Rapid And Green Detection Of Pb And Cr In Potatoes By Laser Induced Breakdown Spectroscopy

With the development of the human material standard of living, green agricultural products have become the focus of attention of people’s daily life, and the safety of agricultural products will directly influence people’s health. The overproof of heavy metals residue in the vegetables have a significant impact on human body, and once the heavy metal residue in vegetables, it cannot be eliminated by the methods of boiling or soaking cleaning, the harm to human body is cumulativity and with a long incubation period.Potato is one of five major staple foods. With the advantages of high nutritive value,adaptable and big capacity, which is the world’s third most important food crop after wheat and corn. But the heavy metals will be enriched in potato while it was planted in the polluted soil, then the quality of potato will be influenced. On account of that, it is significant to enhance the determination of heavy metal in potatoes. Laser induced breakdown spectroscopy(LIBS) technology has a rapid multi-element detection,environmental protection, multi-elemental detection at the same time etc.. Therefore, in this work LIBS technology was utilized to analyse quantitatively lead(Pb) and Chrome(Cr)in potatoes.Firstly, the rapid detection of LIBS testing setup was built. In order to obtain a stabilized determine environment, making the LIBS has a better effect in the detection of heavy metals in agricultural products, the parameters such as the angle of optical fiber and focal point were adjusted etc.. Then the impact of water content in the wet polluted potatoes to LIBS determination was discussed, contrasting the LIBS monitor consequences between the dry and wet potatoes samples, the result obviously showed that the testing stability of dry sample was better than wet sample. So as to improve the stability of the LIBS, the dry potatoes sample need to simple and rapid pretreatment such as drying,crushing, and so on. The dry potatoes sample with the powder sheeting.Secondly, working conditional parameters for influencing LIBS detection in detecting heavy pollution in potatoes such as the spectral acquisition delay time、gate time and laser energy have been optimized. The results showed optimal parameters are 2μs 、8ms and90 mJ respectively.Lastly, spectral data of the 96 potatoes samples were pretreated by different data smoothing from 3 points to 17 points. Then smoothed data was analyzed by standard normal variable transformation(or the mean centralized, or the first derivative of denoising,or second derivative of denoisingor, multiple scatter correction,). Using the linear regression, partial least squares and synergy interval partial least square method to quantitative analysis the Pb and Cr in the polluted potatoes. The calibration curves model about LIBS signal intensity and the content of Pb and Cr in potatoes was constructed.Compared the prediction results and the actual results of the several models, feasibility forrapid elemental concentration measurement of potatoes by the LIBS technique was verified,and the research for rapidly detecting heavy metals in other agriculture produces by LIBS provide theoretical basis and technical support.