Applications Research Of Dispersive Liquid-liquid Microextraction

Dispersive liquid-liquid microextraction(DLLME)is a new technology which was proposed after the technology of liquid-liquid extraction and developed based on the single drop microextraction.It was proposed at 2006 by Assad,incorporating sampling,extraction and enrichment into one step,which was a simple,rapid,efficient,environment friendly technology.Therefore,it was widely used and quickly developed.To the DLLME,with the continuous improvement and innovation by some subsequent scholars,a lot of novel technologies of DLLME were put forward.Moreover,they made it possible to connect DLLME with a variety of other technologies.The application of novel improved technology of DLLME combined with gas chromatography/mass spectrometry(GC-MS)to extract the target compounds in aqueous solution was study.The main contents of this paper were given as follows:Frist,aromatic galangal water was taken as the research object,using surfactant assisted emulsification combined with response surface methodology(RSM)and direct sample introduction(DSI)device coupled by gas chromatography/mass spectrometry(GC/MS)for the extraction and determination of the compounds in galangal aromatic water.Tween 80 was selected as the dispersant instead of traditional organic dispersant of dispersive liquid-liquid microextraction to make extractant of toluene evenly distributed into the sample solution,so as to achieve the purpose of extraction different compounds in galangal aromatic water.Tween 80 is a high boiling point substance,which is not easy to be vaporized in GC inlet and cause the inlet pollution and blockage.In this paper,we introduced the technology of direct sample introduction(DSI).It overcame the drawback of GC injection port pollution by Tween 80,because Tween 80 was hard to be gasified.The results of this study can provide reference for surfactant assisted emulsification microextraction combined with GC-MS analyse the components in aromatic water or soaked water.It also can provide analysis method guidance to quality control of aromatic plants water as well as provide reliable scientific basis for spice resource allocation.Second,five of triazole fungicides(triadimefon,myclobutanil,tebuconazole,epoxiconazole and difenoconazole)were selected as the research objects,using ultrasound assisted salting-out homogenous liquid-liquid extraction for the quantitative determination of triazole pesticides in water samples coupled with gas chromatography-mass spectrometry(GC-MS).In this work,water-miscible solvent of acetonitrile was used as extractant instead of high toxic extractant in traditional dispersive liquid-liquid microextraction to form a homogeneous water solution,after that,salting out a small amount of acetonitrile to the purpose of extraction and enrichment.Under optimum conditions,matrix matched calibration curves were established using blank water sample.Good linear relationships as well as low limits of detection,LODs(0.4-14.4 ?g L-1)and quantification,LOQs(1.3-48.1 ?g L-1)were obtained.The relative standard deviations(RSD%)of blank water sample and real environment water sample were 4.5-8.1%and 0.4-8.1%,respectively,with enrichment factor(EF)of 120-185.Recoveries obtained from spiked environmental water samples at three concentration levels ranging from 89.6 to 119%.Wide linear ranges,low LODs and LOQs,and high EFs are the main advantages of the proposed method.The results obtained with the proposed method could be considered in agreement with the current EU legislation,which revealed that it can be successfully applicable for the determination of triazole pesticide in water samples.Third,a novel method termed "ultrasound assisted salting-out homogenous liquid-liquid extraction" was developed for the determination of different compounds in osmanthus aromatic water used ethyl acetate and acetonitrile as extractants.Besides,up-and-down manunal shaker ultrasound assisted emulsification liquid-liquid microextraction was introduced with toluene as exteactant to the extraction of the chemical compounds in Jingui aromatic water,the obtained results was analysed by contrasted with the extraction results of ethyl acetate and acetonitrile.After analysis and study,we could know that three kinds of osmanthus aromatic water contain more than 40 compounds,mainly for alcohol,ketone,phenol,aldehyde,single terpenoids,oxygen olefinic and olefin substances.The main common compounds were some spices materials of linalool oxide,nonanal and ionone as well as some has medicinal and nutritional value compositions of Megastigma-4,6,8-triene and elemene.These ingredients give osmanthus aromatic water unique fragrance and nutritional medicinal value.