葫［7］环联脲作为毛细管电泳分离介质的研究

以葫［7］环联脲(CB［7］)作为毛细管电泳添加剂,成功地分离了6种硝基苯类化合物。考察了pH值对电渗流的影响,初步评价了其基本的电泳性能,结果表明在所考察的pH值范围内(pH 2~6.5),葫［7］环联脲是质子化的,且吸附到毛细管内壁上,这使得毛细管内壁带上正电荷,电渗流反向;初步考察了葫［7］环联脲的浓度对分离的影响,证明了用葫［7］环联脲作为添加剂可完全分离对硝基乙苯、对硝基甲苯、对氯硝基苯、间二硝基苯、2,4-二硝基氯苯和硝基苯这6种物质,最佳的缓冲液为10 mmol/L Na2HPO4（用盐

Study on Cucurbit[7] uril-Mediated Capillary Electrophoresis

The use of a novel macrocyclic molecule, cucurbit[7] uril (CB[7]), as an additive in capillary electrophoresis (CE) for the separation of several neutral nitrobenzenes is reported. Disodium hydrogen phosphate-hydrochloric acid was used as the buffer solvent with the UV detection at 254 nm. During the running process, CB [7] bore positive charge under the studied pH range (pH 2 - 6.5) and was adsorbed onto the inner wall of fused silica capillary, leading to a reversal of the electroosmotic flow (EOF). The effects of buffer pH and CB [7] concentration on the EOF behavior were investigated. The influences of the CB [7] concentration on electrophoretic behaviors of nitrobenzenes were also studied, and it was found that the selectivity increased with CB[7] concentration. The results showed that CB [7] provided good selectivity for nitrobenzenes and successful separation was obtained under optimum condition (10 mmol/L Na2HPO4 (pH 2.47, adjusted by HCl)-methanol (90 : 10, v/v), containing 5 mmol/L CB[7]). Possible explanation is also proposed.