Real-time measurement of constituents in solid materials using particle flow spark induced breakdown spectroscopy
This paper presents an analytical scheme that combines spark-induced breakdown spectroscopy with particle flow (PF-SIBS) for the real-time measurement of the constituents in powdered materials. With high voltage power supply instruments, a vibrational feeder and a spectrometer, the measuring system is low-cost and robust. To demonstrate its applicability, particle samples with varied carbon content were tested in LIBS and PF-SIBS for the comparison of their relative standard deviation (RSD), false spectra ratio, signal-to-noise ratio (SNR) and calibration results. The RSD of the C I 247.86 nm line in LIBS ranged from 35.72% to 62.51% for eight samples, while for PF-SIBS it ranged from 19.63% to 46.57%. The SNR of the Si I 288.15 nm was set as the index for the partial breakdown spectral identification and about 10% of the spectra were identified as false in LIBS, while all the spectra were identified as true spectra in PF-SIBS. The SNR of the C line in PF-SIBS was enhanced by 4 times as compared with LIBS. Since lines emitted from the tungsten electrode are inevitable, a correction method was employed to correct the interference between the C I 247.86 nm and W II 247.77 nm lines. The correlation coefficient, R2, of the linear multivariate calibration of LIBS was 0.957, while that of PF-SIBS was greater than 0.990 and can reach 0.995 after C–W interference correction. With interference correction in PF-SIBS, the average absolute error of the sample validation was 0.38% and the limit of detection (LOD) was 0.46%. These results demonstrate the feasibility of PF-SIBS as a powerful detection technology for the real-time measurement of the constituents in powdered materials and the interference correction can improve the measurement effect at low concentration.