title: Memory effects on adsorption tubes for mercury vapor measurement in ambient air: elucidation, quantification, and strategies for mitigation of analytical bias.
abstract: The short- and long-term memory effects associated with measurements of mercury vapor in air using gold-coated silica adsorption tubes have been described. Data are presented to quantify these effects and to determine their dependence on certain relevant measurement parameters, such as number of heating cycles used for each analysis, age of adsorption tube, mass of mercury on adsorption tube, and the length of time between analyses. The results suggest that the long-term memory effect is due to absorption of mercury within the bulk gold in the adsorption tube, which may only be fully liberated by allowing enough time for this mercury to diffuse to the gold surface. The implications of these effects for air quality networks making these measurements routinely has been discussed, and recommendations have been made to ensure any measurement bias is minimized.
authors.affiliation: Analytical Science Division, National Physical Laboratory, Teddington, TW11 0LW, UK. richard.brown@npl.co.uk
authors.forename: Richard J C
authors.initials: RJ
authors.lastname: Brown
authors.forename: Yarshini
authors.initials: Y
authors.lastname: Kumar
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Brown
authors.forename: Ki-Hyun
authors.initials: KH
authors.lastname: Kim
mesh_terms: D000327:Adsorption; D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry; D004784:Environmental Monitoring / Q000295:instrumentation* / Q000379:methods; D006046:Gold / Q000737:chemistry; D006358:Hot Temperature; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D012107:Research Design; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D000393:Air Pollutants; D006046:Gold; D012822:Silicon Dioxide; D008628:Mercury