Analytical Chemistry Section, CSIR-Indian Institute of Toxicology Research, MG Marg, Lucknow 226 001, Uttar Pradesh, India.
Anal Bioanal Chem. 2013 Jan;405(1):341-9. doi: 10.1007/s00216-012-6474-9. Epub 2012 Oct 19.
The present communication describes the preparation and evaluation of a molecularly imprinted polymer (MIP) as a solid-phase extraction (SPE) sorbent and simultaneous ethyl chloroformate (ECF) derivatization and pre-concentration by dispersive liquid-liquid microextraction (DLLME) for the analysis of t,t-muconic acid (t,t-MA) in urine samples using gas chromatography-mass spectrometry. The imprinting polymer was prepared using methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, 2,2-azobisisobutyronitrile as the initiator and t,t-MA as a template molecule. The imprinted polymer was evaluated for its use as a SPE sorbent by comparing both imprinted and non-imprinted polymers in terms of the recovery of t,t-MA from urine samples. Molecular modelling studies were performed in order to estimate the binding energy and efficiency of the MIP complex formed between the monomer and the t,t-MA. Various factors that can affect the extraction efficiency of MIP, such as the loading, washing and eluting conditions, were optimized; other factors that can affect the derivatization and DLLME pre-concentration were also optimized. MIP in combination with ECF derivatization and DLLME pre-concentration for t,t-MA exhibits good linearity, ranging from 0.125 to 2 μg mL(-1) (R(2) = 0.9971), with limit of detection of 0.037 μg mL(-1) and limit of quantification of 0.109 μg mL(-1). Intra- and inter-day precision was found to be <6%. The proposed method has been proven to be effective and sensitive for the selective pre-concentration and determination of t,t-MA in urine samples of cigarette smokers.
本通讯描述了一种分子印迹聚合物（MIP）的制备和评估，该聚合物可用作固相萃取（SPE）吸附剂，并通过分散液液微萃取（DLLME）进行乙基氯甲酸酯（ECF）衍生化和预浓缩，用于使用气相色谱 - 质谱法分析尿液样品中的反式 - 粘康酸（t，t-MA）。印迹聚合物是使用甲基丙烯酸作为功能单体、乙二醇二甲基丙烯酸酯作为交联剂、2,2-偶氮二异丁腈作为引发剂和 t，t-MA 作为模板分子制备的。通过比较印迹和非印迹聚合物从尿液样品中回收 t，t-MA 的能力来评估印迹聚合物作为 SPE 吸附剂的用途。为了估计单体与 t，t-MA 之间形成的 MIP 配合物的结合能和效率，进行了分子建模研究。优化了各种可以影响 MIP 萃取效率的因素，如加载、洗涤和洗脱条件；还优化了其他可以影响衍生化和 DLLME 预浓缩的因素。MIP 与 ECF 衍生化和 DLLME 预浓缩相结合，用于 t，t-MA 具有良好的线性范围，从 0.125 到 2 μg mL(-1)（R(2) = 0.9971），检测限为 0.037 μg mL(-1)，定量限为 0.109 μg mL(-1)。日内和日间精密度小于 6%。该方法已被证明可有效且灵敏地用于选择性预浓缩和测定吸烟人群尿液样品中的 t，t-MA。
