U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Main content area

Construction of a Wireless Communication Contact Closure System for Liquid Chromatography with Multiple Parallel Mass Spectrometers and Other Detectors

William Craig Byrdwell
Journal of laboratory automation 2014 v.19 no.5 pp. 461-467
aerosols, atmospheric pressure, automation, detectors, electrolytes, ionization, light scattering, liquid chromatography, mass spectrometry, pumps, spectrometers
A contact closure system was constructed that uses 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 14 instruments, pumps, detectors, or other components. Default high, closed low, TTL logic (5-volt) 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 eight-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, a corona charged aerosol detector, and two syringe pumps supplying electrolyte, are all synchronized to start simultaneously. A wide variety of liquid chromatography–mass spectrometry experiments using multiple liquid chromatographs and mass spectrometers simultaneously, LCx/MSy, including column-switching experiments, can be reconfigured simply by toggling switches.