Suedee Roongnapa, Intakong Wimon, Dickert Franz L
Molecular Recognition Materials Research Unit, Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hatyai, Songkla 90112, Thailand.
Talanta. 2006 Aug 15;70(1):194-201. doi: 10.1016/j.talanta.2006.04.033. Epub 2006 Jun 9.
An alternative screening method for haloacetic acids (HAAs) disinfection by-products in drinking water is described. The method is based on the use of piezoelectric quartz crystal microbalance (QCM) transducing system, where the electrode is coated with a trichloacetic acid-molecularly imprinted polymer (TCAA-MIP). This MIP comprises a crosslinked poly(ethyleneglycoldimethacrylate-co-4-vinylpyridine). The coated QCM is able to specifically detect the analytes in water samples in terms of the mass change in relation to acid-base interactions of the analytes with the MIP. The TCAA-MIP coated QCM showed high specificity for the determination of TCAA in aqueous solutions containing inorganic anions, but its sensitivity reduced in water samples containing hydrochloric acid due to a mass loss at the sensor surface. Cross-reactivity studies with HAA analogs (dichloro-, monochloro-, tribromo-, dibromo-, and monobromo-acetic acids) and non-structurally related TCAA molecules (acetic acid and malonic acid) indicated that recognition of the structurally related TCAA compounds by the TCAA-MIP-based QCM is due to a carboxylic acid functional group, and probably involves a combination of both size and shape selectivity. The total response time of sensor is in the order of 10min. The achieved limits of detection for HAAs (20-50mugl(-1)) are at present higher than the actual concentrations found in real-life samples, but below the guidelines for the maximum permissible levels (60mugl(-1) for mixed HAAs). Recovery studies with drinking water samples spiked with TCAA or spiked with mixtures of HAAs revealed the reproducibility and precision of the method. The present work has demonstrated that the proposed assay can be a fast, reliable and inexpensive screening method for HAA contaminants in water samples, but further refinement is required to improve the limits of detection.
本文描述了一种用于饮用水中卤乙酸（HAAs）消毒副产物的替代筛选方法。该方法基于压电石英晶体微天平（QCM）传感系统，其电极涂覆有三氯乙酸分子印迹聚合物（TCAA-MIP）。这种MIP由交联的聚（乙二醇二甲基丙烯酸酯-co-4-乙烯基吡啶）组成。涂覆的QCM能够根据分析物与MIP之间酸碱相互作用引起的质量变化，特异性地检测水样中的分析物。涂覆有TCAA-MIP的QCM对含有无机阴离子的水溶液中TCAA的测定具有高特异性，但在含有盐酸的水样中其灵敏度降低，这是由于传感器表面的质量损失。对HAA类似物（二氯、一氯、三溴、二溴和一溴乙酸）和与TCAA无结构关联的分子（乙酸和丙二酸）的交叉反应研究表明，基于TCAA-MIP的QCM对结构相关的TCAA化合物的识别是由于羧酸官能团，可能涉及尺寸和形状选择性的结合。传感器的总响应时间约为10分钟。目前HAAs的检测限（20-50μg l-1）高于实际生活样品中的实际浓度，但低于最大允许水平的指导值（混合HAAs为60μg l-1）。对添加了TCAA或HAAs混合物的饮用水样品进行的回收率研究表明了该方法的重现性和精密度。目前的工作表明，所提出的检测方法可以成为一种快速、可靠且廉价的筛选水样中HAA污染物的方法，但需要进一步改进以提高检测限。
