多分离模式液相色谱法同时分析阴、阳离子的研究

Simultaneous Determination of Anions and Cations by Multimodal Liquid Chromatography

采用基于纳米聚合物-硅胶混合技术,同时具有反相、阴、阳离子交换的多分离模式色谱分离功能的Acclaim Trinity P1色谱柱,直接电导检测,建立了同时分析Li＋, NH＋4, K＋, HCOO-, NO-2, Cl-, NO-3和Br-8种离子的分析方法。通过探讨淋洗液对离子保留的影响,优化得到实验条件如下：淋洗液：25 mmol/L乙酸钠＋50%（V/V）乙腈,用冰醋酸调至pH 5.0；柱温：30℃；流速：0.50 mL/min；直接电导检测。8种阴阳离子（Li＋, NH＋4, K＋, HCOO-, NO-2, Cl-, NO-3和Br-）能够同时被分离和检测。化肥样品经稀释溶解过滤后直接进样,结果表明,8种离子的线性范围为0.5～200 mg/L,线性相关系数均大于0.9997,相对标准偏差RSD （n=9）为1.3%～2.5%,检出限（S/N=3）在0.16～1.70 mg/L之间。将本方法用于化肥中阴阳离子的测定,加标回收率为95.8%～103.8%。

A new method has been established for simultaneous determination of anions and cations in fertilizer sample by multimodal liquid chromatography with direct conductivity detection. An Acclaim Trinity P1 column based on nanopolymer silica hybrid technology with multimodal separation functional groups reversed-phase/anion-exchange/cation-exchange was used for the analysis. The chromatographic conditions were optimized and the effect ion of eluent on retention was discussed. Eight ions （ Li＋, NH＋4 , K＋, HCOO-, NO-2 , Cl-, NO-3 and Br-） were separated and determined simultaneously by using 25 mmol/L CH3 COONa solution containing 50% acetonitrile at pH=5. 0 as mobile phase. The flow rate was 0. 50 mL/min and the temperature was 30 ℃. Under the optimum conditions, the linear ranges of the method were in the range of 0 . 5-200 mg/L for all the ions with correlation coefficient of 0 . 9997-0 . 9999 . Whereas the detection limits （S/N=3） were in the range of 0. 16-1. 72 mg/L and the relative standard deviations （RSD, n=9） were in the range of 1 . 3-2 . 5%. The method was applied to the determination of anions and cations in the fertilizer samples with satisfied results and the recoveries were in the range of 95 . 8%-103 . 8%.