Vol.5 No.4 2013

Research paper : Standardization of environmental analysis methods of hazardous chemicals (S. Taniyasu et al.)−277−Synthesiology - English edition Vol.5 No.4 (2013) be high because the state-of-the-art analysis devices had fluororesin components. To solve this issue, the system blank was reduced to tens of fg (1 fg = 10-15 g) by eliminating parts such as the degassing device and switching valve that were not essential for measurement by the LC-MS/MS. Because the SPE cartridge[23] that contained the existing octadecyl group (C18) was highly contaminated and not suitable for low concentration analysis, we developed the PFOS/PFOA analysis method using the Oasis®HLB cartridge that had both the hydrophilic and lipophilic properties, manufactured by the Waters Corporation. This was confirmed to have less contamination compared to the C18 SPE cartridge[23] and could be applied to low concentration samples such as the outer seawater.[26][28] However, the Oasis®HLB cartridge with excellent low contamination and high recovery rate is only limited to the measurement of PFOS/PFOA, and it was not suitable for the extraction of short-chain compounds such as perfluorobutanoic acid (PFBA). Therefore, we focused on the property of PFOS/PFOA as organic acids, and by reducing the contamination to a minimum by using the Oasis®WAX cartridge of Waters Corporation that had the anion exchange capability suitable for the adsorption and capture of acidic substance. We developed the analysis condition where carbonic acid with carbon chain length from C2 to C18 and sulfonic acid from C2 to C10 could be adsorbed and recovered, as well as PFOS and PFOA (Fig. 6).[13][30] The reduction of contamination and system blank of the equipment and reagents used[12][24][25] and its importance were also addressed in ISO 25101.When an ordinary reverse phase HPLC column such as ODS (octadecylsilyl silica gel) column was used, elution occurred in the order of short to long chain, and the short-chain compound such as PFBA showed poor peak formation and the separation with the foreign substances was insufficient (Fig. 7a). On the other hand, in the separation column with ion exchange capacity, the order of elution reversed, and elution occurred from long to short chain, and the peak formation and foreign substance separation were improved (Fig. 7b).[30] Crosschecking by two types of separation columns with different separation principles by concurrent check of the ion strength ratio of the measured mass showed that the reliability dramatically increased compared to the conventional single column measurement. In both ISO 25101 and JIS method, the reverse phase column is used as the separation column since only PFOS and PFOA are subjects of analysis. However, it is written in the JIS Annex (Informative) that the measurement of related chemical substances with short-chain compound other than PFOS and PFOA can be measured, the reverse phase column and the separation column with ion exchange capacity are both described, and the importance of crosschecking using the two types of separation columns is discussed.In general, when the detection sensitivity is insufficient, the amount of the sample is increased. However, in our case, by reducing the amount of the sample, the effect of coexisting substances on the analysis sensitivity (matrix effect) decreased,[12] and as a result, the measurement sensitivity was increased. With this technique, the limit of quantification can be increased by minimizing the contamination, even in the previous generation devices with low sensitivity. Since the latest measuring device uses a lot of fluororesin and has in general a higher system blank, what determines the methodological detection limit and precision for PFOS is, at present, not the sensitivity of the device, but how strictly the QA/QC is preformed. The highly sensitive analysis method is not truly necessary for rivers and coastal waters in Japan that are the usual monitoring targets. However, for outer sea environmental monitoring to understand the global dynamics, advanced QA/QC is essential in addition to high sensitivity. Such research papers were the basis of ISO 25101.4 Reliability of the developed analysis methodIn ISO /TC147 (water quality) /SC2 (physical, chemical and biochemical methods), the quality control studies (studies to determine whether the analysis method used is adequate) are conducted in multiple laboratories according to the standard operation procedure (SOP) for the analysis method to be used as a standard, and the performance data obtained must be comparable with the standard. On the other hand, in Japan, the performance data of the analysis method have not necessarily been released in the past. In the Research Project for Creating Standards to Meet Social Needs “Strategic Project to Build the JIS System for Environmental Measurement that Contributes to the Strengthening of Fig. 6 Solid phase extraction method using the weak anion exchange cartridge (Oasis®WAX)Sample preparationAdding internal standardWater samplesSolid-phase extraction (SPE) methodConcentrationi.e.) 25 mM acetic acid buffer solution (pH4)Cleansingi.e.) Methanol 0.1 % ammonia/methanolElutionSample irrigated with wateri.e.) 0.1 % ammonia/methanol Methanol WaterConditioning


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