Round robins Applications

Applications Dissolution/reprecipitation is claimed to be the most widespread approach to polymer/additive analysis [603], but recent round-robins cast some doubt on this statement. Dissolution appears to be practised much less than LSEs. However, in cases where exhaustive extraction is difficult, e.g. for polyolefins containing high-MW (polymeric) additives, a dissolution/precipitation method is preferred. 

Various workers have discussed methodology for the determination of polychlorodibenzo-p-dioxins and dibenzofurans in sediments [110, 111, 115] and silts [109]. The method described by Smith et al. [110] for the determination of polychlorodibenzo-p-dioxins and dibenzofurans in soils and discussed in section 5.7.1.1 is also applicable to sediments. Taguchi [112] presented preliminary results obtained in a round robin inter-... 

Peplinski B, Schultze D, Wenzel J (2001) Interlaboratory comparison (round robin) on the application of the Rietveld method to quantitative phase analysis by X-ray and neutron diffraction. In Delhez R, Mittemeijer EJ (eds) Proc 7th European powder diffraction conference (EPDIC-7), Barcelona, Spain, 20th 23rd May 2000, Trans Tech Publications Ltd, Switzerland, p 124... 

Crosland et al. [264] reported on the application of the ethylenediaminete-traacetic acid extraction procedure to soil analysis. A round robin involving... 

Thellen, C., Blaise, C., Roy, Y. and Hickey, C. (1989) Round Robin testing with the Selenastrum capricomutum microplate toxicity assay, in M. Munawar, G. Dixon, C.I. Mayfield, T. Reynoldson and M.H. Sadar (eds.), Environmental Bioassay Techniques and their Application Proceedings of the Is International Conference held in Lancaster, England, 11-14 July 1988, Kluwer Academic Publishers, Dordrecht, Netherlands, pp. 259-268. 

Most methods (electron probe microanalysis, micro-Auger, secondary ion mass spectrometry) cannot be considered as really accurate methods except when applied to quite simple systems. Their application relies on the use of CRMs but these are, with very few exceptions, not available. The reason for the lack of CRMs is the absence of any reliable methods of microanalysis. None of the limited range of primary methods is applicable for the analysis of a solid at a microscopical level. The world of microanalysis is badly in need of at least one method which is able to act as a reference for the other techniques and to link RMs or round-robin exercises to the SI units [22],... 

In such conditions what is needed are RMs containing an accurately known concentration of the analytes as they appear in a well-characterised solid material in its natural status (thus not as a doped substance). At present it is an open question as to what methods are applicable to round robins and certification exercises and what methods ultimately could serve as the primary reference to the SI. None of the so-called primary methods of analysis is appropriate for the purpose. 

Quality control of laboratories depends on the availability of CRMs, round-robin studies, intercomparisons and proficiency tests between methods and between laboratories. Of special importance is a full knowledge of the complex analytical process and the painstaking pursuit of the true value by defining all sources of errors and the application of an adequate error source budget. The application of Poisson and Bayesian statistics could have some advantage. 

Comparative studies of neodymium measurements in UOj fuel for the future application of local burn up calculations have been carried out by the SIMS analysis of a Nd implanted UOj single crystal. Samples for a round robin test were produced by the implantation of " Nd (5 x 10 ° at cm , 400 keV) in a UOj single crystal. Different depth profiles of the Nd "/ U+ ratio and especially the NdO /Nd, UO+/U+ and U02 /U+ ratios obtained by SIMS are not constant over time and indicate evidence of some fluctuations during the analysis. SIMS plays a dominant role for particle analysis, but also LA-ICP-MS with lower spatial resolution can be applied to identify anomalies in the isotopic composition of radionuclides. 

With the initial aim of evaluating the applicability of the ISO 15024 standard for fracture toughness testing for non-unidirectional composite laminates, ESIS TC4 has conducted a number of round robin studies on cross-ply laminates with different stacking sequences. We report here the results of two test laboratories from the 3 round robin activity in which double cantilever beam (DCB) specimens made from unidirectional (0°/0°-interface) composite laminates were compared to DCB-specimens with 0°/90°- and 90790° interfaces. In the analysis, correlation with observations from the delamination growth (e.g., deviation from the mid-plane) and post-test (e.g., fracture surface) inspection was attempted. The results are compared with some results in the literature. 

Fast separations of 16 PAHs were achieved within 6-7 min using packed columns. A comparison study of the PAH molecular shape recognition properties of liquid-crystal-bonded phases in packed-column SFC and HPLC found that the selectivity was enhanced in SFC. The result of an interlaborotory round-robin evaluation of SFC for the determination of PAHs also shows that SFC possesses distinct advantages over GC-mass spectrometry (MS) and nuclear magnetic resonance (NMR) including speed, cost, and applicability. 

The successful testing of DDM method for structure refinement purposes allows us to predict its applicability in other fields of powder diffraction, such as the analysis of microstructure and quantitative phase analysis (QPA). Trial runs of DDM for the XRD data supplied by the International Union of Crystallography Commission on Powder Diffraction for the Size-Strain and QPA round-robins gave encouraging results. Respective examples are included in the DDM program package. In particular, the biases in the phase contents determined by DDM refinement for the QPA round-robin samples from the weighted amounts were less than 1 wt.%. 

This chapter focuses on the application of quantitative phase analysis (QPA) techniques for the extraction of phase abundance from diffraction data. Rather than repeat the extensive coverage of the QPA methodology covered in other texts, the focus will be on the basis and application of the most commonly used techniques. These were identified from participant responses to the recent round robin on QPA sponsored by the International Union of Crystallography (lUCr) Commission on Powder Diffraction (CPD). By far the greatest number of participants in that study used whole pattern (Rietveld based) methods but there are still several users of traditional single peak based methods and there are still many applications for which these methods suffice. Issues in the measurement of precision and accuracy will also be discussed. 

In the last few years EDXRF using polarized and focused excitation has become a very powerful analytical technique for the analysis of low S content in automotive fuel. The technique shows the potential to achieve repeatability and reproducibility values, which are comparable to reference methods for this application. In preparation for a new ASTM and El norm, a new round robin with a larger number of participants is under way. 

Many HPLC methods for phospholipids have been developed, but chromatographic resolution and dynamics of detection are not always satisfactory. For each source of phospholipids, special standards are needed due to the different distribution of fatty acids. These standards are expensive and in some cases are not available. Another problem is represented by the analysis of phospholipids in complex matrices. In many cases, separation is impossible or very difficult, not least due to the surface activity, which is desired in the application of phospholipids, but which complicates the analysis of these compounds. Therefore, a method is needed which is selective in the detection of phospholipids in order to avoid a separation from the matrix. The P NMR spectroscopy of phospholipids meets these requirements. The I.L.P.S. (Internationa Lecithin and Phospholipid Society) has chosen the P NMR method as the reference method [62],[63],[64]. It has been tested world-wide by round robin tests in comparison to various HPLC and TLC methods. With triphenylphosphate as internal standard, a pulse angle of 15°, 10-s relaxation delay, and 32-256 accumulations, the method has a precision of <0,5%. 

Performance of several of these kits has been assessed by field personnel in round robin tests. Correlation of activity assays and population estimates is variable. In general these kits have a narrower range of application than growth-based assays and it is therefore important to select a kit with a detection range appropriate to the problem under consideration [25]. 

Similar encouraging results have been reported by Moore and Williams [55] who led a round-robin series of tests using, for example, a five-layer structure which formed a polypropylene/tie-layer/poly(ethylene vinyl alcohol)/tie-layer/polypropylene laminate approximately 120 xm thick, as used widely in packaging applications. They also reported that a characteristic value of the adhesive fracture energy, Gg, independent of the peel angle, 0, was obtained. 

The 7 round robin used a sample of polyvinylchloride (PVC) producing fairly linear loading curves up to the maximum load, followed by unstable (brittle) fracture, as illustrated in Figure 4. To assess the applicability of the protocol to moderately nonlinear fractures, a sample of rubber-toughened polymethylmethacrylate (RTPMMA) showing some ductility and limited stable crack propagation before the load drop, as seen in Figure 5, was used. 

The comparability of MALDI results obtained in different laboratories can only be ensured by using standardized conditions of measurement, and identical sample and matrix preparation methods. Therefore, national and international MALDI-TOF MS round robin tests have been jjetfotmed. Their results were used to create national and international norms (ASTM, DIN, and ISO) for the determination of molecular masses and mass distributions of important polymer classes (PS, PMMA, and PEO). The classification of MALDI as an equitable (standardized) method relating to other established methods of polymer characterization may give an important push for increasing the application of MALDI MS. 

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