Studies On Capillary Electrophoretic Enzyme Immunoassay With Electrochemical Detection For Tumor Markers

Capillary electrophoretic enzyme immunoassay with electrochemical detection isan attractive method due to its high sensitivity and low detection limit. Theorthoaminophenol(OAP)-H₂O₂-horseradis hperoxidase(HRP) enzyme-linkedimmunoassay system was used. The method was used to detect AFP, CEA, PSA, HCG,T4, and detect PSA, CEA, HCG simultaneously. Details of selection for optimum conditions werepresented. The system had extremely high sensitivity. HRP can be measured with adetection limit of 1.09×10^-12 mol/mL (S/N=3), and a linear range of2.3×10^-12～3.5×10^-15 mol/mL.This method has been successfully applied to the detection of alpha-fetoprotein(AFP). The detection limits (S/N=3) was 0.48 ng/mL, and the linear range is 1.5～66.6 ng/mL.Under the optimum conditions, the human serum samples were detected. The resultsshowed good corresponding relationship with those in spectrophotometric ELAISAmethod.This method has been successfully applied to the detection of carcinoembryonicantigen (CEA). The detection limits (S/N=3) was 0.17 ng/mE, and the linear range is1.6～69.0 ng/mL. Under the optimum conditions, the human serum samples weredetected. The results showed good corresponding relationship with those inspectrophotometric ELAISA method.This method has been successfully applied to the detection of prostatespecificantigen (PSA). The detection limits (S/N=3) was 0.22 ng/mL, and the linear range is2.1～80.2 ng/mL. Under the optimum conditions, the human serum samples weredetected. The results showed good corresponding relationship with those inspectrophotometric ELAISA method.This method has been successfully applied to the detection of human chorionicgonagotropin (HCG). The detection limits (S/N=3) was 0.30 ng/mL, and linear range is1.7～132.5 ng/mL. Under the optimum conditions, the human serum samples were detected. The results showed good corresponding relationship with those inspectrophotometric ELAISA method.This method has been successfully applied to the detection of thyroxine (T4). Thedetection limits (S/N=3) was 1.0 ng/mL, and linear range is 1.7～260.0 ng/mL. Under theoptimum conditions, the human serum samples were detected. The results showedgood corresponding relationship with those in spectrophotometric ELAISA method.