Research On The Analysis Methods Of Four Task-specific Ionic Liquids In Water,Soil And Plants

Ionic liquids（ILs）are a new type of room temperature molten salts,which are liquid at or near room temperature.ILs is composed of larger organic cations（such as imidazole,quaternary ammonium,quaternary phosphonium and pyridine）and smaller inorganic or organic anions（such as PF₆-、BF₄-、Cl-、Br-、NO₃-、CH₃COO-、（CF₃SO₂）₂N-、（CN）₂N-、CH₃CO₂-）.Task specific ionic liquids（TSILs）are a kind of ionic liquids that introduce different functional groups to the cations or anions of ionic liquids,so as to endow ionic liquids with some special properties and meet specific requirements or special applications.In functionalized ionic liquids,the properties of ionic liquids and functional groups have changed significantly.For example,in organic reactions,it is not only used as a solvent,but also as a reagent,carrier or catalyst to affect the reaction process.TSILs have been widely used in separation,electrochemistry,catalysts,organic synthesis and so on.At present,more and more enterprises at home and abroad have invested in the production of ionic liquids.Once ionic liquids are used on a large scale,the inevitable loss and waste of ionic liquids will cause harm to the organisms in water and soil.Therefore,it is necessary to establish a separation system of functional ionic liquids with simple operation and high sensitivity Analysis method is of great significance.In this paper,four kinds of functional ionic liquids were determined by high performance liquid chromatography（HPLC）and high performance liquid chromatography mass spectrometry（HPLC-MS/MS）.A method for the determination of four kinds of functional ionic liquids in water,soil and plant samples was established.The main research contents and conclusions are as follows:（1）The determination conditions of HPLC were established as follows:the model of HPLC was Agilent 1260;the chromatographic column was XDB-c18;the DAD detector;the determination wavelength was 212 nm;the injection volume was10μl;the flow rate of mobile phase was 0.8ml/min;the column temperature was30℃;the mobile phases and ratios of four kinds of functional ionic liquids were as follows:（1）The mobile phase of[HOEMIm]BF₄was methanol:water（0.2%phosphoric acid）=30:70;（2）The mobile phase of[C₂NH₂MIm]BF₄was acetonitrile:water=35:65;（3）The mobile phase of[MOEMIm]BF₄was methanol:water（0.2%phosphoric acid）=20:80;（4）The mobile phase of[HOEMIm]NO₃was methanol:wate（0.2%phosphoric acid）=30:70;（2）The determination conditions of triple quadrupole liquid chromatography-mass spectrometry were established:the model of HPLC was Agilent 1290 UPLC;the chromatographic column was eclipse xdb-c18;the injection volume was 10μl;the flow rate of mobile phase was 0.3ml/min;the column temperature was 25℃;the mobile phase was methanol:water（ammonium acetate buffer solution,p H=8）=30:70;the mass spectrometry conditions were Agilent 6470Qqq;ESI（+）,MRM detection,the main parameters are as follows:Mass spectrometry conditions:Agilent 6470 qqq;ESI（+）,MRM detection,the parameters are as follows:（1）The precursor ion of[HOEMIm]BF4 is 127,the product ion is 83,and the collision energy is 20.（2）The precursor ion of[C₂NH₂MIm]BF₄is 126,the product ion is 83.1,and the collision energy is 12.（3）The precursor ion of[MOEMIm]BF₄is 126.9;the product ion is 127.1;the collision energy is 5.（4）The precursor ion of[HOEMIm]NO₃is 141.1;the product ion is 109;the collision energy is 20.By comparing liquid chromatography with liquid chromatography-mass spectrometry,the sensitivity of liquid chromatography-mass spectrometry is higher,and four kinds of functional ionic liquids can be detected at the same time under one condition.In this experiment,the residues of functional ionic liquids in water,soil and plant samples were determined by high performance liquid chromatography-mass spectrometry.（3）To establish a method for the determination of TSILs residues in water,the standard addition method was used to test the addition recovery of four kinds of functional ionic liquids in water.The concentrations of ionic liquids were set as 0.01,0.1,1 and 10μg/ml respectively,and six parallel samples were set for each concentration,which were determined by HPLC-MS/MS.The standard recoveries of various functional ionic liquids ranged from 97.33%to 101.75%,the coefficient of variation ranged from 0.54%to 1.90%,and the detection limit was between0.91ng/m L and 1.39ng/m L,which indicated that the method could meet the requirements of residue analysis of functional ionic liquids in water.（4）In order to establish a method for the determination of TSILs in soil,the rapid solvent extraction（ASE）method was used to extract ionic liquids from soil.The parameters of the instrument were as follows:temperature:105℃;pressure:110 bar;time:30 min.three kinds of extraction solvents were tried:（1）hexane and acetone（1:1）;（2）water and acetone（1:1）;（3）water and methanol（2:1）.By comparing the recovery,the best extraction solvent was determined as water and methanol（2:1）.The reliability of the method was verified by the addition recovery experiment.Four addition concentrations of 0.01,0.1,1 and 10μg/g were set in the experiment,and the optimized extraction method was used.After extraction,The standard recoveries of ionic liquids ranged from 74.95%to 93.91%,the coefficient of variation ranged from0.76%to 2.30%,and the detection limit was 0.77ng/g-1.03ng/g.The results show that the method can meet the requirements of residue analysis of TSILs in soil samples.（5）In order to establish a method for the determination of TSILs in plant samples.Flour and cucumber were selected as plant samples.The parameters of the instrument are as follows:temperature:105℃;pressure:110 bar;time:30 min.The extraction solvent of cucumber is methanol and water（1:2）,and the extraction solvent of flour is methanol and acetone（2:1）.The experimental settings were 0.01,0.1,1 and 10ug/g.The results showed that the recoveries of functional ionic liquids in flour ranged from70.52%to 87.95%,the coefficients of variation ranged from 0.57%to 3.88%,and the detection limits ranged from 0.49ng/g to 0.60ng/g.The recoveries of functional ionic liquids in cucumber ranged from 74.26%to 79.04%,the coefficients of variation ranged from 0.38%to 2.60%,and the detection limits were between 0.32ng/g and0.48ng/g.The results show that the method can meet the requirements of residue analysis of TSILs in plant samples.In this study,a simple and sensitive method for the determination of ionic liquids was established,which can provide a scientific analysis method and evaluation basis for the study of the residues in environmental samples after the use of ionic liquids...