Microfluidic paper-based analytical device for particulate metals

Mallory M. Mentele, Josephine Cunningham, Kirsten Koehler, John Volckens, Charles S. Henry

Research output: Contribution to journalArticlepeer-review

221 Scopus citations


A microfluidic paper-based analytical device (μPAD) fabricated by wax printing was designed to assess occupational exposure to metal-containing aerosols. This method employs rapid digestion of particulate metals using microliters of acid added directly to a punch taken from an air sampling filter. Punches were then placed on a μPAD, and digested metals were transported to detection reservoirs upon addition of water. These reservoirs contained reagents for colorimetric detection of Fe, Cu, and Ni. Dried buffer components were used to set the optimal pH in each detection reservoir, while precomplexation agents were deposited in the channels between the sample and detection zones to minimize interferences from competing metals. Metal concentrations were quantified from color intensity images using a scanner in conjunction with image processing software. Reproducible, log-linear calibration curves were generated for each metal, with method detection limits ranging from 1.0 to 1.5 μg for each metal (i.e., total mass present on the μPAD). Finally, a standard incineration ash sample was aerosolized, collected on filters, and analyzed for the three metals of interest. Analysis of this collected aerosol sample using a μPAD showed good correlation with known amounts of the metals present in the sample. This technology can provide rapid assessment of particulate metal concentrations at or below current regulatory limits and at dramatically reduced cost.

Original languageEnglish (US)
Pages (from-to)4474-4480
Number of pages7
JournalAnalytical Chemistry
Issue number10
StatePublished - May 15 2012
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry


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