The randomness of analyte deposition in the matrix also leads to clumping and uneven distribution, and therefore inconsistent spectra. Those problems led other research teams to develop matrix-less methods using electrochemically etched porous surfaces in silicon, but they have proven to be difficult to manufacture. That's a problem, notes Cuiffi, especially if you are developing automated systems.
Low ionization leads to weak signals.
To get around this problem, Cuiffi and his collaborators used a plasma-enhanced chemical vapor deposition technique to produce a thin film of rodlike silicon columns, which rise from a glass or plastic substrate. It's like bundling match sticks together. Under specific conditions, the clusters are uniform, and that should lead to consistent ionization yields, more reproducible spectra, and an automation-friendly approach, says Cuiffi. Even better, the films are easily manufactured, he says, and their properties are easy to manipulate. They can be high-throughput.