Enrichment of Malachite Green in Fishpond Water by Sulfo-Functionalized Magnetic Beads

Sulfo-functionalized magnetic beads were prepared by covalently conjugating aminobenzenesulfonic acid onto carboxyl surface of magnetic beads with 1-ethyl-3-(3-dimethylaminopropyl)carbo-diimide(EDC)/N-hydroxysulfo succinimide(Sulfo-NHS) method.Those beads were used as dispersive solid phase extraction sorbent,and hence,a high efficient extraction procedure was developed for enriching trace amounts of malachite green(MG) in fishpond water.Parameters of adsorption and desorption of MG including pH value of fishpond water and elution solution were optimized.Results showed that sulfo-functionalized magnetic beads exhibited the high efficiency on enrichment of MG in fishpond water at pH 3.0-6.0 and the highest efficiency achieved at pH 4.0(82.4%±5.5%,n=3).Acetonitrile was effective in eluting MG on the magnetic beads.At pH 4.0 and 25 ℃,the adsorption behavior followed Langmuir adsorption isotherm with a maximum adsorption capacity of 66.67 μg/g and a Langmuir adsorption equilibrium constant of 0.375 L/μg.