Morphology-controlled electrochemical sensing amaranth at nanomolar levels using alumina

► A facile way to tune morphology and sensing properties of alumina was developed. ► Oxidation activities of amaranth on alumina surface were morphology-dependent. ► Alumina microfibers were more active and greatly increased the signal of amaranth. ► Sensitive, rapid, selective and accurate method was developed for amaranth detection.