Analysis of Compound-specific Carbon Isotopic Composition of Polycyclic Aromatic Hydrocarbons by PTV-GC-IRMS
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摘要:
环境样品中PAHs的单体碳同位素比值在迁移转化过程中能基本保持稳定,是重要的溯源指标,可通过气相色谱-同位素比值质谱(GC-IRMS)分析获得。对于低PAHs含量的样品,满足GC-IRMS检出限是高精度、准确分析单体碳同位素比值的前提。本文优化了一种程序升温汽化进样(PTV)方法,通过对PTV进样模式及进样口参数进行优化调整,提高目标物谱峰强度,进而提高GC-IRMS碳同位素分析的灵敏度。实验对比研究了恒温不分流、PTV不分流和溶剂分流进样模式,并对PTV进样口参数包括进样口压力梯度、传输温度和时间、蒸发温度和时间、进样口不分流时间进行了对比优化,以选出最优的PAHs单体碳同位素分析条件。结果表明:在PTV不分流进样、进样口压力40psi—60psi—70psi梯度升高、传输温度320℃、传输时间1.0min、蒸发温度55℃、蒸发时间2.5min、不分流时间1.5min条件下,PAHs的单体碳同位素结果最优。增加预柱可以提高峰强,尤其5环PAHs的峰强度提高达50%~100%。单体碳同位素分析精度(1σ)在0.5‰以内,系统性碳同位素分馏可以采用双标法校正。优化后的PTV-GC-IRMS方法可以实现低含量PAHs单体碳同位素的高精度、准确分析,扩大了同位素溯源在环境研究中的适用性。
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关键词:
- 气相色谱-同位素比值质谱法 /
- 多环芳烃 /
- 单体碳同位素 /
- 程序升温汽化 /
- 溯源
Abstract:BACKGROUND The carbon isotope ratio of PAHs is stable in the migration and transformation, which is an important traceability index and can be analyzed by gas chromatography-isotope ratio mass spectrometry (GC-IRMS). For samples with low PAH content, meeting the detection limit of GC-IRMS is the premise for high-precision and accurate analysis of the carbon isotope ratio.
OBJECTIVES To establish a PTV injection method with stronger intensity of PAHs, thereby improving the sensitivity of GC-IRMS carbon isotope analysis.
METHODS Parameters of the programmed temperature vaporization (PTV) injector were optimized, including injection mode (constant temperature splitless, PTV splitless and solvent split), pressure process, sample transfer temperature and time, evaporation temperature and time, and splitless time.
RESULTS The optimized parameters were PTV splitless, transfer temperature of 320℃, transfer time of 1.0min, injection pressure operating in a gradient of 40—60—70psi, evaporation temperature of 55℃, evaporation time of 2.5min, and splitless time of 1.5min. Pre-columns reduced the peak width and increased the peak intensity, especially high boiling point PAHs as benzo(a)pyrene, indeno(1, 2, 3-cd)pyrene, dibenzo(a, h)anthracene and benzo(g, h, i)perylene increased by 50%-100%. The precision of δ13C of 16 PAHs determined by the optimized PTV-GC-IRMS were within 0.5‰. The fractionation within the system can be corrected by two PAH references.
CONCLUSIONS The optimized PTV-GC-IRMS can adjust the precision and accuracy of compound-specific carbon isotope analysis of PAHs at low concentrations, and expand the applicability of isotope tracing in environmental studies.
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表 1 溶剂分流和不分流进样模式下PAHs单体碳同位素的分析精度
Table 1. Analysis precision of δ13C of PAHs by PTV solvent split and PTV splitless modes
PAHs化合物 SS模式δ13C (‰) SD(1σ, n=3) SL模式δ13C (‰) SD(1σ, n=3) 第1次 第2次 第3次 第1次 第2次 第3次 萘 -25.97 -25.62 -25.68 0.18 -25.46 -25.26 -25.50 0.13 苊烯 -23.06 -22.89 -22.85 0.11 -22.76 -22.59 -22.74 0.09 苊 -23.74 -23.39 -23.42 0.19 -23.35 -23.26 -23.60 0.17 芴 -27.63 -26.83 -26.73 0.49 -26.71 -26.23 -26.58 0.25 菲 -25.74 -25.10 -24.98 0.41 -25.00 -24.58 -24.62 0.23 蒽 -23.74 -24.01 -23.79 0.15 -24.37 -23.55 -24.57 0.54 荧蒽 -24.97 -24.46 -23.99 0.49 -24.65 -23.89 -23.90 0.43 芘 -25.23 -25.25 -24.76 0.28 -25.27 -24.83 -25.10 0.22 苯并(a)蒽+䓛 -24.63 -24.46 -24.91 0.23 -24.61 -24.29 -24.34 0.17 苯并(b)荧蒽+苯并(k)荧蒽 -26.95 -27.08 -26.96 0.07 -27.34 -26.45 -26.81 0.45 苯并(a)芘 -24.81 -24.57 -24.19 0.31 -25.25 -24.92 -24.73 0.26 茚并(1, 2, 3-cd)芘+二苯并(a, h)蒽 -24.51 -24.03 -23.90 0.32 -24.96 -24.61 -23.70 0.65 苯并(g, h, i)苝 -28.36 -27.25 -27.08 0.70 -27.80 -27.07 -27.80 0.42 表 2 优化后的分析方法对PAHs的单体碳同位素的分析精度
Table 2. Precision of δ13C of PAHs by the optimized instrument method
PAHs化合物 δ13C(‰) SD(1σ, n=5) 第1次 第2次 第3次 第4次 第5次 萘 -24.43 -25.19 -24.48 -24.22 -25.17 0.45 苊烯 -22.88 -22.71 -22.27 -22.69 -23.02 0.28 苊 -23.16 -23.2 -23.23 -22.96 -22.97 0.13 芴 -26.22 -26.24 -26.12 -26.16 -26.27 0.06 菲 -24.05 -24.63 -23.72 -24.64 -24.04 0.40 蒽 -24.58 -24.64 -24.05 -24.54 -24.46 0.24 荧蒽 -23.63 -23.91 -23.30 -23.16 -23.56 0.29 芘 -25.07 -24.86 -24.82 -24.90 -25.04 0.11 苯并(a)蒽+䓛 -24.29 -24.42 -24.19 -24.21 -23.97 0.16 苯并(b)荧蒽+苯并(k)荧蒽 -26.33 -26.62 -26.34 -26.41 -26.35 0.12 苯并(a)芘 -24.83 -25.39 -24.64 -25.06 -24.63 0.32 茚并(1, 2, 3-cd)芘+二苯并(a, h)蒽 -24.04 -23.85 -24.26 -23.15 -23.39 0.46 苯并(g, h, i)苝 -27.01 -27.05 -27.02 -27.10 -26.84 0.10 -
[1] Yuan G L, Wu L J, Sun Y, et al. Polycyclic aromatic hydrocarbons in soils of the central Tibetan Plateau, China: Distribution, sources, transport and contribution in global cycling[J]. Environmental Pollution, 2015, 203: 137-144. doi: 10.1016/j.envpol.2015.04.002
[2] 黄勇, 王安婷, 袁国礼, 等北京市表层土壤中PAHs含量特征及来源分析[J]. 岩矿测试, 2022, 41(1): 54-65. http://www.ykcs.ac.cn/cn/article/doi/10.15898/j.cnki.11-2131/td.202104270056
Huang Y, Wang A T, Yuan G L, et al. The content characteristics and source analysis of polycyclic aromatic hydrocarbon in topsoil of Beijing City[J]. Rock and Mineral Analysis, 2022, 41(1): 54-65. http://www.ykcs.ac.cn/cn/article/doi/10.15898/j.cnki.11-2131/td.202104270056
[3] 谢曼曼, 刘美美, 王淑贤, 等. 土壤中多环芳烃单体碳同位素分析的分离净化方法研究[J]. 岩矿测试, 2021, 40(6): 962-972. doi: 10.15898/j.cnki.11-2131/td.202109280131
Xie M M, Liu M M, Wang S X, et al. Study on separation of polycyclic aromatic hydrocarbons in soils for compound-specific carbon isotope analysis[J]. Rock and Mineral Analysis, 2021, 40(6): 962-972. doi: 10.15898/j.cnki.11-2131/td.202109280131
[4] 母清林, 方杰, 邵君波, 等. 长江口及浙江近岸海域表层沉积物中多环芳烃分布、来源与风险评价[J]. 环境科学, 2015, 36(3): 839-846. doi: 10.13227/j.hjkx.2015.03.012
Mu Q L, Fang J, Shao J B, et al. Distribution, sources and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Yangtze Estuary and Zhejiang coastal areas[J]. Environmental Science, 2015, 36(3): 839-846. doi: 10.13227/j.hjkx.2015.03.012
[5] Wang X C, Sun S, Ma H Q, et al. Sources and distribution of aliphatic and polyaromatic hydrocarbons in sediments of Jiaozhou Bay, Qingdao, China[J]. Marine Pollution Bulletin, 2006, 52(2): 129-138. doi: 10.1016/j.marpolbul.2005.08.010
[6] 张明, 唐访良, 吴志旭, 等. 千岛湖表层沉积物中多环芳烃污染特征及生态风险评价[J]. 中国环境科学, 2014, 34(1): 253-258. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGHJ201401050.htm
Zhang M, Tang F L, Wu Z X, et al. Pollution characteristics and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Xin'anjiang Reservoir[J]. China Environmental Science, 2014, 34(1): 253-258. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGHJ201401050.htm
[7] O'Malley V P, Abrajano T A, Hellou J. Stable carbon isotopic apportionment of individual polycyclic aromatic hydrocarbons in St. John's Harbour, Newfoundland[J]. Environmental Science & Technology, 1996, 30(2): 634-639.
[8] Garbarienè I, Garbaras A, Masalaite A, et al. Identifi-cation of wintertime carbonaceous fine particulate matter (PM2.5) sources in Kaunas, Lithuania using polycyclic aromatic hydrocarbons and stable carbon isotope analysis[J]. Atmospheric Environment, 2020, 237: 117673. doi: 10.1016/j.atmosenv.2020.117673
[9] 白慧玲, 刘效峰, 宋翀芳. 太原市采暖期PM10中PAHs的碳同位素组成及源贡献率[J]. 中国环境科学, 2014, 34(1): 7-13. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGHJ201401002.htm
Bai H L, Liu X F, Song C F. Carbon isotope compositions and source apportionments of PAHs in PM10 of Taiyuan City during heating period[J]. China Environmental Science, 2014, 34(1): 7-13. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGHJ201401002.htm
[10] Okuda T, Kumata H, Naraoka H, et al. Origin of atmo-spheric polycyclic aromatic hydrocarbons (PAHs) in Chinese cities solved by compound-specific stable carbon isotopic analyses[J]. Organic Geochemistry, 2002, 33(12): 1737-1745. doi: 10.1016/S0146-6380(02)00180-8
[11] Mikolajczuk A, Przyk E P, Geypens B, et al. Analysis of polycyclic aromatic hydrocarbons extracted from air particulate matter using a temperature programmable injector coupled to GC-C-IRMS[J]. Isotopes in Environmental and Health Studies, 2010, 46(1): 2-12. doi: 10.1080/10256010903356920
[12] 苑金鹏, 钟宁宁, 吴水平. 土壤中多环芳烃的稳定碳同位素特征及其对污染源示踪意义[J]. 环境科学学报, 2005, 25(1): 81-85. doi: 10.13671/j.hjkxxb.2005.01.014
Yuan J P, Zhong N N, Wu S P. Stable carbon isotopic composition of polycyclic aromatic hydrocarbons in soil and its implications for the pollutants tracing[J]. Acta Scientiae Circumstantiae, 2005, 25(1): 81-85. doi: 10.13671/j.hjkxxb.2005.01.014
[13] 焦杏春, 王广, 叶传永, 等. 应用单体碳同位素分析技术探析农田土壤中多环芳烃的植物降解过程[J]. 岩矿测试, 2014, 33(6): 863-870. doi: 10.15898/j.cnki.11-2131/td.2014.06.017
Jiao X C, Wang G, Ye C Y, et al. Study on the phytodegradation of PAHs from farmland soil using compound-specific isotope analysis technique[J]. Rock and Mineral Analysis, 2014, 33(6): 863-870. doi: 10.15898/j.cnki.11-2131/td.2014.06.017
[14] Kim M, Kennicutt ⅡⅡ M C, Qian Y. Molecular and stable carbon isotopic characterization of PAH contaminants at McMurdo Station, Antarctica[J]. Marine Pollution Bulletin, 2006, 52(12): 1585-1590. doi: 10.1016/j.marpolbul.2006.03.024
[15] 陆燕, 王小云, 曹建平. 沉积物中16种多环芳烃单体碳同位素GC-C-IRMS测定[J]. 石油实验地质, 2018, 40(4): 532-537. https://www.cnki.com.cn/Article/CJFDTOTAL-SYSD201804012.htm
Lu Y, Wang X Y, Cao J P. Compound-specific carbon stable isotope analysis of 16 polycyclic aromatic hydrocarbons in sediments by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS)[J]. Petroleum Geology & Experiment, 2018, 40(4): 532-537. https://www.cnki.com.cn/Article/CJFDTOTAL-SYSD201804012.htm
[16] Yan B, Abrajano T A, Bopp R F, et al. Combined applica-tion of δ13C and molecular ratios in sediment cores for PAH source apportionment in the New York/New Jersey harbor complex[J]. Organic Geochemistry, 2006, 37(6): 674-687. doi: 10.1016/j.orggeochem.2006.01.013
[17] Lu Y, Li D, Wang X, et al. Assessment and implication of PAHs and compound-specific δ13C compositions in a dated marine sediment core from Daya Bay, China[J]. International Journal of Environmental Research and Public Health, 2022, 19(8): 4527. doi: 10.3390/ijerph19084527
[18] McRae C, Snape C, Sun C, et al. Use of compound-specific stable isotope analysis to source anthropogenic natural gas-derived polycyclic aromatic hydrocarbons in a lagoon sediment[J]. Environmental Science & Technology, 2000, 34(22): 4684-4686.
[19] 李琪, 李钜源, 窦月芹, 等. 淮河中下游沉积物PAHs的稳定碳同位素源解析[J]. 环境科学研究, 2012, 25(6): 672-677. https://www.cnki.com.cn/Article/CJFDTOTAL-HJKX201206012.htm
Li Q, Li J Y, Dou Y Q, et al. Compound-specific stable carbon isotopic analysis on origins of PAHs in sediments from the middle and lower reaches of the Huaihe River[J]. Research of Environmental Sciences, 2012, 25(6): 672-677. https://www.cnki.com.cn/Article/CJFDTOTAL-HJKX201206012.htm
[20] Hall J A, Barth J A C, Kalin R M. Routine analysis by high precision gas chromatography/mass selective detector/isotope ratio mass spectrometry to 0.1 parts per Mil[J]. Rapid Communications in Mass Spectrometry, 1999, 13(13): 1231-1236. doi: 10.1002/(SICI)1097-0231(19990715)13:13<1231::AID-RCM579>3.0.CO;2-B
[21] Schmitt J, Glaser B, Zech W. Amount-dependent isotopic fractionation during compound-specific isotope analysis[J]. Rapid Communications in Mass Spectrometry, 2003, 17(9): 970-977. doi: 10.1002/rcm.1009
[22] Glaser B, Amelung W. Determination of 13C natural abund-ance of amino acid enantiomers in soil: Methodological considerations and first results[J]. Rapid Communications in Mass Spectrometry, 2002, 16(9): 891-898. doi: 10.1002/rcm.650
[23] Blessing M, Jochmann M A, Haderlein S B, et al. Optimi-zation of a large-volume injection method for compound-specific isotope analysis of polycyclic aromatic compounds at trace concentrations[J]. Rapid Communications in Mass Spectrometry, 2015, 29(24): 2349-2360.
[24] Mikolajczuk A, Geypens B, Berglund M, et al. Use of a temperature-programmable injector coupled to gas chromatography-combustion-isotope ratio mass spectrometry for compound-specific carbon isotopic analysis of polycyclic aromatic hydrocarbons[J]. Rapid Communication of Mass Spectrometry, 2009, 23(16): 2421-2427.
[25] Qiao Y, Lyu G, Song C, et al. Optimization of programmed temperature vaporization injection for determination of polycyclic aromatic hydrocarbons from diesel combustion process[J]. Energies, 2019, 12(24): 4791.
[26] Maricq M M. Chemical characterization of particulate emissions from diesel engines: A reviews[J]. Journal of Aerosol Science, 2007, 38(11): 1079-1118.
[27] Poster D L, Schantz M M, Sander L C, et al. Analysis of polycyclic aromatic hydrocarbons (PAHs) in environmental samples: A critical review of gas chromatographic (GC) methods[J]. Analytical and Bioanalytical Chemistry, 2006, 386(4): 859-881.
[28] Zwank L, Berg M, Schmidt T C, et al. Compound-specific carbon isotope analysis of volatile organic compounds in the low-microgram per liter range[J]. Analytical Chemistry, 2003, 75(20): 5575-5583.
[29] de Souza C V, Corrêa S M. Polycyclic aromatic hydrocarbon emissions in diesel exhaust using gas chromatography-mass spectrometry with programmed temperature vaporization and large volume injection[J]. Atmospheric Environment, 2015, 103: 222-230.
[30] Pavón J L P, del Nogal Sánchez M, Laespada M E F, et al. Determination of aromatic and polycyclic aromatic hydrocarbons in gasoline using programmed temperature vaporization-gas chromatography-mass spectrometry[J]. Journal of Chromatography A, 2008, 1202(2): 196-202.
[31] Bruno P, Caselli M, de Gennaro G, et al. Determination of polycyclic aromatic hydrocarbons (PAHs) in particulate matter collected with low volume samplers[J]. Talanta, 2007, 72(4): 1357-1361.
[32] Crimmins B S, Baker J E. Improved GC/MS methods for measuring hourly PAH and nitro-PAH concentrations in urban particulate matter[J]. Atmospheric Environment, 2006, 40(35): 6764-6779.
[33] Drabova L, Pulkrabova J, Kalachova K, et al. Rapid deter-mination of polycyclic aromatic hydrocarbons (PAHs) in tea using two-dimensional gas chromatography coupled with time of flight mass spectrometry[J]. Talanta, 2012, 100: 207-216.
[34] Yusà V, Quintas G, Pardo O, et al. Determination of PAHs in airborne particles by accelerated solvent extraction and large-volume injection-gas chromatography-mass spectrometry[J]. Talanta, 2006, 69(4): 807-815.
[35] 钟志铭, 黄子敬, 符靖雯. QuEChERS结合PTV-GC-MS/MS测定食用菌中多种农药残留[J]. 分析试验室, 2016, 35(6): 648-653. https://www.cnki.com.cn/Article/CJFDTOTAL-FXSY201606008.htm
Zhong Z M, Huang Z J, Fu J W. Determination of pesticide residues in edible mushrooms by QuEChERS-PTV-gas chromatography-triple quadrupole mass spectrometry[J]. Chinese Journal of Analysis Laboratory, 2016, 35(6): 648-653. https://www.cnki.com.cn/Article/CJFDTOTAL-FXSY201606008.htm
[36] García-Rodríguez D, Carro-Díaz A M, Lorenzo-Ferreira R A, et al. Determination of pesticides in seaweeds by pressurized liquid extraction and programmed temperature vaporization-based large volume injection-gas chromatography-tandem mass spectrometry[J]. Journal of Chromatography A, 2010, 1217(17): 2940-2949.
[37] 张弛, 宋莹, 潘家荣, 等. 气相色谱-质谱大体积进样法测定果汁中90种农药残留[J]. 分析化学, 2015, 43(8): 1154-1161. https://www.cnki.com.cn/Article/CJFDTOTAL-FXHX201508009.htm
Zhang C, Song Y, Pan J R, et al. Determination of 90 pesticide residues in fruit juices using QuEChERS cleanup and programmable temperature vaporizer-based large volume injection by gas chromatography-mass spectrometry[J]. Chinese Journal of Analytical Chemistry, 2015, 43(8): 1154-1161. https://www.cnki.com.cn/Article/CJFDTOTAL-FXHX201508009.htm
[38] 袁河, 赵振宇, 吴建霞, 等. 程序升温汽化-气相色谱-三重四极杆串联质谱法(PTV-GC-MS/MS)同时测定小麦中的109种农药残留[J]. 酿酒科技, 2016(6): 120-128. https://www.cnki.com.cn/Article/CJFDTOTAL-NJKJ201606036.htm
Yuan H, Zhao Z Y, Wu J X, et al. Simultaneous determination of 109 pesticide residues in wheat by PTV-GC-MS/MS[J]. Liquor-making Science & Technology, 2016(6): 120-128. https://www.cnki.com.cn/Article/CJFDTOTAL-NJKJ201606036.htm
[39] 黄子敬, 陈孟君, 符靖雯, 等. PTV-GC-MS/MS及UPLC-MS/MS测定水产品中多种农兽药残留[J]. 化学研究与应用, 2018, 30(8): 1376-1387. https://www.cnki.com.cn/Article/CJFDTOTAL-HXYJ201808028.htm
Huang Z J, Chen M J, Fu W J, et al. Multiresidue determination of pesticide and veterinary drugs in aquatic products by PTV-GC-MS/MS and UPLC-MS/MS[J]. Chemical Research and Application, 2018, 30(8): 1376-1387. https://www.cnki.com.cn/Article/CJFDTOTAL-HXYJ201808028.htm
[40] 楼小华, 高川川, 朱文静, 等. PTV-GC-MS/MS同时测定烟草中202种农药残留[J]. 烟草科技, 2013(8): 45-57. https://www.cnki.com.cn/Article/CJFDTOTAL-YCKJ201308013.htm
Lou X H, Gao C C, Zhu W J, et al. Simultaneous determination of 202 pesticide residues in tobacco by PTV-gas chromatography-tandem mass spectrometry[J]. Tobacco Chemistry, 2013(8): 45-57. https://www.cnki.com.cn/Article/CJFDTOTAL-YCKJ201308013.htm
[41] Júnior E F, Caldas E D. Simultaneous determination of drugs and pesticides in postmortem blood using dispersive solid-phase extraction and large volume injection-programmed temperature vaporization-gas chromatography-mass spectrometry[J]. Forensic Science International, 2018, 290: 318-326.
[42] Dugheri S, Mucci N, Pompilio I, et al. Determination of airborne formaldehyde and ten other carbonyl pollutants using programmed temperature vaporization-large volume injection-gas chromatography[J]. Chinese Journal of Chromatography, 2018, 36(12): 1311-1322.
[43] Dugheri S, Marrubini G, Speltini A, et al. Fully automated determination of trimellitic anhydride in saturated polyester resins using programmed temperature vaporization-large volume injection-gas chromatography previous aqueous derivatization with triethyloxonium tetrafluoroborate[J]. Chromatographia, 2020, 83(5): 601-613.
[44] Combs M, Noe O. Use of a PTV injector to achieve inverse-large volume injection: Injection of volatile analytes in a semi-volatile solvent[J]. Journal of Separation Science, 2001, 24(4): 291-296.
[45] Zech M, Glaser B. Improved compound-specific δ13C analysis of n-alkanes for application in palaeo-environmental studies[J]. Rapid Communications in Mass Spectrometry, 2008, 22(2): 135-142.