Lever M
Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand.
Biochim Biophys Acta. 1998 Sep 16;1425(1):61-73. doi: 10.1016/s0304-4165(98)00051-8.
With water as the elution solvent, zwitterionic solutes and polyols were retained on HPLC columns, more than was water, by totally hydrophobic packing materials. Relative retentions were systematically affected by oxygen functional groups in the packing material, explicable as specific retention of water. Reproducible elution sequences of 20 solutes at a variety of hydrophobic surfaces (aromatic and both long- and short-alkyl aliphatic surfaces) showed there is a general process, consistent with interactions with hydration water at the surface having solvent properties distinct from bulk water. Early eluting solutes included glycine, sarcosine and taurine. Glycine betaine followed both these and N,N-dimethylglycine. The natural betaines propionobetaine and dimethylsulfoniopropionate also preceded glycine betaine. Dimethylsulfoxide was strongly retained, as (to a lesser extent) was proline betaine. Polyols eluted in the sequence sorbitol, trehalose, glycerol. Changes in the chemical nature of the surface or base material affected relative retentions of water and solutes. The presence of hydrogen-bonding functions increased retention of polyols, as well as water, relative to zwitterionic solutes. Specific effects retention, constraining models based on the formation of low-density water.
以水作为洗脱溶剂时，两性离子溶质和多元醇在高效液相色谱柱上的保留程度超过水，这是由完全疏水的填充材料造成的。填充材料中的氧官能团会系统地影响相对保留率，这可以解释为水的特异性保留。在各种疏水表面（芳香族以及长链和短链烷基脂肪族表面）上对20种溶质进行的可重现洗脱序列表明，存在一个普遍过程，这与在具有与本体水不同的溶剂性质的表面上与水合水的相互作用一致。较早洗脱的溶质包括甘氨酸、肌氨酸和牛磺酸。甜菜碱在这两种物质以及N,N-二甲基甘氨酸之后洗脱。天然甜菜碱丙氨酸甜菜碱和二甲基磺基丙酸盐也先于甘氨酸甜菜碱洗脱。二甲基亚砜被强烈保留，脯氨酸甜菜碱也有一定程度的保留（程度较轻）。多元醇按山梨醇、海藻糖、甘油的顺序洗脱。表面或基础材料化学性质的变化会影响水和溶质的相对保留率。相对于两性离子溶质，氢键功能的存在增加了多元醇以及水的保留率。特异性保留效应限制了基于低密度水形成的模型。
