Suchergebnisse

Chemistry Department, Government Arts and Science College, Durg, India School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur-492 010, India Manuscript received 3 May 2001, revised 24 September 2001, accepted 28 December 2001 A sensitive spectrophotometric method has been developed for the determination of benzene based on nitration of benzene to 1,3-dinitrobenzene and its subsequent reduction to 1,3-phenylenediamine. The 1,3-phenylenediamine so formed is determined by diazotization-coupling reaction using 1,3,5-trihydroxybenzene as coupling agent. The yellow orange azo dye formed in alkaline medium is measured spectrophotometrically at 415 nm. Beer's law is obeyed at 0.2-2.0 ppm benzene. The molar absorptivity is 3.07 x 104 dm3 mo-1 cm-1• The standard deviation and relative standard deviation are ±0.01 and 1.62%, respectively, for 40 µg of benzene per 25 ml analyzed over 7 days. The method may be used to determine benzene in petrol vapour, coke oven effluent and cigarette smoke.