The BIOREMA project—Part 2: International interlaboratory comparison for biodiesel test methods

The results of an interlaboratory comparison, using various measurement methods to carry out biodiesel testing, are presented and the findings are discussed. The interlaboratory comparison was organised within the framework of an EU-funded project called BIOREMA. A general overview of the project and results of an interlaboratory comparison on bioethanol are published as Part 1 and 2 of this series of papers. In the study presented here, reference values, provided by national metrology institutes and expert laboratories, were used for evaluating the results. Consensus values, derived from the results of all participants, were used to assess any bias between the results from the national metrology institutes and testing laboratories. The emphasis in this interlaboratory comparison was not the performance rating of the individual laboratories, but recognising and interpreting differences caused by the measurement methods applied. For most biodiesel parameters, a good agreement of measurement results was found among different methods, and between the consensus and reference values. The study material was a rapeseed oil fatty acid methyl ester, for which it was demonstrated that it is feasible to prepare and characterise reference materials for biodiesel with well-established reference values for many parameters.     

The BIOREMA project—part 1: Towards international comparability for biofuel analysis

There is an increasing demand to accurately measure the quality of biofuel products (e.g. biodiesel and bio-ethanol). This demand is driven in Europe by directives promoting the use of renewable sources of energy and worldwide by national and international legislation setting out quality requirements for these fuels. Until now, there has been no international consensus on the minimum technical specifications to ensure biofuel quality. Furthermore, it is unclear which reference materials and measurement techniques are needed to provide the quality assurance and quality control framework to underpin these legislative requirements. As part of the European Commission’s 7th Framework Programme, the BIOREMA project (REference MAterials for BIOfuel specifications) demonstrated the feasibility of preparing biodiesel and bio-ethanol reference materials with reference values traceable to the international system of units for a range of parameters at levels relevant to technical specifications. However, the project concluded also that further research is needed to improve the current measurement capabilities for some parameters. Within the BIOREMA project, two global interlaboratory comparisons were carried out, using the biodiesel and bio-ethanol test materials prepared during the feasibility stage of the project, as well as two biodiesel standard reference materials from the National Institute of Standards and Technology (NIST, USA). The exercises showed that the measurement capabilities of the field laboratories were in many cases satisfactory, whereas for other laboratories the availability and regular use of certified reference materials would likely enhance the measurement capabilities for many of the parameters studied. A general overview of the BIOREMA project is presented in this paper. The details of the production of the two types of BIOREMA reference materials, and the results of the interlaboratory comparison for the bio-ethanol and biodiesel study materials, are discussed in parts 2 and 3 of this series of papers.     

The interlaboratory comparison "IMEP-19 trace elements in rice"—a new approach for measurement performance evaluation

The aim of IMEP is to present objectively the quality of chemical measurements. Participants in IMEP compare their reported measurement results with independent external certified reference values with demonstrated traceability and uncertainty, as evaluated according to international guidelines. IMEP-19 focused on measurements of trace elements in rice aiming to support the Commission Regulation (EC) No. 466/2001 on maximum levels for certain contaminants in foodstuff. Measurement results for the elements Cd, Cu, Pb and Zn were reported by 267 field laboratories involved in food analysis from 43 countries. Performance criteria for the evaluation of the reported measurement results in IMEP-19 are suggested. The chosen performance indicators not only take into account the deviation of the reported measurement value from the certified reference value, but also set criteria for maximum and minimum acceptable uncertainty. The IMEP-19 participants' performance is reviewed by means of using new simple graphical tools, called "Naji plots".     

EQRAIN: uranium and plutonium interlaboratory exercises from 1997 to 2016—comparison to ITVs-2010

Since 1987, the CEA’s Committee for the establishment of analysis methods (CETAMA) has regularly implemented interlaboratory comparisons, entitled “evaluation of the quality results of analysis in the nuclear industry” (EQRAIN). Notably, the EQRAIN U and EQRAIN Pu interlaboratory comparisons assess proficiency in measuring a mass content of uranium or plutonium in reference solutions. This paper presents the results of measurement uncertainty assessments from EQRAIN U and EQRAIN Pu comparisons over 20 years of exercises (1997–2016). The mathematical approach developed in this work allowed to estimate the impact of short-term systematic and random errors to the overall uncertainty of each analytical method used in the interlaboratory comparison program. This statistical analysis shows a good consistency between measurement uncertainty values from EQRAINs and the measurement uncertainty target values established by the International Atomic Energy Agency for nuclear material balances (ITVs-2010).

     

Correction to: EQRAIN: uranium and plutonium interlaboratory exercises from 1997 to 2016—comparison to ITVs-2010

Journal of Radioanalytical and Nuclear Chemistry - In the original publication of the article, the values of u(s), u(r) and ITV for HKED were published incorrectly in Table 6.     

The passivity of titanium—part III: characterization of the anodic oxide film

Journal of Solid State Electrochemistry - The kinetic parameters of the formation of the anodic titanium oxide film on Ti in 0.5 M H2SO4 have been determined using potentiostatic...     

Validation interlaboratory trial for ISO 12010: Water quality—Determination of short-chain polychlorinated alkanes (SCCP) in water

A validation interlaboratory trial was carried out to prepare ISO 12010: Water quality??Determination of short-chain polychlorinated alkanes (SCCP) in water??Method using gas chromatography/mass spectrometry (GC-MS) and electron capture negative ionisation (ECNI). The task was to determine the sum of short-chain polychlorinated n-alkanes with carbon chain lengths of C₁₀?CC₁₃ and a chlorine content between 49% (g/100?g) and 67% (g/100?g) in water by GC-ECNI-MS. The quantification had to be performed by multiple linear regression as described in ISO/DIS 12010, the compulsory method. Samples distributed were real river samples, and waste water spiked with a target concentration of 0.4 and 0.6???g/L for the sum of SCCPs, i.e. a concentration around the environmental quality target level according to the European Water Framework Directive. The different types of water samples tested were surface water with <150?mg/L suspended matter, surface water with 0.5?g/L suspended matter, and filtered waste waster. The interlaboratory trial included the extraction of the water samples, a column chromatographic clean up, a concentration step, and integration of chromatographic unresolved complex mixtures as well as the calibration and quantification by multiple linear regression. The reproducibility standard deviation of the standard concentration was 11.9%. Reproducibility standard deviations of concentrations in the three different water samples between 27.8 and 34.2% were achieved by 10?C12 participating laboratories from six countries.     

Is the assessment of interlaboratory comparison results for a small number of tests and limited number of participants reliable and rational?

Tests and/or test items can sometimes be expensive, unique, or only performed in a few laboratories. There can be cases where assigned values are unknown, there is no information, or only poor information on the probability density function attributed to the test result. Sometimes there are neither reference materials nor the ability to establish consensus values due to a lack of experts. It can be impossible to repeat a test on the same item because it is destroyed during the test itself, or the homogeneity of tested items is unknown and no criteria can be established. Specified technical requirements concerning proficiency testing and interlaboratory comparison schemes are generally not applicable in this situation. However, interlaboratory comparison could allow laboratories to have more confidence in their results. The present paper discusses three statistical methods of assessing interlaboratory comparison results obtained in such conditions. Two methods are based on an assigned value determined from participant results through robust analysis. The third is based on the compatibility of results assessed using the ζ parameter. This paper focuses on an interlaboratory comparison for two laboratories, each testing three samples. The use of statistical methods turns out to be high risk, particularly in terms of falsely accepting results. Additionally, is shown that methods dedicated to small samples are also not efficient in detecting discrepancies of test results.     

The Quadrature Discretization Method (QDM) in comparison with other numerical methods of solution of the Fokker–Planck equation for electron thermalization

The determination of the relaxation of electrons in atomic gases continues to be an important physical problem. The main interest is the determination of the time scale for the thermalization of electrons in different moderators and the nature of the timedependent electron energy distribution. The theoretical basis for the study of electron thermalization is the determination of the electron distribution function from a solution of the Lorentz–Fokker–Planck equation. The present paper considers a detailed comparison of different numerical methods of solution of the Lorentz–Fokker–Planck equation for the electron distribution function. The methods include a pseudospectral method referred to as the Quadrature Discretization Method (QDM) which is based on nonstandard polynomial basis sets, a finitedifference method, and a Lagrange interpolation method. The Fokker–Planck equation can be transformed to a Schrödinger equation, and methods developed for the solution of either equation apply to the other.     

The program “MULTINAA” for various standardization methods in neutron activation analysis

A compute program MULTINAA was developed to facilitate the evaluation of NAA data. It is written for the VAX/VMS syste and opeates in the Canberra/ND Genie spectroscopy software environment. MULTIINAA can be appliede to relative,k ₀-, monostandard (modified) and absolute methods, including the fast neutron threshold reaction. For each calculation, the available standardizations can be used individually or mixed. In all the standardization modes MULTINAA fetches the data directly from the -ray spectra and libraries, thus reducing the manual work to a minimum. MULTINAA is flexibkle to meet various situations in NAA practical work. The required neutron flux parameters all the non-relative methods are supplied by an accompanying program MULTIFLUX.     

A comparison of analytical methods for the quantification of a reactive β-cyclodextrin fixed onto cotton yarns

Cotton yarns bobbins were treated in a water bath with different concentrations of a reactive β-cyclodextrin derivative. To quantify the amount of cyclodextrin fixed on the fiber different analytical methods were tested but none of them was reliable enough in the concentration range under investigation. Therefore, a new analytical method, fast and effective, was developed. From the measurement of cyclodextrin bath exhaustion, the amount of cyclodextrin chemically fixed and that physically adsorbed on the textile substrate was estimated. Two washing cycles were carried out to investigate the cyclodextrin washing fastness.     

Anharmonic treatment of vibrational resonance polyads—the diborane: a critical case for numerical methods

Based on accurate computational results, the IR spectra of diborane B₂H₆ and its deuterated derivative B₂D₆ were experimentally revisited to reconsider or complete their band assignments. A pure, variational approach, developed in both mechanical and electrical anharmonicities, was applied to study the diborane molecule for which many uncertainties remain in the spectral IR assignment. This work, together with all the experiments on this system over recent decades, shows the difficulty of interpreting the spectral data, making it a “benchmark” ideal for testing the mathematical approaches for the implementation of vibrational codes.     

Analytical methods for selected emerging contaminants in human matrices—a review

Emerging contaminants are a broad category of chemicals, previously unknown or unrecognized as being of concern, but which, because of their potential health effects associated with human exposure, are under increasing scrutiny. To accurately measure their levels in biological matrices, specific and sensitive analytical methods have recently been developed. We have reviewed here the methods used for analysis of selected emerging organic contaminants, for example metabolites of organophosphate triesters, metabolites of new phthalates or phthalate substitutes, perchlorate, organic UV filters, and polycyclic siloxanes, in human matrices. Although the use of new techniques and approaches has been emphasized, we also acknowledge methods previously used for other contaminants and adapted for the emerging contaminants listed above. In all cases, chromatography and mass spectrometry were the techniques of choice, because of their selectivity and sensitivity for measurements at ng?g^?1 levels. Critical issues and challenges have been discussed, together with recommendations for further improvement in particular cases (e.g. metabolites of phthalates or their substitutes). In particular, the use of labeled internal standards, the availability of certified reference materials, and the need for interlaboratory comparison exercises are key aspects of further development of this field of research.

The 3rd International Conference on Ion Exchange, ICIE ''''03

First Circular / Pre-registration (e-mail edition) July 14-18, 2003 Kanazawa Institute of Technology, Nonoichi, Ishikawa Pref., JAPAN Organized by Japan Association of Ion Exchange (JAIE) INVITATION On behalf of the Japan Association of Ion Exchange (J…     

Flavanoid part 71: A novel photosynthesis of 3α-hydroxybenzylflavones from 3-arylideneflavanones

E-3 Arylideneflavanones4on UV irradiation using quartzware undergo auto-oxidation to 3-aroylflavones5. Photolysis using pyrex filter in the presence of iodoform furnishes 3-α-hydroxybenzylflavones indicating the intermediacy of the hydroperoxide11 and form a new general method for the synthesis of these compounds not available by other routes.