Yao and Chen(see Analytical Chemistry (Washington, DC, United States) (2011), 83 (6), 1879-1882) have shown a method for determination of water traces in dimethyl sulfoxide (DMSO). The described method is interesting, but in our opinion, it can be entirely replaced by other methods using the same reagents and based on measurement of Eu(III) luminescence lifetimes. Moreover, there is quite a lot of inaccuracy in the article which we would like to comment. Finally, we want to briefly show a few other possible applications of the method described in this comment.