LAUSR

A cost-effective point-of-care (POC) device including a potentiostat, a modified screen printed electrode (SPE) placed in a custom-designed microfluidic chamber, and a homemade syringe pump setup was developed as an electrochemical assay for determination of dopamine (DA), ascorbic acid (AA), and uric acid (UA) in human plasma and urine. SPE was modified with three-dimensional graphene/carbon nanotube (3DG/CNT) used as a new electrochemical sensor. A microcontroller-based potentiostat was developed to perform cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements. The syringe pump system based on open source electronics was made to guide the solution through a microfluidic chamber. In order to improve the quantification accuracy, the DPV peaks were resolved, using partial least square (PLS) method. The detection limits were AA (2.5 μM), DA (0.4 μM), and UA (0.6 μM) (signal to noise ratio, 3). The linear dynamic ranges were 4-2000, 0.5-2000, and 0.8-1500 μM for DA, AA, and UA, respectively. The precision of the method (RSD, n=3) was < 2.2 %.