Liquid-Phase Microextraction Technology Of Computer-Controlled For Environmental Analysis

In the1990s, a simple and solvent free method known as liquid-phasemicroextraction has emerged dramatically as an alternative sample preparation technique.This novel technique overcomes a few disadvantages of conventional sample preparationtechniques, only requiring umpty microlitres of organic solvents. It combines extraction,concentration and sample introduction in a single step and it is a sensitive andenvironmental friendly sample preparation technique. In this article, liquid-phasemicroextraction technology of computer-controlled combined with LC-MS is used in theanalysis of PFOA and PFOS in water samples; ultrasound-assisted water extractioncombined with liquid-phase microextraction technology of computer-controlled andGC-MS is used in the analysis of chlorobenzenes in soil samples. The main conclusionsare as follows：(1) Liquid-phase microextraction technology of computer-controlled was establishedusing the high precision injection pump Versa Pump6(V6) syringe and switch valve50120Intellect valve of American Kloehn company. The volume of liquid-phasemicroextraction can be precisely controlled by the system which improves the accuracyand precision of liquid-phase microextrction, laying solid foundation for the subsequentexperiments.(2) A novel green analytical method for determination of PFOA and PFOS in watersamples, based on liquid-phase microextraction technology of computer-controlledcombined with HPLC-MS was developed. The best results were shown as follows:1-Octanol as extraction solvent, pH=3water sample as donor phase, pH=11ammoniumacetate of1mmol/L as acceptor phase, effective length10cm of polypropylene hollowfiber membrane, extraction temperature20, stirring speed1300rpm, extraction time20min. Under the optimized conditions, linearity (r~2≥0.9967) was obtained in the range of0.5–20ng/mL. The limits of detection of PFOA and PFOS defined for a signal-to-noiseratio of3(S/N=3) were0.03ng/mL and0.15ng/mL, respectively. The recoveries ofPFOA and PFOS were122%and96%, respectively. The reproducibility were rangingfrom2.50%to4.35%(n=5). (3) A novel green analytical method for determination of chlorobenzenes in soilsamples, based on ultrasound-assisted water extraction combined with liquid-phasemicroextraction technology of computer-controlled and GC-MS was developed. The bestultrasonic conditions were shown as follows:0.5g soil sample adding10mL ultrapurewater, in the room temperature, ultrasonic power100W, ultrasonic time30min. In addition,the best extraction conditions:1-Octanol as extraction solvent and acceptor phase, ultrasonicsoil sample as donor phase, effective length8.6cm of polyvinylidene fluoride hollow fibermembrane, stirring speed1000rpm, extraction time20min. Under the optimized conditions,the limits of detection of chlorobenzenes were in the range of0.05-0.1μg/g(S/N=3). Goodlinear range (0.2-10μg/g, r~2≥0.9959) was obtained for all the analytes. The recoveries ofchlorobenzenes were obtained from82.47%to99.94%with relative standard deviationranging between1.79%and2.97%in spiked soil samples(n=5).