In-Line Concentration on Chitosan and the Use of 2,2′-Dipyridyl-2-Pyridylhydrazone for the Flow-Injection Spectrophotometric Determination of Lead

Abstract

A flow-injection system with spectrophotometric detection involving the in-line concentration was developed for lead determination in natural water samples. Lead concentration was carried out in a mini-column packed with novel stuff chitosan, and sorption occurred at pH=6 - 9. The amount of lead flowing through the chitosan was controlled by time, the CTAB surfactant was passed through a mini-column and a 0.2 M NaOH stream was used as the eluent. The eluted lead merged with 2,2′-dipyridyl-2-pyridylhydrazone (DPPH) reagent synthesised in the author’s lab and with a borate solution; complex formation took place at pH 11 - 12 inside a following reactor and monitoring was carried out at 468 nm. The detection limit was 0.13 µg l^-1 and, the sample throughput was 25 h^-1. The accuracy was assessed by running spiked river-water samples.