Molinate quantification in environmental water by a glutathione-S-transferase based biosensor

► A glutathione-S-transferase biosensor was developed to quantify molinate herbicide. ► GST was immobilized onto electrode via aminosilane-glutaraldehyde covalent attachment. ► The GST-based biosensor exhibited good accuracy and linearity over a wide concentration range. ► The enzymatic biosensor was successfully applied in rice paddy field floodwater. ► The proposed device is suitable for molinate screening in environmental water.