A membraneless gas-diffusion unit – multisyringe flow injection spectrophotometric method for ammonium determination in untreated environmental samples

• Type: Article in International Scientific Journal
• Date: 2011

Authors

M. Inês G.S. Almeida (Author) Other; José Manuel Estela (Author) Other; Marcela A. Segundo (Author) FFUP; Víctor Cerdà (Author) Other

Journal

Title: Talanta

Vol. 84 No. 5

Pages: 1244-1252

ISSN: 0039-9140

Publisher: Elsevier

Indexing

ISI Web of Science

Scientific classification

FOS: Medical and Health sciences > Health sciences

CORDIS: Physical sciences > Chemistry > Analytical chemistry

Other information

Resumo (PT): 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 L−1 of NH4+, a limit of detection of 2.20 mg L−1 and a determination frequency of 11 h−1 were obtained. <br> <br> Keywords: Membraneless gas-diffusion; Multisyringe flow injection analysis; Ammonium; Wastewater samples; River water samples; Automation <br> <a target="_blank" href="http://www.sciencedirect.com/science/article/pii/S0039914011000609 "> Texto integral</a> <br> <br>

Abstract (EN): 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 L−1 of NH4+, a limit of detection of 2.20 mg L−1 and a determination frequency of 11 h−1 were obtained. <br> <br> Keywords: Membraneless gas-diffusion; Multisyringe flow injection analysis; Ammonium; Wastewater samples; River water samples; Automation <br> <a target="_blank" href=" http://www.sciencedirect.com/science/article/pii/S0039914011000609"> Full text</a> <br> <br>

Language: English

Type (Professor's evaluation): Scientific