A new formaldehyde optical sensor: Detecting milk adulteration


A sensor consisting of an optical fibre with the exposed tip coated with the polyoxometalate salt [(C4H9)(4)N](4)H [PMo10V2O40], specially designed to be insoluble in water, which UV-Vis spectrum changed in contact with formaldehyde, is presented. The sensor limit of detection for formaldehyde was 0.2 mg L-1, and the limit of quantification was 0.6 mg L-1, which were close to the conventional spectrophotometric method values of 0.2 mg L-1 and 0.5 mg L-1, respectively, and lower than the tolerable limit for ingested food. The sensor was tested for formaldehyde quantification in milk, as its deliberate addition is a matter of concern. The results obtained analysing formaldehyde in milk samples by the optical sensor and by the conventional method were not statistically different (alpha = 0.05).



subject category

Chemistry; Food Science & Technology; Nutrition & Dietetics


Verissimo, MIS; Gamelas, JAF; Fernandes, AJS; Evtuguin, DV; Gomes, MTSR

our authors


Thanks are due to FCT/MCTES for the financial support to CESAM (UID/AMB/50017/2019) and to CICECO-Aveiro Institute of Materials (UID/CTM/50011/2019), through national funds.; M. Verissimo would like to acknowledge the Portuguese Foundation for Science and Technology (FCT), for the post-doctoral grant BPD/394267/2013.

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