| Volatile organic compounds secondary amines (dimethylamine, diethylamine and so on) have some common characters. They have low boiling point and easily volatilize into the air, which pollute environment and affect human health. Therefore, rapid and sensitive method is important for health security of human being and environment. There are reports on the analysis methods and origin of poisonous volatile pollutants organic amines in the air, but there is little research on secondary amines in water. Gas chromatography (GC) and headspace-gas chromatography/mass spectrometry (HS-GC/MS) were established for dimethylamine and diethylamine determination in water environment in this paper, and compared the two methods. We developed a new simpler, sensitiver preparation technique and established analytic method for secondary amines in water through the research on dimethylamine and diethylamine.Gas chromatography (GC) method for the determination of dimethylamine and diethylamine in water environment was analysed. CP7448 capillary column(60m×0.32 mm×0.5μm), injector temperature of 200℃and detector temperature of 250℃were used, the high purity nitrogen with a flow rate of 1 mL/min were chosen, the oven temperature was programmed at 35℃for 15 min, then rised to 80℃at a rate of 5℃/min. The results showed that the linearity of dimethylamine and diethylamine were good in the concentration range of 14.2 mg/L to 35.9 mg/L, correlation coefficients were 0.9993 and 0.9968; The recovery of water sample were 53.3%-92.7%, and the relative standard deviation were 2.0%,6.3%,respectively. But this method is not suitable for the analysis of samples with low content of dimethylamine and diethylamine in water.Headspace-gas chromatography/mass spectrometry (HS-GC/MS) method for the determination of volatile component dimethylamine and diethylamine in water environment was studied. Effect of gas-liquid phase ratio,equilibrium temperature, equilibrium time and salt on sensitivity of headspace gas chromatography were discussed. The factors influencing the analysis such as flow rate, column temperature, split ratio, equilibrium temperature, equilibrium time and salt were discussed. The optimized experimental conditions were as follows:Agilent HP-5MS capillary column (30.0 m×0.25 mm×0.25μm), oven temperature of 50℃, headspace temperature of 80℃and equilibrium time of 30 min were chosen. El source temperature of 230℃, energy of 70 eV, solvent delay of 1.35 min and interface temperature of 230℃were used. The linearity of dimethylamine (1.80 mg/L-35.9 mg/L) and diethylamine (1.42 mg/L to 35.9 mg/L) were satisfied, the correlation coefficients were 0.9993,0.9968; the lowest determination limits were 0.09 mg/L, 0.12 mg/L, respectively; the recovery of water samples were 85.9%-116.1%; the relative standard deviations were 5.5%,2.0%. The results indicated that the method explored in the present study is suitable for detection of these two chemical substances in water environment.The results showed that the HS-GC/MS was superior to GC for the analysis of volatile and low content amine components after comparing the above two analysis methods. Given the distillation pretreatment was omitted and the sample can be injected directly, the HS-GC/MS is an effective analysis method for the determination of dimethylamine and diethylamine in water environment. HS-GC/MS is sensitive, accurate and easy to perform.The water samples in some area in dry season and rain season were determined by headspace-gas chromatography/mass spectrometry (HS-GC/MS). The results showed that most of the water samples in dry season were found dimethylamine, which the concentration range is 2.21 mg/L-4.06 mg/L. Only some deep well water was found diethylamine. Most of the water samples in rain season were found dimethylamine and diethylamine, which the concentration range was 4.66 mg/L-5.06 mg/L and 2.19 mg/L-4.03 mg/L, respectively.
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