School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur 492010, Chhattisgarh, India.
School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur 492010, Chhattisgarh, India; School of Studies in Environmental Science, Pt. Ravishankar Shukla University, Raipur 492010, Chhattisgarh, India; National Center for Natural Resources, Pt. Ravishankar Shukla University, Raipur 492010, Chhattisgarh, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2022 Feb 15;267(Pt 2):120523. doi: 10.1016/j.saa.2021.120523. Epub 2021 Oct 21.
This paper describes the sensing application of citrate functionalized gold nanoparticles (AuNPs) employing for the determination of L-cysteine in food and water samples. It is established with diffuse reflectance Fourier transform infrared (DRS-FTIR) spectroscopic analysis. The disappearance of the thiol (-SH) band in the FTIR spectra and the shift in the peaks of the amino group (NH) and carboxylate group (-COO) indicated the Au-S interaction and the aggregation of the NPs. The signal intensity of L-cysteine was enhanced due to hot-spots formed by the aggregation of AuNPs producing the effective absorption of electromagnetic radiation in the IR region for molecular vibration. The relationship between AuNPs and L-cysteine was theoretically investigated by the Density Function Theory (DFT) based on LANL2DZ with the aid of the Gaussian 09 (C.01) software. Interaction between AuNPs and L-cysteine molecules resulted to a shift to higher wavelengths in the plasmon bands, further verified by transmission electron microscopes (TEM), which have indicated random aggregated particles. Further dynamic light scattering (DLS) measurements showed a relatively high degree of polydispersity confirming the aggregation of the particles. Under optimized conditions, the calibration curve showed a good linearity range from 20 to 150 μg mL with a correlation coefficient (R) 0.990. The limit of detection and quantification were 1.04 and 3.44 μg mL, respectively by DRS-FTIR. This modified AuNPs sample was used successfully in milk and water samples with adequate results to determine L-cysteine.
本文描述了采用柠檬酸盐功能化金纳米粒子（AuNPs）的传感应用，用于测定食品和水样中的 L-半胱氨酸。它是通过漫反射傅里叶变换红外（DRS-FTIR）光谱分析建立的。FTIR 光谱中巯基（-SH）带的消失和氨基（NH）和羧酸盐（-COO）峰的位移表明 Au-S 相互作用和 NPs 的聚集。由于 AuNPs 的聚集形成热点，增强了 L-半胱氨酸的信号强度，从而在 IR 区域产生了分子振动的电磁辐射的有效吸收。通过基于 LANL2DZ 的密度泛函理论（DFT），并借助 Gaussian 09（C.01）软件，从理论上研究了 AuNPs 和 L-半胱氨酸之间的关系。AuNPs 和 L-半胱氨酸分子之间的相互作用导致等离子体带向更高波长的位移，这进一步通过透射电子显微镜（TEM）得到证实，TEM 表明存在随机聚集的颗粒。进一步的动态光散射（DLS）测量显示出相对较高的多分散性，证实了颗粒的聚集。在优化条件下，校准曲线显示出从 20 到 150μgmL 的良好线性范围，相关系数（R）为 0.990。通过 DRS-FTIR，检测限和定量限分别为 1.04 和 3.44μgmL。该改良的 AuNPs 样品成功用于牛奶和水样中，结果令人满意，可用于测定 L-半胱氨酸。
