title: Evaluation of sorbent materials for the sampling and analysis of phosphine, sulfuryl fluoride and methyl bromide in air.
abstract: Phosphine (PH3), sulfuryl fluoride (SO2F2) and methyl bromide (CH3Br) are highly toxic chemical substances commonly used for fumigation, i.e., pest control with gaseous pesticides. Residues of fumigation agents constitute a health risk for workers affected, and therefore accurate methods for air sampling and analysis are needed. In this study, three commercial adsorbent tubes; Carbosieve SIII™, Air Toxics™ and Tenax TA™, were evaluated for sampling these highly volatile chemicals in air and their subsequent analysis by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). The breakthrough volume (BTV) of each fumigant was experimentally determined on the different adsorbents at concentrations at or above their permissible exposure limits, using a method based on frontal chromatography of generated fumigant atmospheres. Carbosieve SIII™, a molecular sieve possessing a very high specific area, proved to be a better adsorbent than both Air Toxics™ and Tenax TA™, resulting in at least a 4-fold increase of the BTV50%. BTV50% for Carbosieve SIII™ at 20°C was measured as 4.7L/g, 5.5L/g and 126L/g for phosphine, sulfuryl fluoride and methyl bromide, respectively, implying safe sampling volumes of 1.9L, 2.2L and 50L, respectively, for a commercial tube packed with 800mg Carbosieve SIII™. The temperature dependence of BTV was strong for Carbosieve SIII™, showing a reduction of 3-5%/°C in breakthrough volume within the range -20 to 40°C. Furthermore, although Carbosieve SIII™ reportedly has a higher affinity for water than most other adsorbents, relative humidity had only a moderate influence on the retention capacity of phosphine. Overall, the applicability of Carbosieve SIII™ adsorbent sampling in combination with TD-GC-MS analysis was demonstrated for highly volatile fumigants.
authors.affiliation: The Swedish Defence Research Agency, FOI CBRN Defence and Security, SE-901 82 Umeå, Sweden.
authors.forename: R
authors.initials: R
authors.lastname: Magnusson
authors.affiliation: The Swedish Defence Research Agency, FOI CBRN Defence and Security, SE-901 82 Umeå, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Rittfeldt
authors.affiliation: The Swedish Defence Research Agency, FOI CBRN Defence and Security, SE-901 82 Umeå, Sweden. Electronic address: astot@foi.se.
authors.forename: C
authors.initials: C
authors.lastname: Åstot
mesh_terms: D000388:Air / Q000032:analysis; D002845:Chromatography; D005651:Fumigation; D008401:Gas Chromatography-Mass Spectrometry; D005740:Gases / Q000032:analysis; D006813:Humidity; D006842:Hydrocarbons, Brominated / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D010720:Phosphines / Q000032:analysis*; D013441:Sulfinic Acids / Q000032:analysis*; D013696:Temperature
chemical_list: D005740:Gases; D006842:Hydrocarbons, Brominated; D010573:Pesticide Residues; D010720:Phosphines; D013441:Sulfinic Acids; C048899:sulfuryl fluoride; C005218:methyl bromide; C044646:phosphine
keywords: BTV determination; Frontal chromatography; Fumigants; Sorbent tubes; TD–GC–MS