Rapid, nondestructive near-infrared assay for water in sealed dimethyl sulfoxide compound repository containers

Water contamination in dimethyl sulfoxide (DMSO) compound libraries is a recognized problem in the pharmaceutical industry. We describe a nondestructive, near-infrared (NIR) assay for water contamination inside the sealed containers used for compound libraries. This assay does not require opening the containers. We also report our observation of the permeation of water from laboratory air through the sealed container and into the DMSO solution over a period of months, as well as the rate of water absorption by DMSO directly exposed to laboratory air.