Interlaboratory calibration

Overview. Polychlorinated Biphenyls. Polycyclic Aromatic Hydrocarbons Determination. Polymers Natural Rubber Synthetic Polyurethanes. Quality Assurance Quality Control Instrument Calibration Interlaboratory Studies Reference Materials Production of Reference Materials Method Validation Accreditation Clinical Applications Water Applications. Sample Handling Comminution of Samples Sample Preservation Automated Sample Preparation Robotics. Sampling Theory Practice. Solvents. Supercritical Fluid Chromatography Overview Applications. Vitamins Overview Fat-Soluble. 

See also Quality Assurance Quality Control Instrument Calibration Interlaboratory Studies Reference Materials Production of Reference Materials. Spectrophotometry Overview. 

See alsa Quality Assurance Instrument Calibration Interlaboratory Studies Reference Materials Method Validation Traceability Accreditation. Surface Analysis Overview X-Ray Photoelectron Spectroscopy. 

In case of fast gradient (below 15 min), S could be considered constant for all the investigated molecules and wiU only have a small influence on the retention time of the compounds. Thus, the gradient retention times, of a calibration set of compounds are linearly related to the ( )o values [39]. Moreover, Valko et al. also demonstrated that the faster the gradient was, the better the correlation between t, and < )o [40]. Once the regression model was established for the calibration standards, Eq. 8 allowed the conversion of gradient retention times to CHI values for any compound in the same gradient system. Results are then suitable for interlaboratory comparison and database construction. The CH I scale (between 0 and 100) can be used as an independent measure of lipophilicity or also easily converted to a log P scale. 

Musial CJ, Uthb JF (1983) Interlaboratory calibration results of polychlorinated biphenyl analyses in herring. J Assoc Off Anal Chem 66 22-31. 

M. L. Magee, J. T. On mass spectrometer instrument standardization and interlaboratory calibration transfer using neural networks. Anal. Chim. Acta 1997,384, 511-532. 

National Tests. It is clearly possible to remove the technical barrier to trade represented by different national fire test procedures, by providing a facility for a manufacturer to conduct the relevant tests once and within his home country, with a guarantee of acceptability of the results by all Member States. This requires laboratories to equip themselves with all the necessary equipment and for an extensive interlaboratory collaboration and calibration procedure to be introduced, which would ensure mutual acceptance of test results. 

In addition, a system for making sure staff are appropriately qualified and trained for the work that they are doing must be in place. This will enable an auditor to see clearly the demonstrated competence of the staff and how this has been checked. The requirements for all major items of equipment must be listed, to ensure that the equipment in use is suitable for the task, is in working condition and, where necessary, is calibrated. For all of the instrumentation there needs to be a documented schedule for maintenance. Measurements must be traceable, that is, the laboratory must be able to show how the calibration of measurement instruments is traceable to National or International Standards. Where this presents practical problems, as in some chemical measurements for example, interlaboratory comparison and the use of reference materials (and preferably Certified Reference Materials) will be required. 

Currie, L. A., Polach, H. A., Exploratory Analysis of the International Radiocarbon Cross-Calibration Data Consensus Values and Interlaboratory Error, Proceedings of the 10th International Radiocarbon Conference, Radiocarbon. 22, 933... 

Quantification is usually achieved by a standard addition method, use of labeled internal standards, and/or external calibration curves. In order to allow for matrix interferences the most reliable method for a correct quantitation of the analytes is the isotope dilution method, which takes into account intrinsic matrix responses, using a deuterated internal standard or carbon-13-labeled internal standard with the same chemistry as the pesticide being analyzed (i.e., d-5 atrazine for atrazine analysis). Quality analytical parameters are usually achieved by participation in interlaboratory exercises and/or the analysis of certified reference materials [21]. 

Based on their use in industrial and domestic applications and abundance in environmental samples, six surfactants were selected by the participants of interlaboratory study I. Two different standard mixture solutions (standards II and 12) were distributed to all participants for the preparation of the calibration graphs. Standard II contained Arkopal N100 (NPEO), Marlamid DF 1218 (coconut fatty acid diethanolamide, CDEA) and Marlon A 350 (linear alkylbenzene sulfonate, LAS) at 1000 mg L-1 for each compound, while standard 12 contained Rewopol NOS 5 (nonylphenol ethoxylate sulfate, NPEO-SO4),... 

Quality control, however, needs more attention. For example, it has been reported that much of the chemical data produced by the International Indian Ocean Expedition is unusable because of doubts about its accuracy. Such reports are a perennial source of confusion in marine chemistry. Better calibration, universal standards, and interlaboratory comparison are essential if we are to continue our present field methods, in which independent investigators make measurements that are presumably comparable (NRC, 1971, pp. 54-55). 

Unfortunately, and probably unavoidably, from the earliest research until the present, investigators have not used the same standardization process. Furthermore, standardization practices within different research groups have only rarely followed the meticulous series of in-house calibrations, verifications, and interlaboratory comparisons long prescribed by the conununity of measurement specialists. Several quantitatively crucial studies, however, have followed sound measurement procedures (see, e.g.. Chapter 9). 

The links to be established with all stakeholders should be clearly specified to enable the laboratory to function efficiently and meet the needs of its customers (the society through legislation and individuals). The laboratory is supplied with products (reagents, equipment, reference materials), receives services (accreditation, certification, provision of interlaboratory comparison schemes) and cooperates with other laboratories (cooperation in testing, provision of calibration services). 

Reliability Competence of personnel Suitability of equipment Calibration of equipment Interlaboratory comparisons Method validation... 

These concentrations were established by interlaboratory calibration... 

Intra- and interlaboratory calibration of the DR CALUX bioassay for the analysis of dioxins and dioxin-like chemicals in sediments... 

The results of the multiple analysis of the standard 2,3,7,8-TCDD calibration curves are also be used to determine the per-participant LOD and LOQ taking into account interlaboratory variation (Table 3). This results show that on average, the partieipants of the calibration study meet the set LOD and LOQ derived from the intralaboratory study. 

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