磁分子印迹聚合物-分散相固相微萃取与超高效液相色谱-串联质谱联用检测尿液中的马尿酸和甲基马尿酸

Toluene and xylene are widely used in the process of industrial production and could cause great damage to human health. Therefore, the prevention of occupational exposure damage of toluene has become an important problem to be solved in the occupational health field of China. Hippuric acid and methy hippuric acid, as the final metabolite of toluene and xylene in human body, were listed as the biomarker, respectively. And the concentration of hippuric acid and methyl hippuric acid in human body could reflect the degree of occupational exposure of toluene and xylene. In this work, dispersive micro-solid phase extraction (D-μ-SPE) was employed for the sample pretreatment, which as an "environmentally friendly" sample preparation technology was developed in the last decade. The D-μ-SPE method possesses many advantages, including simple, green, and safe etc. In this work, a magnetic molecular imprinting polymer was prepared and as sorbent was employed in the D-μ-SPE method. A new method for the determination of hippuric acid and methy hippuric acid in urine will developed combined with ultra performance liquid chromatography -tandem mass spectrometry. Compared with the standard method, the new method has better performance in analysis time, sensitivity and selective.

甲苯和二甲苯等有机溶剂被广泛应用于工业生产，并对接触劳动者的身体健康造成巨大伤害。因而，预防职业性甲苯接触损伤已成为我国职业卫生领域亟待解决的重要问题之一。尿液中的马尿酸和甲基马尿酸作为甲苯和二甲苯在人体内的最终代谢物，并作为二者的生物标记物，而尿液中马尿酸和甲基马尿酸的浓度高低直观地反映了劳动者的甲苯类环境职业暴露程度。本项目拟选用近几年发展起来的新型“环境友好型”样品前处理技术-分散相固相微萃取技术（D-μ-SPE）应用于实际尿样的前处理，该方法具有绿色、高效、简单和安全等优点。本项目计划以马尿酸作为模板分子，制备一种新型的磁分子印迹聚合物，该材料同时吸收了纳米粒子和分子印迹材料的优点，并作为D-μ-SPE吸附材料与超高效液相色谱-串联质谱联用建立一个检测尿液样品中马尿酸和甲基马尿酸的新方法。与目前使用的行业标准法相比，新方法在分析速度、灵敏度、选择性等方面都将具有明显的优势。

甲苯和二甲苯为无色和不溶于水的有毒有机溶剂，且广泛应用于油漆、汽车等行业。而这些行业的工人因长期暴露于甲苯和二甲苯环境中，脑和神经系统容易造成损伤。甲苯和二甲苯通过呼吸作用进入人体后，通过代谢过程转换为马尿酸(HA)和甲基马尿酸(MHA)。在职业卫生健康监测中通常选择HA和MHA作为甲苯和二甲苯职业暴露的生物标志物。因此，开发高灵敏度、高选择性检测尿液中HA和MHA的新方法对于甲苯和二甲苯职业暴露监测具有重要意义。本项目以马尿酸(hippuric acid, HA)为模板分子制备了具有纳米结构的磁分子印迹聚合物(Fe3O4@SiO2@MIP)。Fe3O4@SiO2@MIP作为磁固相萃取(MSPE)技术的吸附材料萃取尿液样品中马尿酸和甲基马尿酸(2-甲基马尿酸， 2-MHA、3-甲基马尿酸， 3-MHA和4-甲基马尿酸，4-MHA)。采用了FT-IR、XRD、XPS、TEM、BET和VSM等不同表征手段对Fe3O4@SiO2@MIP的结构和性能进行了表征。Fe3O4@SiO2@MIP对四个目标分析物的印迹因子(IF)分别为4.6、2.7、2.0和1.8；选择性系数(SC)分别为1.7、2.3和2.6。 为了获得较高萃取效率，方法对吸附剂量、萃取时间、pH、离子浓度、解吸溶剂和解吸时间等因素进行了优化。4种目标分析物经1mM NaOH洗脱解吸后，采用超高效液相色谱-串联质谱(UPLC-MS/MS)对其进行检测。在最优萃取条件下，对新建立方法的分析性能进行评估，方法检出限为89 ng·L-1 (HA) - 170 ng·L-1 (4-MHA)，定量限为300 ng·L-1 (HA) - 570 ng·L-1 (4-MHA)；线性范围为500 ng·L-1 - 10 mg·L-1；日内标准偏差范围为6.4 - 9.6% ( n = 6, c = 10 μg·L-1)，日间标准偏差范围为9.2 -11.5% ( n = 6, c = 10 μg·L-1)。该方法成功地应用于尿液实际样品中HA和MHA的分析，回收率结果良好。