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采用五氟苯甲基溴(PFBBr)衍生、顶空固相微萃取(HS-SPME)结合气相色谱质谱仪(GC-MS)测定了啤酒中的硫化氢。顶空固相微萃取采用65μm PDMS/DVB纤维,先将纤维插入装有PFBBr溶液的顶空瓶中,在顶空部分吸附PFBBr,再将纤维插入装有5 mL啤酒的20 mL顶空瓶的顶空部分,在55℃萃取20 min,衍生和萃取都在顶空瓶内完成。采用GC-MS检测,特征离子为m/z394(五氟苯甲基硫醚)。硫化氢在线性范围(1～40μg/L)内其响应值与质量浓度有较好的线性关系,相关系数达到0.994。被测样品相对标准偏差RSD=2.8%(n=5),向样品中加入10,20,40μg/L的标准溶液,测得加标回收率为91.5%～96.1%(n=3)。
Hydrogen sulfide in beer was determined by pentafluorobenzyl bromide (PFBBr) derivatization and headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) Headspace solid-phase microextraction using 65μm PDMS / DVB fibers, the first fiber into the headspace filled with PFBBr solution in the headspace adsorption PFBBr, and then the fiber into the 20mL headspace bottles containing 5mL beer Headspace, extracted at 55 ℃ for 20 min, derivatization and extraction were completed in the headspace bottle. Using GC-MS detection, the characteristic ion was m / z 394 (pentafluorobenzyl sulfide). In the linear range of hydrogen sulfide (1 ~ 40μg / L), the response value of hydrogen sulfide had a good linear relationship with the mass concentration, and the correlation coefficient reached 0.994. The relative standard deviation (RSD) of the tested sample was 2.8% (n = 5). The standard solutions of 10, 20 and 40 μg / L were added to the samples and the recoveries were 91.5% -96.1% (n = 3).