Detection of adulteration in sunflower oil using paper-based microfluidic lab-on-a-chip devices

Edible oils form an integral component in the human diet as well as in the industrial preparations. Any adulteration in oil is concerning from nutritional as well as economical perspective. Although analytical techniques exist for detection of adulterants in oil, most of them require sophisticated instruments, and trained professionals. Microfluidic based lab-on-a-chip technologies have rapidly progressed over the recent years and offer promising alternatives in this regard. In this work, we report development of a paper-based microfluidic lab-on-a-chip for detection of palm oil contamination in sunflower oil. We use the paper-based microfluidic colorimetric detection approach that indicates the presence of adulteration in a visual manner. The data is analyzed using digitally acquired images along with ultraviolet–visible spectrophotometry. The paper-based microfluidic device is fabricated and tested for 10–50% (v/v) palm oil adulteration in sunflower oil. Further, we employ the device for free fatty acid content tests in oil samples. Visual signal acquired from the device is optimized by varying phenolphthalein proportions. The stability of visual colorimetric signal is examined over time and is found to remain steady over the trial period of six days considered in this work. The integration of the detection device with smartphone imaging can prove to be useful for onsite data collection. We believe the approach presented here can be extended to food quality monitoring portable platforms.