Du Min

Recognition and adjustment for strip background baseline in fluorescence immuno-chromatographic detection system

Fluorescence immune-chromatography is a kind of immunoassay which is widely used in quantitative detection area. However, the background baseline drift with relatively large amplitude during test is a huge problem for the overall performance of the quantitative detection system, and the existing background baseline recognition and adjustment methods were based on online or offline data processing, which brings huge computational burden. To solve this problem, this paper proposed a background baseline recognition and adjustment method from the aspect of optical design. It integrated background acquisition, conditioning and control functions which could adjust the photo-electric signal of the background in real time until the sampling value of background baseline was within the threshold. Finally, the peak value of the test strip was detected. To examine the performance of the system, ten standard test strips with different concentrations were selected for background baseline detection. Besides, linearity and coefficient of variation (CV) of the system was also calculated. Results showed that the fluctuation range of baseline was within±4% of the threshold, whereas the CV of the test strip background was 2.57%. Furthermore, although the occupancy rate of background amplitude for A/D unit was decreased from 31.7% to 2.4%, CV of the system was still lower than 3%, which indicates that the system has much wider detection range than other congeneric detection devices.