A study was performed which evaluated the ability of a charcoal bed breakthrough detector to be utilized under conditions where a binary mixture of solvents was passed through a bed. A Taguchi Gas Sensor (TGS 812) was used. Acetone and toluene were tested in a simulated charcoal bed system both singly and in binary mixtures over a range of concentrations. TGS response to acetone was much greater than to toluene. In addition, acetone achieved the charcoal service life endpoint (ie. 10% of the challenge concentration) more quickly. Toluene concentrations at the 10% breakthrough times for the acetone were insufficient to appreciably affect sensor response. It would thus appear that this detector can be utilized for the detection of a mixture of acetone and toluene if the alarm signal on the detector is preset for acetone. Sensor sensitivities were much weaker than found in a previous study with the same sensor.