Table 2.

The calibration curves of the biosensor with 0.4 wt% and 0 wt% immobilized Fe₃O₄ nanoparticles in the presence of various concentrations of 2,4-D. The inhibition was evaluated in the presence of two concentrations of AA2P substrate.

Amount of Fe3O4 (wt %)	Concentration of AA2P(μM)	Slope (% inhibition/μgL−1)	Intercept	Correlation coefficient, R2	Linear range 2,4-D (μgL−1)
0	80	0.579±0.095	12.41±1.60	0.9255	1 - 30
0.4	80	1.067±0.069	10.24+1.07	0.9834	0.5 - 30
0.4	120	1.041±0.183	13.24±2.83	0.8900	0.5 – 30