A three-dimensional printed electromembrane extraction device for capillary electrophoresis

A concentric electromembrane extraction preconcentration device was designed and fabricated using fused deposition modelling 3D printing. The device consisted of a hemispherical electrode sample vial printed from a filament of conductive polylactic acid (PLA), into which sat a smaller hemispherical 3D printed porous membrane acceptor vial. Application of voltage between a point-electrode placed in the center of 20 μL solution inside the acceptor vial and the electrode vial containing 1 mL of sample, enabled anion migration through the 3D printed porous material into the acceptor solution. Electromembrane extraction was proved using fluorescein for imaging of the extraction process, with preconcentration rates of 0.833 μM/sec at 120 V with close to 95% recovery. The performance of the fabricated porous 3D printed device was evaluated for the preconcentration of anions from water prior to capillary electrophoresis detection. Preconcentration factors ranging between 36–44 were obtained for chloride, nitrate, perchlorate and sulfate, while a lower performance was observed for weaker acids as fluoride and phosphate (3–4). The limit of detection (LOD) was determined to be 0.16 μM, 0.18 μM and 0.18 μM for NO₃⁻, ClO₄⁻ and SO₄^2- respectively. The extraction and quantitation of ions from a soil slurry without filtration, namely NO₃⁻ and SO₄^2- content was determined to be 0.24 and 0.03 mmol/100 g of soil, respectively which are values in the range of those typically reported in soil samples.