Integrated microfluidic immunoassay for the rapid determination of clenbuterol

Abstract

An integrated microfluidic immunoassay system was established for high throughput analysis of clenbuterol. This system consisted of an integrated microchip and a linear confocal laser induced fluorescence (LIF) scanner. The microchip was composed of three layers: a fluidic channel layer, a PDMS membrane layer and a pneumatic control layer. The multi-layer chip was integrated with 36 pneumatic micro-valves and multiple micro-pumps to realize the flexible reagent delivery, facilitating the automatic assays with less consumption of samples and reduced analysis time. The homemade LIF scanner was able to simultaneously detect multi-channels and provide the potential capability of high throughput assays. The performance of the system was demonstrated by the determination of clenbuterol, one of the most widely used β-agonists. Under the optimal conditions, the linear range and the limit of detection of clenbuterol were 0∼5.0 ng mL⁻¹ and 0.088 ng mL⁻¹, respectively. The recovery rates determined with pig urine samples of 1.0 ng mL⁻¹ and 2.0 ng mL⁻¹ were 98.74% and 102.51% (n = 3), respectively. The total detection time was less than 30 min. The system had the potential application for rapid detection of multiple β-agonists in clinical, pharmaceutical and chemical analyses.