Electrochemical sensing of SDS and PmB at concentrations from 1 to 1000 ppm in presence of 2 mM KFeCy redox reporter. (A) Cyclic voltammogram overlaying sensing response to KFeCy (in yellow), SDS (in cyan), and PmB (in red). (B) Total charge transferred from sensors incubated with solutions containing increasing concentrations of SDS or PmB compared to charge transferred from bare MSEs (black dashed line). Times required for the sensor to reach the peak electrochemical signal are noted above each bar. Reported charge transfer values are means and error bars are standard deviations of n = 3 replicates.