Detection and Identification of Trace Organic Substances in Sewage by Gas Chromatography-Mass Spectrometry. I. Neutral Components

Trace neutral organic substances in raw sewage (influent) and secondary effluent (effluent) were investigated to reveal the fate of organic substances in the environment by gas chromatography-mass spectrometry (GC-MS) technique. Water samples (influent : 5 l ; effluent : 50 l) were separated into the filtrate and unfilterable matter through a Teflon filter having 1 μm pore size, under added pressure (1-3.2 kg/cm2). Organic substances in unfilterable matter were extracted with benzene-ethanol (1 : 1) in a Soxhlet extractor for 24 hr. The filtrate was passed through a column (1.5×12 cm) of Amberlite XAD-2 resin (20-50 mesh) and organic substances adsorbed on the column was eluted with 150 ml of ether. The ether extract was concentrated to below 1 ml in a Kuderna-Danish evaporator. The concentrate loaded on the top of a silica-gel (100-200 mesh) column (1×20 cm), was fractionated in turn with 20 ml of isooctane, 25 ml of isooctane-benzene (1 : 1), and 15 ml of benzene-methanol (1 : 1). Determination of normal alkanes (C18-C33) and polycyclic aromatic hydrocarbons (biphenyl, acenaphthene, 2, 3-dimethylnaphthalene, fluorene, phenanthrene, pyrene, benzo [a] fluorene, anthracene, benzo [b] fluoranthene, and benzo [a] pyrene), which were respectively present in the isooctane and isooctane-benzene fractions, were performed by mass fragmentography. A number of polar organic substances, including plasticizers (dialkyl phthalates, dialkyl adipates, and dialkyl carbonates) and sterols (coprostanol, cholesterol, campesterol, and sitosterol) were found in benzene-methanol fractions by a computerized GC-MS system.