A nanomagnetic and 3-mercaptopropyl-functionalized silica powder for dispersive solid phase extraction of Hg(II) prior to its determination by continuous-flow cold vapor AAS

The authors describe a method for the trace determination of Hg(II) in human fluids using magnetic dispersive solid phase extraction. A silica powder magnetized with Fe3O4 nanoparticles was functionalized with 3-mercaptopropyl groups, and the resulting sorbent was characterized by scanning electron microscopy, energy dispersive X-ray, X-ray diffraction, vibrating sample magnetometry and FTIR. Following microwave-assisted digestion of the sorbent, mercury was quantified by continuous-flow CV-AAS. Factors affecting the sorption and desorption of Hg(II) were optimized. The calibration plot is linear in the 0.2-50.0 mu g L-1 Hg(II)) concentration range. The accuracy in real sample analysis is in the range from 87 to 114%, and precision varies bteween 2.4 and 8.9%. The method was successfully applied to the determination of low levels of Hg(II) in plasma, urine and saliva.