Steady-state measurements are presented of the concentration of fructose 1,6-bisphosphate (F16BP) in a flow reactor containing the enzymes phosphofructokinase 1, fructose 1,6-bisphosphatase, and creatine kinase, under the regulation of combinations of the regulatory species fructose 2,6-bisphosphate, citrate, glycerol S-phosphate, and adenosine S-monophosphate. We use a recently described capillary electrophoresis protocol for sample analysis, which allows for the simultaneous separation and quantification of many glycolytic species, including isomers. We compare our results to theoretical work on logical properties of biological reaction networks and conclude that the fructose 6-phosphate/fructose 1,6-bisphosphate interconversion cycle can be considered to be a switch in glycolysis : a fuzzy logic aggregation operator.