A facile, sensitive, and selective sensor was developed to detect chloroform using biosurfactant ethoxylated phytosterol-capped gold nanoparticles (BPS-GNPs). The BPS-GNPs were induced to aggregate rapidly with the addition of chloroform. Detection of additional chloroform of relatively small volume can be easily realized by monitoring the color fading of BPS-GNP aqueous solution by the naked eye. The presence of the chloroform with extremely small volume can be monitored by UV-vis spectra. A possible detection mechanism based on "double interface competitive adsorption" was proposed. Other common organic substances were used to further verify the selectivity of the detection. (C) 2017 Elsevier B.V. All rights reserved.