To uncover the molecular composition of samples outside the lab, researchers have been shrinking mass spectrometers to make them portable. Various mass analyzers—the components of the spectrometer that sort molecular fragments and send them into the detector—have already been miniaturized, including ion traps and single quadrupoles. But triple quadrupoles, the mass analyzers of choice for most quantitative mass spec applications, have not been miniaturized—until now.
The work “marks important progress in mass spec miniaturization,” says R. Graham Cooks, a chemistry professor at Purdue University. “Almost all previous miniature mass spectrometers have used ion traps.”
“The mass spectrometer for targeted compound quantitation is the triple quad, whether the application is environmental monitoring, food safety, clinical analysis, or whatever,” says Richard A. Yost, a chemistry professor at the University of Florida. “This is really the first commercial attempt to develop a practical small-sized and potentially field-deployable triple-quad platform.”
The overall mass analyzer is about 9.5 inches long, about one-quarter of the size of those used in conventional triple-quadrupole instruments, according to Steven Wright, the Microsaic scientist who led the development. The researchers demonstrated the analyzer’s abilities by coupling it to a liquid chromatograph and by using it to perform both single-stage and tandem mass spectrometry.
Microsaic wants to use the mini analyzer for field applications such as food analysis, including the detection of pesticide residues on apples. “We’ve shown that we can detect pesticides at 10 ppb,” a desirable level of detection in pesticide monitoring, Wright says.
But don’t expect to see a commercial instrument just yet. “There’s a great deal of system engineering to do,” Wright explains. “We have the core of the system. The physics works, and we’ve got the performance, but now we have to build a system around it.”