| Currently,the detection of metal element contents in soil and corn samples in situ cannot be achieved in real time.Commonly,researchers detect the metal elements existed in a sample by using the traditional method of inductively coupled plasma atomic absorption spectroscopy.Obviously,it is a complicated process and a time consuming method.Therefore,a novel method for the situ detection of the metal elements in soil and corn samples has a great practical significance to be developed.This thesis aims to develop a novel method based on the use of laser induced breakdown spectroscopy technology to quickly detect the metal elements Cu,Mn in soil and corn samples after the analysis of traditional metal element detection methods was studied.Analytical applications of Laser Induced Breakdown Spectroscopy(LIBS),namely optical emission spectroscopy of laser-induced plasmas,have been constantly growing up due to its intrinsic conceptual simplicity and versatility.LIBS has a significance that will influence the investigators who are engaged in the detection of the metal elements in environmental monitoring,agricultural measurement and life science.However,it suffers from the instrumentation limitations from the principle of LIBS.There are many difficulties in the practical applications,including multiple noise sources,low analysis accuracy and poor repeatability.In this paper,the characteristics of laser induced plasma,the principle of plasma emission spectroscopy and the construction of LIBS experimental platform are studied.The optical system structure for the LIBS experimental platform is also been studied,and the control system of the optical path in this LIBS platform and the trigger signal of laser pulse are improved by optimizing the parameters which affect the performance of LIBS spectroscopy.The experiment and data analysis for the detection of metal elements Cu,Mn in corn and soil samples by using LIBS were studied.Experiments were performed by using the different concentrations metal elements Cu and Mn in corn and soil samples,and the contents of the metal elements Cu,Mn were obtained from the LIBS spectroscopy by subtracting background spectroscopy in the spectral data obtained from the minimal value screening method.Qualitative and quantitative analysis can be performed by LIBS both by drawing calibration lines and by using calibration-free methods and some of its features,so as fast multi-elemental response,micro-destructiveness,instrumentation portability,have rendered it particularly suitable for analytical applications in the field of environmental science,agriculture and life sciences.The experimental results show that the detection limit of Cu in soil is 13.61μg.g-1,and Cu,Mn detection limit is 12.39μg.g-1 and 14.35μg.g-1 in corn seeds,it also show that the laser induced breakdown spectroscopy can quickly detect the metal elements in soil and corn samples,which provides a new way for rapid and quantitative detection and analysis of metal elements. |
