A feedback-controlling digital microfluidic fluorimetric sensor device for simple and rapid detection of mercury (II) in costal seawater

By combination of miniaturization potential of digital microfluidics (DMF) and sensitivity of fluorescence probe, an integrated sensor device has been initially constructed for mercury detection in coastal waters. The actuation feature of the detecting target, seawater droplet, which remains unclear, was basically explored. To overcome a potential risk of driven failure, induced by diversity ion ingredients in seawater, a feedback control loop was included into control system. Analyzing method for coastal waters was well established on DMF, which showed satisfied stability and selectivity in Hg sensing under high salinity condition, with the sensitivity of Hg2+ at the parts per billion level and total testing time less than 20s. With the advantages of being fast, amenable to automation and low cost, this device is promising for the formation of simple and rapid sensor device, especially for a routine monitoring and emergency detection of Hg/or other metals in coastal waters. Display Omitted •A rapid and sensitive sensor device toward Hg/or other metals analyzing in coast seawaters was established.•Actuation features of seawater on digital microfluidics were investigated.•The stability and selectivity of RS fluorescent probe of Hg sensing in high salinity setting were demonstrated.•The real samples were tested and the feasibility of the platform was demonstrated.•A feed-back loop was included in the control system to insure the actuation of droplet.