A method that utilizes activated carbon as a solid phase extraction was developed for the simultaneous preconcentration of eight trace heavy metals, including trace Zn(Ⅱ),Cd(Ⅱ),V(Ⅲ),Co(Ⅱ),Ni(Ⅱ),Pb(Ⅱ),Mn(Ⅱ) and Cr(Ⅲ),prior to the measurement by microwave plasma torch-atomic emission spectrometry(MP-AES).Influences of some analytical parameters including pH value of sample,amount of adsorbent,flow rate and volume of sample,elution condition were optimized.Moreover,effects of foreign ions on recoveries of the determined elements were studied.The experiment showed that foreign ions did not influence recoveries of the determined elements.Under the optimized conditions,the detection limits for Zn(Ⅱ),Cd(Ⅱ),V(Ⅲ),Co(Ⅱ),Ni(Ⅱ),Pb(Ⅱ),Mn(Ⅱ) and Cr(Ⅲ) were 0.45,0.35,0.25,0.06,0.40,0.25,0.20,0.20 μg?L-1,respectively.The relative standard deviations(n=8) for the determined elements(10 μg?L-1) were lower than 5%.The largest preconcentration factors were about 50 for V(Ⅲ),Pb(Ⅱ) and Cr(Ⅲ),and not less than 300 for the rest of heavy metals.The method was validated using a certified reference material,and was also applied successfully in the determination of eight heavy metals in natural waters.
关键词
活性炭预富集微波等离子体原子发射光谱仪(MP-AES)重金属
Keywords
activated carbonpreconcentrationmicrowave plasma torch-atomic emission spectrometryheavy metal