Document Detail

Renewable urea sensor based on a self-assembled polyelectrolyte layer.
MedLine Citation:
PMID:  11996366     Owner:  NLM     Status:  MEDLINE    
A renewable urea sensor based on a carboxylic poly(vinyl chloride) (PVC-COOH) matrix pH-sensitive membrane has been proposed, in which a positively charged polyelectrolyte layer is first constructed by using a self-assembly technique on the surface of a PVC-COOH membrane, and urease, with negative charges, is then immobilized through electrostatic adsorption onto the PVC-COOH membrane, by controlling the pH of the urease solution below its isoelectric point. The response characteristics of the PVC-COOH pH-sensitive membrane and the effects of experimental conditions have been investigated in detail. Compared with conventional covalent immobilization, the urea sensor made with this self-assembly immobilization shows significant advantage in terms of sensitivity and ease of regeneration. The potential responses of the urea sensor with self-assembly immobilization increase with the urea concentration over the concentration range 10(-5) - 10(-1) mol l(-1), and the detection limit is 0.028 mmol(-1). Moreover, this type of urea sensor can be repeatedly regenerated by using a simple washing treatment with 0.01 mol l(-1) NaOH (containing 0.5 mol l(-1) NaCl) and 0.01 mol l(-1) HCl. The urease layers and the polyelectrolyte layers on the PVC-COOH membrane are removed, the potential response of the sensor to urea solutions of different concentrations returns nearly to zero, and another assembly cycle of urease and polyelectrolyte can then be carried out.
Zhaoyang Wu; Lirui Guan; Guoli Shen; Ruqin Yu
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Analyst     Volume:  127     ISSN:  0003-2654     ISO Abbreviation:  Analyst     Publication Date:  2002 Mar 
Date Detail:
Created Date:  2002-05-08     Completed Date:  2002-05-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372652     Medline TA:  Analyst     Country:  England    
Other Details:
Languages:  eng     Pagination:  391-5     Citation Subset:  IM    
Chemistry and Chemical Engineering College, State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha, China.
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MeSH Terms
Biosensing Techniques
Urea / analysis*
Reg. No./Substance:
57-13-6/Urea; EC

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