Researchers have developed a new cost-effective sensor that can detect toxic chemicals such as formalin in food samples such as canned meat, fish and honey. The Shiv Nadar Institution of Eminence Delhi-NCR team noted that the chemical sensor for monitoring environmental pollutants offers cost-effective, easy synthesis and excellent water solubility.
The chemosensor, described in the journal ChemComm, also provides good sensing capability for formaldehyde or formalin – a naturally occurring organic compound down to 0.3 micromoles (µM).
According to the Food Safety and Standards of India (FSSAI) Regulations 2011, formalin is not permitted for use in food. However, the chemical is often used as a preservative for fish and meat. It is also used as a disinfectant to treat external parasites and fungi in aquaculture.
The researchers noted that the sensor can spectroscopically distinguish formaldehyde from other analogs at ppm concentrations. It can also be visually monitored at higher concentrations. The detection method can monitor formaldehyde in real samples, including canned fish and chicken. It can also quantify other analogues in honey such as methyl glyoxal (MGO).
Anumesh Samanta Assistant Professor, Department of Chemistry, School of Natural Sciences, Shiv Nadar Institution of Eminence said that “ We used a simple optical method, mainly fluorescence, to detect formaldehyde,”Low concentrations of formaldehyde can be detected with a fluorimeter, and higher concentrations can be detected with the naked eye using a simple UV torch. This sensing method is easy and cheap for real-world analysis of samples, including canned fish and honey,” said Samanta.
Current fluorescent small-molecule sensors for formaldehyde are either partially or insoluble in aqueous solution, limiting actual use in preserved food samples, the researchers said. Several colorimetric chemosensors or test kits have been developed, but they are not as sensitive as fluorescence techniques, they said.
According to the researchers, there was an urgent need to develop an alternative highly water-soluble fluorescence-based small molecule chemosensor. Samantha said that from a chemical point of view, reactive carbonyl species (RCS) detection is solely dependent on o-phenylenediamine derivatives (OPD).
However, none of the current chemical sensors are effective for the simultaneous detection and discrimination between formaldehyde and other analogs such as methylglyoxal (MGO). “Our design principle, its synthesis and application are unique compared to similar studies in this field of research,” said Samanta. “This research is a proof of concept and a practical demonstration of the analysis of toxic pollutants in food samples,” he added. The research team is trying to develop a test kit that can be detected by a mobile device on the spot instead of using any spectrophotometer, Samanta added.
