Fig. 1. Laser-induced breakdown spectroscopy detection system. (a) Schematic of the internal structure; (b) Physical diagram

Fig. 2. Spectrum of standard sample. (a) 200-550 nm band; (b) 288.0-296.9 nm band

Fig. 3. Effect of delay time on the spectral intensity and signal-to-background ratio. (a) Si(I) 288.158 nm; (b) C(II) 296.786 nm

Fig. 4. Effect of defocus amount on the spectral intensity and signal-to-background ratio. (a) Si(I) 288.158 nm; (b) C(II) 296.786 nm

Fig. 5. Effect of laser energy on the spectral intensity and signal-to-background ratio. (a) Si(I) 288.158 nm; (b) C(II) 296.786 nm

Fig. 6. Calibration curves obtained by internal standard method.(a) Si(I) 288.158 nm/ Fe(II) 274.932 nm; (b) C(II) 296.786 nm/ Fe(II) 288.076 nm