Submitted to: Journal of Laboratory Automation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2014
Publication Date: 7/21/2014
Publication URL: http://handle.nal.usda.gov/10113/61937
Citation: Byrdwell, W.C. 2014. Construction of a wireless communication contact closure system for liquid chromatography with multiple parallel mass spectrometers and other detectors. Journal of Laboratory Automation. 10.1177/2211068214543372. Interpretive Summary: This report describes a system that was built in our lab to simultaneously start all instruments that are participating in an experiment using wireless communication. Signals from instruments that inject samples for analysis communicate wirelessly with detectors and other instruments to coordinate data acquisition with the start of a sample injection. Experiments can be reconfigured, and different detectors can run with different instruments in a wide variety of combinations, simply by toggling switches to activate or deactivate instruments for participation in an experiment.
Technical Abstract: A contact closure system has been constructed and implemented that utilizes two contact closure sender boards that communicate wirelessly to four contact closure receiver boards to distribute start signals from two or three liquid chromatographs to fourteen instruments, pumps, detectors, or other components. Default high, closed low, TTL logic (5V) start signals from two autosamplers are converted to simple contacts by powered relay boards that are then connected to two 16-channel wireless contact closure sender boards. The contact closure signals from the two sender boards are transmitted wirelessly to two pairs of 8-channel receiver boards (total of 32 contact signals) that distribute the start signal to 14 switches that allow selection of which start signal is sent to which instrument, pump, or detector. The contact closure system is used for ‘quadruple parallel mass spectrometry’ experiments in which four mass spectrometers, using three different atmospheric pressure ionization modes, plus a UV detector, an evaporative light scattering detector (ELSD), a corona charged aerosol detector (CAD), and two syringe pumps supplying electrolyte are all synchronized to start simultaneously from a single start signal. A wide variety of LC-MS experiments using multiple liquid chromatographs and mass spectrometers simultaneously, LCx/MSy, including column-switching experiments, can be reconfigured simply by toggling switches to send start signals from up to four sources out to any available instrument, pump, or detector.