones in tilapia fillets by LC-ESI-MS-MS QToF

A method for simultaneous determination of flumequine (FLM), oxolinic acid (OXO), sarafloxacin (SAR), danofloxacin (DAN), enrofloxacin (ENR), and ciprofloxacin (CIP) in tilapia (Orechromis niloticus) fillets, using liquid chromatography-tandem mass spectrometry (LC-ESI-MS-MS QToF) is presented. The quinolones were extracted from the food matrix with a solution of 10% trichloroacetic acid-methanol (80:20 v/v) with ultrasonic assistance. Clean-up of the extract solution was performed by using polymeric solid-phase extraction cartridges. The LC separation was carried out on an octadecyl hybrid silica column (C₁₈, 150 mm × 3 mm, 5 μm). The column temperature was set at 30 °C, and gradient elution (0.2 mL min⁻¹) was performed using water and acetonitrile, both containing 0.1% of acetic acid, as mobile phase components. The analytes were ionized using electrospray in the positive polarity mode. The following analytical results were obtained: linearity was about 0.99 for all the quinolones; intra and inter-assay precision (RSD%) were lower than 12.7 and 20%, respectively; and recoveries were from 89 to 112%. The quantitation limits were below the maximum residue limits established for the analytes. The method is suitable for the determination of quinolone residues in fish fillets and the QToF technique made it possible to obtain m/z ratios with less than 10 ppm of error for each analyte.     

Evaluative quality parameters in nondestructive control of adhesive metallic bonds in machine units

The correlation between the evaluative quality parameter, namely, the specific electrical resistance, and the strength of an adhesive bond is theoretically substantiated, which confirms the possibility of using the electrical method of nondestructive control of roller-bearing type adhesive metallic bonds. Results of experimental studies are presented that verify the correctness of the theoretical concepts.     

Preparation of high specific activity radiotracers for radioanalytical studies

High specific activity radiotracers are very suitable for studies related to the toxicological impact of trace elements onto human health. In order to investigate the metabolic behaviour of Low Level Exposure (LLE) to trace elements, it is necessary to carry out in-vitro and in-vivo experiments with tracers whose concentration is of the same order of magnitude as the present environmental exposure values (ng-g/kg day). Preparations, separations and purifications of some No Carrier Added (NCA) radiotracers (⁴⁸V,^95m,96Tc,^{195m,g,197m,g}Hg,¹⁹⁹Au,²⁰²Tl) produced by either cyclotron or nuclear reactor irradiation, are presented and discussed. This work reviews the more recent advances in this field carried out by our groups.     

Application of instrumental radioanalytical techniques to nuclear waste testing and characterization

This paper describes the validation of a multi-technique analytical methodology that uses inductively coupled plasma-mass spectrometry, α-spectrometry, and γ-spectrometry for the routine analysis of samples containing transuranic radionuclides. This methodology is capable of the determination of concentrations of both²³⁸Pu and²⁴¹Pu in the presence of²³⁸U and²⁴¹Am without the need for chemical separations. The relative merits of these three techniques were evaluated as they are applied in a nuclear waste material and spent nuclear fuel testing program by analytical (1) standards and (2) solutions prepared from the dissolution of glasses doped with²³⁷Np,²³⁹Pu, and²⁴¹Am. The uncertainty associated with technique was within ±4% for standards and ±10% for doped nuclear waste glasses. The methodology was then used to analyze three fully radioactive waste glasses.     

Application of thermogravimetry in the quality control of mebendazole

A study was made of the thermal behavior of the starting materials, their mixtures and the resulting mebendazole tablets. The thermal curves were obtained with a Shimadzu thermobalance, model TGA-50, using an air flow of 50 mL min^–1 and a heating rate of 10°C min^–1 in the temperature interval 30–900°C. The reaction constant velocities for the mebendazole salt and tablets were determined isothermally, using the Arrhenius expression. The thermal stability of mebendazole tablets is lower than that of the mebendazole salt, due to the presence of starch and lactose in the composition. Analysis of the data reveals that thermogravimetry is a powerful tool in pharmaceutical technology and quality control.The authors thank CNPq/PADCT for financial support.     

Application of radionuclide sources for excitation in energy-dispersive X-ray fluorescence analysis

Summary X-ray fluorescence (XRF) analysis is in broad application in many fields of science where elemental determinations are necessary. Solid and liquid samples are analyzed by this method. Solids are introduced in thin or thick samples as melted glass, pellets, powders or as original specimen. The excitation of X-ray spectra can be performed by specific and polychromic radiation of X-ray tubes, by protons, deuterons, -particles, heavy ions and synchrotron radiation from accelerators and by -particles, X- and -rays and by bremsstrahlung generated by ^–-particles from radionuclide sources. The radionuclides are devided into groups with respect to their decay mode and the energy of the emitted radiation. The broad application of radionuclides in XRF excitation is shown in examples as semi-quantitative analysis of glasses, as quantitative analysis of coarse ceramics and as quantitative determination of heavy elements (mainly actinides) in solutions. The advantages and disadvantages of radionuclide excitation in XRF analysis are discussed.

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Anwendung von Radionuklidquellen zur Anregung in der Energie-dispersiven Röntgenfluorescenz-Analyse

Zusammenfassung Die Röntgenfluorescenzanalyse (RFA) ist auf all denen Gebieten der Wissenschaften verbreitet, in denen die Bestimmung der Elemente notwendig ist. Mit Hilfe dieser Methode können feste und flüssige Proben analysiert werden. Dünne oder dicke, feste Proben werden als geschmolzene Gläser, Tabletten, Pulver oder in Originalform eingesetzt. Die Anregung der Röntgenspektren erfolgt durch die spezifische und kontinuierliche Strahlung von Röntgenröhren, durch Protonen, Deuteronen, -Teilchen, schwere Ionen und Synchrotronstrahlung aus Beschleunigern und durch -Teilchen, Röntgen- und -Strahlung sowie durch von ^–-Teilchen erzeugte Bremsstrahlung von Radionuklidquellen. Die Radionuklide werden auf Grund ihrer Zerfallsart und auf Grund der Energie der emittierten Strahlung geordnet. Die breite Anwendung von Radionukliden für die Anregung bei der RFA wird an Hand von Beispielen wie der semiquantitativen Analyse von Gläsern, der quantitativen Analyse grober Keramik und der quantitativen Bestimmung schwerer Elemente (hauptsächlich der Aktinide) in Lösungen gezeigt. Die Vor- und Nachteile der RFA mit Radionuklidanregung werden diskutiert.

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Dedicated to Prof. Dr. K. H. Lieser on the occasion of his 65th birthday

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The author wishes to thank the Director of the Institute of Nuclear Chemistry at the Technische Hochschule Darmstadt, Prof. Dr. K. H. Lieser, for having the possibility to work in the field described in this paper.     

模式识别在食品质量控制方面的应用进展

本文介绍了食品质量研究中常用的一些化学模式识别方法的基本原理,并介绍了模式识别结合红外、原子吸收、原子发射、气相色谱、液相色谱、质谱、电子鼻传感器等检测技术在食品质量控制中的应用.对化学计量学在食品质量控制中的应用前景作了展望.     

A proficiency test scheme for the quality control of black tea and development of quality control material for internal quality control

A proficiency test (PT) was organized for quality control analysis of black tea. Test materials for the analyses of total content of powder tea, moisture, total ash, acid-insoluble ash, water-soluble ash, alkalinity of water-soluble ash, water extract, crude fiber and caffeine were sent to the participant laboratories (n:43) in 2009. The assigned value, standard deviation of the parameters and z-scores of the participant laboratories were calculated using the data reported by the participants. The percentage of the reported results for analytes was found to be ranged from 67.5 to 100%. Acceptable z-scores were achieved by 80.5–97.5% of the participant laboratories. More than 15% of unacceptable results were obtained for acid-insoluble ash and caffeine analyses. The quality control material for quality control analysis of black tea was developed from the remaining material.     

Liquid scintillation radioassay for multiple radionuclide mixtures by the most probable value theory

Multiple radionuclide mixtures which have similar scintillation pulse height distributions can be accurately radioassayed by the most probable value theory. This liquid scintillation technique is based on the construction of more observation equations than the number of nuclides to be analyzed. The technique has been applied to³H–¹⁴C–¹²⁵I and³H–¹⁴C–⁵¹Cr mixture samples, and found to be very practicable with the aid of computerized data processing for mixture samples having a wide range (ca. 10 times) of activity ratios.     

A pilot study for the statistical treatment of nutritional parameters in the quality control of canned fishing goods.

This pilot study was derived as a consequence of European Directives 496/90 and 493/91 in which a regulation on the labeling of canned fishing goods was established. The study was intended primarily to assess whether different Spanish canned fishing goods might be differentiated by their basic nutritional composition (i.e., ash, chlorine as NaCl, fat, humidity, total proteins, and dry residue) and, second, to study each particular type of good. Accordingly, a univariate nonparametric statistical test and 2 multivariate chemometric techniques (factor and cluster analyses) were used. The pilot study revealed that (1) the basic nutritional variables did not allow a clear distinction among canned goods when different commodities were considered, but they seemed useful for obtaining information for only one type of good; and (2) the variables that gave the most useful information to visualize the appearance of groups in the data sets were humidity, dry residue, fat, and proteins, although their particular usefulness was found to be different when different species were considered.     

Positive confirmation of identity of doping agents using gas chromatography-mass spectrometry with Fourier transform infrared spectrometry

During the past two decades, the use of retention times in gas chromatography has been augmented by mass spectrometric data. By providing both the retention indices and spectrometric data, this technique has greatly improved gas chromatographic identification analysis. However, although gas chromatography-mass spectrometry has become pre-eminent, several drawbacks still remain. The mass spectral library often gives erroneous identifications when concentrations near the detection limit are analysed, when gas chromatographically interfering substances are present, or when structural isomers or compounds exhibiting identical retention behaviour are analysed. Linked with gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy can be a powerful complementary technique in peak identification analysis. Some spectral data to illustrate this point are presented.     

Application of modern thin-layer chromatographic techniques for confirmation of results in pesticide multi-residue analysis

Summary An HPTLC method has been examined for its suitability to confirm GLC results in pesticide multi-residue analysis and has been found to be highly efficient and of low cost. If no GLC facilities are available. HPTLC together with the cleanup procedure according to DFG will be a suitable way for multi-residue detection and determination.     

Capillary gas chromatography/mass spectrometry with chemical ionization and negative ion detection for confirmation of identity of patulin in apple juice

Gas chromatography/mass spectrometry (GC/MS) with negative ion chemical ionization permits detection of underivatized patulin in apple juice extracts while minimizing co-extractive responses. The technique has been used with a variety of capillary columns in quadrupole, ion trap, and magnetic sector GC/MS instruments to confirm presumptive findings of patulin in apple juice at concentrations ranging from 68 to 3700 micrograms/L. The demonstrated ability to use any of these 3 mass spectrometers and several capillary columns to confirm the identity of patulin are significant strengths of the technique.     

Application of chemometrically processed chemical and thermoanalytical data for quality control of soybean oils

The quality assessment of commercial soybean oils was evaluated on the basis of chemical and thermal analyses. The most substantial chemical parameters, viz. the density, refractive index and saponification, iodine and acid numbers were estimated. The thermal parameters were determined on the grounds of the TG and DTG curves. There are temperatures for the onset, end and successive mass losses. To find the relation between the chemical and thermal parameters, regression and principal component analyses were applied. The results of principal component analysis indicate that the TG and DTG techniques are at least in equal degree useful in defining the quality of soybean oils, as compared with the chemical analyses.     

Application of capillary electrophoresis in the quality control of osmotically treated water

Summary This paper discusses the use of capillary zone electrophoresis (CZE) with indirect UV detection for the separation and detection of ions. By use of a 70 cm×75 μm i.d. capillary at −15 kV and an electrophoretic buffer containing sodium chromate, 1-butanol, and cetyltrimethylammonium bromide as electroosmotic-flow modifier (pH 8) nine inorganic and organic anions were separated in less than 10 min. By use of the same type of capillary at 20 kV and an electrophoretic buffer containing imidazole and 18-crown-6 (pH 5) eight cations were separated in less than 5 min. The different variables that affect the separation were studied and optimized; the compounds were detected at low mg L⁻¹ levels after hydrodynamic injection under pressure. The method was tested with osmotically treated waters, and the results compared with those obtained by ion chromatography for anion analysis and by atomic absorption spectroscopy for cation analysis.