Dimethyl sulfoxide (DMSO) occurs naturally in marine waters and is an important compound in the marine cycling of dimethyl sulfide (DMS). DMS is the primary reduced sulfur species input into the lower troposphere where it plays a key role in cloud formation through the creation of sulfuric acid. Cloud cover affects the Earth's albedo, influencing climate. In seawater, non-volatile DMSO is both a source and a sink for DMS through bacterial consumption and secondary photo-oxidation, respectively. Data have been published using three different analytical methods for the detection and quantification of DMSO in marine systems. Each of the three methods utilizes a different reducing agent: titanium chloride, cobalt-doped sodium borohydride, or DMSO reductase to reduce DMSO to DMS before separation and detection by gas chromatography. All three methods were compared and contrasted to determine differences resulting from analytical technique. Conditions of each method were optimized prior to evaluation. Standard curves were constructed and compared. Analyses of dissolved, particulate, and total DMSO were performed on several marine algal cultures.