Surfactants are often used to create low or "ultralow" oil-water interfacial tensions (IFTs). These molecules, in some cases, may also lead to the inadvertent formation of microemulsion phases which can obscure IFT measurements. Here, we present a case study of such an issue. We also introduce a little-known micropipette technique which has many advantages over the more common spinning drop method for determining low/ultralow IFTs. (C) 2011 Elsevier Inc. All rights reserved.