Plaisen Siwat, Cheewasedtham Wilairat, Rujiralai Thitima
Department of Chemistry, Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University Hat Yai Songkhla 90112 Thailand
Analytical Chemistry and Environment Research Unit, Division of Chemistry, Department of Science, Faculty of Science and Technology, Prince of Songkla University Pattani 94000 Thailand.
RSC Adv. 2018 Jun 13;8(38):21566-21576. doi: 10.1039/c8ra03497d. eCollection 2018 Jun 8.
Inorganic bromide (Br) is an important contaminant ion as it can originate from the overuse of illegal methyl bromide as a fumigant in stored rice samples. Herein, we developed a simple and highly sensitive colorimetric sensor for bromide ion detection in rice samples. The sensor is based on the anti-aggregation of gold nanoparticles (AuNPs) by Br in the presence of Cr, which made the method more selective than other typical aggregations of nanoparticles. The AuNPs underwent an aggregation process as a result of the coordination of Cr and the carboxylate group of a citrate ion stabilized the AuNPs, resulting in a red-to-blue color change. When Br was pre-mixed with the AuNPs and Cr was added, the solution color changed from blue to red with an increase in the Br concentration. The anti-aggregation process can be detected with the naked eye and monitored using UV-vis spectrophotometry. The linear calibration curve ranged between 0.31 and 3.75 μM Br with a low LOD and LOQ of 0.04 and 0.13 μM. The recovery was excellent, ranging from 79.9-92.2% with an RSD of less than 4.0%. The good inter-day and intra-day precisions were 2.9-6.4% and 3.1-7.1%, respectively. The developed sensor has proved to provide a robust method for Br detection in rice samples.
无机溴化物（Br）是一种重要的污染离子，因为它可能源于在储存的大米样品中过度使用非法熏蒸剂甲基溴。在此，我们开发了一种简单且高度灵敏的比色传感器，用于检测大米样品中的溴离子。该传感器基于在Cr存在下Br对金纳米颗粒（AuNPs）的抗聚集作用，这使得该方法比其他典型的纳米颗粒聚集方法更具选择性。由于Cr的配位作用，AuNPs经历了聚集过程，柠檬酸根离子的羧基稳定了AuNPs，导致颜色从红色变为蓝色。当Br与AuNPs预混合并加入Cr时，随着Br浓度的增加，溶液颜色从蓝色变为红色。抗聚集过程可用肉眼检测，并使用紫外可见分光光度法进行监测。线性校准曲线的范围为0.31至3.75 μM Br，检测限（LOD）和定量限（LOQ）较低，分别为0.04和0.13 μM。回收率极佳，范围为79.9 - 92.2%，相对标准偏差（RSD）小于4.0%。日间和日内精密度良好，分别为2.9 - 6.4%和3.1 - 7.1%。已证明所开发的传感器为大米样品中Br的检测提供了一种可靠的方法。
