Graphene oxide modified cellulose paper-based device: A novel platform for cooking oil quality evaluation
Atitiya Saedan, Jutiporn Yukird, Nadnudda Rodthongkum, Sarute Ummartyotin
Abstract
A novel platform of microfluidic paper-based analytical device (μPAD) with colorimetric acid-base titration for cooking oil quality evaluation was created and oleic acid was selected as a model analyte. Graphene oxide (GO) was used to modify cellulose paper for improved visualization and increased hydrophobicity of the colorimetric sensor . μPAD with colorimetric acid-base titration was prepared by immobilizing phenolphthalein and primary standard of Na 2 CO 3 on GO-modified cellulose paper and applied for oleic acid detection. The neutralization of oleic acid on the cellulose paper was illustrated by color disappearance from pink to colorless. This platform provided a linearity of (0–2% v/v), covering a cut-off oleic acid level (1.0%) for evaluation of cooking oil quality. This device, designed with 3D-μPAD, created the automatic lateral-flow channel for semi-quantitative analysis of cooking oil without instrumental requirement. The content of oleic acid equated to the number of pink-detection area disappearing. Ultimately, this device was successfully applied for cooking oil quality evaluation in real waste cooking oil samples.