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Research paper : Standardization of environmental analysis methods of hazardous chemicals (S. Taniyasu et al.)−281−Synthesiology - English edition Vol.5 No.4 (2013) gravimetric blending method (one of the preparation methods used frequently by the national metrology institutes[41]), and the concentration of the reference material was calculated by multiplying the dilution ratio and purity of K-PFOS. This concentration (certified value) is traceable to the SI. As described above, upon determining the certified value and uncertainty (Table 1), the development of the reference material of K-PFOS in methanol was completed in FY 2009[42] (Fig. 10). The ISO international method (March 2009) and the world’s first CRM (2010) became available at almost the same time as the addition of PFOS to the POPs Convention (August 2010).On the other hand, we would like to point out the use of Oasis®WAX cartridge as the problem indirectly generated in this standardization. The analysis of the PFOS/PFOA-related substances by ISO 25101 assumes basic knowledge of the analysis method and strict quality control conditions, and the reliability and reproducibility of the analysis value may decrease when such conditions are insufficient. The Oasis®WAX cartridge used frequently in SPE can produce excellent results for the various PFOS/PFOA-related substances from C2 to C18, if the appropriate buffer solution is used as the cleansing fluid for low-concentration samples, as described in the original paper,[13] which has become the basic technology for ISO 25101 and JIS K 0450-70. However, when the simplified elution method using formic acid (described in guidelines such as Guideline for Wastes Containing PFOS (2010)) was used, we found that the recovery varied greatly depending on the matrix. Therefore, reliability could not be maintained unless the elution condition was optimized sufficiently when the formic acid was used. The reasons for the decrease in the recovery and reproducibility of the short-chain (PFBA) were the same when the SPE cartridge that had similar property as the Oasis®WAX cartridge was used. Moreover, in recently conducted research, it was confirmed that particularly strict desalinization and elution condition controls were necessary in cases where the SPE cartridge was used for seawater analysis. If limited to the PFOS/PFOA measurement of carbon chain 8 in the high-concentration sample, the SPE for simple C18 or polymers was easier for less experienced people to use, although there were problems such as the contamination and low recovery of related compounds other than PFOS/PFOA. In the ISO 25101 and JIS K 0450-70, the C18[23] and polymer SPE (such as the Oasis®HLB cartridge[26][28]) were given as examples where SPE cartridges other than the Oasis®WAX cartridge could be used in the ISO Annex (Informative) and the JIS Annex (Informative).At this point, there may be insufficient understanding for the most important essence of QA/QC of how to confirm the reliability of the “PFOS analysis technology using the solid phase extraction and liquid chromatograph tandem mass spectrometer” that is the basic concept of ISO 25101. The problem of ISO is that there is no “explanation” at the end like JIS, and there is hardly any detailed explanation such as the reasons and background for conducting a certain analysis procedure. JIS documents the items that were discussed in the process of JIS standardization and the detailed explanation of the reasons and background of standardization, not just the performance data, so the user can thoroughly understand each procedure. It is necessary to enforce the good laboratory practice (GLP)Term 8 by returning to the fundamentals of analytic chemistry; to obtain high quality study data and to ensure that the study data are of the same level and therefore allowing the mutual acceptance of the study data among different countries and laboratories.6 ConclusionsThe CSCL is controlled by three ministries: the Ministry of Environment; Ministry of Economy, Trade and Industry; and the Ministry of Health, Labour and Welfare. The POPs Convention is handled in the same framework. If the sharing of appropriate information and trans-ministry support for international standardization can be achieved, the establishment of several international standards in the environmental analysis field can be expected based Note) Relative standard uncertainty: The relative amount where the uncertainty arising from measurement result expressed by measurement standard deviation etc. (so-called standard uncertainty) is divided by the measurement result.0.001 Solvent blank0.066 Stability0.474 Homogeneity0.515 Preparation of solution0.059 Purity assessmentRelative standard uncertainty(%)Factors of uncertaintyFig. 10 Potassium perfluorooctanesulfonate in methanol (NMIJ CRM 4220-a)Table 1. Factors of uncertainty on potassium perfluorooctanesulfonate in methanol

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