Simultaneous reflectance and fluorescence measurements for portable formaldehyde determination in milk using a multi-channel spectrometer sensor

Abstract

This study introduces a novel optical method for formaldehyde determination in milk, based on the hypothesis that simultaneous reflectance and fluorescence measurements can enhance detection sensitivity compared to traditional methods. We aimed to address the challenge of accurately measuring low concentrations of formaldehyde in milk, a crucial issue for food safety. By employing a multi-channel spectrometer sensor and exploiting the reaction of formaldehyde with acetylacetone to form 3,5-diacetyl-1,4-dihydrolutidine (DDL), we measured reflectance of DDL at 415 nm and fluorescence at 515 nm. The method demonstrated linearity (0.1–4 mg L−1 for reflectance, 0.1–3 mg L−1 for fluorescence) with detection limits of 0.027 mg L−1 (reflectance) and 0.030 mg L−1 (fluorescence). We successfully determined formaldehyde in milk samples (46 to 114 μg L−1) and observed a 60 % reduction in formaldehyde concentrations. This research underscores the importance of heat treatment in ensuring food safety.