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

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 microextraction(DLLME)-gas chromatography(GC).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: 200μL chlorobenzene(extraction solvent) and 2.5mL acetone(dispersion solvent) were added to the water samples,then set at room temperature for 8 min,centrifugation at 3000r/min for 8 min,finally,1μL sedimented phase was injected into GC for analysis.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 μg/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.