A versatile triple-channel fluorescent probe for quantitative detection of three preservative residues in mushroom products (bisulfite, daminozide and hypochlorite)

A triple-channel fluorescent probe (MPIM) was developed for real-time detection of bisulfite (HSO₃⁻), hypochlorite (ClO⁻) and unsym-dimethylhydrazine ((CH₃)₂NNH₂) residue in mushroom products with different preservative processing (sulfur dioxide fumigation, spray with daminozide, or chlorinated disinfection and canning). In an optimized solvent environment, MPIM exhibits distinguishable fluorescent responses toward HSO₃⁻, (CH₃)₂NNH₂ and ClO⁻. The probe MPIM itself emit bright orange-red fluorescence (λ_em = 626 nm), while it will change to purple fluorescent emission (λ_em = 389 nm) when exposed to HSO₃⁻, turn to blue fluorescence (λ_em = 436 nm) when exposed to (CH₃)₂NNH₂, and covert to green emission (λ_em = 490 nm) when in contact with ClO⁻. These transformation of fluorescent signals can be directly observed by the naked eye. At the same time, MPIM showed excellent low detection limit for HSO₃⁻, (CH₃)₂NNH₂ and ClO⁻ (the detection limits were 19 nM, 17.3 nM and 7.9 nM, respectively). The probe MPIM has been successfully applied for detecting HSO₃⁻, (CH₃)₂NNH₂ or ClO⁻ in three kinds of actual mushroom products. Moreover, an intelligent detection sensor platform is constructed by combining the MPIM loaded strips with smart phone RGB analysis software. The intelligent detection platform shows satisfactory chroma change results. Therefore, the successful construction of MPIM is expected to develop into an effective tool for assessing illegal or excessive addition of these preservatives in mushroom samples, which has a exciting prospect in the field of food safety detection in the future.