MASS-SPECTRAL RECORDING AND STORING SYSTEM BASED ON GPIB DATA TRANSFER FOR LASER IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY

A data acquisition scheme based on a general-purpose interface bus (GPIB) for data transfer from a digital storage oscilloscope (DSO) to a PC is investigated for recording and storing transient signals generated by laser-induced multiphoton ionization or laser desorption ionization time-of-flight mass spectrometry. With this scheme and the use of commercial software, the data acquisition rate is generally low, typically 1 or 2 Hz for 20-Kbyte transients, We have developed a software to maximize the speed of data transfer and storage. This software is incorporated into LabWindows for data analysis. We demonstrate that it is possible to record and store mass spectra at a speed ranging from 14 spectra/s for a transient record length of 20 Kbytes to 50 spectra/s for a record length of 1 Kbyte by using this DSO-GPIB-PC scheme. This simple and readily adaptable system is found to be adequate and useful for many operations in laser work where relatively higher repetition rates are required. The applications of the system are demonstrated for recording and constructing ion chromatograms in liquid chromatography/time-of-flight mass spectrometry. In addition, it is shown that the data system can not only replace the traditional boxcar integrator for signal monitoring but also provide multiple ion monitoring for recording wavelength spertra in laser ionization spectroscopy.