Anionic metabolite profiling by capillary electrophoresis–mass spectrometry using a noncovalent polymeric coating. Orange juice and wine as case studies

• A new coating material (TEDETAMA-co-HPMA, 50:50 copolymer) for CE–MS was evaluated.
• The CE–MS method was applied to anionic metabolite profiling.
• Fast analyses, high separation efficiencies and good reproducibility were obtained.
• Feasibility of the CE–MS method is demonstrated through the analysis of food samples.

In several metabolomic studies, it has already been demonstrated that capillary electrophoresis hyphenated to mass spectrometry (CE–MS) can detect an important group of highly polar and ionized metabolites that are overseen by techniques such as NMR, LC–MS and GC–MS, providing complementary information. In this work, we present a strategy for anionic metabolite profiling by CE–MS using a cationic capillary coating. The polymer, abbreviated as PTH, is composed of a poly-(N,N,N’,N’-tetraethyldiethylenetriamine, N-(2-hydroxypropyl) methacrylamide, TEDETAMA-co-HPMA (50:50) copolymer. A CE–MS method based on PTH-coating was optimized for the analysis of a group of 16 standard anionic metabolites. Separation was achieved within 12 min, with high separation efficiency (up to 92,000 theoretical plates per meter), and good repeatability, namely, relative standard deviation values for migration times and peak areas were below 0.2 and 2.1%, respectively. The optimized method allowed the detection of 87 metabolites in orange juice and 142 metabolites in red wine, demonstrating the good possibilities of this strategy for metabolomic applications.