A simple digital integrator for real-time display of spectral areas.

Abstract Methods for determining spectrum areas range in sophistication from the “cutting and weighing” technique to computer analysis. We describe here a simple digital circuit designed for a ratiometric spectrofluorometer which permits the real-time determination and display of spectral areas. This inexpensive circuit facilitates the subtraction of background signal and the calculation of relative quantum yields. A brief study concerning the quenching of fluorescein emission upon binding to antifluorescein IgG antibody demonstrates the utility of the system.