In the present study, we have successfully synthesized and characterized carboxy methyl cashew gum modified gold nanoparticles (CMCG-AuNPs) via a microwave-assisted method and used as a calorimetric probe for selective detection of Hg²⁺ ions as well as catalytic reduction of methyl red in an aqueous medium. The effect of different parameters including concentration and irradiation time on the formation of CMCG-AuNPs was also investigated. The presence of strong surface plasmon resonance (SPR) peak in the visible region indicated the formation of AuNPs. The characterization techniques were identified the interaction between the CMCG and AuNPs with estimation of size and morphology. The face centred cubic (FCC) crystal structure was identified by using XRD and supporting with SAED pattern. TEM images of CMCG-AuNPs were exhibited as polydispersed with spherical in shape and the average particle size was 12 ± 3 nm. The synthesized CMCG-AuNPs were utilized to sensing Hg²⁺ ions in an aqueous medium, the presence of Hg²⁺ ions selectively among other metal ions, the CMCG-AuNPs were aggregated by changing the color from wine red to purple blue accompanied by change in the position of SPR peak and intensity. It was observed as a strong linear relationship based on the change in intensity, the limit of detection was determined to be 0.277 nM. The catalytic activity was also examined for the reduction of methyl red (MR) in the presence of CMCG-AuNPs was completed within 12 min and followed pseudo-first order kinetics with a rate constant of 0.261 min⁻¹. From the obtained results, the synthesized CMCG-AuNPs were useful for detection of heavy metal ions as well as toxic pollutants degradation via a green method, and utilized sensing, environmental, and biomedical application in future.

在本研究中，我们通过微波辅助方法成功合成和表征了羧甲基腰果胶修饰的金纳米粒子 (CMCG-AuNPs)，并将其用作量热探针用于选择性检测 Hg ²⁺离子以及甲基红在水性介质中的催化还原。还研究了不同参数（包括浓度和照射时间）对 CMCG-AuNP 形成的影响。可见区域中强表面等离子体共振 (SPR) 峰的存在表明 AuNP 的形成。表征技术确定了 CMCG 和 AuNP 之间的相互作用，并估计了尺寸和形态。面心立方 (FCC) 晶体结构是通过使用 XRD 和 SAED 图案支持来识别的。CMCG-AuNPs 的 TEM 图像显示为多分散的球形，平均粒径为 12 ± 3 nm。合成的 CMCG-AuNPs 用于检测水介质中的Hg ^{2+离子，Hg 2+的存在}在其他金属离子中选择性离子，CMCG-AuNPs 通过将颜色从酒红色变为紫蓝色，伴随着 SPR 峰位置和强度的变化而聚集。观察到基于强度变化的强线性关系，检测限确定为 0.277 nM。还检查了在存在 CMCG-AuNP 的情况下甲基红 (MR) 的还原在 12 分钟内完成的催化活性，并遵循伪一级动力学，速率常数为 0.261 分钟^-1。从获得的结果来看，合成的 CMCG-AuNPs 可用于通过绿色方法检测重金属离子和有毒污染物降解，并在未来用于传感、环境和生物医学应用。