Determination of Anilines Pollutant in Water by Monolithic Column-online Solid Phase Microextraction-Liquid Chromatography
For extraction column and valve system compatibility issues in on-line SPE-liquid chromatography analysis,we have built the large inner diameter extraction monolithic column compatible with liquid chromatography and related valve,pumping system.A large inner diameter(530 μm i.d.),uniform and stable silica monolithic capillary column has been prepared by using two hybrid precursor-tetramethoxysilane and methyltrimethoxysilane.After the modification of C 18 group,the results of frontier analysis show that the monolithic column has a larger adsorption capacity,wherein Ν-methylaniline is approximately 214 g/g,and N,N-Dimethylaniline is about 388 g/g.The column permeability is good,so the on-line solid phase extraction can be completed requires only the injection pump.The monolithic column was connected to the sample preparation equipment made by our laboratory and with the combination of liquid chromatography for online enrichment and separation,and it was applied to the determination of trace aniline categories compounds in river water.The mobile phase consisted of 15% methanol and 85% water solution in volume ratio;the flow rate for chromatographic separation was 0.5 mL/min;the detection wavelength was 254 nm.The recoveries were in the range of 81.9%-91.3%,and the relative standard deviation(RSDs) of intraday and interday were not larger than 7.6% at 0.1,1 and 10 g/L three spiked levels for all analytes.