Time-based multisyringe flow injection system for the spectrofluorimeric determination of aluminium

摘要

A time-based multisyringe flow injection procedure with spectrofluorimetric detection is proposed n this paper for the determination of aluminium in drinking water. The flow methodology is based on the simultaneous or sequential injection of sample and chelating reagent (viz. 8-hydroxyquinoline-5-sulphonic acid) plugs using a multicommultation approach so hat three successive injections may be performed with a sole displacement of the piston driver bar of the burette. Thus, an injection throughput as high as 154h~(-1) is achieved by sampling a 182 #mu#l sample zone. In order to enhance the luminescence, the reaction is carried out in micellar medium using hexadecyltrimethylammonium chloride as surfactant. THe influence of geometric and hydrodynamic variables as well as several parameters such as multicommutation timing, ligand and sufactant concentration and reagent pH was assessed.Under the selected working conditions, a linear dynamic range form 10 to 500 #mu#g l~(-1) Al(III), a 3#sigma# detection limit of 0.5#mu#gl~(-1) and a coefficient of variation of 0.6% at the 30#mu#g l~(-1) level were obtained. The analytical features were compared with those reported in previous flow injection and sequential injection methods. The multisyringe technique was successfully applied to the determination of aluminium in drinking water at low mineralisation levels, validating the results by inductively coupled plasma atomic emission spectrometry.