Application Of LIBS On Analysis Of Trace Elements In Chinese Medicinal Materials

The research of real time,online,and highly sensitive detection based on the laser-induced breakdown spectroscopy(LIBS)are currently one of very interested subjects in the field of elemental analysis.Chinese medicinal materials(CMMs)have been popularly used to cure many kinds of diseases because they are not only rich in organic molecules but also contain many kinds of trace elements which are beneficial to human body.Compared with traditional methods such as the graphite furnace atomic absorption spectrometry,the inductively coupled plasma mass spectrometry,the inductively coupled plasma atomic emission spectrometry,laser-induced breakdown spectroscopy has the advantages of small amounts of sample,no complex sample pretreatment,simultaneous measurement of multi-element,at present it has been considered to be a potential analytical method for quality identification and rapid detection of heavy metals in CMMs.According to the practical application requirements of quality identification and rapid detection of heavy metals in CMMs,the following work has been carried out:(1)The samples of Codonopsis pilosula from nine habitats were selected,and the free calibration LIBS method was used to measure the LIBS spectroscopy and obtain the corresponding content of trace elements.To check the spectral stability and measurement accuracy,these results were compared with the results of the inductively coupled plasma mass spectrometry(ICP-MS)and the liquid cathode glow discharge atomic emission spectrometry(LCGD-AES).It shows that the analysis results of CMMs based on CF-LIBS technology are in good agreement with other two methods,but the spectral stability and measurement accuracy need to be improved.(2)In order to improve the stability of the spectroscopy and accuracy of measurement,this paper proposes a method for chinese medicinal materials based on high pure graphite target,and combined with CF-LIBS method,the spectroscopy stability of the Codonopsis pilosula sample is increased by 2-3 times,and the measurement accuracy is reduced to less than 10%.In addition,in order to determine the detection ability of heavy metal elements Cr,Pb and Cd in the Codonopsis pilosula sample,the standard samples of these three elements were prepared.By drawing the standard curve,the detection limit(LOD)values were obtained,which are less than 10 ?g/g.The above research is expected to provide a reference for the rapid detection of CMMs,the monitoring of the planting environment and the development of relevant detection equipment.