| dc.description.abstract | In this research, the chitosan/GQDs/Fe3O4 modified electrode has been
successfully carried out in measuring cholesterol using the cyclic voltammetry method.
The chitosan/GQDs/Fe3O4 modified electrode was fabricated using the
electrodeposition method using a ratio of 2:1:1 using 1.5% chitosan, GQDs 250 mg/L,
and Fe3O4 variations of 50, 75, 100, 125, and 150 mg/L. Surface analysis of the
modified electrode was carried out using the Fourier Transform Infra-Red (FT-IR),
Field Emission-Scanning Electron Microscopy (FE-SEM), and X-Ray Diffraction
(XRD) methods. Testing the sensing properties of the chitosan/GQDs/Fe3O4 modified
electrode was carried out using the cyclic voltammetry method using voltage range
parameters of -1V to +1V and a scan rate of 125 mV/s. Testing was carried out with
variations of cholesterol of 50, 100, 150, 200, 250, and 300 mg/dL and blood serum
dissolved in phosphate buffer solution. The results of the test produced a
Chitosan/GQDs/Fe3O4 modified electrode with an Fe3O4 concentration of 100 mg/L
which is an electrode with good performance. The limit of detection (LOD) and Limit
of quantitation (LOQ) in cholesterol detection were 15,24 mg/dL and 50,81 mg/dL. In
real sample testing, the modified electrode was also considered capable of detecting
cholesterol in blood serum. This is evidenced by the obtained percentage errors, which
were 0.88% for serum A, 1.01% for serum B, 0.54% for serum C, and 1.32% for serum
D. Therefore, the chitosan/GQDs/Fe3O4 modified electrode can be further applied as
a working electrode material for electrochemical sensors in cholesterol detection. | en_US |
