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由于近年来我国经济的快速发展与工业化的逐步加速,水体的化学污染日益严重,并影响到了水源地饮用水的安全[1-4]. 水源地中检出的各类有机微污染物浓度较低,并且环境体系基质较为复杂。在使用传统的一维气相色谱质谱联用技术(GC-MS)对这类复杂样品进行分析时,通常不能将混合物充分分离,造成组分共洗脱、峰容量不足的现象,且无法达到较低的检测限,为有机物的鉴定带来困难[5].
全二维气相色谱是通过调制器将两根相互独立,极性不同,分离机理不同的色谱柱串联起来,从而提供物质的正交分离,使峰容量极大提高[6-9]. 同时,由于调制器的聚焦作用,使得全二维气相色谱与一维气相色谱相比检测灵敏度得到提高[10-14]. 目前全二维气相色谱飞行时间质谱联用技术(GC×GC-TOFMS)对水环境中的污染物分析已有大量应用,但较多是对某种或某一类目标有机物的靶向分析研究. 何晓蕾等 [15]通过使用全二维气相色谱-飞行时间质谱测定了焦化废水中16种多环芳烃(PAHs)的含量,并通过仪器数据处理软件建立了该类废水中整体有机物的组成比对方法. 张红庆等 [16]建立了地下水中低环多环芳烃及其衍生物的GC×GC-TOFMS检测方法,用于河北地区6个地下水样品中低环多环芳烃的检测,其中4个样品有检出. Matamoros等[17]通过使用GC×GC-TOFMS同时对河流中包括农药、多环芳烃(PAHs)、药物和个人护理品(PPCPs)在内的97种痕量有机污染物进行检测,检测限(LODs)为0.5—100 ng·L−1. Teehan等[18]使用GC×GC-TOFMS对幼年小嘴鲈鱼体内有机污染物进行靶向与非靶向分析研究,对包括多氯联苯、多溴二苯醚、有机氯农药、药物与个人护理品在内的127种已知污染物进行定量分析,并通过非靶向分析发现与健康鲈鱼相比,患病鲈鱼体内中酯类、酮类、含氮化合物含量增加. 对于目标有机物的靶向分析只能对已知污染物进行定性定量研究,但在复杂的环境样本中还存在大量的未知污染物,当今随着对新兴污染物的识别分析、生态与环境风险评估等领域研究的逐步重视,对于大量未知化合物具有较好分离效果,同时具备较低检出限、较高分辨率的非靶向高通量筛查技术也逐步为研究人员所需要,GC×GC-TOFMS是同时具备以上优点的检测方法.
本文通过使用GC×GC-TOFMS对我国东南地区某水库水源地进行有机污染物非靶向筛查,通过RTI指数的筛查提升识别结果的准确性. 之后对检出丰度较高的污染物种类与特征进行了定性分析,以期为我国水源地中未知污染物的识别提供参考.
全二维气相色谱-飞行时间质谱(GC×GC-TOFMS)非靶向筛查水源地中微量有机污染物
Non-targeted screening of trace organic pollutants in source water by GC×GC-TOFMS
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摘要: 全二维气相色谱-飞行时间质谱联用技术(GC×GC-TOFMS)由于其检测限低、分离效果好等优势已广泛应用于环境领域研究中. 通过使用此技术对我国东南地区水库中有机微污染物进行非靶向定性筛查,在2个水体样本中分别检测出1780、1861个质谱峰,通过谱库匹配,分别匹配到958、961个化合物,其中与谱库保留时间指数偏差在±10%以内的物质185、177种,±2%以内的物质114、117种,通过对保留时间指数进行控制,提升了非靶向识别的准确性. 全部5个采样点中保留指数偏差在±10%以内共识别出255种有机物,包括脂肪族化合物115种、芳香族化合物96种、脂环族化合物44种;元素组成为CH和CHO的化合物占比83.33%—89.73%,占检出物质的绝大多数. 全二维气相色谱-飞行时间质谱技术能够准确地定性筛查出环境水体中大量未知有机微污染物,为识别水质特征提供重要依据.
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关键词:
- 全二维气相色谱-飞行时间质谱 /
- 有机组分 /
- 非靶向分析 /
- 水源
Abstract: Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS) has been widely used in environmental research due to its advantages of low detection limit and good separation effect. By using this technique, non-targeted qualitative screening of trace organic pollutants in reservoir water in Southeast China were conducted in this study and 1780, 1861 peaks were detected in 2 water samples. 958, 961 substance results were matched through mass spectral library matching, among which 185, 177 substances deviated from the mass spectral library retention index within ± 10%, and 114, 117 within ± 2%. By controlling the retention time index, the accuracy of non-targeted recognition is improved. 255 organic compounds, including 115 aliphatic compounds, 96 aromatic compounds and 44 alicyclic compounds, were identified with the retention index deviation within ±10% at all 5 sampling sites. Compounds composed of CH and CHO accounted for 83.33%—89.73%, accounting for the majority of detected substances. Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry can accurately and qualitatively screen a large number of unknown organic micropollutants in environmental water, providing an important basis for identifying water quality characteristics.-
Key words:
- GC×GC-TOFMS /
- organic component /
- non-targeted analysis /
- water source.
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表 1 峰面积最高10种化合物的保留时间、保留时间指数与峰面积(± 2%)
Table 1. Retention time, retention time index and peak area of the 10 compounds with the highest peak area (± 2%)
化合物
CompoundCAS号
CAS No.保留时间/s
Retention time保留时间指数
Retention time index峰面积
Peak area一维
1D二维
2D计算值
Value of calculation谱库
Value of references误差
Error棕榈酸 57-10-3 2740 2.405 1971.4 1968 0.0017 127084825 植烷 638-36-8 2270 1.66 1810 1792 0.0100 119510764 2,2,4-三甲基-1,3-戊二醇二异丁酸酯 6846-50-0 1630 2.355 1600 1588 0.0075 87311395 正二十七烷 593-49-7 4500 1.901 2700 2700 0 84183675 正十九烷 629-92-5 2540 1.75 1900 1900 0 68729599 邻苯二甲酸二(2-乙基己基)酯 117-81-7 4170 3.29 2546 2529 0.0065 65372134 邻苯二甲酸二异丁酯 84-69-5 2440 3.71 1867 1870 -0.0017 53808241 邻苯二甲酸二丁酯 84-74-2 2710 3.91 1961 1965 -0.0021 51905211 3-甲基十七烷 6418-44-6 2160 1.705 1773.3 1770 0.0018 46760307 2-甲基十九烷 1560-86-7 2710 1.74 1960.7 1963 -0.0011 45302799 表 2 峰面积最高10种化合物的保留时间、保留时间指数与峰面积(± 2%—± 10%)
Table 2. Retention time, retention time index and peak area of the 10 compounds with the highest peak area (± 2%—± 10%)
化合物
CompoundCAS号
CAS No.保留时间/s
Retention time保留时间指数
Retention time index峰面积
Peak area一维
1D二维
2D计算值
Value of calculation谱库值
Value of references误差
Error二十六碳-1-烯 18835-33-1 4060 2.365 2495.7 2593 −0.0375 46696625 正十八烷 593-45-3 2480 1.695 1880 1800 0.0444 42040238 2-甲基十八烷 1560-88-9 2050 1.665 1736.7 1863 −0.0677 16029795 芥酸酰胺 112-84-5 4660 3.515 2776 2625 0.0576 8713692 1-二十二烯 1599-67-3 3580 2.325 2292 2193 0.0451 7617602 27-甲基二十八烷 1560-98-1 5220 1.995 3063.2 2859 0.0714 5526594 十九烷醇 1454-84-8 2990 2.018 2063 2176 −0.0519 4946841 十一醇 112-42-5 1260 2.13 1476.7 1371 0.0771 4553385 二十烷醛 2400-66-0 3900 2.395 2426.1 2224 0.0909 4085180 正十七烷 629-78-7 1610 1.6 1593.3 1700 −0.0628 3560206 表 3 各元素组成峰面积占比与数量占比
Table 3. Proportion of peak area and quantity of each element composition
元素组成
Element composition峰面积占比
Proportion of total peak area数量占比
Proportion of quantityCH 32.65%—63.04% 27.05%—37.50% CHO 34.64%—61.80% 51.56%—61.48% CHNO 0.50%—2.01% 2.74%—7.24% CHOSi 0.73%—3.33% 3.42%—4.69% CHS/CHNS/CHOS/CHNOS 0.13%—0.78% 0.66%—2.74% -
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