Shenyang Institute Of Automation Makes New Progress in Improving Long-Term Stability Of Spectroscopic Measurements

Journal of Analytical Atomic Spectrometry Cover Story

Schematic diagram of ID-PLS method
In the field of spectroscopy, long-term stability has always been an important indicator of instrument performance, which is crucial for realizing high-precision measurements, and LIBS (laser-induced breakdown spectroscopy) has shown great potential in the field of spectroscopy due to its advantages of fast detection speed, no sample pretreatment, and real-time in-situ detection, etc. However, in practical applications, especially in the field of laser-induced breakdown spectroscopy (LIBS), it is very difficult to achieve long-term stability in the field. However, in practical applications, especially in complex industrial environments, the signal drift problem caused by environmental interference has become a major bottleneck restricting the wide application of LIBS technology. Recently, the LIBS research team at the Shenyang Institute of Automation, Chinese Academy of Sciences, has made new progress in this field.
To address this challenge, the LIBS team proposed the ID-PLS method after in-depth research. First, the researchers obtained the ideal value of the intensity ratio based on a quantitative model, and then introduced the intensity ratio drift value (i.e., the deviation between the detected value and the ideal value), which realized the accurate characterization of the fluctuation of the spectrum in the process of long-time detection. Second, the researchers utilize the partial least squares algorithm (i.e., PLS algorithm) in machine learning to learn the relationship between the drift value and the intrinsic law of the spectrum, calibrate the spectral detection value to the vicinity of the ideal value, and ensure that the lower limit of its calibration effect is not lower than that of the traditional average internal standard method, thus significantly improving the long-term stability of the spectral measurement. The experimental results show that the long-term stability of LIBS measurements is effectively enhanced by the ID-PLS method.
In order to further verify the effectiveness of the ID-PLS method, the research team applied it to the self-developed LIBS steel composition sensor and tested it on different low-alloy steel samples. The test results show that compared with the traditional drift correction method, the ID-PLS method performs better in the comprehensive calibration performance of multiple elements such as C, Si, Mo, Ni, Cu and Mn, providing a practical solution to enhance the long-term stability of the spectral sensor.
The research result, titled Combination of Internal Standard and Dominant Factor PLS for Improving Long-term Stability of LIBS Measurements, has been published in the Journal of Analytical Atomic Spectroscopy (JASP), a journal in the field of spectroscopy. Journal of Analytical Atomic Spectrometry as a cover paper. This research was supported by the National Key Research and Development Program of China.