Abstract:

Purpose: To develop a protein microarray method for the simultaneous detection of multiresidues of two
veterinary drugs, sulfonamides and quinolones, in milk with a visual protein chip. Methods: A 96-well microplate was
used as solid support, on which artificial antigens of sulfonamides and quinolones were immobilized, respectively. After
immobilization, a mixture of antibodies to two analytes and either standard solutions containing the analytes or samples were
added to the array reaction area. Silver nanoparticles (AgNPs)-labeled goat anti-mouse IgG were used as an indicator and
nanosilver enhancement technique was applied to amplify the detection signals, producing black image on array spots visible
with naked eyes. The signals were detected with a visual scanner; therefore the analyte residues could detected quantitatively.
Results: The linear ranges for sulfonamides and quinolones were 0.3–7.2 ng/mL and 0.4–18 ng/mL respectively. The
recovery rates were in the range of 83% to 110% for milk samples at spiked levels of 0.5/0.5, 2.0/3.0, and 5.0/15.0 ng/mL
with coefficient of variation (CV) values < 10%. Conclusions: These results indicate that the protein microarray method is
suitable for the routine screening of multiresidues of sulfonamides and quinolones in milk.

Key words: protein chip, indirect competition, multiresidue detection, sulfonamides, quinolones