Voltammetric determination of lead (ll) using a carbon paste electrode modified with eucalyptus' essential oil

Date

4-2004

Degree

Bachelor of Science in Agricultural Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Elmer Rico E. Mojica

Co-adviser

Norriel S. Nipales

Committee Member

Jose Rene L. Micor

Abstract

A novel carbon paste electrode modified with Eucalyptus essential oil was investigated for voltammetric behavior prior to and after lead (II) accumulation. Preliminary investigation demonstrated the ability of the eucalyptus' essential oil modified CPE to accumulate lead (II) ions on its surface and generate peaks within -400 mV to -600 mV range. Optimization of experimental parameters for the analysis was determined. The optimized parameters were 10% modifier, 0.1M HCL as supporting electrolyte, 2.0 minutes accumulation, pH 6 of the accumulating solution, 300 seconds deposition time and -1500 mV deposition potential. The selectivity of eucalyptus' essential oil modified CPE towards lead (11) was analyzed by studying the interferences from other metals. Several metals were tested such as cadmium (II), copper (II), cobalt (II), zinc (II) and mercury (11) which showed peaks at their respective potential region. Mercury (11), giving the highest signal is possible to be the major interference in this study. The regenerative ability of the eucalyptus' essential oil modified CPE shows that regeneration of the electrode is possible. However, such method greatly affects the sensitivity of the electrode towards the analyte. Linearity of peak current response against variable lead (II) concentration was established up to 20 ppm giving a linearity coefficient of 0.9972, LOD of 0.8254, and LOQ of 2.751. Analysis of the laboratory waste using differential pulse anodic stripping voltammetry (DPASV) gave a lead (II) concentration equal to 13.85. A parallel analysis of the laboratory waste on atomic absorption spectroscopy (AAS) gave a lead (II) concentration of 52.38 ppm. The values obtained from two methods were significantly different. This can be attributed mainly on the presence of the interfering ions that can compete with the binding of lead (II) on the eucalyptus' essential oil modified CPE.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2004 A13 I43

Document Type

Thesis

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