A short column packed with thiol-Sepharose is used in an apparatus for detecting disulfides in liquid chromatography eluates. After a thiol-disulfide interchange reaction with the polymer bound thiol occurs, one part of the disulfide leaves in the eluate stream as a thiol, which may then be detected with a mixing manifold and an absorbance detector. The response of this system to cystine has been found to be linear for injections of 0.15 µg to 2.5 µg. © 1978, American Chemical Society. All rights reserved.