Quantification interlaboratory studies

CRM for road dust (BCR-723) containing 81.3 2.5 Jg/kg Pt, 6.1 1.9 ig/ kg Pd, and 12.8 1.3 Jg/kg Rh, was introduced [49, 228]. It is widely used for quality control of results obtained in the analysis of environmental materials (e.g., airborne particulate matters, dusts, soils, and sediments). Comparison of results obtained using different analytical procedures and interlaboratory studies are recommended when there is a lack of suitable CRM (e.g., in examination of clinical samples). The use of standards based on real matrices (e.g., saliva, plasma, ultrafiltrates, and lung fluids) instead of synthetic solutions is recommended in such analyses. Difficulties with the identification and quantification of different metal species in examined samples make the reliability of results of great importance. The use of various instrumental techniques for examination of particular samples can be helpful. The application of chromatography, mass spectrometry, and electrochemistry [199] HPLC ICP MS and HPLC MS/MS [156] ESI MS and MALDI [162] micellar electrokinetic chromatography, NMR, and MS [167] AAS, ESI MS, and CD spectroscopy [179] SEC IC ICP MS and EC ESI MS [180] and NMR and HPLC [229] are examples of such approaches. 

Often the purpose of collaborative trials is to evaluate a new analytical method operated in several laboratories. According to lUPAC a collaborative study is an interlaboratory study in which each laboratory uses the defined method of analysis to analyze identical portions of homogeneous materials to assess the performance characteristics obtained for that method of analysis, e.g., specificity, selectivity, sensitivity, range, limit of quantification, limit of detection, linearity, accuracy, and precision. Only methods giving small interlaboratory variations will be adopted for use as a standard method. Attention has to be paid to the design of collaborative studies for... 

Another important point was made by this study if possible, use reference samples with gene expression levels similar to those expected for the test samples. This should improve quantification at the low end. Moreover, the Tan et al., (2003) and Barczak (2003) studies also demonstrate the need for the standardization of commercial microarray products and reference standards so that both interlaboratory and cross-platform performances can be properly assessed. While commercial microarrays from different vendors all claim substantial gene probe "real estate," the number of probes in common is smaller. This makes it difficult to compare experiments across platforms, especially those from major suppliers such as Affymetrix, Agilent, and Amersham (Figure 2.8). 

In addition, we conducted the interlaboratory validation study for these kits. The results are shown in Table 15.6. The data suggest that both ELISA kits are precise and reliable tools for the quantification of buckwheat soluble protein in processed foods. 

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