Intelligent smartphone-based portable network diagnostics for water   security Case Study realtime pH mapping of tap water
  Using a field-portable, smartphone fluorometer to assess water quality based on the pH response of a designer probe, a map of pH of public tap water sites has been obtained. A custom designed Android application digitally processed and mapped the results utilizing the GPS service of the smartphone. The map generated indicates no disruption in pH for all sites measured. All the data are assessed to fall inside the upper limit of local government regulations and are consistent with authority reported measurements. The work demonstrates a new security concept: environmental forensics utilizing the advantage of real-time analysis for the detection of potential water quality disruption at any point in the city. The concept can be extended on national and global scales to a wide variety of analytes. 
Arafat Hossain, John Canning, Sandra Ast, Peter J. Rutledge, and Abbas   Jamalipour
physics.ins-det cs.CY