介绍了一种无需对样品进行除氯处理,采用全新的离子色谱柱,抑制型电导离子色谱法检测,测定超高Cl-基体下痕量亚硝酸盐及其它常见阴离子的方法。其中Cl-浓度与亚硝酸盐浓度比可达到50000∶1甚至100000∶1,实现良好分离。选择色谱条件为:IonPac AS23阴离子交换柱,手工配制碳酸盐淋洗液等度淋洗,抑制型电导检测。污水样品通过Dionex OnGuardⅡRP柱和0.22μm微孔尼龙膜处理。该方法采用25μL进样,8种常见阴离子的检出限为0.2~5.8μg/L,线性范围均超过2个数量级,相关系数r在0.9996~0.9999的范围内,连续11次进样检出所有阴离子的RSD均小于5%,加标回收率结果在93%~106%之间。该方法具有选择性好,灵敏度高,操作简单等特点,从根本上解决了高氯离子基体中痕量亚硝酸盐及其它常见阴离子检测的问题,用于实际污水样品的检测。
The present paper introduced a method in which pretreated samples by OnGuard Ⅱ RP cartridges and 0.22μm micropore nylon membrane to remove hydrophobic compounds and tiny particles followed by separating and detecting common anions including trace nitrite in superhigh chloride concentration sewage samples by ion chromatography. The method may separate chloride and nitrite beautifully whose ratio are 50000:1 or even 100000: 1. The separation and determination of anions were obtained by the brand-new high capacity carbonate selectivity IonPac AS23 column produced by dionex corporation recently with manual prepared Na2 CO3/NaHCO3 eluent and suppressed conductivity detector. The method detection limits are from 0.2 to 5.8μg/L by 25μL-injection; it may calibrate over two or three orders of magnitude in concentration of 8 anions while the range of linear correlation coefficients is from 0.9996 to 0.9999; RSDs are below 5% for all of anions while the recoveries are between 93% and 106%. The above method possesses the advantages of good selectivity, high sensitivity and easy operation. It solved one of the most difficult puzzles in ion chromatography that separate ultrahigh chlorite and trace nitrite in samples which had been proved by analysing actual samples with satisfactory results.