This articledescribesthedesignandfabricationofanovellab-on-paperdeviceforpHsensingusing
curcumin nanoparticles(CURNs).Inordertofabricatethelab-on-paper,thewaxdippingmethodwas
used. ThecolorofloadedpaperwithCURNschangedfromyellowtoorangeandredtobrowninthepH
rangeof7–13.Theimageofthelab-on-paperwastakenbyadigitalcameraandthepicturewas
processed andanalyzedusingAdobePhotoshopsoftware.ThechangeinmeancolorintensitywithpH
wasrecordedandemployedasananalyticalsignalforquantitativesensingofpH.Theparameters
affecting thepHsensorwereoptimizedtoenhancetheselectivityandsensitivityofthemethod.Under
optimum conditions,themeancolorintensitywaslinearlyproportionaltothepHintherangeof8–13.
The relativestandarddeviationsof10replicatemeasurementsofpH9andpH12were2.3%and1.5%,
respectively.ThedevelopedsensorwassuccessfullyappliedtothedeterminationofpHindifferent
watersampleswithsatisfactoryresults