title: Determination of carbon monoxide with a modified zeolite sorbent and methanization-gas chromatography.
abstract: The purpose of this study was to develop an alternative sorbent sampling technique to concentrate CO from an air sample for subsequent instrumental analysis. Y52 zeolite doped with 9.4 wt % cuprous ions was found to have high capacity, stability to air, and thermal reversibility for CO. The Cu(I)-modified zeolite was packed in glass tubes, preceded by a drying tube containing silica gel. Air was sampled through the tubes at the flow rate of 100 mL/min. Collected CO was thermally desorbed at 300 degrees C and determined by gas chromatography with reduction of CO to methane and flame ionization detection (TD-GC-CH4-FID). Breakthrough capacity of the sorbent was found to be 2.74 mg CO per gram of sorbent. For 2-L air samples containing 12.5 to 100 ppm CO and 50% relative humidity at room temperature, recovery of CO was found to be 96.6% with pooled relative standard deviation of 5.8%. The estimated detection limit for a 2-L sample was 0.2 ppm. Collected CO was stable at room temperature for 1 day and up to 7 days at 4 degrees C if the sorbent tube was flushed with helium before storage. In field testing, the ratio of CO measured by the new technique and by a reference technique was found to be 0.93 with pooled relative standard deviation of 6.3%. This unique new sorbent coupled with TD-GC-CH4-FID shows promise as a sensitive and specific alternative for measurement of CO in air.
authors.affiliation: Tulane University School of Public Health, Department of Environmental Health Sciences, New Orleans, LA 70112, USA.
authors.forename: C
authors.initials: C
authors.lastname: Juntarawijit
authors.forename: H G
authors.initials: HG
authors.lastname: Poovey
authors.forename: R J
authors.initials: RJ
authors.lastname: Rando
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002248:Carbon Monoxide / Q000032:analysis*; D002849:Chromatography, Gas / Q000379:methods; D003300:Copper; D004867:Equipment Design; D008697:Methane; D017641:Zeolites
chemical_list: D000393:Air Pollutants; D017641:Zeolites; D003300:Copper; D002248:Carbon Monoxide; D008697:Methane