In this study, we have established a portable, sensitive, and efficient method for the detection of erythromycin (ERY) in serum, as well as in food samples, including milk and water, which present a significant challenge. Herein, we have designed a polyvinyl alcohol (PVA) hydrogel film platform that facilitates a dual-mode ratio metric fluorescence/colorimetry sensing system using an aluminum metal-organic framework (Al-MOF) with the emission wavelength of 418 nm and CdTe QDs at the emission wavelength of 528 nm as fluorophores. The variation of the I 418 /I 528 ratio versus ERY concentration was linear at a concentration range of up to 242 nM and 728 pM with a detection limit of 2.16 nM and 2.42 pM in liquid state and hydrogel film, respectively. This solid- state assay indicates a 500-fold improvement in sensitivity compared to the liquid state and also strong selec tivity observed for ERY over other drugs such as amoxicillin, ceftazidime, and so forth. Furthermore, a visual sensing platform supported by smartphones was developed to accurately determine ERY by identifying the precise variations in RGB values. Additionally, this assay was effectively used to detect ERY in serum, tap water, and milk samples with exceptional sensitivity and accuracy in both liquid and hydrogel forms.
