Lab‐on‐a‐Chip for hydrogen sulphide detection—Part II: Integrated with screen‐printed electrode

Abstract

AbstractThe measurement of hydrogen sulphide (H2S) has held the attention of the analytical community due to its unique physiological and pathophysiological roles in biological systems. This work reports fabrication and characterization of screen‐printed electrode (SPE) integrated lab‐on‐a‐chip (LOAC) for H2S detection. The device has been designed to detect all forms of H2S present in the plasma; however, current work is a proof of concept of device operation for free sulphide. The device consists of three distinct layers for H2S separation and SPE to detect H2S. It operates with pH‐dependent liberation and trapping from samples introduced. The first layer, the releasing layer, consists of a releasing chamber for the liberation of H2S. The second layer, a silicone membrane, is where gas diffuses from the sample layer to the third layer. The third layer, the trapping layer, is integrated with SPE to determine the concentration of H2S. The device uses an electrochemical technique. First, electrode performances are tested on the cell vial to establish suitability for subsequent LOAC incorporation. Common metal electrodes are compared with boron‐doped ultra‐nano‐crystalline diamond (BDUNCD) electrode and SPE. The range of detection, detection limit, and sensitivity of the electrode are characterized. In conclusion, a proof of concept of an electrochemical sensing of H2S in a LOAC is reported. The device is portable, robust and can easily be fabricated. Transfer data indicated that 10% sulphide detected into the trapping chamber in a reproducible manner at 20 min. The SPE integrated LOAC shows a huge advantage over conventional techniques.