DNA-Modified Electrode for the Detection of Aromatic Amines

A new electrochemical biosensing strategy has been developed for trace measurements of toxic aromatic amine compounds. The device relies on the intercalative collection of aromatic amines onto the immobilized dsDNA layer followed by potentiometric stripping quantitation of the accumulated species. The enhanced sensitivity, accrued from the DNA collection process, is coupled to new selectivity dimensions provided by the structural requirements for such intercalative binding. The extent and rate of the accumulation are strongly dependent upon the structure of the aromatic amine species. Having the amino substituent in a slightly different position produces a dramatic effect upon the response. Nanomolar detection limits are obtained after a 10-min accumulation. Applicability to river water and groundwater samples is demonstrated. Such DNA-based devices hold great promise for environmental screening of toxic aromatic amines and for elucidating molecular interactions between intercalating pollutants with DNA.