Study On The Application Of Trace Analysis Of Amino Compounds Based On Capillary Electrophoresis Coupled With Microextraction Technology

1. PrefaceCapillary electrophoresis (CE) technology, followed the high performance liquid chromatography (HPLC), is one of the new separation technologies which have developed rapidly in nearly thirty years. It has the advantages of high pressure liquid chromatography (HPLC) and gel electrophoresis, such as, the high separation efficiency, high analysis speed, small sample consumption and various operating modes, and so on. Capillary electrophoresis apparatus coupled with amperometric detection (AD), capacitively coupled contactless conductivity detection (C4D), laser induced fluorescence (LIF) and mass spectrometry (MS) has got a new breakthrough, and widely used in the separation and detection of cell, protein, amiino acids, inorganic ions, organic compounds and drugs, and widly applied in the environmental chemistry, food chemisty, pharmaceutical chemistry, biological medicine, and many other fields. Microextraction technology is an important adjunct to the complex sample analysis and trace analyte detection. This paper has discussed the application of environmental water and food sample anasyses based on the solid/liquid microextraction-capillary electrophoresis-amperometric detection/capacitively coupledcontactless conductivity detection technology (CE-AD, CE-C4D).2. Simultaneous determination of biogenic amines by capillary electrophoresis with capacitively coupled contactless conductivity detectionA novel method has been developed for the simultaneous separation and determination of eight biogenic amines, including spermine, spermidine, histamine, putrescine, cadaver, phenylethylamine, tyramine and tryptamine based on18-crown-6modified capillary zone electrophoresis combined with capacitively coupled contactless conductivity detection (CZE-C4D). We have investigated the experimental parameters that affect the separation and detection, such as the pH and concentration values of running buffer, buffer modifers, separation voltage, and injection time, et al. Under the optimum conditions, eight biogenic amines can be baseline separated in150mmol/L18-crown-6/500mmol/L acetic acid solution at separation voltage16kV within24min, exhibiting a linear calibration over3-4orders of magnitudeand the detection limits were in the range of0.044～0.15μg/mL(S/N=3). The method can detect the above analytes directly without derivative, and sample pretreatment is simple, which provides a fast and reliable method for the simultaneous determination of biogenic amines in environmental water and food samples (such as brandy and distillate spirits).3. Sensitive determination of chloroanilines in water samples by hollow fiber-based liquid-phase microextraction prior to capillary electrophoresis with amperometric detectionA hollow fiber-based liquid-phase microextraction (HF-LPME) method has been developed for enrichment of trace chloroanilines in water samples. Target analytes including aniline, three mono-chlorinated aniline isomers (o-chloroaniline, m-chloroaniline andp-chloroaniline) and four mono-chlorinated methylaniline isomers (2-chloro-4-methylaniline,3-chloro-4-methylaniline,4-chloro-2-methylaniline and5-chloro-2-methylaniline) were determined by CE with amperometric detection (CE-AD) after microextraction. Several factors that affect separation, detection and extraction efficiency were investigated. Under the optimum conditions, eight aniline compounds could be well separated from other components coexisting in water samples within25min, exhibiting a linear calibration over three orders of magnitude (r>0.998); the obtained enrichment factors (EFs)were between51and239, and the limits of detection were in the range of0.01-0.1ng ml-1. The proposed method has been applied for the analyses of real environmental water and sewage samples with relative recoveries in the range of83-108%.