Studies On The Content Of Heavy Metals In Radix Salvia Mitiorrhiza

As the dried root of Salvia Miltiorrhiza Bge., Radix Salvia Miltiorrhiza (RSM) is a commonly-used Traditional Chinese Medicine (TCM) for removing blood stasis, relieving pain, promoting blood circulation, tranquilizing mind and relieving vexation. Through all-round saw about the factors including sample pretreatment, working conditions of atomic absorption spectrometry, sample determination and so on, a sensitive, reliable method for the determination of heavy metals content in RSM was established. The thesis contains following main parts:The pretreatment of RSM samples by microwave digestion was investigated. Factors such as grain size, digesting pressure, digesting time were investigated one by one. The best digestion condition was then selected: 5 mLHNO3 was used as digesting acid, grain size 40, digesting pressure 2.0 Mpa, and digesting time 14 min. It can make the digesting course completely.The best working condition of the graphite furnace to determine Pb and Cd was investigated respectively. As Pb and Cd were prone to volatilize, the matrix modifier must be added in the course for the sake of heightening ashing temperature. The courses of drying, ashing, atomizing and clearing of graphite tube were investigated with NH4H2PO4 and Mg(NO3)2 as a matrix modifier, which could enchance the ashing tempetature of Pb, Cd to 800℃and 600℃,the atomization temperature of Pb,Cd were 2100℃and 2000℃. Methodology validation showed that Pb and Cd in RSM can be determined quickly and precisely, and the result was satisfying.The best working condition of atomic absorption spectrometry to determine As, Hg was investigated including effects of reducing agent, sodium hydroxide, carrier liquid, acid medium on atomic absorbance signals, experiment of the pressure of carrier gas, and the choice of prereducer of As.Combined with the methodology guideline including linear range, detection limit, precision, accuracy, the method set-up was verified. The detection limits of Pb, Cd, Cu, As, Hg were 0.99μg/L, 0.16μg/L, 0.012μg/mL, 0.87μg/L, 0.46μg/L respectively. Experiments of repeatability and recovery showed favorable precision and accuracy. Using the method set-up in front, the contents of Pb, Cd, Cu, As, Hg in 70 samples of RSM from different habitats (Shanxi, Henan, Sichuan, Chongqing, Zhejiang, Hebei province/citie ) were determined, and the result was satisfying.