高温裂解/离子色谱法间接检测金属催化剂中的噻吩

Indirect Determination of Thiophene in Metal Catalysts by Ion Chromatography Coupled with Pyrolysis

建立了高温裂解/离子色谱法间接测定金属催化剂中噻吩含量的分析方法。金属催化剂样品经高温燃烧裂解,使其表面吸附的噻吩转化为SO2和SO3,用含H2O2的碱性吸收液吸收并氧化为SO4^2-,再采用离子色谱法检测吸收液中的SO4^2-浓度,间接计算出金属催化剂中噻吩含量。离子色谱条件为IonPac AS18(4.0 mm×250 mm)阴离子分析柱和IonPac AG18(4.0 mm×50 mm)阴离子保护柱,15 mmol/L氢氧化钾淋洗液,电导检测器检测。结果显示,SO4^2-在2.0~60 mg/L质量浓度范围内线性良好,相关系数为0.9998,SO4^2-的仪器检出限(S/N=3)为1.42μg/L,间接计算得噻吩的检出限和定量下限分别为0.25、1.82μg/g,噻吩的加标回收率为94.7%~97.8%,相对标准偏差(RSD)为1.5%~2.0%。该方法稳定性好、灵敏度高、准确度高,为化工生产过程中噻吩杂质的准确快速检测以及固体样品中有机杂质的检测提供了新思路及新方法。

A novel method was developed for the indirect determination of thiophene in metal catalysts by ion chromatography(IC)with pyrolysis.After combusted in the high temperature oven,the sulfur of thiophene in catalyst was transformed into SO2 and SO3,and then absorbed and oxidized to SO4^2-by absorbing solution containing H2O2.The content of thiophene could be calculated indirectly from the content of SO4^2-in the absorbing solution,which was detected by ion chromatography with suppressed conductivity detector.IonPac AS18(4.0 mm×250 mm)and IonPac AG18(4.0 mm×50 mm)columns were used for elution of the analyte with 15 mmol/L KOH as eluent.In the IC detection,the linear relationship for SO4^2-was excellent in the range of 2.0-60 mg/L with a correlation coefficient of 0.9998.The limit of detection(LOD,S/N=3)for SO4^2-was 1.42μg/L,and the LOD and the limit of quantitation(LOQ)for thiophene in metal catalysts were 0.25μg/g and 1.82μg/g,respectively.The recovery for thiophene ranged from 94.7%to 97.8%,with the relative standard deviation(RSD)of 1.5%-2.0%.The novel method is stable,rapid and sensitive,and it provides a new idea for the analysis of thiophene in the chemical production and some organic impurities in solid samples.