3D-printed micro-pore evaporator for increasing concentration of analytes in aqueous solutions†

To address the detection limit challenges of analytical instruments at low concentrations, this study explores the development of a concentrator, fabricated via micro-3D printing technology, relying on solvent evaporation through micro-pores. The operating temperature can be as low as room temperature, allowing for compatibility with biomolecules that are sensitive to high temperatures. Moreover, the device is suitable for processing small sample volumes ranging from hundreds to tens of microliters. There are three designs of the hydrophilic biocompatible polymer tube, each featuring micro-pores with diameters of 30, 50 and 70 μm, spaced at distances of 150, 250 and 350 μm, respectively. All designs have the same total length of 16 mm and identical contact surface area. The tube is surrounded by an outer tube for a sweeping gas at a flow between 20 and 100 mL min⁻¹ for evaporation rate control. Theoretical calculations and experimental data were used to quantify device's performance and capabilities. Experiments conducted with deionized water and with aqueous glucose solutions demonstrate the device's capability to achieve up to a 10-fold concentration increase. The study also addresses potential issues such as analyte loss and the influence of various parameters like sweeping gas flow rates and liquid feeding rates on the concentration process. This work demonstrates the potential of the micro-3D printed device as a reliable and efficient method for sample concentration, critical for enhancing detection sensitivities for various applications such as bioassays and biosensors.