Practical and Efficient: A Pocket-Sized Device Enabling Detection of Formaldehyde Adulteration in Vegetables

Abstract

Formaldehyde, as a carcinogenic substance, is often intentionally used to adulterate vegetables to increase their shelf life, and the adhesive tape used to attach labels can also leave formaldehyde on the surface of vegetables. However, as the “gold” standard, gas chromatography (GC) and high-performance liquid chromatography (HPLC) are expensive for individual tests and confined to the laboratory owing to their size and a suitable detector (low-cost, portable, fast detection speed) to check formaldehyde contamination in vegetables not being available. Here, we tested formaldehyde contamination in vegetables using a low-cost and hand-held detector combined with a screen-printed electrode (SPE) amperometric sensor and an open-sourced potentiostat. The analyzer can detect a concentration of 100 μmol/L formaldehyde and achieve a good linear range between 100 and 1000 μmol/L. Furthermore, the detector successfully identified formaldehyde contamination in 53 samples of six different kinds of vegetables even after residual formaldehyde on the surface was evaporated. Most importantly, under the practicability-oriented idea, a cost-effective strategy was implemented for this detector design rather than using other pricey methods (e.g., photolithography, electron-beam evaporation, chemical deposition), which enormously reduces the cost (under ∼USD 0.5 per test) and meets all of the requirements of ASSURED device. We believe this cheap, portable detector could help law-enforcing authorities, healthcare workers, and customers to screen formaldehyde contamination easily. Also, the cost-saving strategy is appropriate for low-income areas, where there is a lack of laboratories, funds, and trained experts.

Side-Effect of Soil Fumigation and Soil Drench by some Methyl Bromide Alternatives on three Soil Enzyme Activities

“…DHase enzyme is considered to play a significant role in the biological oxidation of soil organic matter by donating hydrogen from organic substrates to inorganic acceptors (Zhang et al, 2021;Moeskops et al, 2010). Also, the DHase activity is considered to be an indicator of the oxidative metabolism in soils and thus of the microbial activity (Trevors, 1984).…”

High sensitive assay of formaldehyde using resonance light scattering technique based on carbon dots aggregation

“…FA is widely used as a preservative in food. If people eats food contaminated FA for a long time, even though can cause numerous diseases (Zhang et al, 2022a(Zhang et al, , 2022b. Therefore, it is necessary to determine FA in food samples.…”

“…There are also some serious health issues for human when they consume food contaminated by FA such as vomiting, pain or coma (Nordin et al, 2011). According to the report of European Union, the minimum daily exposure to FA is 100 mg kg À1 from animal and lant origin food (Zhang et al, 2022a(Zhang et al, , 2020b, and it is strictly forbidden to use formalin adulteration in China (Aquilina et al, 2014). Therefore, developing a sensitive, selective, and convenient method of detecting FA is urgent.…”

Polyaniline-Coated Surface-Modified Ag/PANI Nanostructures for Antibacterial and Colorimetric Melamine Sensing in Milk Samples

“…Additionally, the role of NPs as biosensors for different adulterants in food samples is gaining more attention for quick real-time analysis . Food adulterants like melamine, salicylic acid, urea, and H 2 O 2 are common additives in infant milk formula and food packaging materials . More specifically, melamine high doses (i.e., >1 mg/kg for infant formula and >2.5 mg/kg for other dairy items) can be toxic.…”

“… 11 Food adulterants like melamine, salicylic acid, urea, and H 2 O 2 are common additives in infant milk formula and food packaging materials. 12 More specifically, melamine high doses (i.e., >1 mg/kg for infant formula and >2.5 mg/kg for other dairy items) can be toxic. Therefore, determination of melamine in milk samples is a critical clinical requirement to avoid toxicity for higher melamine contents in food products.…”