title: Continuous real-time monitoring of phosphine concentrations in air using electrochemical detectors interfaced by radio telemetry.
abstract: This work involves the novel use of a radio telemetry-based system that continuously monitors phosphine using two different types of electrochemical detectors (ECD/RT). The ECD/RT units were used to monitor phosphine inside and at varying distances from large tobacco storage warehouses. A master controller unit transferred the data to a personal computer that received and displayed the data. Supervisory control and data acquisition software assimilated the data from each ECD/RT unit, displayed and updated it as new transmissions were received, and stored the data in secure databases. Phosphine concentrations outside five warehouses simultaneously under fumigation and at the facility boundaries were <0.3 parts per million (ppm). Phosphine levels ranged from 0 to 580 ppm inside sealed warehouses. A comparison was made between the data collected at an ECD/RT unit approximately 4 m downwind of a sealed warehouse and a colorimetric tube at the same location. The final phosphine concentration from the colorimetric method was 0.05 ppm and the average over the 20-minute collection period for the ECD/RT was 0.13 ppm. This system allows for continuous, remote monitoring around warehouses under fumigation and superior time resolution allowing timely response to fugitive emissions of phosphine.
authors.affiliation: Lorillard Tobacco Co., Danville, Virginia 24540, USA. tthorn@lortobco.com
authors.forename: Tommy G
authors.initials: TG
authors.lastname: Thorn
authors.forename: Edward M
authors.initials: EM
authors.lastname: Chodyniecki
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Ingold
authors.forename: Gerald A
authors.initials: GA
authors.lastname: Long
authors.forename: Charles D
authors.initials: CD
authors.lastname: Miller
authors.forename: Edward A
authors.initials: EA
authors.lastname: Robinson
authors.forename: F Scott
authors.initials: FS
authors.lastname: Cowan
authors.forename: Robert L
authors.initials: RL
authors.lastname: Thomas
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis*; D004563:Electrochemistry; D004784:Environmental Monitoring / Q000379:methods*; D007306:Insecticides / Q000032:analysis*; D010571:Pest Control; D010720:Phosphines / Q000032:analysis*; D011846:Radio Waves; D012984:Software; D013686:Telemetry; D014026:Nicotiana
chemical_list: D007306:Insecticides; D010720:Phosphines; C044646:phosphine