顶空固相微萃取法用于饮用水源水中苦味酸的间接测定

建立了间接测定饮用水源水中苦味酸的前处理方法——顶空固相微萃取法(HS-SPME)。用带65μm聚二甲基硅氧烷-二乙烯基苯(PDMS-DVB)涂层的固相微萃取柱顶空萃取水中苦味酸与次氯酸钠的反应产物——氯化苦(硝基三氯甲烷),氯化苦用气质联用仪检测,采用质谱的选择离子模式和内标法进行定量。实验优化了萃取条件,如萃取柱涂层、水样与次氯酸钠体积比例、样品体积、预反应时间、盐度、样品pH、反应和萃取的温度、萃取时间等。使用优化后的条件,获得方法检出限和校准曲线r分别为0.8μg/L和0.9950。线性范围2.0—20.0μg/L;饮用水源水加标回收率均值和相对标准偏差分别为106.5%和9.0%(n=6)。方法适用于饮用水源水中苦味酸的间接测定。

Indirect Determination of Picric Acid in Drinking Source Water by Head Space Solid Phase Microextraction

Head space solid phase microextraction(HS-SPME) method followed by gas chromatography and mass spectrometry(GC-MS) was developed for indirect analysis of picric acid in drinking source water.Chloropicrin,the product of picric acid with sodium hypochlorite solution,was extracted by 65μm PDMS-DVB fiber,and then separated and detected by GC-MS with selective ion mass(SIM) mode and internal standard quantitative method.With optimizing conditions,such as the selection of SPME coatings,the volume ratio of sample and sodium hypochlorite solution,sample volume,reaction time,NaCl quantity,sample pH,reaction-extraction temperature and extraction time etc,correlation coefficient and detection limit were respectively 0.9950 and 0.8μg/L with linear range of 2.0—20.0μg/L.Average recovery was 106.5%(n = 6) in drinking source water samples,and the relative standard deviation was 9.0%.HS-SPME a pre-processing method,was capable to the indirect determination of picric acid in drinking source water sample.