【作者】 刘敏；

【导师】 吴明火；

【作者基本信息】 大连理工大学 ， 环境工程（专业学位）， 2018， 硕士

【摘要】 苯甲酸类物质是一类重要的化合物,被广泛应用于工业、农业及食品等多个领域。由于其被广泛应用,难免进入环境介质,如土壤、水环境。因其具有一定毒性,进入环境后会对动物或人体产生潜在危害。因此,环境中苯甲酸类物质监测十分必要。由于其在环境介质中含量较低,往往需要用高效灵敏的方法来检测,其中液相色谱-质谱联用法（LC-MS）是最为有效的方法之一。为实现对苯甲酸类物质更为快速且准确的定量分析,克服基质干扰效应及提高检测能力,本论文发展了一种基于稳定同位素标记的液相色谱-高分辨质谱（HPLC-HRMS）的方法,结合固相萃取（SPE）技术后可实现对环境中的痕量苯甲酸类物质的分析。实验中,首先合成了一对季铵型的标记试剂,通过标记反应可将原本在负离子模式下检测的苯甲酸类物质转化为在正离子模式下检测,显著提高了其在ESI源中的离子化效率,增强了检测信号响应,从而提升了仪器的检测能力;在LC-MS分析中,轻/重同位素标记产物保留时间相同,可以克服基质效应,提升定量分析的准确性。标记试剂的具体合成步骤为:（1）N,N-二甲基乙二胺在碱性条件下与氨基保护试剂二碳酸二叔丁酯（（BOC）₂O）反应;（2）所得叔丁氧羰基（BOC）保护的中间产物的叔胺基在碱性条件下与碘甲烷或氘代碘甲烷发生取代反应生成季铵盐,从而引入相应的同位素;（3）所得的季铵盐在HCl的乙酸乙酯溶液中脱去BOC保护基,复原被保护的伯胺基,可用于标记羧基。通过优化合成条件,每步反应效率均在98%以上。标记试剂合成后,选用了主要包括七种不同的苯甲酸和六种苯甲酸农药或农药代谢产物,对其标记条件、SPE过程及HPLC-HRMS分离检测条件等进行了系统优化。为证实该方法在环境样品分析中的适用性,实验中用大辽河河口水样对方法进行了验证。对河水中加标6种不同浓度（0.02⁵μg/L）的苯甲酸农药或农药代谢产物,在测试浓度范围内得到了良好的线性（R²≥0.99）;多次平行分析的结果也验证了其较好的重现性（相对标准偏差RSD≤10%）;通过比较不同加标浓度（1μg/L,5μg/L和10μg/L）样品中实测值与理论值,确定方法准确度为84%¹02%;检测不同加标浓度样品,计算方法回收率为82.3¹00.2%之间,方法最低检测为0.01μg/L⁰.2μg/L。该结果显示了方法具有良好的抗基质干扰能力,实现了对复杂环境中苯甲酸类污染物的准确定量,也可拓展应用于其它领域复杂样品中苯甲酸类物质的检测。更多还原

【Abstract】 Benzoic acids（BAs）are an important class of chemical compounds and widely used in many fields such as industry,agriculture and food.Thus they will inevitably enter the environment,such as soil,water and food.Because of the toxicity,they may cause potential harmful effect to animals or humans after entering the environment.Therefore,it is necessary to monitor the BAs in the environment.Because BAs in environmental media were at trace levels,highly sensitive analytical methods were needed for termination,and liquid chromatography-mass spectrometry（LC-MS）is one of the most effective and widely used methods.In order to realize more rapid and accurate quantitative analysis of BAs,overcome matrix interference effect and improve detection capability,a stable isotope labeling method combined with HPLC-HRMS and solid phase extraction（SPE）was developed to determine trace BAs pollutants in the environment.Firstly,a pair of quaternary ammonium isotope labeling reagents was synthesized.The BAs,conventionaly were detected in negative mode,could be converted to positive mode after labeling.After derivitzation,the ionization efficiency of the BAs in ESI was dramatically improved,and the signal response was also enhanced,which led to a better detection capability of the instrument.In LC-MS,the retention time of the analytes labeled with light and heavy labeling reagent were identical,and the matrix effect could be well corrected,resulting in better accuracy in quantitative analysis.The synthesis steps of the labeling reagents were:（1）N,N-dimethylene-diamine reacted with an amino protecting reagent Di-tert-butyl dicarbonate（（BOC）₂O）under basic condition;（2）The obtained intermediate product protected by BOC was reacted with methyl iodide or deuterium substituted methyl iodide under alkaline conditions to turn the tertiary amine to quaternary ammonium and introduce the corresponding isotopes;（3）The BOC protecting group was dissociated in HCl ethyl acetate solution to recover the primary amine group which was used for labeling pollutants with carboxyl group.After optimizing the synthesis conditions,the reaction efficiency of over 98%for each reaction step was achieved.After synthesis of the labeling reagents,seven different BAs and six benzoic acid pesticides or pesticide metabolites were selected as analytes.and the experimental conditions for labeling,SPE,and HPLC-HRMS were systematically optimized.In order to verify the applicability of the method,it was applied to the analysis of BAs in real environmental water samples collected from Liao River estuary.Six BA pesticide or pesticide metabolite standards with different concentrations（0.02-5μg/L）were spiked to the samples,and good linearities（R²≥0.99）and rebpoducibility（relative standard deviation,RSD≤10%,n=3）were obtained.The accuracy of 84%¹02%was achieved by comparing the experimental and theoretical values of spiked samples（1μg/L,5μg/L and 10μg/L）.The recoveries of the SPE for all tested compounds were 82.3%¹00.2%.LODs of the tested BAs were all in the range of 0.01-0.2μg/L.All these results indicated that this newly developed methodexhibitedexcellentanti-matrixinterferencecapability,realizingaccurate quantification of BA pollutants in the environment,which could be further applied to the analysis of BAs in other complex samples.更多还原