“In RoSA-MS, a sampling probe is attached to a robotic arm that has 360° rotation through 6 individual joints,” state the researchers in their paper. “A 3D laser scanner, also attached to the robotic arm, generates a digital map of the sample surface that is used to direct a probe to specific (x, y, z) locations. The sampling probe consists of a spring-loaded needle that briefly contacts the object surface, collecting trace amounts of material.
“The probe is then directed at an open port liquid sampling interface coupled to the electrospray ion source of a mass spectrometer. Material on the probe tip is dissolved by the solvent flow in the liquid interface and mass analyzed with high mass resolution and accuracy. The surface of bulky, nonplanar objects can thus be probed to produce chemical maps at the molecular level.”
While the technique is still in the developmental stages, the researchers have been testing it outside the lab. Currently, refinements are still needed so the system will be able to handle more unwieldy pieces without assistance from a human counterpart. The researchers also found that the system was only capable of discerning specific types of molecules as they used a specialized camera for managing the robotic arm during plasma ionization collection. They have, however, been able to detect caffeine from within a cup of coffee.
As they continue in their work, the team plans to examine irregular 3D printed shapes in regards to direct surface sampling. The researchers have also been working with applications to include:
- Food sample surfaces
- Lifestyle chemistry
- Chemical reactions on curved substrates
The design for both the probe and the ionization source are easily modified, meaning the system could lend itself to many other applications.
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[Source: ACS]