在线基体消除-离子色谱法测定墨水染料中的氯及硫酸盐

摘要

An on-line removing matrix method with pre-concentration of the analytes was developed for the simultaneous determination of impurity anions(e. g. chloride, sulfate) in ink dye by ion chro-matography (IC). The sample was diluted with de-ionized water, filtrated by 0.22μm nylon mem-brane and then injected into the IC system directly without any further pretreatment. The sample solu-tion in the loop was delivered by de-ionized water, and then filtrated on line by DIONEX OnGuard II P column and IonPac NG1 column for pre-removing of dyestuff and hydrophobic components. The an-alytes flowing out in the dead time were concentrated in the high capacity anion-exchange guard col-umn IonPac AG11 - HC. The concentrator then stepped in the IC system when the valve switched to injection mode. The chloride and sulfate were separated on a DIONEX IonPac AS23 (4 mm x 250 mm) column by using 4. 5 mmol/L Na2CO3 -0. 8 mmol/L NaHCO3 as the eluent at a flow rate of 1.2 mL/min. The analytes were detected with a Dionex DS6 conductive detector and quantitively analyzed by the external standard method. The results indicated that the linear ranges of Cl'and SO42- were 0. 05 - 5. 0 mg/L( r = 0. 999 8 ) and 0. 1 -10 mg/L( r = 0. 999 7 ) , respectively. The average recov-eries were in the range of 94% - 103% with relative standard deviations ( RSDs) no more than 1. 0% . The detection limits(S/N= 3) were 0. 02 mg/L for Cl- and 0. 05 mg/L for SO42-. The method was applied in the determination of chloride and sulfate in ink dye samples with satisfactory results.%建立了一种在线基体消除的方法,采用离子色谱法测定了墨水染料中的氯和硫酸盐.样品经溶解、稀释后直接进样,在纯水的输送下依次经过DIONEX OnGuardⅡP和IonPac NG1柱,在线实现了墨水样品中染料和疏水性干扰基体的去除,死时间流出的待测阴离子浓缩于阴离子交换柱IonPac AG1 1 - HC.浓缩柱经阀切换进入离子色谱系统,以4.5 mmol/L Na2CO3 -0.8 mmol/L NaHCO3作为淋洗液,流速1.2 mL/min,待测离子经IonPac AS23(4 mm ×250 mm)分析柱分离,采用DIONEX DS6电导检测器检测,外标法定量.Cl-和SO:-的线性范围分别为0.05～5.0、0.1～10.0 mg/L,相关系数分别为0.9998和0.999 7,加标回收率为94％～103％,相对标准偏差(n=11)小于1.0％,检出限(S/N=3)分别为0.02、0.05 mg/L.该方法用于墨水染料中氯和硫酸盐的测定,结果满意.