离子色谱法测定新鲜蔬菜中的无机阴离子

Ion chromatographic determination of inorganic anions in fresh vegetables

以流速1 2mL/min,流动相为1 7mmol/LNaHCO3∶1 8mmol/LNa2CO3混合液,色谱条件为:阴离子分离柱DionexAS14S柱(4mm×250mm)及相应保护柱IonPacAG14(4mm×50mm),自动连续再生抑制装置SRS-ULTRA4mm,建立了外加水模式抑制电导检测的离子色谱法对蔬菜中4种阴离子进行了分离测定.结果表明,F-、Cl-、NO-3和NO-2的检出限(5S/N)分别为0 05,0 05,0 01和0 01mg/L,相关系数分别为0 9990,0 9991,0 9995和0 9992,RSD分别为0 71%,0 75%,1 20%和1 50%.

A determination method of four inorganic anions (F^-,Cl^-,NO^-_3 and NO^-_2) with ion chromatography(IC) was studied. All these anions were separated on Dionex AS14S column and IonPacAG14 column anion exchange column using a mixed solution of 1.7 mmol/L NaHCO_3∶1.8 mmol/L Na_2CO_3 as eluant. The flow rate of the mobile-phase was 1.2 ml/min. Standard solutions of F^-,Cl^-,NO^-_3 and NO^-_2 with the same concentrations of 1.00,2.00,5.00 and 10.00 mg/L were prepared and tested for precision (n=9) under the optimized IC conditions. The RSDs were 0.71%,0.75%,1.2% and 1.5% respectively. Linearities among the peak height, the anions and their respective concentrations as described above were also found with coefficients as follows:F^-:r=0.9990,Cl^-: r=0.9991,NO^-_3:r=0.9995,NO^-_2:r=0.9992. Detection limits(5 S/N) of these anions were of 0.05,0.05,0.01,0.01 mg/L for F^-,Cl^-,NO^-_3 and NO^-_2 respectively.