Round-robin study

A round robin study of accuracy and precision of the coulometric procedure identified sources of systematic error.33 In some labs, either the instruments were inaccurate or workers did not measure the quantity of standards accurately. In other cases, the solvent was not appropriate. Commercial reagents are designed for Karl Fischer analysis. Reagents recommended by the instrument manufacturer should be used with each instrument. 

EPA round robin studies is another quality assessment tool that is effective in revealing deficiencies in laboratory s ability to correctly identify and quantify environmental pollutants. The EPA performs these studies on a regular schedule and evaluates the results for the purpose of establishing interlaboratory precision, which is a measure of variability among the results obtained for the same sample at different laboratories. (Interlaboratory precision or reproducibility is another secondary DQI.)... 

Examine results of the recent EPA round robin study as they indicate the laboratory s ability to perform accurate analysis. A laboratory that does not participate in the EPA studies cannot be compared to other laboratories in terms of analytical accuracy. 

Such methods, although not considered as primary methods of analysis because of a remaining fudge factor , may be reasonable substitutes for exploitation in round-robin studies, for the production of usable RMs and for practical analysis. 

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. 

Clement RE, Bolelie B, Taguchi V. 1986. Comparison of instrumental methods for chlorinated dibenzo-p-dioxin (CDD) determination Interim results of a round-robin study involving GC/MS, MS/MS and high resolution MS. Chemosphere 15 1147-1156. 

In an attempt to standardize the analysis of OS, a round-robin test on whole milk powder and skim-milk powder was organised by Appelqvist (1996). Analyses of OS were carried out in 17 laboratories and the differences in the level found led Appelqvist (1996) to conclude that it is still premature to establish true values for the level of OS in certain foods. The results of a second round-robin study on egg and milk powders showed that several OS in the samples were not determined or were below the determin-... 

Welch et al. evaluated analytical procedures and environmental issues. They investigated methods for the extraction and detection of cocaine, some of its metabolites, morphine, and codeine from hair. They concluded from a round-robin study that extractions with 0.1 ATHCL are as efficient to remove the target compounds from hair as enzymatic digestion that dissolve the hair. GC/MS with either El or Cl provides accurate determinations of the targeted compounds. External contamination by powdered or vapor-deposited cocaine was incompletely removed by all approaches tested, making it difficult to differentiate incorporated drug from external contamination. This was also proved in extensive laboratory experiments by Wang and Cone. ... 

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. 

The comparison of the results of a round-robin study published by GrCnli et al. to our results for p = 40 K/min (the only heating rate investigated in both studies) shows that the correspondence between the experimental mass loss curves is very good. Nevertheless, the activation energy of 198.4 kJ/mol for the irreversible 1" order reaction from this work is considerably lower than the 211 - 232 kJ/mol found for the results from the different laboratories participating in the round-robin study. Instead,... 

GrPnli M., Antal M.J and Vdrhcgyi G. (1999) A round-robin study of cellulose pyrolysis kinetics by thermogravimetry. Ind. Eng. Chem. Res., 38,2238-2244... 

TABLE 1 Features of Compaction Simulators Used in the Bateman and Coworker Round-Robin Study... 

Bateman and coworkers report a comparative analysis of six different hydraulically powered compaction simulators manufactured by a variety of vendors (Table 1), In their round-robin study, they found that the compaction simulators were comparable when operated within a moderate compression stress range of 50-2(X)MPa. However, at higher pressures, correction factors needed to be applied because of elastic distortion and differences in loading characteristics of the hydraulic systems (5). These results are not surprising since like rotary tablet presses, compaction simulators are not perfectly rigid. Therefore, compaction simulators should be properly calibrated (including corrections for mechanical flexure and electronic noise) to ensure the collection of quality experimental data. 

In practice, two obstacles limit the ease for switching from one cTnl assay to another. First, there is currently no primary reference cTnl material available for manufacturers to use for standardizing then assays. Second, assay concentrations fail to agree because of the different epitopes recognized by the different antibodies used. An effort has been underway since 2001 by the AACC Subcommittee on Standardization of cTnl to prepare a primary reference material. In collaboration with the National Institute for Standards and Technology (NIST), two reference materials—-a TIC ternary complex and an IC binary complex— have been identified. Working with NIST and the in vitro diagnostic industries, preliminary round robin studies have demonstrated that while standardization of assays remains elusive, harmonization of cTnl concentrations by different assays has been narrowed from a twentyfold difference to a twofold to threefold difference. 

Formaldehdye generation and recovery studies 3.) Air exchange measurement techniques 4.) Preconditioning of test boards 5.) Temperature effect on chamber formaldehyde concentrations 6.) Relationship of popular quality control test methods to the large chamber 7.) Loading, air exchange rate, and wood product combination effects on chamber formaldehyde concentrations 8.) Chamber Round Robin studies between Georgia-Pacific s chamber and other outside lab chambers 9.) Chamber concentrations and its relationship to actual field measurements. 

As with many other analytical techniques, the temperature axis used in differential thermal analysis (and DSC) must be calibrated with materials having known transition temperatures. The International Confederation of Thermal Analysis (ICTA) has been very active in developing a set of standard materials for this purpose (19) and has worked with the U.S. National Bureau of Standards to have these materials made commercially available (20). The U.S. National Bureau of Standards GM 754-GM 760 DTA temperature standards are listed in Table 6.2. They cover the temperature range from —83 to 925 C. The results of an ICTA round-robin study with 24 cooperating laboratories have been reported by Menis and Sterling (20). 

Following the guidelines of ASTM D 6300, repeatability (r) and reproducibility (R) were determined from the data shown in Table 6. The results are given in Table 7 along with the mean of each sample and the standard deviations of r and R. The repeatability results show significant improvement over that of the ASTM D 7039-04. The reproducibility results are similar to that of inter-laboratory study (ILS) in 2002 [3]. Further interlaboratory round robin studies will be needed to confirm the reproducibility. 

Multiple techniques can be used to measure the particle size distribution, for example electrozone sensing, sedimentation, laser diffraction, and microscopy. With the exception of microscopy, they all require calibration and the results depend on the technique. For example, in a round-robin study reported in Reference 4, the commonly used electrical sensing zone technique (Coulter Counter) was compared to microscopy and sedimentation. The average particle size determined by the electrical sensing zone method was by about 25%... 

Proficiency testing or laboratory performance study or round-robin study Cooperative trial... 

Arsenic implants of high energy were measured in a round-robin study with 3 keV Cs ions, recording the... 

IPC-TR-579, Round Robin Reliability Evaluation of Small Diameter Plated Through Holes in Printed Wiring Boards, Institute of Interconnecting and Packaging Electronic Circuits, Lincoln-wood, 111. The IPC recently initiated a second round robin study, the results of which should be available in about 1996. 

Pfeifer et al. (2002) organized a round-robin study of a series of activated carbons prepared from olive stones. The objective of such a study was to make a comparative assessment of the results of studies using several appropriate techniques. A summary of the findings is given, initially, as below. 

Method B Lower Limit of Quantitation—In the round-robin study to develop statistics for this method, participants were asked to report results to the nearest 100 mg/kg. The lower limit of quantification could therefore only be determined to be in the range from 870 to 1180 mg/kg. ... 

For polydisperse samples, even in a mixture of two monodisperse spheres, the result however may still be far from satisfactory. In a round-robin study performed by eight laboratories a mixture of 400 nm and 1000 nm monodisperse latexes was measured using different PCS instruments and the data were processed using different inversion algorithms. The modality, mean diameter, and percentages of each population retrieved from the eight laboratories varied widely [81, 82]. 

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