时间分辨荧光免疫分析仪测量时间稳定性的研究与设计

Research and Design of Measuring Time Steady in Time-Resolved Fluoroimmunoassay Instrument

时间分辨荧光免疫分析仪的测量精度取决于微弱荧光信号的测试精度,而测量时间不稳定将导致测量的荧光信号强度发生波动。针对影响测量时间精度的3个因素(时基信号误差、触发误差、量化误差),采用TX2108带温度补偿的晶体振荡器作为时基信号源,减小时基信号误差;采用RISC结构的高速单片机及性能稳定的74HC系列外围器件,减小触发误差;采用双游标法使测时分辨力提高3个数量级,减小量化误差。实验表明:在保证同样测量精度的前提下,所需测量次数由1 000次减少到120次。

The accuracy of time-resolved fluoroimmunoassay （TRFIA） instrument depends on that of the weak fluorescence signal detection, while the instability of the measuring time may result in that of intensity of fluorescence signal. Aiming at the three factors leading to the poor accuracy of the measuring time （the error in time basis, triggering error, quantization error）, TX2108 crystal oscillator with temperature compensating is employed as the time-basis signal source to reduce the error in time basis; RISC-base high speed MCU and high reliable 74HC chips are utilized to ensure the simultaneous performance of the optical excitation and fluorescence signals such that the triggering error can be reduced; Dual-vernier method is used to raise the measuring resolution for 3-times magnitude such that the quantization error is reduced. The experiment results show that, in the same measuring precision, measuring times are reduced from 1 000 to 120.