Strontium oxides with enzyme-like activity: A colorimetric sensor array for highly sensitive discrimination of bisphenols

Bisphenols are widely used in food packaging materials, and because of their endocrine disrupting effects on the human body, fast yet facile detection is essential for food safety and human health. Traditional analytical methods face disadvantages of cumbersome operation and the need of bulk instruments. To circumvent these issues, we constructed colorimetric sensor arrays based on peroxidase-like activities of three strontium oxides for four bisphenols determination. Bisphenols are absorbed on surface of strontium oxides, blocking catalytic sites and leading to decline of enzyme-like activities in turn. Different bisphenols have diverse inhibition effect on catalytic activities of the three nanozymes, and each bisphenol possesses a unique fingerprint. Though principal component analysis, bisphenol A, bisphenol S, bisphenol B and bisphenol AF with concentrations ranging from 0.0002 to 1 μg mL⁻¹ were discerned well by the developed sensor arrays. Additionally, different concentrations of each bisphenol and different ratios of mixed bisphenols were successfully discriminated, and canned fruit as real sample was applied to evaluate practical applicability of the nanozyme based sensor arrays. This work is expected to provide a simple and fast method for discrimination of structural analogues and contribute to food quality and safety monitoring aspects.