分散液液微萃取-气相色谱法测定环境水样中间甲苯酚

Determination of m-cresol in Environmental Water Sample by Dispersive Liquid-liquid Microextraction Coupled with Gas Chromatography

针对环境中痕量的间甲苯酚用一般仪器很难直接分析测定的问题,提出将分散液液微萃取技术与气相色谱联用测定环境水样中间甲苯酚的新方法。实验考察了影响分散液液微萃取效率的因素,包括萃取剂种类和用量、分散剂种类和用量、萃取时间、离心时间和盐度等,确定了最佳萃取条件为:200μL氯苯(萃取剂)和2.5mL丙酮(分散剂)混匀后,快速注入水样,室温静置8min,以3000r/min离心8min,吸取1μL沉积相进行气相色谱分析。实验结果为:在最佳的萃取条件下,间甲苯酚的富集倍数为98.7倍,方法的线性范围为0.05~50mg/L,检出限为4.2μg/L(S/N=3),相对标准偏差为5.64%。将方法用于实际水样的测定,水样的加标回收率在86%~122%,相对标准偏差(RSD)为3.3%~7.3%(n=3),实验表明该方法操作简便快速、成本低、环境友好,可用于实际水样的测定。

Based on the problem that trace m-cresol at low concentrations was difficult to direct determination, a new method was developed for the determination of m-cresol in environmental water sample by dispersive liquid-liquid mi- croextraction （DLLME）-gas chromatography （G C）. The factors relevant to the microextraction efficiency, such as the type and volume of extraction solvent and dispersion solvent, the extraction time, centrifuging time and the salt effect were investigated and optimized. The optimal extraction conditions were as follow： 200/~L chlorobenzene （ex- traction solvent） and 2.5mL acetone （dispersion solvent） were added to the water samples, then set at room temper- ature for 8 min, centrifugation at 3000r/rain for 8 rain, finally, lt^L sedimented phase was injected into GC for anal- ysis. The results could be concluded as follows： under the optimized extraction conditions, the maximum enrichment factors was 98.7, the linear relationship between the peak area and the concentration of m-cresol were in the range of 0.05 - 10 mg/L, the limit of detection （ S/N = 3） was 4.2 t^g/L and the relative standard deviations （RSD） was 5. 64%. The recoveries were within 86% - 122% for different real water samples with relative standard deviation （RSD） between 3.3% -7.3% （n = 3）. The obtained results showed that the DLLME-GC method simple, low- cost, environment-friendship, and suitable for the determination of environmental water samples.