Simultaneous anodic stripping voltammetric determination of lead and cadmium with a carbon paste electrode modified by tributyl phosphate

A novel chemiluminescence (CL) flow sensor has been developed for the monitoring of iron(III). The analytical reagents involved in the CL reaction, including luminol and hexacyanoferrate(II) were both immobilized on an anion-exchange resin column. When sodium sulfate solution was passed through the column, these two reagents were eluted from the resins and then mixed with an iron(III) stream. By the fast reaction between iron(III) and hexacyanoferrate(II), the complex Prussian Blue was generated, which could catalyse the luminol oxidation by dissolved oxygen in alkaline aqueous solution to produce CL. The CL emission intensity was correlated with the standard iron(III) concentration in the range 0.01-Smgl^–1, and the detection limit was 7 × 10^–3mgl^–1 iron(III). A complete analysis, including sampling and washing, could be performed in l min with a relative standard deviation of less than 5%. The sensor was stable for over 200 times and has been applied successfully to the determination of iron in blood samples.