The invention discloses a method for detecting residual
kanamycin and application thereof, and belongs to the technical field of analysis
chemistry, wherein the detection method is based on
aptamer initiated cyclic
enzyme digestion of
exonuclease III (Exo III). According the method, mercapto self-
assembly is utilized, single stranded
DNA (ssDNA) that is complementary with
kanamycin aptamer (K-
aptamer) is grafted on the surface of a gold
electrode, then a little amount of K-aptamer is added, and the K-aptamer is matched with ssDNA to form a little amount of
double stranded DNA (dsDNA). Then Exo III is added, the ssDNA in dsDNA can be specifically digested by Exo III, thus the residual aptamers are released, the released aptamers can combine with ssDNA to form dsDNA, another
enzyme digestion is triggered then, and after several circulations, the modified ssDNA is completely digested by enzymes.
Kanamycin exists in the
system, through the combination between
kanamycin and aptamers, the circulation
enzyme digestion is inhibited, thus ssDNA is preserved, and the amount of preserved ssDNA is related with the concentration of kanamycin. An electro-
analysis method is used to absorb electrical
signal molecules namely hexaammine
ruthenium (RuHeX) through
static electricity absorption so as to quantitatively detect residual kanamycin; and the method has high sensitivity and can sensitively detect residual kanamycin in milk.