Determination of Nitrobenzene and Aniline in Groundwater by Closed Cycle Needle Trap-Gas Chromatography
Needle trap(NT) is a solventless sample preparation technique that integrates extraction,concentration and injection and it is usually used for trace analysis.In this study,after comparing six different sampling methods,we established an ultrasonic-closed cycle headspace-NT method for the determination of nitrobenzene and aniline in groundwater.The sampling conditions for the determination of nitrobenzene and aniline were studied and optimized.The desorption conditions in the GC split/splitless inlet were compared with the OPTIC2 inlet.The results show that the OPTIC2 inlet displayed sharp and sensitive peaks than the former.Besides,the best desorption temperature was obtained.Carry over was below 0.79% in TENAX NT.The detection limits of aniline and nitrobenzene were in the range of 2.9-3.7 μg/L and 0.7-1.9 μg/L,respectively.The average recoveries of aniline and nitrobenzene were in the range of 83%-113%.