Fig. 1. Schematic diagram of the portable LIBS instrument
(a): Optical layout;(b): Internal structure charts of the instrument

Fig. 2. A typical sediment LIBS spectrum

Fig. 3. Flow chart of concentration prediction of Zn in sediment using portable LIBS system

Fig. 4. The RSD results of Zn with different standardized methods

Fig. 5. Calibration curve for Zn in sediment
(a): Calibration curve for Zn with univariate quantitative method; (b): Calibration curve for Zn with BP neural network

Fig. 6. The emission intensities of Ca Ⅰ 422 nm and Zn Ⅰ 468 nm as a function of sample’s drying time

Fig. 7. Field measurements pictures and site positions in Jiaozhou Bay
(a): Field measurement picture of the portable LIBS system; (b): Site map for sediments sampling;(c): Picture of a typical sediment sample; (d): A typical sediment LIBS spectrum on site