Hebei Key Laboratory of Organic Functional Molecules, College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050024, Hebei, China.
Hebei Key Laboratory of Organic Functional Molecules, College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050024, Hebei, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2022 Dec 5;282:121708. doi: 10.1016/j.saa.2022.121708. Epub 2022 Aug 2.
Surface enhanced Raman spectroscopy (SERS) is a promising technique for trace determination. More and more attention is focused on hybrid SERS substrates, which coupled with noble metal nanoparticles and carbon-based materials. Herein, expanded graphite (EG) is used to prepare EG-covered support by ultrasonic washing and filtration. Such support is flexible and can be cut into any shape. And the contact angle (θe) for Au nanorods (Au NRs) sol on the EG-covered support was 108.2° and the hydrophobic surface is helpful for Au NRs to construct 'hot spots' during evaporation. The limits of detection (LOD) for crystal violet (CV), thiram, malachite green (MG) and methylene blue (MB) were as low as 1 ppb, 50 ppb, 1 ppb and 1 ppb, respectively. Moreover, a fast and convenient 'paste-sampling' method could be employed for trace contaminants on real samples, because EG-based Au NRs substrate is of flexibility and porosity. Thus, CV residue on shrimp could be determined lower than 1 ppb and thiram residue on grapes could be identified lower than 50 ppb. In addition to high sensitivity, the stability of EG-based Au NRs substrate is also very good. Even after acid/alkali pretreatment (pH = 4∼10) or 30 min of thermal treatment (T = 20∼100 °C), the enhancement of the substrate remained stable. What's more, the substrate could be stored as long as 30 days. The highly stable, sensitive, cost-effective and easy-to-produce EG-based Au NRs substrates exhibit a great potential to promote application of SERS for routine analysis.
表面增强拉曼光谱（SERS）是痕量测定的一种很有前途的技术。越来越多的人关注混合 SERS 基底，它与贵金属纳米粒子和碳基材料相结合。在此，通过超声清洗和过滤将膨胀石墨（EG）用于制备 EG 覆盖的基底。这种基底具有柔韧性，可以切成任何形状。并且 Au 纳米棒（Au NRs）溶胶在 EG 覆盖的基底上的接触角（θe）为 108.2°，疏水性表面有助于 Au NRs 在蒸发过程中形成“热点”。结晶紫（CV）、福美双、孔雀石绿（MG）和亚甲蓝（MB）的检测限（LOD）低至 1 ppb、50 ppb、1 ppb 和 1 ppb。此外，由于 EG 基 Au NRs 基底具有柔韧性和多孔性，可以采用快速简便的“粘贴采样”方法用于实际样品中的痕量污染物。因此，虾上的 CV 残留量可低于 1 ppb 检测，葡萄上的福美双残留量可低于 50 ppb 检测。除了高灵敏度，EG 基 Au NRs 基底的稳定性也非常好。即使经过酸碱预处理（pH = 4∼10）或 30 分钟的热处理（T = 20∼100°C），基底的增强效果仍然稳定。更重要的是，基底可以储存长达 30 天。高稳定性、高灵敏度、高性价比且易于生产的 EG 基 Au NRs 基底具有很大的潜力，可以促进 SERS 在常规分析中的应用。
