Diatomite, supplied by World Minerals (Diafil295), had average surface area of 30.1 m2/g. The diatoms used for this research composed of 86-93% Sio2. Polyvinyl alcohol (PVOH) was supplied by Sekisui Specialty Chemicals (Selvol 523) and bromocresol purple, a pH sensitive dye from Alfa Aesar, was used to create the coating for sensor paper. Acidic paper was used as a substrate for the sensor paper prototype development.