Dabek-Zlotorzynska Ewa, Piechowski Maria
Analysis and Air Quality, Environmental Science and Technology Centre, Science and Technology Branch, Environment Canada, 335 River Road, Ottawa, Ontario, Canada.
Electrophoresis. 2007 Oct;28(19):3526-34. doi: 10.1002/elps.200700109.
A simple and reliable CE method with direct UV detection has been developed to separate eight isomeric benzoic acids in atmospheric aerosols and vehicular emission without complex sample pretreatment. Optimal electrophoretic conditions, with migration times under 5 min, were obtained by using a 50 mM acetate buffer (pH 4.7) containing a dynamic surface coating EOTrol LN (0.005% w/v). The separations were carried out in a cathode to anode direction (-30 kV) allowing the low cathodal EOF ( approximately 1 x 10(-9) m(2)V(-1)s(-1)) to extend the effective separation by slowing the movement of the studied aromatic acids. Moreover, the sensitivity of the method at 200 nm was enhanced by using a field-amplified sample injection (FASI) with electrokinetic (EK) sample injection (-2 kV, 60 s). Prior to sample injection, a short water plug (3 s at 0.5 psi) was introduced. Under these conditions, the method was capable of detecting the analytes in deionized water with LODs (S/N = 3) as low as 0.1 microg/L for most of the studied acids. In the presence of 10 mg/L of sulphate (added to simulate a sample matrix), LODs ranged from 0.26 to 0.62 microg/L. The validation of the method has proven an excellent separation performance and accuracy for the determination of isomeric benzoic acids in the studied matrices.
已开发出一种简单可靠的毛细管电泳（CE）方法，采用直接紫外检测，无需复杂的样品预处理即可分离大气气溶胶和车辆排放物中的八种异构苯甲酸。通过使用含有动态表面涂层EOTrol LN（0.005% w/v）的50 mM醋酸盐缓冲液（pH 4.7），获得了迁移时间在5分钟以内的最佳电泳条件。分离在阴极到阳极方向（-30 kV）进行，低阴极电渗流（约1×10⁻⁹ m²V⁻¹s⁻¹）通过减缓所研究芳香酸的移动来延长有效分离。此外，通过使用电动（EK）进样（-2 kV，60 s）的场放大进样（FASI）提高了该方法在200 nm处的灵敏度。在进样前，引入一段短的水塞（0.5 psi下3 s）。在这些条件下，该方法能够检测去离子水中的分析物，对于大多数所研究的酸，检测限（S/N = 3）低至0.1 μg/L。在存在10 mg/L硫酸盐（添加以模拟样品基质）的情况下，检测限范围为0.26至0.62 μg/L。该方法的验证已证明在测定所研究基质中的异构苯甲酸时具有出色的分离性能和准确性。
