An improved biomonitoring system for the analysis of 2,4,6-trichlorophenol (TCP) in urine samples has been developed. The principle of the biosensor device is the detection of laser-induced fluorescence (LIF) in single microdroplets by a homogeneous quenching fluorescence immunoassay (QFIA). The competitive immunoassay occurs in microdroplets (d = 58,4 μm) produced by a piezoelectric generator system with 10-μm-diameter orifice. A continuous Ar ion laser (488 nm) excites the fluorescent tracer; its fluorescence is detected by a spectrometer attached to a 512 × 512 cooled, charge-coupled device camera. Fluorescence is quenched by specific binding of TCP polyclonal antibodies to the fluorescent tracer (hapten A−fluorescein); the quenching effect is diminished by the presence of the analyte. Thus, an increase in the signal is produced in a positive dose-dependent manner when TCP is present in the sample. In 10 mM PBS buffer, the IC50 of the LIF-microdroplet QFIA is 0.45 μg L-1 reaching a LOD of 0.04 μg L-1. The QFIA with the same reagents performed in microtiter plate format achieved a LOD of 0.36 μg L-1 in buffer solution. Performance in human urine was similar to that observed in the buffer. A LOD of 1.6 μg L-1, with a dynamic range between 4 and 149.5 μg L-1 in urine, was obtained without any sample treatment other than dilution with the assay buffer. The detectability achieved is sufficient for occupational exposure risk assessment.
一种改进的
生物监测系统已被开发,用于分析尿液样本中的
2,4,6-三氯苯酚(
TCP)。该
生物传感器设备的原理是通过均相淬灭荧光免疫分析(QFIA)检测单个微液滴中的激光诱导荧光(LIF)。竞争性免疫分析在由压电发生器系统产生的直径为58.4微米的微液滴中进行,液滴孔径为10微米。连续的
氩离子激光(488纳米)激发荧光示踪剂;其荧光通过连接到512 × 512冷却电荷耦合器件相机的光谱仪进行检测。荧光通过
TCP多克隆
抗体与荧光示踪剂(半抗原A-
荧光素)的特异性结合而被淬灭;分析物的存在减少了淬灭效应。因此,当样本中存在
TCP时,信号以正剂量依赖的方式增加。在10 mM PBS缓冲液中,LIF-微液滴QFIA的IC50为0.45 μg L-1,达到的检测限(LOD)为0.04 μg L-1。使用相同试剂在微孔板格式下进行的QFIA在缓冲溶液中实现了0.36 μg L-1的检测限。人尿中的性能与在缓冲液中观察到的相似。获得的尿液检测限为1.6 μg L-1,动态范围在4到149.5 μg L-1之间,只有通过试剂缓冲液进行稀释而无需其他样本处理。所达到的可检测性足以用于职业接触风险评估。