Determination of Heavy-Metal Concentrations in Water by PIXE Analysis Using Zr as an Internal Standard

Abstract

A metal-preconcentration procedure, which consists of a combination of chelation by dibenzyldithiocarbamate ions with subsequent condensation into dibenzylidene-D-sorbitol gels, has been reformed by using Zr as an internal standard. The colloidal gels formed in solutions were collected on a nuclepore filter for direct irradiation by 3 MeV proton beams in a system of vertical beam type in-air PIXE. The methodology was tested for simultaneous determination of the concentrations of seven metals ( Fe , Co , Ni , Cu , Cd , Hg , Pb ) in 25 ml of an aqueous sample. A good linear relationship was obtained between the nominal concentration and the elemental X-ray yields normalized with Zr - K α ones. Absolute values of concentration in the sample solutions can be determined with an experimental error less than ±14 % in the 5-100 ppb range by employing published data pertinent to the inner shell ionization and subsequent X-ray emission of the heavy metals.