PENCIL GRAPHITE ELECTRODE MODIFIED WITH MOLECULARLY IMPRINTED POLY(GLYCINE) FOR VOLTAMMETRIC DETERMINATION OF RHODAMINE B

• Main Author: Marcelina Putri, Vina
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/75449
• Institution: Institut Teknologi Bandung

Rhodamine B is a carcinogenic synthetic dye that is widely misused as a food colorant. This compound is electrochemically active and could be detected using voltammetry method. Pencil graphite electrode (PGE) is a working electrode that is categorized as lack of development although having many advantages. However, bare PGE is still less sensitive. Thus, in this research determination of rhodamine B was evaluated using PGE modified by molecularly imprinted polymer (PGE-MIP) with glycine as its monomer to increase PGE’s sensitivity and can be used for samples. In this research, the optimum PGE-MIP preparation was carried out by varying composition ratio of monomer glycine and rhodamine B and varying electropolymerization cycle. After that, optimization of rhodamine B measurement was carried out by finding the optimum pH measurement and voltammetry technique. Peak current as a response of rhodamine B was measured by PGE-MIP which is higher than PGE modified by nonimprinted polymer (PGE-NIP) and PGE-bare. The optimum conditions for PGE-MIP preparation were obtained using a molar ratio of rhodamine B and glycine 1:3 with 10 electropolymerization cycles. Meanwhile, the optimum conditions for rhodamine B measurement were obtained at pH 7 using square wave voltammetry technique. Measurements of both repeatability and reproducibility tests of 1 mM rhodamine B solution have %RSD of 5.54% (n=30) and 4.45% (n=3). PGE-MIP has a dynamic range in the concentration of 1- 100 ????M with a detection limit of 1.7 ????M. Scan rate analysis shows that the electron transfer process at the surface electrode is controlled by the diffusion process. The result of rhodamine B analysisin the crackers sample using PGE-MIP (voltammetric method) was not significantly different compared with UV-VIS spectrophotometric method.