Development of a chitosan- modified sol-gel derived electrode: preliminary investigation for analysis of mercury (II) solutions

Date

10-2000

Degree

Bachelor of Science in Agricultural Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Norriel S Nipales

Co-adviser

Maxima E. flavier

Committee Member

Ma. Cecilia D. de Mesa

Abstract

Chitosan has the ability to form stable complexes with metal ions due to the presence of amine groups. As an electrode modifier, it showed high sensitivity to mercury (11) ions. To ensure stability of the chitosan-modified electrodes, the sol-gel process was used to encapsulate chitosan on the electrode surface. A maximum of 400 mg of modifier material consisting of 20% chitosan and 80% graphite powder was effectively encapsulated by 1300 p.1 sol. Standard deviation of the peak currents of several electrodes was 9.1478 [tA and regeneration techniques were investigated to allow repeated use of the electrode in analysis. Cyclic voltammograms of the chitosan-modified solgel-derived electrode (ChSGE) showed electroinactivity from —1000 to 1500 mV. The mercury (11) peak appeared in the potential range between 150 to 200 mV. Optimum conditions for mercury (11) analyses were determined. Accumulation time of 15 minutes, the use of 0.1 M HCI as supporting electrolyte and a deposition time of 30 seconds gave the best results. The electrode gave limits of detection of 8 ppm using differential pulse anodic stripping voltammetry (DPASV). Determination of mercury (11) concentration in laboratory waste using ChSGE electrodes with DPASV gave comparable results with standard mercury vapor analysis by atomic absorption spectrophotometry (AAS).

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2000 A13 M33

Document Type

Thesis

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