离子色谱法测定大气降尘中四种阴离子

ION-CHROMATOGRAPHIC DETERMINATION OF 4 INORGANIC ANIONS IN DUSTFALL

以流速 1.5ml·min- 1,0 .2 4mol·L- 1Na2 CO3和 0 .30mol·L- 1NaHCO3混合液为淋洗液 ,在YSA 4型阴离子分离柱上分离 ,采用带电导检测器的离子色谱仪对大气降尘中四种阴离子进行分离测定 ,F- 、Cl- 、NO- 3、SO2 - 4的检出限 (3S/N)分别为 0 .0 0 1,0 .0 0 1,0 .0 0 6 ,0 .0 0 4mg·L- 1,相关系数分别为 0 .9991,0 .9986 ,0 .9997,0 .9984 ,RSD分别为 0 .80 % ,0 .76 % ,1.80 % ,1 90 %。

A simple and rapid method for the determination of four inorganic anions (F - Cl - NO - 3 and SO 2- 4) by ion chromatography (IC) with conductivity detection was studied. All these anions were separated on YSA 4 anion exchange column using a mixed solution of 0.24mol·L -1 Na 2CO 3 and 0.30mol·L -1 NaHCO 3 as eluant. The flow rate of the mobile phase was 1.5ml·min -1 . Standard solutions of F - Cl - NO - 3 and SO 2- 4 having the same concentrations of 1.25, 2.50, 7.50 and 15.00mg·L -1 were prepared and tested for precision ( n =10) under the optimized IC conditions. RSD′s found were 0.80%, 0.76%, 1.80% and 1.90% respectively. Linearities between the peak height and the anions and their respective concentrations as described above were also found and their regression equations were as follws: F -: h =3.528 c -0.278 ( r =0.9991), Cl -: h =18.095 c -0.151 ( r =0.9986), NO - 3: h =1.175 c +0.362 ( r =0.9997), SO 2- 4: h =4.496 c -0.0357 ( r =0.9984). Detection limits (3 S/N ) of these anions were found to be 0.001, 0.001, 0.006 and 0.004mg·L -1 for F - Cl - NO - 3 and SO 2- 4 respectively. The entire process of analysis was completed within 16min.