Partition coefficients (K) of vitamins (riboflavin, nicotinic acid, nicotinamide, folic acid, cyanocobalamin) in aqueous two‐phase systems (ATPS) composed by polyethylene glycol (PEG 4000, PEG 6000) and organic salt (sodium citrate and sodium tartrate) at T = 298.15 K and p = 1 bar have been studied. Data on liquid–liquid equilibria of the ATPS considered in this study have been taken from the literature (PEG‐Na₃Citrate) or measured in this work (PEG‐Na₂Tartrate) for PEG 4000 and PEG 6000 at T = 298.15 K and p = 1 bar. The experimental K values were validated by electrolyte perturbed‐chain‐statistical associating fluid theory predictions. The neutral cyanocobalamin has the highest K values among all studied vitamins at any ATPS studied in this work. This finding contrasted with expectations based on literature data which let assume that charged species have typically the highest K values in the considered ATPS. Thus, besides the typically strong charge–charge interactions especially specific forces (e.g., hydrogen bonding) explains the strong PEG‐cyanocobalamin interaction resulting in the high K values.

中文翻译：

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水溶性维生素在可生物降解的水两相系统中的分配：电解质扰动链统计与流体理论预测和实验验证

聚乙二醇（PEG 4000，PEG 6000）和有机盐（柠檬酸钠和酒石酸钠）组成的水两相系统（ATPS）中的维生素（核黄素，烟酸，烟酰胺，叶酸，氰钴胺）的分配系数（K）在T = 298.15 K和p = 1 bar的条件下进行了研究。本研究中所考虑的ATPS的液-液平衡数据已从文献（PEG-Na ₃柠檬酸盐）中获得，或在这项工作中（PEG-Na ₂酒石酸盐）在T = 298.15 K和p = 1巴。实验K电解质扰动链统计流体理论预测值验证了这些值。在这项工作中研究的所有ATPS中，中性氰钴胺素在所有研究的维生素中具有最高的K值。这一发现与基于文献数据的预期形成对比，后者基于假设带电物种在所考虑的ATPS中通常具有最高的K值。因此，除了通常具有很强的电荷-电荷相互作用之外，尤其是比力（例如氢键）还解释了导致高K值的强PEG-氰钴胺素相互作用。