A microdots array-based fluoremetric assay with superwettability profile for simultaneous and separate analysis of iron and copper in red wine

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 preprocessing. 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