Study on the Methodology of Quantitative Gold Immunochromatographic Strip Assay

The paper aims to develop a rapid, simple and single copy gold immunochromatographic strip assay method for the quantitative determination of trace concentrations in serum or urine. The image of gold immunochromatographic strip is taken by CCD, and after a proper process, the reflective integral optical density is extracted as the feature based on Lambert-beer law. In order to improve the measure property, the relative detection method is applied by which the interference in the test and control lines can be cancelled out each other. The proposed method is tested by the quantitative detection of human chorionic gonadotropin (hCG) using 14 standard samples with different concentration. For the first nine samples, the measured relative integral optical density increases linearly with hCG concentration with R² =0.9975 and a line equation is derived. Based on the linear relation, the hCG concentrations of another five samples are measured, which are strongly correlated with standard concentrations with R² =0.9914. These results indicate the good linear response property and accuracy of the developed method, respectively.