反相离子对高效液相色谱法分离金属配合物｛Fe［3-(2-吡啶基)-5,6-二苯基-1,2,4-三嗪］3｝2+几何异构体

采用反相离子对高效液相色谱法分离测定了金属配合物｛Fe［3-(2-吡啶基)-5,6-二苯基-1,2,4-三嗪］3｝2+ (［Fe(PDT)3］2+)的两种几何异构体,研究了流动相中有机改性剂(乙腈、甲醇)的含量、不同种类和浓度的离子对试剂(高氯酸钠和十二烷基硫酸钠(SDS))对色谱分离的影响。并在不同的试验条件下,对所获得的色谱参数(保留因子(k)、分离度、选择性因子等)进行了探讨。在不同种类及浓度的离子对试剂条件下,二元流动相中乙腈的含量与两种几何异构体的ln k之间均呈显著的线性关系。研究进一步发现SDS的浓度变化对异构体的保留因子影响程度更为显著。在上述实验的基础上,引入更能灵活调节洗脱强度和分离度的三元流动相(乙腈/甲醇/水),优化选择了三元流动相中有机改性剂的比例以及离子对试剂的种类和浓度,使得异构体的色谱分离得到了满意的结果。实验结果表明,异构体的峰面积(A)和浓度(C)之间的线性关系良好,面式和经式异构体的检测限分别为4.28和3.44 ng/mL (S/N=3)。

Separation of geometrical isomers of {Fe[3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine]3} ([Fe(PDT)3]) using ion-pair reversed-phase high performance liquid chromatography

A method has been developed for the separation of two geometrical isomers of the {Fe[3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine]3}2+([Fe(PDT)3]2+) using ion-pair reversed-phase high performance liquid chromatography (RP-HPLC). The effects of the chromatographic conditions, such as the content of acetonitrile and the type and concentration of the ion-pair reagents (sodium perchlorate (NaClO4) or sodium dodecyl sulfate (SDS)) in the binary mobile phase (acetonitrile and water), on the retention factor (k), resolution, and selectivity were iscussed. It was found that no matter how the ion-pair reagent was NaClO4 or SDS at different concentrations, the acetonitrile content in the mobile phase has good linear regression equations with the ln k of the two isomers. It was also observed that SDS showed more positive effect on the k of the two geometrical isomers than that of NaClO4. Moreover, the separation of the two isomers in the ternary mobile phase (acetonitrile, methanol and water) was developed. The chromatographic conditions, including the content of the organic modifier (acetonitrile and methanol) and the type and concentration of the ion-pair reagents (SDS and NaClO4), were optimized. Two geometrical isomers were rapidly and successfully separated under the optimized conditions, which used acetonitrile/methanol/water (20: 50: 30, v/v/v) as the mobile phase and 60 mmol/L NaClO4 as the ion-pair reagent. Good linear regression equations between the peak areas and concentrations for the two isomers were obtained. The detection limits of the fac-isomer and mer-isomer were 4.28 and 3.44 ng/mL (S/N = 3), respectively.