在线固相萃取高效液相色谱法同时测定人尿液中7种多环芳烃代谢物
2014-12-18游钒等
游钒等
摘 要 采用双三元液相色谱系统结合荧光检测器,建立了在线固相萃取液相色谱法同时测定人尿液中7种多环芳烃代谢物的方法。目标化合物首先在Turboflow Cyclone固相萃取柱上在线富集浓缩,然后通过六通阀转移至Hypersil Green PAH色谱柱,以乙腈水为流动相进行梯度洗脱分离,流速1.0 mL/min,柱温30 ℃,荧光检测器检测,分离周期为20 min。在优化的色谱条件下,5~2000 ng/L或50~20000 ng/L范围内,7种多环芳烃代谢物均呈良好的线性关系(r≥0.999),方法检出限为0.5~15 ng/L,加标回收率为80.7%~110.7%。应用本方法对吸烟和非吸烟人群尿液中7种多环芳烃代谢物的含量进行了测定,吸烟者尿液中的2羟基萘、1羟基萘、2羟基菲、2羟基芴、4羟基菲、6羟基显著高于非吸烟者。
1 引 言
多环芳烃(PAHs) 是人类最早发现的一类环境有机致癌化合物[1,2]。PAHs广泛存在于空气颗粒物和烟熏烧烤类食品中。另外,香烟烟雾中也含有高浓度的PAHs。PAHs 种类繁多、在环境中分布广,主要通过呼吸道、消化道和皮肤进入人体,经体内代谢转化后,生成DNA加合物。所以,PAHs在致癌类化合物中占有相当重要的地位[3]。自20世纪80年代, 许多学者研究人体对PAHs的暴露综合评价的生物标志物[4]。目前研究最多的接触生物标志物是尿中的单羟基多环芳烃(OHPAHs) [5]。高沸点多环芳烃的代谢产物主要通过粪便排泄(在尿中排泄小于1% ),而且尿中的浓度非常低[6]。因此,尿中常用于生物监测的多环芳烃代谢物主要是芘、萘、菲和等环数不大于4、由PAHs产生的OHPAHs[5~7]。
尿液中多环芳烃代谢物的含量极低,且尿液成分较复杂,所含杂质可能对色谱柱造成损害,所以,直接进样不能满足分析要求。现有方法通常采用离线固相萃取减少基质干扰,提高检测灵敏度,但操作繁琐费时,重现性不理想,且固相萃取柱多为一次性使用,人力与时间成本高。在线固相萃取(Online SPE)是近年发展起来的一种全自动样品前处理方式,具有富集纯化一步完成、固相萃取柱可多次使用、重现性好、自动化程度高等优点,已被应用于食品、环境、生物等样品中痕量有机物的检测[8~10]。
目前,测定OHPAHs 的方法主要有高效液相色谱荧光检测法(HPLCFLD) [11,12]、气相色谱质谱法(GCMS)[13~15]、液相色谱质谱法(LCMS)[16~20]。其中,GCMS法需要衍生,操作繁琐;LCMS法仪器价格昂贵。而HPLCFLD法仪器普及率高,测定OHPAHs不需衍生,结合在线富集技术甚至可获得比LCMS法更高的灵敏度。本研究利用双三元液相系统,采用基于快速涡流色谱的Turboflow Cyclone固相萃取柱对目标尿样进行在线富集纯化,将大分子杂质提前分离去除,延长了固相萃取柱使用寿命,进一步降低了交叉污染率,而以Hypersil Green PAH专用色谱柱对7种多环芳烃代谢物实现快速分离的方法也未见报道。利用本方法对实际样品(吸烟者和非吸烟者尿样)进行了测定。与文献[11,12,20\]比较,本方法不需经传统的固相萃取纯化、富集及氮吹浓缩过程,样品经酶解、离心和过滤等操作过程,可直接进样测定,且方法灵敏度比文献[11,12\]高(除1羟基萘外,检出限达ng/L水平),准确度和重现性好,简单快速(包括固相萃取和色谱分析仅需20 min);在线固相萃取柱可重复使用,柱效高,分离度好,大大简化了样品前处理过程,分析成本大为降低,特别适合批量样品的分析测定。
2 实验部分
2.1 仪器与试剂
3 结果与讨论
3.1 分析柱及色谱条件选择
文献[12\]报道,采用普通C18色谱柱和甲醇水系统对羟基多环芳烃可实现有效分离。本实验发现该条件下分离时间为30~40 min,分离效率较低,且经在线固相萃取后,色谱峰形容易发生拖尾,影响定量分析准确性。优化色谱条件后,本实验最终选择Hypersil Green PAH柱作为分析柱、乙腈水系统进行梯度洗脱,主要原因是该柱对多环芳烃类化合物保留较强,可使用乙腈含量较高的流动相初始比例,有利于阀切换时将待测物快速转移至分析柱,从而抑制色谱峰展宽,提高方法灵敏度。在确定的梯度和流速条件下,考察柱温(30, 35 和40 ℃)对实验的影响,结果表明,柱温对分离的影响较小。从保护色谱柱角度考虑,将柱温确定为30 ℃。根据荧光扫描光谱结果,结合灵敏度、干扰和基线噪声确定待测物荧光激发和发射波长。在优化的色谱条件下,单样品分析周期仅为20 min,所有待测物12 min内可实现完全分离。
3.2 样品溶剂选择
先后使用不同浓度甲醇水溶液(0~50%)作为溶剂稀释样品和标准溶液,结果表明,极性相对较小的1羟基芘和6羟基受溶剂组成影响较大。随着溶剂中甲醇比例增加(0~40%),方法回收率由30%~50%提高至90%~110%,并趋于稳定,但当溶剂中甲醇比例增加至50%时,极性较大的2羟基萘和1羟基萘在富集过程中可被提前洗脱,回收率由80%~100%下降至60%~80%,兼顾不同极性待测物,最终选择40%甲醇作为样品和标准溶液的溶剂。
3.3 酶解条件选择
PAHs在人体内代谢为OHPAHs后在酶的作用下与葡萄糖醛酸或磺酰基结合,以结合态从尿液排出。因此要测定OHPAHs前,需先将尿样酶解。综合参考文献[11\]和[20\]的酶解条件,采用混合水解酶对尿样进行酶解。每个样品相当于加入3000 U β葡萄糖苷酸酶和70 U芳基硫酸酯酶。
3.4 固相萃取柱选择
分别以Accucore Defender C18柱、Acclaim PAII柱和TurboFlow Cyclone柱为固相萃取柱,考察其对样品的在线富集能力。结果表明,在优化洗脱条件下,待测物均可实现100%保留。但使用前两种小柱时,分析柱的柱压在进样2~5次后快速上升,其原因可能是样品进样量较大,为获得良好的色谱峰形,在线转移采用反冲固相萃取柱的方式,导致样品中被固相萃取柱保留的大分子物质等杂质在多次进样后堆积于分析柱前端,引起柱压上升;选择TurboFlow Cyclone柱后,实际进样50次时,其分析柱柱压和分离效果均无明显变化,主要是由于该富集柱采用表面多孔大粒径键合相为填料,富集过程中高速通过的流动相在柱内形成涡流,使大分子物质快速洗脱,与小分子有机物实现有效分离,不但降低了基质干扰,同时也延长了色谱柱的使用寿命。
3.5 方法线性范围、相关系数、检出限及精密度
4 结 论
本研究建立了在线固相萃取高效液相色谱荧光检测法同时测定人尿液中7种多环芳烃代谢物的方法,生物样品经酶解离心过滤后即可直接进样,自动实现蛋白和部分杂质的去除以及目标化合物的富集,有效降低了基质干扰,增强了方法灵敏度,可用于人尿液中多环芳烃代谢物的高通量筛查和测定。
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丁昌明, 金银龙, 林少彬. 分析化学, 2012, 40(3): 397-402
Simultaneous Determination of Seven Metabolites of Polycyclic
Aromatic Hydrocarbons in Human Urine by Online Solid Phase
ExtractionHigh Performance Liquid Chromatography
YOU Fan1,2, ZHU Lan2, HE Ling2, RAN LiangJi3, JIN Yan3, SUN ChengJun*1
1(West China School of Public Health, Sichuan University, Chengdu 610041, China)
2(Sichuan Center For Disease Control And Prevention, Chengdu 610041, China)
3(Thermofisher Scientific (China) Corporation, Shanghai 201203, China)
Abstract A novel method for the simultaneous quantification of seven metabolites of polycyclic aromatic hydrocarbon in human urine was developed using online solid phase extractionHPLC with double ternary liquid chromatography system combined with fluorescence detector. The target compounds were online concentrated on the Turboflow Cyclone solid phase extraction column at first, then transferred by the sixway valve to the Hypersil Green PAH column for separation with acetonitrile and water as mobile phase at a flow rate of 1.0 mL/min and at 35 ℃. A single sample analysis cycle took only 20 min. Under the optimized chromatographic conditions, the method showed good linear relationship (r≥0.999) in the range of 5-2000 ng/L or 50-20000 ng/L. The LODs were 0.5-15 ng/L, and the recoveries were 80.7%-110.7%. The proposed method was successfully applied in the detection of metabolites of polycyclic aromatic hydrocarbons in urine from several smokers and nonsmokers. The concentrations of 2hydroxynaphthalene, 1hydroxynaphthalene, 2hydroxyfluorene, 2hydroxyphenanthrene, 4hydroxyphenanthrene and 6hydroxychrysene in the smokers urine were much higher than that in nonsmokers.
Keywords Polycyclic aromatic hydrocarbon; Metabolites; Human urine; Solid phase extraction; High performance liquid chromatography
(Received 31 August 2014; accepted 23 October 2014)
18 ZHAO HengQiang, CHEN JunHui, CHENG HongYan, ZHANG DaoLai, SHI Qian, WANG XiaoRu. Chinese J. Anal. Chem., 2010, 38(11): 1599-1603
赵恒强, 陈军辉, 程红艳, 张道来, 史 倩, 王小如. 分析化学, 2010, 38(11): 1599-1603
19 Xu X, Zhang J F, Zhang L, Liu W L, Weisel C P. Rapid Commun. Mass Spectrom., 2004, 18(19): 2299-2308
20 DING ChangMing, JIN YinLong, LIN ShaoBin. Chinese J. Anal. Chem., 2012, 40(3): 397-402
丁昌明, 金银龙, 林少彬. 分析化学, 2012, 40(3): 397-402
Simultaneous Determination of Seven Metabolites of Polycyclic
Aromatic Hydrocarbons in Human Urine by Online Solid Phase
ExtractionHigh Performance Liquid Chromatography
YOU Fan1,2, ZHU Lan2, HE Ling2, RAN LiangJi3, JIN Yan3, SUN ChengJun*1
1(West China School of Public Health, Sichuan University, Chengdu 610041, China)
2(Sichuan Center For Disease Control And Prevention, Chengdu 610041, China)
3(Thermofisher Scientific (China) Corporation, Shanghai 201203, China)
Abstract A novel method for the simultaneous quantification of seven metabolites of polycyclic aromatic hydrocarbon in human urine was developed using online solid phase extractionHPLC with double ternary liquid chromatography system combined with fluorescence detector. The target compounds were online concentrated on the Turboflow Cyclone solid phase extraction column at first, then transferred by the sixway valve to the Hypersil Green PAH column for separation with acetonitrile and water as mobile phase at a flow rate of 1.0 mL/min and at 35 ℃. A single sample analysis cycle took only 20 min. Under the optimized chromatographic conditions, the method showed good linear relationship (r≥0.999) in the range of 5-2000 ng/L or 50-20000 ng/L. The LODs were 0.5-15 ng/L, and the recoveries were 80.7%-110.7%. The proposed method was successfully applied in the detection of metabolites of polycyclic aromatic hydrocarbons in urine from several smokers and nonsmokers. The concentrations of 2hydroxynaphthalene, 1hydroxynaphthalene, 2hydroxyfluorene, 2hydroxyphenanthrene, 4hydroxyphenanthrene and 6hydroxychrysene in the smokers urine were much higher than that in nonsmokers.
Keywords Polycyclic aromatic hydrocarbon; Metabolites; Human urine; Solid phase extraction; High performance liquid chromatography
(Received 31 August 2014; accepted 23 October 2014)
18 ZHAO HengQiang, CHEN JunHui, CHENG HongYan, ZHANG DaoLai, SHI Qian, WANG XiaoRu. Chinese J. Anal. Chem., 2010, 38(11): 1599-1603
赵恒强, 陈军辉, 程红艳, 张道来, 史 倩, 王小如. 分析化学, 2010, 38(11): 1599-1603
19 Xu X, Zhang J F, Zhang L, Liu W L, Weisel C P. Rapid Commun. Mass Spectrom., 2004, 18(19): 2299-2308
20 DING ChangMing, JIN YinLong, LIN ShaoBin. Chinese J. Anal. Chem., 2012, 40(3): 397-402
丁昌明, 金银龙, 林少彬. 分析化学, 2012, 40(3): 397-402
Simultaneous Determination of Seven Metabolites of Polycyclic
Aromatic Hydrocarbons in Human Urine by Online Solid Phase
ExtractionHigh Performance Liquid Chromatography
YOU Fan1,2, ZHU Lan2, HE Ling2, RAN LiangJi3, JIN Yan3, SUN ChengJun*1
1(West China School of Public Health, Sichuan University, Chengdu 610041, China)
2(Sichuan Center For Disease Control And Prevention, Chengdu 610041, China)
3(Thermofisher Scientific (China) Corporation, Shanghai 201203, China)
Abstract A novel method for the simultaneous quantification of seven metabolites of polycyclic aromatic hydrocarbon in human urine was developed using online solid phase extractionHPLC with double ternary liquid chromatography system combined with fluorescence detector. The target compounds were online concentrated on the Turboflow Cyclone solid phase extraction column at first, then transferred by the sixway valve to the Hypersil Green PAH column for separation with acetonitrile and water as mobile phase at a flow rate of 1.0 mL/min and at 35 ℃. A single sample analysis cycle took only 20 min. Under the optimized chromatographic conditions, the method showed good linear relationship (r≥0.999) in the range of 5-2000 ng/L or 50-20000 ng/L. The LODs were 0.5-15 ng/L, and the recoveries were 80.7%-110.7%. The proposed method was successfully applied in the detection of metabolites of polycyclic aromatic hydrocarbons in urine from several smokers and nonsmokers. The concentrations of 2hydroxynaphthalene, 1hydroxynaphthalene, 2hydroxyfluorene, 2hydroxyphenanthrene, 4hydroxyphenanthrene and 6hydroxychrysene in the smokers urine were much higher than that in nonsmokers.
Keywords Polycyclic aromatic hydrocarbon; Metabolites; Human urine; Solid phase extraction; High performance liquid chromatography
(Received 31 August 2014; accepted 23 October 2014)