Home About us Contact
|
Home About us Contact | ||
|
|
||
Official Method (official + method)
Selected AbstractsComposite Multienzyme Amperometric Biosensors for an Improved Detection of Phenolic CompoundsELECTROANALYSIS, Issue 22 2003B. Serra Abstract A biosensor design, in which glucose oxidase and peroxidase are coimmobilized by simple physical inclusion into the bulk of graphite-Teflon pellets, is reported for the detection of phenolic compounds. This design allows the "in situ" generation of the H2O2 needed for the enzyme reaction with the phenolic compounds, which avoids several problems detected in the performance of single peroxidase biosensors as a consequence of the presence of a high H2O2 concentration. So, a much lower surface fouling was found at the GOD-HRP biosensor in comparison with a graphite-Teflon-HRP electrode, suggesting that the controlled generation of H2O2 makes more difficult the formation of polymers from the enzyme reaction products. The construction of trienzyme biosensors, in which GOD, HRP and tyrosinase were coimmobilized into the graphite-Teflon matrix is also reported, and their performance was compared with that of GOD-HRP bienzyme electrodes. The practical applicability of the composite multienzyme amperometric biosensors was evaluated by the estimation of the phenolic compounds content in waste waters from a refinery, and the results were compared with those obtained by using a colorimetric official method based on the reaction with 4-aminoantipyrine. [source] A simplified method for HPLC-MS analysis of sterols in vegetable oilEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 12 2008Antonio Segura Carretero Abstract We have developed a liquid-chromatographic method using atmospheric pressure chemical ionization (APCI)-mass spectrometry (MS) detection in positive mode. This method was used to separate and identify 15,sterols and 2,dihydroxy triterpenes in saponified oils, enabling the analysis of these compounds directly from saponified samples without recourse to thin-layer chromatography; this fact thus significantly simplifies the process. The analyses were made using a Waters Atlantis 5,µm dC18 150×2.1,mm column with a gradient of acetonitrile/water (0.01% acetic acid) at a flow rate of 0.5,mL/min and a column temperature of 30,°C. The quantification of several of these compounds in soybean oil, palm oil, seed oil, sunflower oil, olive-pomace oil and virgin olive oil was carried out using their commercial standards, and the results were compared satisfactorily with the official method. [source] Unit cost of Mohs and Dermasurgery UnitJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 4 2010R Wanitphakdeedecha Abstract Background, Appropriate pricing for medical services of not-for-profit hospital is necessary. The prices should be fair to the public and should be high enough to cover the operative costs of the organization. Objective, The purpose of this study was to determine the cost and unit cost of medical services performed at the Mohs and Dermasurgery Unit (MDU), Department of Dermatology, The University of Texas , MD Anderson Cancer Center, Houston, TX from the healthcare provider's perspective. Methods, MDU costs were retrieved from the Financial Department for fiscal year 2006. The patients' statistics were acquired from medical records for the same period. Unit cost calculation was based on the official method of hospital accounting. Results, The overall unit cost for each patient visit was $673.99 United States dollar (USD). The detailed unit cost of nurse visit, new patient visit, follow-up visit, consultation, Mohs and non-Mohs procedure were, respectively, $368.27, $580.09, $477.82, $585.52, $1,086.12 and $858.23 USD. With respect to a Mohs visit, the unit cost per lesion and unit cost per stage were $867.89 and $242.30 USD respectively. Conclusions, Results from this retrospective study provide information that may be used for pricing strategy and resource allocation by the administrative board of MDU. [source] A chromametric method for the rapid assessment of deep frying oil qualityJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2003Xin-Qing Xu Abstract A rapid chromametric method was developed for the assessment of deep frying oil quality based on the strong correlation between colour index and total polar compounds in deep frying oil. Colour indices of frying oil samples, measured by chromameter, decreased significantly during frying and were strongly correlated with frying time (r , 0.95, p < 0.001). Colour indices of a set of oil samples taken from 0 to 80 h of deep frying were also significantly correlated with total polar compounds of the same samples determined using the official method of the American Oil Chemists' Society (r = 0.96, p < 0.001). The equation for conversion of the colour index (x) to the content of total polar compounds (y) in an oil sample is y = 0.0174x2 , 2.9506x + 124.34. In addition, colour indices of 10 different types of frying oils were strongly correlated with the corresponding contents of total polar compounds in the oils with samples taken from 0 to 80 h of deep frying in duplicate (r = 0.95, p < 0.001, n = 220). The results of colour index analyses agreed well with the results of chemical and sensory analyses of the frying oils tested. This chromametric method is rapid, convenient and reliable. Copyright © 2003 Society of Chemical Industry [source] Isotope ratio mass spectrometry coupled to liquid and gas chromatography for wine ethanol characterizationRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 20 2008Ana I. Cabañero Two new procedures for wine ethanol 13C/12C isotope ratio determination, using high-performance liquid chromatography and gas chromatography isotope ratio mass spectrometry (HPLC/IRMS and GC/IRMS), have been developed to improve isotopic methods dedicated to the study of wine authenticity. Parameters influencing separation of ethanol from wine matrix such as column, temperature, mobile phase, flow rates and injection mode were investigated. Twenty-three wine samples from various origins were analyzed for validation of the procedures. The analytical precision was better than 0.15,, and no significant isotopic fractionation was observed employing both separative techniques coupled to IRMS. No significant differences and a very strong correlation (r,=,0.99) were observed between the 13C/12C ratios obtained by the official method (elemental analyzer/isotope ratio mass spectrometry) and the proposed new methodology. The potential advantages of the developed methods over the traditional one are speed (reducing time required from hours to minutes) and simplicity. In addition, these are the first isotopic methods that allow 13C/12C determination directly from a liquid sample with no previous ethanol isolation, overcoming technical difficulties associated with sample treatment. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||