Abstract
An analytical method for dimethyl sulfoxide (DMSO) in aqueous samples at nanomolar levels has been improved. DMSO was reduced to dimethyl sulfide (DMS), concentrated on an adsorbent, and measured by gas chromatography. In the presence of iron chloride, the sodium borohydride (NaBH4) reduction of DMSO proceeded smoothly and efficiently, and the repeatability of this reaction was significantly improved. The detection limit was 0.27 nM for DMSO, and its repeatability of the peak-area measurement was 4.1% as RSD (n = 5).