Diameter-based inkjet-printed paper devices for formaldehyde analysis in foods

Abstract

In this work, we report a newly developed paper-based analytical device (PAD) for determining formaldehyde in foods. Formaldehyde (FA) is considered as a carcinogen and classified as a Type 2 hazardous substance but it is still illegally use as a preservative in many foods to prevent them from spoilage and increase storage time. Current technologies for quantifying FA in foods are expensive, require long analysis times and skill operators, and are difficult to use on-site with acceptable performance. Consequently, a simple, low-cost, portable, instrument-free measurement test is needed to provide affordable and rapid in-field quantification of FA in foods. The developed FA tests, referred to as the FormaSense™, measure FA by observing diameter of a circular pink ring on the paper that is directly proportional to the FA concentration without the interference of food color background problem hence, increasing the test performance. Printing technologies including wax and inkjet printers were employed to demonstrate highly reproducible and scalable fabrication of the paper-based tests. The results of FA analysis in food samples obtained from the FormaSense™ tests are agreeable with those obtained the standard titration methods with good recoveries in the range of 90–107%. • Diameter-based readout paper devices for formaldehyde (FA) analysis in foods. • FA quantification in foods without interferences from food color background. • Highly scalable production of paper devices using inkjet-printing technology.