Study On The Determination Methods For Trace Heavy Metal Elements In Animal Derived Food By ICP-MS And HPLC-AFS

Many farmers feed pigs with fodder containing high copper content in china inorder to make pigs grow faster and look better. The copper is added into fodder in theform of copper sulfate from industry waste so that pigs eat more other metals. Inrecent years, the phenomenon that heavy metals content in pork exceeds limits isbecoming more and more pervasive. People eating that kind of pork are easier to bepoisoned in terms of long-term effects. Microwave digestion（MW） is a popularpretreatment technology and has many advantages. Inductively coupled plasma massspectrometry（ICP-MS）is a inorganic analytical technology developing from1980sand has characters of low detection limit, wide linearity, simple spectra lines, lessinterference, good precision and accuracy. The method for the determination of Cr,Mn, Cu, Zn, Cd and Pb elements in pork by ICP-MS with MW was established. Thedetection limits were ranged from0.0220~0.5501ng/g depending on the elementsdetermined, linear correlation r>0.999. The precision of the method was evaluatedwith relative standard derivation (RSD) in the range of1.3%~8.7%except for Pb(19.9%). Recoveries of spiked samples were in the range of95.7%~115.2%. Theresults show that this method meets the requirements of real sample testing.Mercury exists in three oxidation states, elemental（Hg）, mercuric（Hg2+） andmercurous（Hg+）,they can form both organic and inorganic compounds. Because oflipophilicity, organic mercury is more toxic than inorganic mercury. Seafood is theprimary source of human contamination by MeHg. Over90%of MeHg is absorbedthrough the gastrointestinal tract, then transferred into the bloodstream due to itscomplexation with thiol and to active transport and distributed throughout the bodyand do harm to human’s nervous system, motor system, renal system, cardiovascularsystem, immune system and reproductive system. A simple, rapid, efficient andeconomic method to determine organic mercury is in a great need. Currently, mostresearchers are using HPLC-ICP-MS to analyze mercury. But the costs for purchase,usage and maintenance for ICP-MS are too large to be popularized in most commonlabs. In fact, HPLC-AFS can satisfy most needs. In our research, an efficient and fastHPLC-AFS method was developed, using microwave assisted extraction（MAE）procedure for extraction of MeHg and EtHg in fish tissues. The optimum conditionsfor MAE were found to be0.2g(correct to0.001g) of sample,5mL of solventcontaining5mol/L HCl and0.25mol/L NaCl and an irradiation time of10min at thetemperature of60℃. The accuracy of the method was demonstrated by analyzing MeHg in biological certified reference materials GBW10029and three real samplesand the actual values are close to the standard values supplied.