分步酸解法快速检测发酵液中普鲁兰糖含量

建立分步酸解快速检测发酵液中普鲁兰糖含量的方法。使用不同浓度盐酸对两个相同发酵液样品进行酸解,分别将蔗糖和普鲁兰糖降解为单糖,再利用生物传感分析仪对酸解之后样品中葡萄糖含量进行定量分析,从而利用两者之间葡萄糖含量的差值计算出发酵液中普鲁兰糖的含量。在对酸解时间、盐酸浓度、蔗糖和普鲁兰糖检测范围以及该方法精密度和准确度进行研究之后,确定了蔗糖酸解条件为:0.6 mol/L盐酸、沸水浴3 min;普鲁兰糖的酸解条件为:2 mol/L盐酸、沸水浴30 min。实验证明,此方法精密度良好,RSD为0.7743%,准确度高,回收率为97.96%~100.72%;用时较短,40 min左右即可较准确的测定发酵液中普鲁兰糖含量。实验证明此方法是一种可行的高效、快速测定发酵液中普鲁兰糖含量的方法。     

REMOVAL OF t-BUTYL AND t-BUTOXYCARBONYL PROTECTING GROUPS WITH TRIFLUOROACETIC ACID

The trifluoroacetic acid-mediated removal of t-butyl groups in protected amino acids leads to the formation of t-butyl trifluoroacetate. This t-butyl ester alkylates in trifluoroacetic acid methionine and tryptophan. The t-butyl trifluoroacetate ester can be destroyed by scavengers commonly employed for t-butyl cations, and the reaction rates of the scavengers with the ester are used in the evaluation of scavengers. Scavengers of sulphide structure react with t-butyl trifluoroacetate to form sulphonium compounds, which possess alkylating properties. In the presence of a scavenger during acidolysis, the trifluoroacetic acid and the scavenger will compete in reacting with the t-butyl cations. Kinetic studies show comparable reaction rates with thiophenol as scavenger. The usefulness of adding scavengers to trifluoroacetic acid in deblocking reactions is due to the removal of t-butyl trifluoroacetate in addition to the removal of t-butyl cations. Isobutene reacts with trifluoroacetic acid and yields t-butyl trifluoroacetate. The reaction reaches an equilibrium displaced in favour of the ester at room temperature. Hence no isobutene can be expected to escape during a deblocking reaction in trifluoroacetic acid.     

高效液相色谱法测定微乳体系中胰岛素含量的前处理方法比较

目的 :研究反相高效液相色谱测定微乳体系中胰岛素含量的前处理方法 ,并对 3种前处理方法进行了比较。方法 :采用TritonX 10 0破乳、盐酸酸解、水饱和正丁醇萃取 3种方法对胰岛素微乳体系进行前处理 ,用RP HPLC对处理后样品中胰岛素的含量进行测定。结果 :TritonX 10 0、酸解、萃取 3种方法回收率分别为98 7%～ 10 0 6 % ,94 1%～ 96 8% ,89 2 %～ 92 7% ;RSD分别为 1 5 8%～ 3 2 0 % ,2 0 8%～ 4 30 % ,4 0 7%～6 0 9%。结论 :3种方法中 ,以TritonX 10 0破乳法的结果较为精确 ,回收率较高 ;操作较为方便简单、快速可靠 ;对胰岛素稳定性没有影响 ,样品消耗量较少。     

甘露三糖的制备及其工艺优化

目的:探索水苏糖酸水解制备甘露三糖的方法。方法:通过HPLC定量检测,采用正交试验设计,考察温度、pH值、时间三个影响因素,来确定水苏糖的酸水解工艺;并经柱层析分离得到甘露三糖。结果:在本实验条件下,温度和时间对水苏糖酸水解影响不显著(P<0.05),而酸度对其有显著性影响(P>0.05),确定最佳反应条件为90℃、24 h、pH 2.5。结论:水苏糖酸水解制备甘露三糖的方法可行。