The Study Of Detection Methods For 14 Kinds Of VHHs And 6 Kinds Of Benzene Series By Headspace Gas Chromatography

Headspace gas chromatography is an analysis method conforming to requirement of "green analytical chemistry",with features of gas sampling,short analysis time,no solvents extract during analysis,no harm to analyst and environment,easy operation and simple chromatogram,so it is widely used in food sanitary and anti-epidemic,environment monitoring,available composition analysis of traditional Chinese medicine, residual solvents detection and other fields.This thesis rsearched and established a method to test 14 kinds of Volatile Halogenated Hydrocarbons in soft drink and 6 kinds of benzene series in plastic packaging material by Headspace Gas Chromatography.The pretreatment condition of experiment, chromatographic conditions,parameters affecting headspace gas chromatography procedure,such as the equilibrium time,the equilibrium temperature,needle,transmission -line temperature and the sample matrix were optimized.In the method to test 14 kinds of Volatile Halogenated Hydrocarbons in soft drink,5g sodium carbonate and 10min ultrasonic time were used during the sample pretreatment;the chromatographic conditions were OV-1701 column(50m×0.20mm×0.32μm),the ECD detector temperature was 375℃,the sampler temperature was 200℃,high nitrogen(≥99.9%) at the column pressure of 25psi was used as carrier and the split ratio was 12.5:1;the oven temperature programmed from an initial 50℃held for 3min at a rate of 5℃/min to 120℃held for 1min at the final temperature;the headspace conditions were at the 70℃for oven temperature held for 40min,the needle and transmission-line temperature were 115℃,replace in pressure 30s,inject 4s,emptying 20s and the gas pressure of nebulizer was 2.0×10⁵Pa;the mass spectrometer conditions were EI ionization mode,electron energy 70Ev,interface temperature was 200℃,ion source temperature was 180℃and mass scan range was 30-500u.In the method to test 6 kinds of benzene series in plastic packaging material, manual grinding mode was used during the sample pretreatment;the chromatographic conditions were FFAP column(50m×0.25mm×1.0μm),the FID detector temperature was 250℃,the sampler temperature was 250℃,nitrogen at the flow rate of 0.6ml/min was used as carrier gas and the split ratio was 10:1;the oven temperature programmed from an initial 50℃held for 2min at a rate of 3℃/min to 110℃at the final temperature;the headspace conditions were at the 120℃for oven temperature held for 30min,the needle and transmission-line temperature were 140℃,replace in pressure 30s,inject 4s,emptying 20s and the gas pressure of nebulizer was 1.8×10⁵Pa.The results show:1.The recoveries of 14 kinds of Volatile Halogenated Hydrocarbon were in the range of 88.5～99.5%,the relaive standard deviations were from 1.8%to 7.5%,the determination limits were between 0.08～1.13μg/l.2.The recoveries of 6 kinds of benzene series were in the range of 70.7～97.1%,the relaive standard deviations were from 1.4%to 4.5%,the determination limit was 2.67μg.m^-2.3.The method is rapid,simple and sensitive.Therefore,it is suitable for detection and analysis of practical samples.