Microchip Blood Test Helps Track Chemical Exposure

A microfluidic chip can quantitate as little as 50 femtograms of a perfluorinated compound (PFC) in a 1-µL sample of human blood plasma, report Pan Mao and Daojing Wang of Newomics, a company based in Emeryville, Calif. (Environ. Sci. Technol. 2015, DOI: 10.1021/acs.est.5b01442). To evaluate long-term exposure to persistent pollutants such as PFCs, rapid analysis of small samples is necessary. Mao and Wang’s miniature silicon-based chip incorporates a solid-phase extraction (SPE) column for sample cleanup, a mixer and trap to concentrate analytes, and a liquid chromatography column to separate the analytes before funneling them into a mass spectrometer for detection. The researchers demonstrated the analytical capability of the device by testing human blood plasma—the liquid component of blood that normally carries blood cells and platelets—that was deproteinated before injection, as well as by using a NIST reference material containing several PFCs. The sample run time from analysis through mass spec data collection takes an hour. Changing the extraction column material could allow for on-chip processing of whole blood samples, such as from a finger prick, and changes to the mixer geometry could reduce the assay run time, the researchers suggest.