Modified Carbon Paste Electrode with Methylene Blue for Voltammetric Analysing of Cysteine

• Main Author: Adha Tsaqifah, Ghumaydha
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/42132
• Institution: Institut Teknologi Bandung

Cysteine is an amino acid for synthesising glutathionine. The functions of glutathionine is to regulate the metabolism of vitamins and antioxidants in the human body, so cysteine is often used as food and medicine. The use of cysteine as a drug was developed to treat diseases such as chronic bronchitis, liver failure, and diabetes. Therefore, we need a method for analysing cysteine. In this study, determination of cysteine was developed with the voltammetry technique. In voltammetry, carbon paste electrode is modified to provide good selectivity and sensitivity for analysing cysteine. In this study, carbon paste electrode were modified with molecularly imprinted polymers prepared by electropolymerization using methylene blue as a monomer and cysteine as an analyte using cyclic voltammetry by 20 cycles in the potential range of -1.0 - 1.4 V with a scan rate 100 mV/s. Optimum measurement conditions were obtained using 1 mM blue methylene and 3 mM cysteine. The results of measuring cysteine using the differential pulse voltammetry technique was found the repeatability of the modified electrode with %RSD was 5.05%. The optimum condition linearity's working range was found at concentration of 100 J.!M - 1000 J.!M with a limit of detection was 85.57 J.!M. Determination of cysteine in drug samples by the addition of standard cysteine method showed good accuracy with percent of recovery 100.51 ± 1.88% for the first sample and 101.17 ± 1.70% for the second sample.