Determination Of Organic Pollutants In Environmental Water By Ionic Liquid Dispersive Liquid-liquid Microextraction-high Performance Liquid Chromatography

High performance liquid chromatography is widely used in environment andanalytical chemistry, but is not suitable for complex matrix or samples with lowconcentration. A preconcentration step is often needed before analysis. Traditionalpreconcentration techniques such as liquid-liquid extraction（LLE） and solid phaseextraion（SPE） are time-consuming and need large volume of organic solvents, whichare dangerous for human health and the environment. Recently, analytical method hasbeen oriented towards the development of miniaturized sample, automation, efficientand economical preparation methods. Liquid phase microextraction（LPME） have beendeveploped. Meantime, dispersive liquid-liquid microextration（DLLME） belongs toliquid phase microextration methods, having advantage of using less organic solvent,easy to use, high enrichment and so on. Recent years, ionic liquids as greensolvent‘have been widely used in separation and extraction process. The traditionalsolvent has disadvanges of strong volatility, high toxicity, serious damage to theenvironment, etc. Using ionic liquids instead of organic solvent can overcome theshortcomings from the source. Meanwhile, ionic liquids have the selected dissolutingability for water, organic solvent and other materials through adjusting their structures.This paper used ionic liquids instead of traditional solvent, combing with DLLME andHPLC analysised some matirials in tap water, and assessed the method. It‘s maincontent are as follows:1. A novel procedure for the enrichment and determination of trace diethylphthalate （DEP）, di-n-butyl phthalate （DBP）, di（2-ethyl-hexyl） phthalate （DEHP） anddi-n-octyl phthalate （DOP） in environmental water by ultrasound-assisted（USA）dispersive liquid-liquid microextraction （DLLME） coupled with high performanceliquid chromatography （HPLC） was established using1-octyl-3-methylimidazoliumhexafluorophosphate as an extractant solvent and methanol as a disperser solvent.Experimental conditions such as chromatographic separation and DLLME（speciesand volume of extractants and disperser solvents, ultrasonic microextraction time andionic strength） were examined. Under the optimized conditions, the chromatographicpeak area is proportional to their individual concentration in the range1.00-500μg/L （R>0.995）. The average recoveries were88.2%～91.8%for10.0μg/L and the relativestandard deviations （RSD）2.01%⁶.76%（n=5）. The limits of detection are within0.01⁰.07μg/L. The developed method was successfully applied to the enrichmentand determination of4phthalates in the Yellow River and urban wastewater samples.Satisfactory recovery, good precision and high sensitivity were achieved for analyticalresults.2. A novel procedure for the enrichment and determination of8polychlorinatedbiphenyls（PCBs） in environmental water by USA-DLLME-HPLC was establishedusing [BMIm][TF₂N] as an extractant solvent and acetone as a disperser solvent.Experimental conditions such as chromatographic separation and DLLME（speciesand volume of extractants and disperser solvents, ultrasonic microextraction time andionic strength） were examined. Under the optimized conditions, the chromatographicpeak area is proportional to their individual concentration in the range0.05-10μg/L（R>0.987）. The average recoveries were91.4%～106.1%for0.50μg/L and therelative standard deviations （RSD）2.80%⁶.15%（n=5）. The limits of detection arewithin19.74～61.75ng/L. The developed method was successfully applied to theenrichment and determination of PCBs in the Yellow River and rain water samples.Satisfactory recovery, good precision and high sensitivity were achieved for analyticalresults.3. A novel procedure for the enrichment and determination of bisphenol A （BPA）in environmental water by USA-DLLME-HPLC was established using [OMIm][PF₆]as an extractant solvent and acetonitrile as a disperser solvent. Experimentalconditions such as chromatographic separation and DLLME（species and volume ofextractants and disperser solvents, ultrasonic microextraction time and ionic strength）were examined. Under the optimized conditions, the chromatographic peak area isproportional to their individual concentration in the range0.10-20μg/L （R>0.993）.The limit of detection was0.02μg/L and the relative standard deviations was5.70%.The recovery were95.0%～104.0%. The developed method was successfully appliedto the enrichment and determination of BPA in the Yellow River and rain watersamples. Satisfactory recovery, good precision and high sensitivity were achieved for analytical results.