Head-space gas chromatography was used to determinate Benzene homologues in water,capillary chromatographic column was used and satisfactory separation was attained.External standard method was adopted in the determination.Linear relationships between values of peak area and mass concentration of the analytes were obtained in the ranges of 0.01 ～ 1.0 mg/L for the Benzene homologues.RSD of RF was found in ranges of 1.52% to 5.43%.Detection limits(3S/N) of method were in range of 1.50×10-3 to 2.60×10-3 mg/L.Recovery and precision of method were tested by standard addition method using a blank water sample as matrix.Values of recovery and RSD’s(n=7) found were in ranges of 84.67% ～ 92.85% and 0.69% ～ 2.85% respectively.

A method was proposed for the separation and determination of five tepyridine derivatives by high performance liquid chromatography. The separation was carried out on a Symmetry C18 （3.9mm i. d. x 150mm, 5~m） column with methanol-water （8：2） as mobile phase and detection wavelength （280nm） in room tempera- ture, isotropic elution. Measurement could be finished in 15min with a good linearity for samples concentration range from 0.1 ~g/mL to 400p~g/mL and the relative standard deviation below 2.2%. This method is simple, efficient, and accurate.

Through the orthogonal experiment,by optimizing the conditions of GAAS which contained slit width,lamp current,ashing temperature,atomization temperature and so on,The article acquired the aim to enhance the detection limit,precision,accuracy of the method.However,the value of linear of r in the method was also greater than 0.999 and had satisfied the real need of determination of alum in environmental water sample.