The Study On Extraction Efficiency Of Ionic Liquids Containing Bis[(Trifluoromethyl)sulfonyl]imide In Dispersive Liquid-Liquid Microextraction

Ionic liquids （ILs） with bis[（trifluoromethyl）sulfonyl]imide（Tf₂N^-） weresynthesized and used as extraction solvent in dispersive liquid-liquid microextraction（DLLME） for extraction and determination of pollutants in real samples byhigh-performance liquid chromatography （HPLC）. The optimization of extractionconditions, such as kind of extraction and dispersive solvent, volume of extraction anddispersive solvent, addition of salt, extraction, temperature, pH and centrifugal timewere studied. Under the optimized conditions, some parameters (i.e., linear range（LR）, repeatability and limit of detection （LOD） of the method were evaluated.Moreover, the proposed IL-DLLME method can be applied to real samples withsatisfactory recovery.1-Hexyl-3-methylimidazolium bis[（trifluoromethyl）sulfonyl]imide（[HMIM][Tf2N]） ionic liquid was synthesized and used as extraction solvent inDLLME for analysis of carbamate pesticides in water samples by HPLC. Under theoptimal conditions, linear ranges were in range of26.6-1064.0μg L-1for fenobucarb,35.3-1410.0for Promecarb,5.2-1040.0μg L-1for Chlorpropham. For selectedanalytes, the developed method exhibited good linearity with correlation coefficients（r2） over a range of0.9994-0.9999. The reproducibility of the method was tested forfive replicate extraction of spiked water sample at different concentration levels of100,200and500μg L-1for all analytes and RSDs ranged from3.0%to6.6%. LODs,based on the ratio of signal to noise（S/N=3）, was in range of0.6-4.0μg L-1. Theproposed method was applied to the analysis of four different sources water samples,relative recoveries were between80.7%and119.9%and RSD values varied between0.5%and7.7%for all analytes in the spiked samples..A novel functionalized symmetrically1,3-dibutylimidazoliumbis[（trifluoromethyl）sulfonyl]imide （[BBIM][Tf2N]） ionic liquid was synthesized, andwas employed as extraction solvent in DLLME combined with HPLC for selectivedetermination of organic pollutants in water sample. Under the optimal conditions,linear ranges were in range of50.0-1000.0μg L-1for fenobucarb and phorate;10.0-1000.0μg L-1for2,4-Dichlorophenol, fenitrothion, parathion, fenthion andchlorpyifos;2.5-250.0μg L-1for biphenyl and anthracene. For selected analytes, thedeveloped method exhibited good linearity with correlation coefficients （r2） over a range of0.9921-0.9999. The reproducibility of the method was tested for fivereplicate extraction of spiked doubly-distilled water at different concentration levelsof100,200and1000μg L-1for fenobucarb, phorate, chlorpyifos;50,100and500μgL-1for2,4-Dichlorophenol, fenitrothion, parathion, fenthion;25,50and250μg L-1forbiphenyl, anthracene and RSD range from3.0%to6.7%. LODs, based on the ratio ofsignal to noise（S/N=3）, was in range of0.0025-5.0μg L-1. This method has been alsosuccessfully applied to analyze the real water samples （tap, well, snow and YellowRiver water） with satisfactory recoveries （82.9-119.6%） and RSD （1.2-7.9%）.A new symmetrically1,3-dihexylimidazolium bis[（trifluoromethyl） sulfonyl]-imide （[HHIM][Tf2N]） ionic liquid was synthesized and exhibitted impressiveselectivity towards the extraction of four polycyclic aromatic hydrocarbons （PAHs）from aqueous samples when used as a extraction solvent in DLLME coupled withHPLC. Under the optimum conditions, the linearity of the method was obtained in therange of1.0-1000.0μg L-1、1.0-500.0μg L-1、0.25-250.0μg L-1，2.5-250.0μg L-1forchloronaphthalene、anthracene、fluorene and chrysene, respectively. The correlationcoefficients （r2） is ranging from0.9995to0.9999. LODs were0.0025-1.0gL-1forfour analytes. RSD varied from0.6-5.2%. Four real samples including tap water,well water, Yellow River water and rain water spiked at three concentration levelswere analyzed and yielded recoveries ranging from91.2-113.8%,92.2-116.9%,82.1-110.2%and84.7-116.2%, respectively.1-Octyl-3-methylimidazolium bis[（trifluoromethyl）sulfonyl]imide（[OMIM][Tf2N]） ionic liquid was synthesized and was for the first time employed asextraction solvent in DLLME combined with HPLC for determination of nitrite ion inwater and biological samples. The method was based on the reaction of nitrite ionwith p-nitroaniline in the presence of diphenylamine in acid media and[OMIM][Tf2N]-DLLME of azo product. The optimization of reaction and extractionconditions were studied. Under the optimal conditions, the proposed method was ableto analyze nitrite ion in water and biological samples with satisfactory recoveryranged from96.1%to106.8%.