DEVELOPMENT OF MULTI-ANALYTE BIOSENSOR BASED ON SCREEN-PRINTED CARBON ELECTRODE (SPCE) MODIFIED WITH GRAPHENE QUANTUM DOTS (GQDS)

• Main Author: Elviana La'salina Muhlis, Rd.
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/85147
• Institution: Institut Teknologi Bandung

The metabolism of the human body produces various fluids containing essential compounds such as glucose, uric acid (UA), dopamin (DA), and ascorbic acid (AA). These compounds play roles in metabolic activities and can be used for the prevention and treatment of various diseases. Additionally, the levels of drugs, such as paracetamol/acetaminophen (AC) in the body, can indicate whether organs like the liver and kidneys are functioning properly. The simultaneous detection of these compounds is crucial for clinical and biological investigations. Electrochemical biosensors based on screen-printed carbon electrodes (SPCE) are a preferred choice for analyte detection due to their portability, high sensitivity, and rapid response. However, SPCEs often face challenges such as weak signals and poor charge transfer. To address these issues, modifications with graphene quantum dots (GQDs) have been implemented. In this final project, an electrochemical biosensor based on SPCE modified with GQDs was developed for multi-analyte detection. The synthesis results of GQDs showed an average size of 3.21 nm with a carbon concentration of 64.7% and oxygen concentration of 35.3%. The performance of SPCE/GQDs@Nafion for AC showed a linear range of 0-2000 ?M, a LoD of 0.378 ?M, and a LoQ of 1.15 ?M. For AA, the linear range was 0-2000 ?M, the LoD was 3.968 ?M, and the LoQ was 12.025 ?M. For UA, the linear range was 0-2000 ?M, the LoD was 2.546 ?M, and the LoQ was 7.716 ?M. For DA, the linear range was 0-50 ?M, the LoD was 0.298 ?M, and the LoQ was 0.905 ?M, while glucose was not detected. Multi-analyte testing showed signal interference among peak currents of the analytes, affecting the calibration plot values and reducing the biosensor's performance in simultaneous analyte detection. The SPCE/GQDs@Nafion can be used to detect AA, UA, and AC in all body fluid samples, but only detect DA in urin samples. This study demonstrates that SPCE modification with GQDs improves the performance of electrochemical biosensors for multi-analyte detection, though further research is needed to address signal interference in multi-analyte testing.