Browsing by Issue Date, starting with "2010-02-19"
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- Quality system design and implementation in proficiency test provider laboratory based in an international normPublication . Pereira, Glauce Guimarães; Estrugo, Angels SahuquilloProficiency testing is defined as the use of interlaboratory comparisons to determine the performance of individual laboratories for specific tests or measurements and to monitor laboratories‘ continuing performance. The number of PTs is increasing in the last years because the result of this exercise is useful not just for costumers, but also for other interested parties, such as regulators, laboratory accreditation bodies and other organizations who specify requirements for laboratories. Hence, it is very important to organize PT with criteria, focus and quality. The objective of this work was design of a quality system in Mat Control Laboratory of the University of Barcelona, according to the ISO/IEC DIS 17043 as a Proficient Test Provider. The quality system proposal for Mat Control was elaborated from September 2009 to January 2010 based on the attendance and participation in PT activities carried out in the Department of Analytical Chemistry of the Faculty of Chemistry, University of Barcelona. Fifteen documents were proposed to compose the structure of the quality system. Seven elaborated ―Standardized Operation Procedures‖ cover technical requirements of ISO/IEC DIS 17043. Instructions for a management equipment procedure shall be done considering mainly ISO/IEC 17025, and this will be a very important step to demonstrate Mat Control‘s competence to run analytical tests. Two ―General Quality Procedures‖ define elaboration, coding and management of documents. Other management requirements are contemplated in the quality manual and will be totally covered with the elaboration of instructions for four management procedures already structured.
- Interaction of alkylphenols and alkylphenol ethoxylates with sewage sludges and soilsPublication . Milinovic, Jelena; Vidal, Miquel; Rigol, Anna; Cavaco, Isabel Maria Palma AntunesA common practice for the reuse of sewage sludge from waste water treatment plants (WWTPs) is its application in agricultural soils as fertilizer.
- Development and application of quality standard procedures ((operation,, verification and maintenance)) for an LC--MS systemPublication . Daniel, Christy Sarmiento; Moyano, Encarnacion; Santos, Javier; Núñez, OscarIn this work, the standard procedures required for the operation, verification and maintenance of a liquid chromatography coupled to mass spectrometry system have been developed. These procedures have been designed and prepared with the aim to establish a quality control system to ensure the proper functioning of each component of the instrumentation, the LC and the MS, and to verify the performance of the LC-MS coupling. For this purpose, standard procedures were elaborated and proved in the normal routine laboratory work to evaluate their real applicability. Moreover, the verification of the performance of the LC-MS system was carried out experimentally through an in-house procedure based on the analysis of naphthylacetics.
- Verification and maintenance of analytical instruments according to ISO/IEC 17025 standardPublication . Zacarias, Marta Isabel Gonçalves; Newton, Alice; Companyó, Ramon; Llauradó, MontserratEquipment verification and preparation of the documents related to this activity were made. The equipment verification was performed on balances and analytical balances, liquid chromatographs and gas chromatographs. With respect to the balances and analytical balances verification, repeatability, trueness and drift assays were performed. A SOP containing the instructions for the verification, forms to register the primary data obtained from the verification assays, excel sheets to carry out the calculations for the assays, verification notebooks including the form mentioned above and archives to save all the results obtained from such assays were prepared. The performance verification was carried out for two liquid chromatographs. The following verification assays were performed: injector precision, flow rate precision, injector linearity and carryover, detector linearity, noise and drift, flow rate trueness and gradient accuracy. A SOP containing the instructions for the verification, an excel sheet to carry out the necessary calculations for the verification assays and an archive to save the obtained chromatograms and results were prepared for each instrument. For one of the liquid chromatographs a SOP containing the maintenance instructions was written. Two gas chromatographs were verified, one with Thermal Conductivity Detector (TCD) and another one with Flame Ionization Detector (FID). The documents related to the verification and mentioned for the liquid chromatographs were also prepared for these equipments. The following verification assays were performed: flow rate precision, detector linearity, noise and drift, oven temperature precision, trueness, linearity and stability. A SOP containing the maintenance instructions was prepared for both gas chromatographs. The proposed objectives were achieved.
- Enrofloxacin in soils: determination of sorption parameters by liquid chromatographyPublication . Medeiros, Joana Pinto Magalhães de; Abadía, Beltrán; Juan, Mercè GranadosThere are several parameters influencing the sorption of analytes to soils. In this Master project, the sorption behavior of enrofloxacin (ENR) was characterized in six soils of basic pH and different properties, through the study of sorption isotherms. The Freundlich model fitted all the data, while the Langmuir equation was adjusted only to the soils showing an L-type isotherm. The values of experimental distribution coefficients (Kd) obtained for ENR ranged from 0.69 to 2.04 L/g, in agreement with the ones found in the literature. Principal component analysis was performed in the set of soils, and the properties that appeared to have a greater influence in ENR sorption were the content in Fe, Al and Mg oxides. In order to determine the role of organic matter (OM) in the ENR sorption process, one of the soil samples was amended with different amounts of humic acids. The values of Kd obtained seem to indicate an increase in sorption with the increase in OM. Further investigation is needed to confirm these findings.
- Process monitoring of continuous flow organic syntheses by means of inline fiber optical Raman spectroscopyPublication . Rehman, Muhammad Saif Ur; Grung, Bjorn; Bjorsvik, Hans-ReneThe objective of the current study was to investigate the feasibility of the inline optical fiber Raman spectroscopy as a tool for the process monitoring of the continuous flow organic syntheses. The synthesis of 2-bromo-3,4,5-trimethoxytoluene (product) was studied as a model reaction under a set of different conditions. The reaction was carried out under the batch as well as in the multi jet oscillating disc (MJOD) milli reactor. The reaction was varied by doubling the concentration of the substrate; 3,4,5-trimethoxytoluene (0.15M, 0.3M and 0.6M) whereas the concentration of the solvent (acetic anhydride) was kept constant. The Raman instrument was adjusted to record five spectra per minute. The recorded spectral data was then preprocessed employing the second order differentiation to minimize the band overlapping in the spectra. Multivariate data analysis namely, Principal Component Analysis (PCA), was used to evaluate the spectra due to the presence of overlapping bands for the purpose of process monitoring. The measurement system was tested against the possible process disturbances, the oscillator and the feeding pumps. PCA showed that these disturbances had no impact on the measurement system. The Raman instrument successfully monitored the different organic reactions and discriminated them on the basis of the type of variation occurred. The Raman frequencies; 675, 1050 and 550 cm-1 were assigned to the solvent, substrate and the product. The various reactions undergoing any disagreement were differentiated from the normal reactions mainly due to the temperature effect, malfunctioning of the pump, lower conversion of the substrate, lower yield of the product, formation of the intermediates etc. The offline results obtained from the NMR spectroscopy verified the outcomes of Raman measurements. Thus, it was concluded that the optical fiber Raman spectroscopy proved to be a reliable, rapid and sensitive inline analytical method for the monitoring of the organic processes. Raman spectroscopy along with an appropriate chemometric tool could be employed as a Process Analytical Technology (PAT) in the pharmaceutical and fine chemical industry.