Iron ion（Fe

3+

）concentration detection is of great significance in ecological environment

and its concentration imbalance will bring damage to ecological health.A dopamine(DOPA)modified glass nanopore sensor for Fe

3+

detection is proposed.Dopamine is immobilized on the nanopore by oxidative self-polymerization.Contact angle and

I-V

measurements show that dopamine can be successfully modified on the inner wall of glass nanopore.With the increase of Fe

3+

concentration

the chelation of F

3+

and dopamine will lead to the reversal of the inner su

rface of the nanopore from negative charge to positive charge

which show that the current change rate decreases first and then increases

accompanied by the change of the rectification direction of the

I-V

curve.An analysis method using the combination of rectification value and current change rate is proposed

which can realize the detection of Fe

3+

concentration as low as micromolar level

overcome the detection blind area of the sensor

and expand the detection range.At the same time

the sensor can be reused and has good stability.