The effect of reusing wipes for particle collection

Published

November 4, 2015

Author(s)

Jessica L. Staymates, Matthew E. Staymates, Jeffrey A. Lawrence

Abstract

This work addresses the need for a method to measure the collection efficiency performance of surface wipe materials as a function of wipe reuse number. The primary purpose of this study is to investigate the effect of wipe reuse, i.e. the number of times a wipe is swiped across a surface, on the overall particle collection and instrument response as it relates to ion mobility spectrometry-based trace chemical detectors. Two types of collection wipes (Teflon coated fiberglass and Nomex) were examined by swiping multiple times, ranging from 0 to 1000, over representative surfaces that are common to security screening environments. Particle collection efficiencies were determined by fluorescence microscopy and particle counting techniques, and were shown to improve dramatically with increased number of swiping cycles. Ion mobility spectrometry was used to evaluate the chemical response of known masses of explosives as a function of the wipe reuse number. Results show that chemical response can be negatively affected, and greatly depends upon the conditions of the surface in which the wipe is interrogating. Scanning electron microscopy images revealed significant surface degradation of the wipes on dirty cardboard at the micron spatial scale level. Additionally, several samples were evaluated by including a seven second thermal desorption cycle at 235°C into each swipe sampling interval. Results were similar to studies conducted without this heating cycle, suggesting that the primary mechanism for wipe deterioration is mechanical rather than thermal.

Citation

International Journal for Ion Mobility Spectrometry

Pub Type

Journals

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Citation

Staymates, J. , Staymates, M. and Lawrence, J. (2015), The effect of reusing wipes for particle collection, International Journal for Ion Mobility Spectrometry, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=918768 (Accessed November 24, 2024)