Interfacing the ultraviolet scanning system of an analytical ultracentrifuge with a digital computer

The ultraviolet scanning system of a Beckman Model E Analytical Ultracentrifuge was interfaced with a Digital Equipment Corporation PDP-15/35 digital computer. The interface permitted the transmission of analog centrifugal scan data to the computer, where it was digitized by a Digital Equipment Corporation A/D converter.

Computer programs were written to allow on-line ultracentrifugal scan data acquisition and output of scan data onto magnetic tape. Computer programs were written to conduct an on-line sedimentation velocity analysis, resulting ultimately in the computation of the sedimentation coefficient and the dispersion coefficient of a macromolecular solute in a dilute monodisperse solution. On-line sedimentation equilibrium analysis programs were also written to calculate the molecular weight of a macromolecule in a dilute monodisperse solution. Data retrieval programs were written to retrieve data stored on magnetic tape and to perform off-line sedimentation velocity and sedimentation equilibrium analyses on the stored ultracentrifugal data.

The programs written were tested upon dilute monodisperse solutions of bovine serum albumin. The sedimentation coefficient and molecular weight calculated by the programs were in agreement with values reported in the literature.