“…Other acceptable methods include portable direct reading instruments and real-time continuous monitoring systems; these methods generally have a sensitivity in the ppm range. The most frequently used analytical methods for water samples containing benzene are GC/MS, GC/FID, and GC/PID (Blanchard and Hardy, (1986); Colenutt and Thorburn (1980);DOI, 1984;EPA, 1984EPA, , 1992Hammers and Bosman, 1986;Harland, et al, 1985;Lysyj, et al, 1980;Michael, et al, 1988;Pereira and Hughes, 1980;Sporstøl, et al, 1985). Benzene is usually isolated from aqueous media by the purge-and-trap method (Brass, et al, 1977;Colenutt and Thorburn (1980);DOI, 1984;EPA, 1979EPA, , 1984EPA, , 1992Hammers and Bosman, 1986;Harland, et al, 1985;Michael, et al, 1988).…”