オーラルセッション
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2C-O2-1520 PDF
水質分析におけるグアニジン類縁化合物のブランク検出事例
The occurrence of seven guanidine derivatives in aquatic environment was investigated. However, 1,3-diphenylguanidine (DPG; 0.39–0.69 ng L-1) and cyanoguanidine (CG; 80–150 ng L-1) were detected from some ultrapure water samples in the blank tests. The other target analytes were below detection limits in the blank tests. Solid phase extraction (SPE) cartridge blank (without loading) was also tested, and only DPG (0.25 ng L-1) was detected as a corresponding value assuming that 100 mL of the sample was loaded. It was difficult to determine that DPG in ultrapure water was derived from blank contamination or the ultrapure water itself. Therefore, we evaluated the blank levels in each analytical batch and compared the sample concentration with the blank concentration to prevent “false positives.” In contrast, CG was detected not from the SPE cartridge blank but from two ultrapure water blanks. Thus, the use of ultrapure water with CG contamination was avoided in this study. Since DPG and CG have been detected from environmental water with high frequency, researchers should always try to reduce the blank level of such ubiquitous compounds to detect their accurate concentrations in water.