Indexed on: 21 Mar '17Published on: 21 Mar '17Published in: arXiv - Physics - Mesoscopic Systems and Quantum Hall Effect
We report a preconcentrating SERS sensor for the analysis of liquid-soaked tissue, tiny liquid droplets and thin liquid films without the necessity to collect the analyte. The SERS sensor is based on a continuous, nanoporous block-copolymer membrane with one side (upper side) composed of an array of porous nanorods having tips functionalized with Au nanoparticles. Capillarity in combination with directional evaporation drives the analyte solution in contact with the flat yet nanoporous underside of SERS sensor through the continuous nanopore system towards the nanorod tips where the SERS hot spots locate. The nanorod architecture increases the sensor surface in the detection volume and facilitates analyte preconcentration driven by directional solvent evaporation. The model analyte 5,5'-dithiobis(2-nitrobenzoic acid) could be detected in a 1 mM solution in ~300 ms after the membrane was brought into contact with the solution. Moreover, a sensitivity of 0.1 ppm for the detection of the dissolved model analyte was achieved.