Metals and metal-binding ligands in wine: Analytical challenges in identification.

Background: Due to important role of metals in the vinification process as well as their impact on the human health, their content in this alcoholic beverage has been extensively studied by many researchers. It is already known that speciation of metals determines their toxicity and bioavailability as well as influences their activity. Understanding the chemistry and knowing the structures of metal complexes could have relevant influence on more effective approaches for prevention of some diseases including cancer. Thus, monitoring and studying the metal complexation process, structures of metal complexes present in wine, as well as their stability, is crucial. Scope and approach: In this review the main developments in the metal complex identification in wine samples are described. The study emphasizes metal complexes with two ligand groups such as polyphenols and organic acids as a group of compounds well known for their health-beneficial nature. Key findings and conclusions: Complexity of the wine matrix related with the presence of numerous organic compounds makes the examination of wine in the context of metal complexes identification a highly challenging task. Metals and metal complexes are present in low concentrations, which can potentially cause interferences during an analytical process. Currently, the most promising technique that can be used for metal complex identification is ESI-MS coupled with separation technique such as liquid chromatography.

Automated summary

Identification of metal complexes in wine samples is a challenging task due to the complexity of the wine matrix with numerous organic compounds, low concentrations of metals and potential interferences during the analytical process. ESI-MS coupled with separation techniques like liquid chromatography is currently the most promising technique for metal complex identification.