*3.5.1 Sensitivity and LOD*

With a regression value of (0.983), the calibration curve became linear in the concentration range (10–50 ng mL−1). This linearity was most likely caused by Ag-VD2 interacting with sufficient Ab-VD2 on the BSA/Ab-VD2/CD-CH/ITO bioelectrode.


#### **Table 1.**

*Comparison of the bio-electrode ab-25OHD-SPE and BSA/ab/CD-CH/ITO.*

The following parameter was determined using the calibration plot (for the range 10–50 ng mL−1): The limit of detection (LOD) was 1.35 ng mL−1, and the sensitivity was 0.2 A ng−1 mLcm−2.
