Liao Pei-Han, Urban Pawel L
Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan.
Department of Applied Chemistry, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan.
ACS Omega. 2019 Nov 8;4(21):19063-19070. doi: 10.1021/acsomega.9b02273. eCollection 2019 Nov 19.
Sampling and extraction of chemical residues present on flat or curved surfaces as well as touch-sensitive objects are challenging. Hydrogels are characterized by high mechanical flexibility and water content. Thus, they are an ideal medium for transferring water-soluble analytes from a sampled surface to the next stage of an analytical workflow. Here, we demonstrate gel-phase microextraction (GPME), in which disks of blended hydrogels are utilized to lift traces of water-soluble substances adsorbed on surfaces. The protocol has been optimized in a series of tests involving fluorometric and mass spectrometric measurements. Compared with the pure agarose hydrogel, most of the tested blended hydrogels provide a higher efficiency for the sampling/extraction of a model analyte, fluorescein. The blended hydrogel disks are incorporated into three-dimensional (3D)-printed acrylonitrile-butadiene-styrene chips to create easy-to-use sampling probes. We exemplify the suitability of this improved GPME approach in sampling chemical residues present on the skin, glass, and daily use objects. In these tests, the extracts were analyzed on a triple quadrupole mass spectrometer fitted with an electrospray ion source operated in the positive- and negative-ion modes. The method enabled the detection of diclofenac on excised porcine skin fragments exposed to a topical nonsteroidal anti-inflammatory drug and sweat residues (lactic acid) left on surfaces touched by humans. The limits of detection for diclofenac and lactic acid in hydrogel extract were 6.4 × 10 and 2.1 × 10 M, respectively. In a model experiment, conducted using the presented approach, the amount of lactic acid on a glass slide with fingerprints was estimated to be ∼1.4 × 10 mol cm.
对平面或曲面以及触摸敏感物体上存在的化学残留物进行采样和提取具有挑战性。水凝胶的特点是具有高机械柔韧性和含水量。因此，它们是将水溶性分析物从采样表面转移到分析工作流程下一阶段的理想介质。在此，我们展示了凝胶相微萃取（GPME），其中混合水凝胶盘用于提取吸附在表面的水溶性物质痕迹。该方案已在一系列涉及荧光和质谱测量的测试中得到优化。与纯琼脂糖水凝胶相比，大多数测试的混合水凝胶在对模型分析物荧光素的采样/提取方面具有更高的效率。混合水凝胶盘被整合到三维（3D）打印的丙烯腈 - 丁二烯 - 苯乙烯芯片中，以创建易于使用的采样探针。我们举例说明了这种改进的GPME方法在对皮肤、玻璃和日常用品上存在的化学残留物进行采样方面的适用性。在这些测试中，提取物在配备有以正离子和负离子模式运行的电喷雾离子源的三重四极杆质谱仪上进行分析。该方法能够检测暴露于局部非甾体抗炎药的切除猪皮肤碎片上的双氯芬酸以及人体接触过的表面上留下的汗液残留物（乳酸）。水凝胶提取物中双氯芬酸和乳酸的检测限分别为6.4×10和2.1×10 M。在使用所提出的方法进行的模型实验中，带有指纹的载玻片上乳酸的量估计约为1.4×10 mol/cm。
