Concentration of Heavy Metals by High-Speed Countercurrent Chromatography

Abstract

Application of high-speed countercurrent chromatography (HSCCC) to the concentration of metal ions has been studied. The stationary phase, containing di(2-ethylhexyl) phosphoric acid (DEHPA) in n-heptane, was continuously fed into the column. The ppb level of metal ions in a 500 mL of the mobile phase was continuously concentrated into small volumes of the stationary phase retained in the column. Concentrated metal ions were eluted with nitric acid and determined by the emission intensity with a direct current plasma atomic emission spectrometer (DCP-AES). The recoveries of Ca, Cd, Mg, Mn, Pb and Zn ranged over 88% at a concentration of 10 ppb each in 500 mL of the sample solution. Versatility of the present method was further demonstrated in determination of trace metals in tap water and deionized water.