Voltammetric determination of lead (II) using kangkong (Ipomea aquatica forsk) modified carbon paste electrode

Date

10-2003

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Elmer Rico E. Mojica

Abstract

The ion- exchange capacity of the leaves and stem of kangkong was used by constructing a carbon paste electrode modified with the leaves and stem of the said plant. The electrochemical property of the modified electrode was determined through cyclic voltammetry. The potential window of both electrodes was between -1500 to 1500 mV. A peak characteristic of the oxidation of P132* (at about -500 mV) was observed when the electrode was dipped in a lead (II) solution. Optimum experimental conditions were determined to obtain the best current response from the two electrodes. The optimized parameters for the carbon paste electrode modified with I. aquatica (CPEMIA) leaf are the following: (i) pH of the accumulating solution: pH 5 (ii) composition of stripping solution: 0.01 M HCI (iii) accumulation time: 4 minutes (iv) electrode composition: 5% modifier (v) deposition time: 300 seconds (vi) deposition potential: -1200 mV. The optimized parameters for the carbon paste electrode modified with the stem of /. aquatica (CPEMIA stem) are almost the same as that of CPEMIA leaf with the exception of the accumulation time. The accumulation time for CPEMIA stem is three minutes. The electrodes are regenerated by 10 multiple stripping followed by soaking in 0.01 M EDTA. Immersion time for CPEMIA leaf was found to be thirty minutes while that of the CPEMIA stem was twenty minutes. No loss of analytical response was observed when the kangkong leaf and stem modified electrodes are regenerated no more than three times. The LOD and LOQ for the CPEMIA stem is 0.91 ppm and 3.00 ppm respectively. The LOQ and LOD of the CPEMIA leaves, on the other hand, is 0.57 ppm and 1.91 ppm respectively.

Language

Filipino

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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