| In recent years, with the rapid development of automobile industry, private cars begin to enter the ordinary family, the utilization rate of gasoline also increases year by year, which causes a lot of chemical pollutants been released, the water environment is polluted more and more seriously. Gasoline contains a large number of aromatic compounds, in general,including benzene, toluene, ethylbenzene, m-xylene, p-xylene,o-xylene(BTEX). A group gasoline additives are volatile organic compounds which added to the gasoline to increase gasoline octane and enhance the efficiency of gasoline combustion. At present, a group gasoline additives which are usually used in China including methyl tert-butyl ether(MTBE), ethyl tert-butyl ether(ETBE), and diisopropyl ether(DIPE), tert-amyl methyl ether(TAME), the formic acid tert-butyl ester(TBF), tert-butyl alcohol(TBA). Studies have shown that MTBE, TBA and BTEX suspected with carcinogenic and mutagenic and reproductive development toxicity, they may caused different degree to human body health. Therefore, In order to reduce the 12 kinds of BTEX and gasoline additives concentration of organic compounds in water,developing a rapid, sensitive and efficient detection method is very necessary.The object of this paper is to develop a detection method for twelve kinds of volatile BTEX and gasoline additives :(1) The use of two sample preparation techniques, purge and trap(P&T) and headspace solid-phase microextraction(HS-SPME) systems, enrich and separate the twelve volatile organic compounds respectively. Experimental parameters for P&T technique and HS-SPME preparation techniques are optimized and compared.(2) A method for determining twelve volatile BTEX and gasoline additives in water has been developed using gas chromatography-triple quadrupole mass spectrometry(GC-QqQ-MS/MS) in multiple reaction monitoring(MRM) mode.Precursor ions and product ions for the twelve analytes are identified for the first time and the chromatographic and mass spectrometry operating conditions are optimized based on the GC-QqQ-MS/MS. Compared with previous methods, the GC-QqQ-MS/MS method offers the following advantages: higher sensitivity, fewer interfering peaks, lower baseline and cleaner chromatograms.(3) The developed method for determining twelve volatil BTEX and gasoline additives in water based on P&T method offers limits of detection(LODs) in the range of 0.52-32 ng/L, the intra-day and inter-day relative standard deviations(RSDs) in the range of 1.99-8.87% and 1.18-12.7% respectively, and recoveries in the range of80.2-114.2% and 80.5-120.1% for surface water and groundwater, respectively. While the HS-SPME method produces LODs ranging from 0.11 to 151 ng/L, the intra-day and inter-day RSDs in the range of 1.19-9.65% and 1.09-9.78%, and recoveries in the range of 73.9-123.1% and 73.7-117.4% for surface water and groundwater, respectively.The both pretreatment method acquires a great of achievements. The HS-SPME-GC-MS/MS method produced lower LODs for BTEX than the PT-GC/MS/MS; however, for rest of the analytes, the PT-GC-QqQ-MS/MS provided lower LODs than the HS-SPME-GC-QqQ-MS/MS.(4) The LODs and LOQs for P&T combined with the GC-QqQ-MS/MS determination of the twelve volatile BTEX and gasoline additives are lower than P&T coupled to the GC-MS. |
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