A bead injection system for copper determination

A bead injection system for copper determination is proposed. Chelex-100 re sin beads are introduced in the system as a suspension that is trapped in t he Jet Ring Cell. The passage of the sample zone by the beads promotes the sorption of Cu(II). When the colorimetric reagent (APDC) perfuses the beads it reacts with copper ions, forming a colored complex that is monitored at 436 nn. After the measurement, the spent beads are sent to waste and a new portion of fresh beads is trapped in the system. The bead injection system is versatile and can be used to concentrate analyte in different sample vo lumes, permitting determinations of a wide range of copper concentrations. The detection limit is 0.5 mu g 1(-1) with a 500 mu l sample, and 1.2 ug 1( -1) a 100 mu l sample.