Evaluation of analytical methods for aloacetic acids in drinking water
Date Issued
2008
Date
2008
Author(s)
Tang, Chin-Chun
Abstract
Nine haloacetic acids (HAAs) in drinking water are disinfection by-products. The method of analyze haloacetic acids are United States Environment Protection Agency method 552.3 and Taiwan Environment Protection Agency NIEA W533.51B, which using esterification and analyzing them by gas chromatography. Because bromocontained trihaloacetic acid esters decompose at high temperature injection port and the esterification efficiency of bromocontained trihaloacetic acids are bad, the analytical methods of haloacetic acids are still not clear. Therefore, we referred to the sample preparation methods of USEPA method 552.3, and using GC/MS to analyze haloacetic acids for investigating the sensitivity of bromocontained trihaloacetic acid esters analysis by using cool on column mode injection or analyzing bromocontained trihaloacetic acids that decomposed bromocontained to methanes at high temperature injection port. n splitless mode injection, it would decrease the situation of thermal decomposition of bromocontained trihaloacetic acid esters when liner did not packed glass wool. For comparing the analysis of haloacetic acids by the two injection systems, we used cool on column mode injection to analyze haloacetic acids was better than used splitless mode injection to do so; however, it was not apparent. Besides, adding 0.6-30 μg/L concentrations of haloacetic acids into double deionized reagent water, the range of detection limit of haloacetic acids was 0.12-6.7 μg/L in cool on column mode injection, and 0.2-5.9 μg/L in splitless mode injection. And we adding 6-200 μg/L concentrations of haloacetic acids into double deionized reagent water, the range of mean recovery of haloacetic acids was 92.79-115.62％ in cool on column mode injection, and 100.07-128.80％ in splitless mode injection. The range of relative standard diversion of haloacetic acids was 6.18-17.62％ in cool on column mode injection, and 1.36-19.44％ in splitless mode injection.ue to the high injection port temperature, bromocontained trihaloacetic acids decomposed to bromocontained methanes easily, thus, analysis of bromocontained trihaloacetic acids may be interfered with the bromocontained methanes that existed in drinking water. For this reason, 50 μg/L bromocontained methanes and 0.1 μg/L bromocontained trihaloacetic acids added to double deionized reagent water. After purging bromocontained methanes 15 minutes by nitrogen gas, the range of detection limit of bromocontained trihaloacetic acids that decomposed bromocontained methanes was 0.11-0.24 μg/L. And we adding 3 μg/L concentrations of bromocontained trihaloacetic acids into double deionized reagent water, the range of mean recovery of bromocontained trihaloacetic acids that decomposed bromocontained methanes was 92.79-115.62％. The range of relative standard diversion of bromocontained trihaloacetic acids that decomposed to bromocontained methanes was 6.18-17.62％.n conclusion, we recommended that using splitless mode injection without glass wool or using cool on column mode injection that decreased the thermal decomposition of bromocontained trihaloacetic acid esters. Besides, directly analyzing bromocontained trihaloacetic acids that decomposed bromocontained to methanes to avoid the decomposition of bromocontained trihaloacetic acid esters at a high injection port temperature and increase the sensitivity of analysis.
Subjects
haloacetic acids
bromocontained trihaloacetic acids
GC/MS
cool on column
splitless
Type
thesis
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