Research Centre of Analytical Instrumentation, School of Mechanical Engineering, Sichuan University, Chengdu, 610065, PR China.
Research Centre of Analytical Instrumentation, School of Mechanical Engineering, Sichuan University, Chengdu, 610065, PR China.
Talanta. 2022 Aug 15;246:123516. doi: 10.1016/j.talanta.2022.123516. Epub 2022 May 2.
Based on microwave plasma torch optical emission spectrometry combined with laser ablation, a direct solid sample detection device was developed for sensitive determination of heavy metals in soil. In the proposed laser ablation microwave plasma torch optical emission spectrometry (LA-MPT-OES) device, a new ablation chamber was designed, which the washout time and the relative standard deviation of this chamber were almost one-third of those of the conventional one, indicating that the proposed chamber had a smaller dead volume to provide efficient and stable transport of ablated sample particles. Meanwhile, to ensure a high signal intensity during a long exposure time, the moving sampling method was used to guarantee a sufficient injection amount. With the optimal experimental parameters, the limits of detection (LODs) of Cu, Pb, Cr and Ag were 0.075, 0.093, 0.068, 0.009 mg·kg, respectively, which was reduced by one to two orders of magnitude compared with that of laser-induced breakdown spectroscopy and X-ray fluorescence and was similar to the LODs of the digestion-required techniques (e.g., ICP-OES and MP-AES) and other LA-related techniques (e.g., LA-ICP-MS). Furthermore, the LA-MPT-OES was applied to the quantitative analysis of standard samples and actual samples, and the obtained determination results were in agreement with the standard values and that of atomic absorption spectrometry. The practicability and accuracy (relative errors were 0.95%-25.9%) of LA-MPT-OES determination of heavy metal elements were also validated.
基于微波等离子体炬光发射光谱结合激光烧蚀，开发了一种直接用于土壤中重金属灵敏测定的固体样品直接检测装置。在所提出的激光烧蚀微波等离子体炬光发射光谱（LA-MPT-OES）装置中，设计了一个新的烧蚀室，其冲洗时间和相对标准偏差几乎是传统烧蚀室的三分之一，表明该烧蚀室具有较小的死体积，能够有效地稳定地输送烧蚀样品颗粒。同时，为了在长时间曝光期间获得高信号强度，采用了移动采样方法以保证足够的进样量。在优化的实验参数下，Cu、Pb、Cr 和 Ag 的检出限（LOD）分别为 0.075、0.093、0.068 和 0.009 mg·kg，与激光诱导击穿光谱和 X 射线荧光相比，降低了 1 到 2 个数量级，与需要消解的技术（如 ICP-OES 和 MP-AES）和其他 LA 相关技术（如 LA-ICP-MS）的 LOD 相当。此外，将 LA-MPT-OES 应用于标准样品和实际样品的定量分析，得到的测定结果与标准值和原子吸收光谱法一致。还验证了 LA-MPT-OES 测定重金属元素的实用性和准确性（相对误差为 0.95%-25.9%）。
