A microdots array-based fluoremetric assay with superwettability profile for simultaneous and separate analysis of...

A microdots array-based fluoremetric method with superwettability profile has been developed for the simultaneous and separate detection of Fe³⁺ and Cu²⁺ ions in red wine samples. A wettable micropores array was initially designed with high density by using polyacrylic acid (PAA) and hexadecyltrimethoxysilane (HDS), followed by the NaOH etching route. Zinc metal organic frameworks (Zn-MOFs) were fabricated as the fluorescent probes to be immobilized into the micropores array to obtain the fluoremetric microdots array platform. It was found that the fluorescence of Zn-MOFs probes could decrease significantly in the presence of Fe³⁺ and/or Cu²⁺ ions towards their simultaneous analysis. Yet, the specific responses to Fe³⁺ ions could be expected if using histidine to chelate Cu²⁺ ions. Moreover, the developed Zn-MOFs-based microdots array with superwettability profile can enable the accumulation of targeting ions from the complicated samples without any tedious pre-processing. Also, the cross-contamination of different samples droplets can be largely avoided so as to facilitate the analysis of multiple samples. Subsequently, the feasibility of simultaneous and separate detection of Fe³⁺ and Cu²⁺ ions in red wine samples was demonstrated. Such a design of microdots array-based detection platform may promise the wide applications in analyzing Fe³⁺ and/or Cu²⁺ ions in the fields of food safety, environmental monitoring, and medical diseases diagnostics.