Mandrile Luisa, Vona Martina, Giovannozzi Andrea Mario, Salafranca Jesús, Martra Gianmario, Rossi Andrea Mario
Chemical Physics and Nanotechnology Department, National Institute of Metrological Research, Strada Delle Cacce 91, 10137, Turin, Italy.
Chemical Physics and Nanotechnology Department, National Institute of Metrological Research, Strada Delle Cacce 91, 10137, Turin, Italy; Chemistry Department, University of Turin, Via Giuria 7, Turin, Italy.
Talanta. 2020 Dec 1;220:121408. doi: 10.1016/j.talanta.2020.121408. Epub 2020 Jul 19.
The potential of surface-enhanced Raman scattering (SERS) has been investigated for the rapid analysis of two representative organotin compounds (OTCs): dibutyltin maleate (DTM) and tributyltin chloride (TBT), after migration tests from polyvinyl chloride (PVC), as a model food packaging material in aqueous food simulant (acetic acid 3% w/v). OTCs, often used as heat stabilizers additives for PVC, are classified as endocrine disrupting chemicals (EDCs) and their migration potential has to be controlled in compliance with the normative prescriptions for food contact materials. In this study, colloidal silver nanoparticles (AgNPs) were applied as liquid SERS substrate for direct-in-liquid analysis of food simulant after standardized migration tests of PVC samples spiked with OTCs. Promising results were obtained, reaching detection limits below the permitted limits for the considered OTCs (i.e. 0.15 mg/l): DTM and TBT were detected down to 0.01 mg/l and 0.08 mg/l, respectively. Calibration curves were calculated for standard solutions of DTM and TBT in the dynamic range between 0 and 1 mg/l (reduced χ = 0.8), and 0.5-5 mg/l (reduced χ = 0.2), respectively. Migrated TBT and DTM were detected in the food simulant, specifically identified and quantified by SERS, with a measurement uncertainty around 10% in all cases. In particular, it was found that TBT can migrate in higher amount compared to DTM when the PVC film is in contact with a slightly acidic matrix. These results were further confirmed by inductively coupled plasma-mass spectrometry and UV-Vis spectroscopy. In the present study, direct-in-liquid SERS approach showed to be very promising because it provides a fast response and it allows to overcome most of the common drawbacks of solid SERS substrates due to inhomogeneity problems and low repeatability.
在以3%（w/v）乙酸作为水性食品模拟物的情况下，研究了表面增强拉曼散射（SERS）用于快速分析两种代表性有机锡化合物（OTC）的潜力，这两种化合物分别是顺丁烯二酸二丁基锡（DTM）和三丁基氯化锡（TBT），它们来自作为食品包装材料模型的聚氯乙烯（PVC）的迁移试验。OTC通常用作PVC的热稳定剂添加剂，被归类为内分泌干扰化学物质（EDC），其迁移潜力必须根据食品接触材料的规范要求进行控制。在本研究中，胶体银纳米颗粒（AgNPs）被用作液体SERS底物，用于对添加了OTC的PVC样品进行标准化迁移试验后的食品模拟物进行直接液体分析。获得了有前景的结果，检测限低于所考虑的OTC的允许限量（即0.15毫克/升）：DTM和TBT的检测限分别低至0.01毫克/升和0.08毫克/升。分别计算了DTM和TBT标准溶液在0至1毫克/升（约化χ = 0.8）以及0.5至5毫克/升（约化χ = 0.2）动态范围内的校准曲线。在食品模拟物中检测到了迁移的TBT和DTM，通过SERS进行了特异性鉴定和定量，所有情况下测量不确定度约为10%。特别是，发现当PVC薄膜与微酸性基质接触时，TBT的迁移量比DTM更高。电感耦合等离子体质谱法和紫外 - 可见光谱法进一步证实了这些结果。在本研究中，直接液体SERS方法显示出非常有前景，因为它提供了快速响应，并且由于不均匀性问题和低重复性，它能够克服固体SERS底物的大多数常见缺点。
