Abstract：
A rapid, straightforward, and sensitive approach to quantifying enantiomeric barbiturates in serum was developed by integrating ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) with large-volume sample stacking (LVSS) in capillary electrophoresis (CE). UA-DLLME was employed for sample preparation, and on-column preconcentration by using LVSS with polarity switching was implemented to enhance sensitivity. We thoroughly investigated and optimized various parameters influencing extraction and stacking to achieve optimal detection performance with the highest enrichment efficiencies. Under optimal extraction conditions (injection of a mixed solution containing 40 μL of CHCl3 and 200 μL of tetrahydrofuran into 1 mL of a sample solution at pH 10.0), LVSS was performed using 600 mM Tris-boric acid (pH 9.5) containing 35 mM hydroxypropyl-β-cyclodextrin and sodium taurodeoxycholate hydrate. A voltage of 20 kV was applied and a preinjection water plug was loaded at a height of 25 cm for 10 s. Subsequently, the sample solution was injected at a height of 25 cm for 480 s, after which a voltage of -20 kV was applied and the sample stacking was initiated. The stacking process was completed when 95 % of the separation current was attained. Under optimized conditions, the contraction folds of the four barbiturate analytes (R, S-Secobarbital, R, S-pentobarbital) were improved by approximately 6400-fold, achieving detection limits of 0.1 ng/mL. The limits of quantification for all analyte enantiomers were 0.5-50 ng/mL, demonstrating good linearity (r > 0.997). Migration times exhibited a relative standard deviation of less than 1.7 %, whereas peak areas for the four analytes exhibited a deviation of 8.7 %. Finally, the established method was effectively applied to the analysis of human serum samples.
摘要：
一个快速的，直截了当，通过将超声辅助分散液液微萃取（UA-DLLME）与毛细管电泳（CE）中的大体积样品堆叠（LVSS）相结合，开发了定量血清中对映体巴比妥酸盐的灵敏方法。UA-DLLME用于样品制备，通过使用具有极性切换的LVSS进行柱上预浓缩，以提高灵敏度。我们彻底研究和优化了影响提取和堆叠的各种参数，以实现具有最高富集效率的最佳检测性能。在最佳提取条件下（将含有40μLCHCl3和200μL四氢呋喃的混合溶液注入pH10.0的1mL样品溶液中），使用含有35mM羟丙基-β-环糊精和牛磺脱氧胆酸钠水合物的600mMTris-硼酸(pH9.5)进行LVSS。施加20kV的电压,并在25cm的高度加载预注入水塞10s。随后,将样品溶液在25厘米的高度注入480秒，之后,施加-20kV的电压并开始样品堆叠。当达到95%的分离电流时,完成堆叠过程。在优化条件下，四种巴比妥酸盐分析物的收缩褶皱(R，S-缩巴比妥,R,S-戊巴比妥)提高了约6400倍，达到0.1ng/mL的检测限。所有分析物对映异构体的定量限为0.5-50ng/mL，表现出良好的线性(r>0.997)。迁移时间表现出小于1.7%的相对标准偏差，而四种分析物的峰面积表现出8.7%的偏差。最后,该方法有效地应用于人血清样品的分析。
