Analysis Of Trace Metals In The Aluminum Alloy By Optical-electrical Double Pulse LIBS Technique

Heavy metal pollution refers to the environmental pollution caused by heavy metals ortheir compounds. The heavy metal content in the environment increases due to human factorssuch as mining, emissions, wastewater irrigation and the use of heavy metals in products,and exceeds the normal range. Heavy metal pollution and its hazards of environmental,biological is very serious, has gained a high degree of attention of scientists around theworld,to solve this problem is imminent. The rapid and sensitive monitoring of the heavymetal content in environmental and industrial products is a very important aspect to solve thisproblem.This paper, in order to obtain higher sensitivity and lower detection limit, we proposedthe optical-electronic dual-pulse LIBS technique on the basis of the LIBS technique.We used the method of electro-deposition to enrichment the trace mercury ions inaqueous solution on high-purity copper rod surface, the gating pulse power optical-electronicdual-pulse LIBS to analyze the trace mercury. The laser pulse stripped out the plasma in thesample surface prior to the spark discharge. Spark discharge excited the plasma stripped outsecondary, enhanced the intensity of atomic emission and extend the time of its radiationsignificantly, enhances the ratio of signal to background. high-sensitivity detection of tracemercury ions could be achieved by this technology, the LOD were1μg/L.Then we tried to add a sleeve closed to the surface of the sample to limit the plasma.Found that the effect of spatial separation was relatively good in the delay time of50-75μs.Finally, we tried to use the DC high voltage current source and capacitor as dischargecircuit; it can achieve fast, instantaneous discharge, to reduce the effect of bremsstrahlungelectron irradiation. In this work, we compared the Analysis sensitivity of differentcapacitance. When the capacitance is2nF, the signal to background ratio was smaller.Through the analysis of metal elements in the standard aluminum alloy by LA-SIBStechnology, the detection limit of cadmium, magnesium, copper, manganese, zinc obtainedwere1.12ppm,5.23ppm,0.49ppm,3.85ppm,1.06ppm. Comparing the LIBS technology thedetection limit were11.65ppm,21.11ppm,1.64ppm,15ppm,10.98ppm.The limit of detection improved4-10times. This technology enhances the flexibility of the application of LIBS,improves the Analysis sensitivity of the LIBS technique.