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采用离子色谱模拟研究了流动相不纯对样品中无机阴离子测定造成的干扰.结果表明,在流动相中加入Cl-,使得其他6种阴离子响应值增加.这主要是由于Cl-加入的同时也带来了相应的阳离子,在通过抑制器时可带来等量的H+,H+伴随着各个阴离子样品一起通过检测器,使总的样品离子响应值增加.在6种阴离子中,F-和NO-2对AS14色谱柱的亲和力和Cl-相近,其响应值随Cl-加入量的变化趋势相似;Br-,NO-3,PO3-4及SO2-4因其对色谱柱的亲和力大于Cl-,它们的响应值随Cl-加入量的变化趋势也相同.对Cl-本身,当流动相中Cl-加入浓度不大于样品中Cl-的浓度(3 mgL-1)时,由流动相中Cl-造成的负系统峰小于样品中Cl-产生的正峰,其响应值基本没有变化.当流动相中Cl-浓度大于样品中Cl-浓度时,流动相中Cl-的负系统峰大于样品中Cl-的正峰,Cl-样品峰被系统峰覆盖.

A series of experiments were conducted by adding Cl- to the eluent to simulate the contaminated eluent. It was found that the added Cl- would cause the peak response of the anions increase largely. Because of the introduction of the superfluous H+, the total conductivity of each anion band was enhanced, and it was regarded as the increase of the sample anion. In the anions except Cl-, for the low affinities of F- and NO-2 for an AS14 column that were close to Cl-, they had the similar variation trends according to the amount of Cl- added to the eluent, and the two anions had the maximal responses when the concentration of Cl- in the eluent was 3 mg*L-1 that was just equal to the content in the sample. As to Br-, NO-3, PO3-4 and SO2-4 whose variation trends were the same, all of the peak responses of the anions reached the maximum when the concentration of Cl- in the eluent was 6 mg*L-1. For Cl-, the peak response hardly changed when the amount of Cl- added was less than or equal to the concentration of 3 mg*L-1 in the sample. When concentration of Cl- added in the eluent was more than that in the sample, the peak area of Cl- began to decrease little by little, and the peak was completely covered up when the concentration of Cl- in the eluent was 6 mg*L-1.