Interlaboratory

Before a procedure can provide useful analytical information, it is necessary to demonstrate that it is capable of providing acceptable results. Validation is an evaluation of whether the precision and accuracy obtained by following the procedure are appropriate for the problem. In addition, validation ensures that the written procedure has sufficient detail so that different analysts or laboratories following the same procedure obtain comparable results. Ideally, validation uses a standard sample whose composition closely matches the samples for which the procedure was developed. The comparison of replicate analyses can be used to evaluate the procedure s precision and accuracy. Intralaboratory and interlaboratory differences in the procedure also can be evaluated. In the absence of appropriate standards, accuracy can be evaluated by comparing results obtained with a new method to those obtained using a method of known accuracy. Chapter 14 provides a more detailed discussion of validation techniques. 

CRITERIA TO SELECT LABORATORIES TO BE PARTICIPATED IN INTERLABORATORY INVESTIGATION BASED ON RANK... 

The principle of insignificancy , enabling use of the given principle for any level of probability is substantiated. The systematic application of the given principle results in developing metrological criteria for pharmaceutical reference substance, analytical validation, evaluation of results of interlaboratory testing and suitability of the analytical equipment for the phamiaceutical analysis. 

Environmental analytical association Ecoanalytica produce standai d samples during last 12 years. Two topics will be discussed. The first is the principles of development of staictures and maintenance of quality of standai d samples. The organization of manufacture and maintenance of their stability ai e considered too in the report. Besides them authors consider scientifically-methodical aspects of preparation of samples for experimental check of technical competence of analytical laboratories and also samples for interlaboratory tests. 

Relyea, J.F. Serne, R.J. "Controlled Sample Program Publication Number 2 Interlaboratory Comparison of Batch Kj Values", Report PNL-2872, Battelle Pacific Northwest Laboratory, 1979. 

Routine use for control purposes has shown the method to be reliable and interlaboratory agreement on data has been good. The method as presented has consistently detected < 1 ppm of sultone in a 38% alkenesulfonate solution. By concentrating the solution of the neutral oil and using silica gel column chromatography, 0.1 ppm of sultone can readily be detected. Further changes in GC conditions and sensitivity can give even lower limits of detection. 

Nilsson, T, Ferrari, R., and Facchetti, S., Interlaboratory Studies for the Validation of Solid-phase Mieroextraction for the Quantitative Analysis of Volatile Organic Compounds in Aqueous Samples, Anu/yrica Chimica Acta 356, 1997, 113-123. 

Davies, P. L., Statistical Evaluation of Interlaboratory Tests, Fresenius Z. Anal. Chem. 331, 1988, 513-519. 

Bauer, C. R, Grant, C. L., and Jenkins, T. R, Interlaboratory Evaluation of High-Performance Liquid Chromatographic Determination of Nitroorganics in Munition Plant Wastewater, Ana/. Chem. 58, 1986, 176-182. 

Hall, P., and Selinger, B., A Statistical Justification Relating Interlaboratory Coefficients of Variation with Concentration Levels, Anal. Chem., 61, 1989, 1465-1466. 

BidlemanTF. 1981. Interlaboratory analysis of high molecular weight organochlorines in ambient air. Atmos Environ 15 619-624. 

A number of handbooks and monographs are available with detailed descriptions of a variety of plant products and their use (Shahidi and Naczk, 1995). From a more practical point of view, an interlaboratory comparison between six university and industry laboratories of 17 extracts of spices, teas, coffees, and grape skin and of tomato peel slurry established within the framework of an EU sponsored programme, would be of interest (Schwarz et al, 2001). In this collaboration, detailed chemical analysis of the content of different phenolic compounds is compared with six antioxidant assays for the 17 extracts including different extraction procedures. 

An interlaboratory study using mixed vegetable reference material showed average relative standard deviations (RSDs) of 23% ranging from 11% for lutein and a-carotene to 40% for lycopene." Triplicate HPLC injections of the same extract showed RSD values of 0% for P-carotene and 6.8% for lutein. ... 

Scott, K. et al.. Interlaboratory studies of HPLC procedures for the analysis of carotenoids in foods. Food Chem., 57, 85, 1996. 

Saurer M, I Robertson, R Siegwolf, M Leuenberger (1998) Oxygen isotope analysis of cellulose an interlaboratory comparison. Anal Chem 70 2074-2080. 

All the analytical data are from the same laboratory consequently, interlaboratory analytical variation is not a factor. The intralaboratory variation for that laboratory was 9.1 percent (i.e., the relative standard deviation based on repetitive analyses of performance evaluation samples). 

The data presented In Figures 2, 3, and 4 are from five different laboratories However, the samples from any one method In each segment were sent to the same contractor thus. Interlaboratory analytical variation Is not a factor In the data columns, but It may be a factor In the data rows The estimated Interlaboratory and Intralaboratory relative standard deviations for TCDD concentrations of 2 to 12 ppb range from 9 to 18 percent and 5 to 13 percent, respectively ... 

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. 

Takacs-Novak, K., Avdeef, A. Interlaboratory study of log P determination by shake-flask and potentiometric methods. J. Pharm. 

Booth E. Crofton P and Roberts LB (1974) The influence of standards on interlaboratory quality control programmes. Clin Chim Acta 55 367-375. 

Ihnat M, Wolynbtz MS (1993) Summary of an interlaboratory characterization (certification) campaign to establish the elemental composition of a new series of agriculture/food reference materials. Fresenius J Anal Chem 345 185-187. 

Kucera j, Mader P, Miholova D, Cibulka J, Faltejsek J and Kordik D (1995) Preparation of the bovine kidney and bovine muscle reference materials and the certification of element contents fi om interlaboratory comparisons. Fresenius J Anal Chem 352 66-72. 

Qubvauviller Ph and Maier EA 1999), Interlaboratory Studies and Certified Reference Materials for Environmental Analysis. Elsevier Publishers B.V., Amsterdam. 

Bogershausen W, Cicciarelli R, Gercken B, Konig E, Krivan V, Muller-Kaeer R, Pavel J. Seltner H, Schelcher J 1997) Pure graphite as a reference material for the determination of trace elements - an interlaboratory collaborative study. Fresenius J Anal Chem 357 266-273. 

Sharpless KE, Gill LM, Margolis SA, Wise SA, Elkins E (1999) Preparation of standard reference material 2383 (baby food composite) and use of an interlaboratory comparison exercise for value assignment of its nutrient concentrations. J AOAC Inti 82 276-287. 

Value assignment based on selected data from interlaboratory studies... 

Fig. 3.4 Results from the interlaboratory study used for certification of benzo[b]fluoranthene in BCR CRM 088 Sewage Sludge...

DE VooGT P, HinschbergerJ, Maier EA, Griepink B, Muntau H, and Jacob J (1996) Improvements in the determination of eight polycydic aromatic hydrocarbons through a stepwise interlaboratory study approach. Fresenius J Anal Chem 356 41-48. 

Ihnat M (2000) Performance of neutron activation analytical methods in an international interlaboratory reference material characterization campaign. J Radioanal Nud Chem 245 73-80... 

Kucera j (1995) Elemental characterization of new Polish and US NIST geological, environmental and biological reference materials by neutron activation analysis and comments on the methodology of interlaboratory comparisons. Chem Anal (Warsaw) 40 405-421. 

Leaver ME, and Bowman WS (1994a) Interlaboratory Measurement Program for the Standard ARD Material NBM-i. Mineral Sdences Laboratories Division Report MSL 94-28 (CR) Draft. CANMET, Natural Resources Canada, Ottawa. 

Quevauviller Ph, and Maier EA (1999) Interlaboratory studies and certified reference materials for environmental analysis - the BCR approach. Elsevier, Amsterdam Quevauviller Ph, Drabaek I, Muntau H, Biahchi M, Bortoli A, and Griepink B (1996a) Certified reference materials (CRMs 463 and 464) for the quafity control of total and methyl mercury determination in tuna fish. Trends Anal Chem 15 160-167. 

It must be remarked that terminology is not consistent and there are many widely used synon)ms. Quality control in this Chapter refers to practices best described as internal quality control. Quahty assessment is often referred to as external quality control, proficiency testing, interlaboratory comparisons, round robins or other terms. Internal Quality Control and External Quality Assessment are preferred because they best describe the objectives for which the RMs are being used, i.e. the immediate and active control of the results being reported from an analytical run or event, and an objective, retrospective assessment of the quality of those results. 

DE Boer J (1997) The preparation of biological reference materials for use in interlaboratory studies on the analysis of chlorobiphenyls, organochlorine pesticides and trace metals. Mar Poll Bull 35 84-92. 

DE Boer J, van der Meer J, Brinkman UATh (1996) Determination of chlorobiphenyls in seal blubber, marine sediment, and fish interlaboratory study. ( Assoc Off Anal Chem 79 83-96. 

Martin-Esteban a, Fernandez P, Camara C, Kramer GN, Maier EA 1997) Preparation, homogeneity and stability of polar pesticides in freeze-dried water interlaboratory exercise. Int. J Environ Anal Chem 67 125-141. 

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

Tuinstea LGMTh, Roos AH, Werdmuller WA (1985) Capillary gas chromatographic determination of some chlorobiphenyls in eel fat interlaboratory study. J Assoc OffAnal Chem 68 756-759. 

Fig- 5-7 Results (lU/mg) of an interlaboratory study to determinate the potency of tylosin CRS 1 by microbiological assay (diffusion method). 

Butler OT, Howe AM (1999) Development of an international standard for the determination of metals and metalloids in workplace air using ICP-AES evaluation of sample dissolution procedures through an interlaboratory trial, f Environ Monit 1 23-32. 

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