Polychlorinated biphenyls detection in organic solvents with paper-based analytical devices.

Abstract

Sample pretreatment process is usually performed before real sample detection. Extraction is one of the most prevalent pretreatment methods. Due to the unequal solubility in two liquid phases, target is extracted (usually from water to organic phase) and further detected with laboratory instruments. Though the analytical instruments have high sensitivity and selectivity, they are relative expensive and require skillful hands, which is restricted to laboratory use. Here, paper-based analytical devices (μPADs) for measuring samples extracted with organic solvents were tested. The μPADs were employed as a filter for buffer exchange, allowing the transfer of targets from organic solvent to water-based buffer, which could be specifically detected by water-based assays. As an example, polychlorinated biphenyls (PCBs) in n-hexane were detected with aptamer and gold nanoparticles (AuNPs) on μPADs within 30\u2005min. The result of color change can be recognized from 70.0\u2005ng/L with low loading amount (0.5 μL). Instead of laboratory instrumental analysis with relative high cost, this assay showed the promising utility of μPADs for target detection after sample pretreatment, which could be utilized as a general platform for inexpensive onsite detection.