A low-cost microcomputer-based data acquisition and analysis system for an electron spin resonance spectrometer: data handling of dilute spin labeled nucleic acids

This article describes the construction of an inexpensive and reliable data acquisition system for a Varian E-line Century Series ESR spectrometer utilizing an Apple II Plus microcomputer. All necessary hardware is readily available and used without modification. A BASIC program for routine collection, display, plotting and disk storage of experimental data has been written and subsequently compiled into machine code for high speed operation. The interface offers distinct advantages in spectral resolution as well as instrument control. An example of signal enhancement via computer controlled time averaging is presented for a spin labeled DNA experiment. The technique has recently been applied to studies of relative binding affinities of gene-32 protein for various spin-labeled polynucleotides.