Dual wavelength/stopped flow spectrophotometry: computer acquisition and analysis.

The adaptation of a commercially available dual wavelength/stopped flow spectrophotometer for use with turbid samples is described. A minicomputer is used to collect and analyze the data, thereby facilitating these experiments. The stopped flow/computer combination has a dead time in the single wavelength mode of 3.5 msec. In the dual wavelength mode, accurate determinations can be made of the time course of reactions that have a $\text{t}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ of 50 msec or longer. The application of this stopped flow spectrophotometer to the measurement of cytochrome P-450 reductase activity in rat liver microsomes is described.