Study On Gas Chromatographic Analysis Of Trace Organic Pollutant In Small Aqueous Sample

A method for the determination of trace organic pollutants such as benzene, nitrobenzene and phenol present in small aqueous samples has been developed. Benzene, nitrobenzene and phenol are chosen as three analytic subjects in our experiment. The concentration and the detecting sensitivity of trace solutes are increased more greatly by means of improving the operating conditions of the liquid-liquid extraction and also the chromatograph with a direct injection port and a flame ionization detection (FID). For trace benzene in small aqueous sample, with carbon disulfide extraction and SE-30 packed column the detection limit of 4J.Lg U?is easily obtainable employing a 5OmL water sample and 2.0 mL carbon disulfide. For trace nitrobenzene in small aqueous sample, with benzene extraction and DB-l capillary column of wide bore the detection limit of 0.5p.g U?can be obtained employing a lOmL water sample and 100 ~L benzene. And with n- hexane extraction detection limit of 1 ~.tg U?can be obtained. For trace phenol in small aqueous sample, with ammonium sulfate enhancement and ethyl acetate extraction and the DB-l capillary column of wide bore the detection limit of 1 p~g U?can be achieved employing a 8mL water sample and 200~tL ethyl acetate. Quantitative calculations are completed by the calibration graphs of the concentration against peak height of the solute. In the aqueous sample biodegraded the added recovery and standard deviation are 96.5% and 6% for benzene from 1 Op.g/L to 1 .Omg/L, 95% and 4% for nitrobenzene from 50p.g/L to 5.Omg/L and 96.9% and 3.1% for phenol from 25p.g/L to SOmg/L. Small volumes of sample and solvent and simple equipment are used in this method. Furthermore it is simple, convenient and rapid and has lower detection limit, better precision and higher accuracy, and so that analytic expense and environmental pollution are decreased.