Department of Analytical Chemistry and Food Sciences and University Materials Institute, University of Alicante, E-03690, Alicante, Spain.
Image Processing Laboratory, University of Valencia, E-46980, Paterna, Valencia, Spain.
Talanta. 2021 Feb 1;223(Pt 2):121736. doi: 10.1016/j.talanta.2020.121736. Epub 2020 Oct 5.
An analytical methodology based in the combination of Thin Film Microextraction with Laser-induced Breakdown Spectroscopy (TFME-LIBS) was investigated, for the first time, for detection of Cu, Cr, Ni and Pb in aqueous solutions. In this methodology, the analytes were extracted in a thin film of adsorbent material deposited on a solid support, which was introduced in the sample to analyse. After extraction, the analytes retained in the adsorbent were analysed by LIBS. In order to obtain adsorbent films useful for the microextraction step, two different experimental procedures for film generation, denoted as Drop Casting Deposition and Mould Deposition, were evaluated. In both cases, graphene oxide was used as adsorbent material. The mould deposition procedure was found to produce more homogeneous graphene oxide layers, leading to more uniform distribution of the adsorbed analytes on the graphene oxide surface. Experimental parameters affecting the TFME procedure, such as the adsorbent amount and extraction time, were studied. Under optimum microextraction conditions, the analytical figures of merit of the proposed TFME-LIBS method were evaluated, leading to limits of detection ranging from 41 μg kg and 52 μg kg. Method trueness, evaluated from the analysis of a real sample of bottle water, led to recovery values about 70%, indicating the existence of strong matrix effects probably due to the presence of major cations in the bottle water. After 50% dilution of the sample with deionized water, recoveries values improved to 100%-108%.
首次研究了基于薄膜微萃取与激光诱导击穿光谱（TFME-LIBS）相结合的分析方法，用于检测水溶液中的 Cu、Cr、Ni 和 Pb。在该方法中，将吸附剂材料的薄膜（沉积在固体支撑物上）用于萃取分析物，然后用 LIBS 分析吸附在吸附剂中的分析物。为了获得适用于微萃取步骤的吸附剂薄膜，评估了两种不同的薄膜生成实验程序，分别表示为滴铸沉积和模具沉积。在这两种情况下，均使用氧化石墨烯作为吸附材料。发现模具沉积程序可以生成更均匀的氧化石墨烯层，从而使吸附在氧化石墨烯表面上的分析物更均匀地分布。研究了影响 TFME 过程的实验参数，例如吸附剂的用量和萃取时间。在最佳微萃取条件下，评估了所提出的 TFME-LIBS 方法的分析性能，得到的检出限范围为 41μg/kg 至 52μg/kg。通过对瓶装水实际样品的分析评估方法的准确性，回收率约为 70%，这表明存在强烈的基质效应，可能是由于瓶装水中存在大量的阳离子。将样品用去离子水稀释 50%后，回收率提高到 100%-108%。
