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On-line solid phase extraction and spectrophotometric detection with flow technique for the determination of nanomolar level ammonium in seawater samples

Citation

Chen, G and Zhang, M and Zhang, Z and Huang, Y and Yuan, D, On-line solid phase extraction and spectrophotometric detection with flow technique for the determination of nanomolar level ammonium in seawater samples, Analytical Letters, 44, (1-3) pp. 310-326. ISSN 0003-2719 (2011) [Refereed Article]

Copyright Statement

Copyright 2011 Taylor & Francis Group, LLC

DOI: doi:10.1080/00032719.2010.500775

Abstract

The determination of low-level ammonium in seawaters suffers from low sensitivity and high contamination; therefore, it is desirable to develop highly sensitive methods for automatic measurements. A highly sensitive and automated flow technique system for nanomolar level ammonium measurement is described. Reagents for Berthelot reaction were automatically added into seawater samples. After a 10min reaction at 40C, the formed indophenol blue compound was on-line extracted onto an Hydrophilic-Lipophilic Balance (HLB) cartridge. The enriched compound was rinsed with water and ethanol solution (30%, v/v) and, in turn, eluted with an eluent containing 30% (v/v) ethanol and 5.0mM of NaOH, and determined with a spectrophotometer at 640nm. Parameter, including extraction conditions, reagent concentrations, pH, temperature, and reaction time, were optimized. Under the optimized conditions, the detection limit was 3.5nM and the linear range was 0428nM. The relative standard deviations were 5.7% (n=8) for 44.6nM standard solution and less than 6.0% (n=35) for samples within concentrations of about 52.4288.7nM; the recovery was in the range 93.6 to 108.5%. The sample throughput was 3h−1. The proposed method provides a simple, cheap, and automatic way to determine ammonium in seawater samples without complicated sample treatment.

Item Details

Item Type:Refereed Article
Keywords:ammonium, seawater, sequential injection, solid phase extraction
Research Division:Chemical Sciences
Research Group:Analytical Chemistry
Research Field:Flow Analysis
Objective Division:Environment
Objective Group:Physical and Chemical Conditions of Water
Objective Field:Physical and Chemical Conditions of Water in Marine Environments
Author:Zhang, M (Dr Min Zhang)
ID Code:104697
Year Published:2011
Web of Science® Times Cited:18
Deposited By:Chemistry
Deposited On:2015-11-18
Last Modified:2017-10-30
Downloads:0

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