Is supercritical fluid chromatography hyphenated to mass spectrometry suitable for the quality control of vitamin D3 oily formulations?

Supercritical fluid chromatography coupled to high-resolution tandem mass spectrometry: an innovative one-run method for the comprehensive assessment of chocolate quality and authenticity

To assess chocolate quality and authenticity comprehensively, a combination of various analytical procedures is involved, thereby making the process time-consuming and costly. Thus, we investigated the potential of ultra-high performance supercritical fluid chromatography coupled to quadrupole-time of flight mass spectrometry (UHPSFC-QTOF-MS) as an alternative to "classic" methods. By combining hexane and aqueous extracts from sequential extraction, a single 8-min analytical run enabled us (i) to determine cocoa butter equivalents (CBEs) and milk fat content based on the detection of selected triacylglycerols, (ii) to calculate dry non-fat cocoa solids based on determined theobromine and caffeine content, and (iii) to profile contained sugars. To obtain the most comprehensive information about sample composition, the MS method comprised a full MS scan for non-target screening and several time-scheduled targeted MS/MS functions ("parallel reaction monitoring") optimized according to the possible concentration ranges of the analytes. For 40 different chocolate samples, our results and those obtained by using standard methods (LC-UV for non-fat cocoa solids, and GC-FID for CBEs) were in good agreement. Compared to the conventional approach for chocolate quality and authenticity control, the presented SFC-MS method is a fast, cost-effective, and efficient alternative, and only samples suspicious for the presence of CBE should be referred to the standard GC-FID method for exact CBE quantification. In the study, also some challenges offered by SFC-MS have been addressed.

Generic SFC-MS methodology for the quality control of vitamin D3 oily formulations

Vitamin D₃ is a key micronutrient whose intakes are inadequate for most populations worldwide. Supplementation with medicines or food supplements is commonly prescribed to correct this imbalance and the quality of these products must be ensured. In this context, a generic methodology for the assay of vitamin D₃ in oily formulations is proposed using supercritical fluid chromatography coupled to mass spectrometry (SFC-MS). It is in line with green analytical chemistry principles and combines the use of i) a fast and robust analytical method (4.0 min analysis time) ii) an easy sample preparation compatible with high throughput analysis ("dilute-and-shoot" approach) and iii) a relevant control strategy. Seventeen products from multiple manufacturers and encompassing a large content range were evaluated in this study. They were classified in four groups to streamline their processing considering the use of a matrix-matched calibration procedure. Matrix effect was thoroughly studied and was found to be low (99-106%), stable intra/inter-series and comparable between the different groups and types of matrices. The implemented control strategy was based on a three-level system suitability tests (SST). Level 1 SST: resolution of the critical pair that was above 1.5 for all analysis series. Level 2 SST: evaluation of the adequacy of the calibration for a QC sample in terms of recovery that was between 97% and 104% with a variability between 1% and 2%. Level 3 SST: method trueness that was between 95% and 102%. Sample analysis highlighted differences in types of products and dosage forms. This is the first study to propose a complete strategy for the quality control of vitamin D₃ oily formulations and should prove useful in QC laboratories.

Applicability of supercritical fluid chromatography - mass spectrometry to metabolomics. I - Optimization of separation conditions for the simultaneous analysis of hydrophilic and lipophilic substances

The aim of this study was to evaluate the suitability of SFC-MS for the analysis of a wide range of compounds including lipophilic and highly hydrophilic substances (log P values comprised between -6 and 11), for its potential application toward human metabolomics. For this purpose, a generic unified chromatography gradient from 2 to 100% organic modifier in CO₂ was systematically applied. In terms of chemistry, the best stationary phases for this application were found to be the Agilent Poroshell HILIC (bare silica) and Macherey-Nagel Nucleoshell HILIC (silica bonded with a zwitterionic ligand). To avoid system overpressure at very high organic modifier proportion, columns of 100 × 3 mm I.D. packed with sub-3 μm superficially porous particles were selected. In terms of organic modifier, a mixture of 95% MeOH and 5% water was selected, with 50 mM ammonium formate and 1 mM ammonium fluoride, to afford good solubility of analytes in the mobile phase, limited retention for the most hydrophilic metabolites and suitable peak shapes of ionizable species. A sample diluent containing 50%ACN/50% water was employed as injection solvent. These conditions were applied to a representative set of metabolites belonging to nucleosides, nucleotides, small organic acids, small bases, sulfated/sulfonated metabolites, poly-alcohols, lipid related substances, quaternary ammonium metabolites, phosphate-based substances, carbohydrates and amino acids. Among all these metabolites, 65% of the compounds were adequately analyzed with excellent peak shape, 23% provided distorted peak shapes, while only 12% were not detected (mostly metabolites having several phosphate or several carboxylic acid groups).