Rapid determination of water- and fat-soluble vitamins with microemulsion electrokinetic chromatography

Simultaneous and accurate determination of water- and fat-soluble vitamins in multivitamin tablets by using an RP-HPLC method

“…A rapid, reliable, and reproducible method based on microemulsion electro kinetic chromatography for the simultaneous determination of 13 types of water-and fat-soluble vitamins was developed. 23 Separate methods based on reversed-phase HPLC for the determination of eight watersoluble vitamins and seven fat-soluble vitamins were proposed. 24 A method for the simultaneous determination of 12 water-and fat-soluble vitamins using gradient HPLC with diode array detection (DAD) was also developed.…”

Advances in the theory and application of MEEKC

“…Greater partition between the ME droplet and the aqueous phase leads to a higher rate of mass transfer and a more efficient separation. Conversely, Yin et al [40] proposed that highly lipophilic compounds have an extreme affinity to the micelles, which results in long migration times and poor resolution. Work by Hansen et al [44] found that MEKC modified with the addition of 1-butanol delivered similar separation efficiencies to MEEKC for separation of neutral aromatic compounds.…”

“…A concentration of 2.4% v/v 1-butanol was found to be the optimum. The addition of organic modifiers has been seen to improve many MEEKC separations [24,40] and the addition of 10% v/v methanol resulted in full baseline resolution of the isoquinolines. Analytes may partition strongly with the ME droplet resulting in poor resolution, however, the presence of an organic modifier can alter this interaction and improve resolution [40].…”

“…Generally pH is optimised between 7 and 9 [40,49,51], and this results in a high EOF with a fast and efficient separation. However, pH values as high as 12 or as low as 2 may be required [52] depending on the pK a of the analytes under investigation and whether there is a need to eliminate ion-pair interactions.…”

“…It has been observed that highly lipophilic compounds are better separated in MEEKC [40]. It has been suggested that solutes can partition more effectively with the MEEKC ME droplet than the rigid micelle in MEKC [41][42][43].…”