Detection of Harmful Benzene, Toluene, Ethylbenzene, Xylenes (BTEX) Vapors Using Electrochemical Gas Sensors

Abstract

Detection of Benzene, Toluene, Ethylbenzene and Xylenes (BTEX) compound using electrochemical mixed potential gas sensor has been reported. In this study, three sensors of different configuration were used to detect BTEX. The sensitivity and selectivity of three sensor configurations to BTEX were compared. The sensor configuration with Strontium doped Lanthanum Chromite (La0.8Sr0.2CrO3, abbreviated as LSCO) electrode and Pt electrode with Yttria-Stabilized Zirconia electrolyte exhibited maximum sensitivity and selectivity to BTEX. The detection limit using the mixed potential tape cast sensor was found to be 0.5 ppm. For all the sensors, the mixed potential was found to vary linearly with BTEX concentration. The use of a cold-wall set-up and heterogeneous catalysis studies are envisioned to lower the BTEX detection limits to ppb levels without compromising sensitivity. BTEX is the abbreviation for the group of volatile organic compounds benzene, toluene, Ethylbenzene and o, p, and m-xylenes. BTEX is present in the environment predominantly due to petroleum and petroleum products. It is a highly volatile compound and well known to volatilize completely from surfaced oil within 24 hours or less. It is believed that the symptoms of dizziness, nausea, vomiting, and headaches from the cleaning crew of the Deep Horizon Oil Spill 1 is due to BTEX emission. In particular, Benzene exposure is of special concern because at some doses chronic exposure to benzene can cause persistent bone marrow damage and acute myeloid leukemia. The American Conference of Governmental Industrial Hygienists’ (ACGIH’s) Threshold Limit Values (TLVs) for BTEX are 0.5, 20, 100, and 100 ppm, for each component respectively. To limit the effect of BTEX on environment (and personal health), it is necessary to develop accurate, cost-effective and reliable sensors to detect their presence.