高效阴离子交换色谱在易极化阴离子痕量分析中的应用

Application of High Performance Anion Exchange Chromatography for Trace Analysis of Polarizable Anions

以45 mmol/L的 NaOH溶液作淋洗液,采用强亲水性的IonPac AS16阴离子交换分析柱和脉冲安培检测器,在15 min内分离检测了Br-,S2O2-3,I-和SCN-4种易极化阴离子,检测限(以3倍信噪比计)分别为0.5,0.2,0.05和2 μg/L (进样25 μL).痕量离子的标准溶液平行9次进样测定的相对标准偏差为0.8%～3.7%.而在相同的色谱条件下,抑制型电导检测器对上述4种阴离子的检测限分别为1,1,2和10 μg/L,平行9次进样测定的相对标准偏差为0.9%～4.7%.通过实验比较可知,脉冲安培检测器的灵敏度是抑制型电导检测器的2～40倍.在测定上述易极化阴离子时,脉冲安培检测器具有选择性强、精密度好和灵敏度高等优点.

Polarizable anions such as Br^-, S2O3^2-, I^- and SCN^- were separated using 45mmol/L sodium hydroxide solution as the mobile phase on a high hydrophilic IonPac AS16 column. With a pulsed amperometric detector, the detection limits were 0.5, 0.2, 0.05 and 2μg/L （25.0μL injected, signal-to-noise ratio of 3） for Br^-, S2O3^2- , I^- and SCN^-. The relative standard deviation （RSD） range of trace anions was from 0.8% to 3.7% （n=9）. Under the same chromatographic conditions, these anions were also determined using a suppressed conductivity detector and the detection limits were 1, 1, 2 and 10μg/L （25μL injected, signal-to-noise ratio of 3）, respectively. The RSD range was from 0.9% to 4.7% （n=9）. Comparing a pulsed amperometric detector with a conductivity detector, the former is 2 to 40 times more sensitive than the latter. For the determination of polarizable anions, a pulsed amperometric detector has higher selectivity, precision and sensitivity.