Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10559873 | Talanta | 2011 | 9 Pages |
Abstract
A new design of a membraneless gas-diffusion (MGD) unit coupled to a multisyringe flow injection system is proposed. The spectrophotometric determination of ammonium using an acid-base indicator was chosen to show the feasibility of this approach. Hence, in alkaline medium, ammonium ions are transformed into ammonia (donor channel) which diffuses through the headspace into the acceptor stream (bromothymol blue solution), causing a pH change and subsequently a colour change. The exploitation of the enhanced potentialities of this re-designed MGD device was the main purpose of the present work. Hence, several strategies concerning flow management were studied seeking to characterize and improve the analytical features of the methodology and moreover, untreated environmental samples were analysed without previous filtration. Consequently, stopped flow in acceptor channel with continuous flow in donor channel was chosen for the application to wastewater and spiked river water samples. A linear concentration range between 10.0 and 50.0 mg Lâ1 of NH4+, a limit of detection of 2.20 mg Lâ1 and a determination frequency of 11 hâ1 were obtained.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
M. Inês G.S. Almeida, José Manuel Estela, Marcela A. Segundo, VÃctor Cerdà ,