LOW-FREQUENCY DIELECTRIC EFFECTS IN THE MEASUREMENT OF BETA-CYCLODEXTRIN INTERACTIONS WITH SODIUM DODECYL-SULFATE

The dielectric response of a range of sodium dodecyl sulphate solution s (0.0035-0.035 M) has been measured in the presence of 0.0081 M beta- cyclodextrin over a frequency range of 10(4) to 10(-2) Hz. The respons e comprised that of the bulk solution in series with that of electrode layers, seen respectively above and below a characteristic frequency which lay between 0.5 and 10 Hz, depending on the system under examina tion. The presence of the electrode layers resulted in conductance eff ects which were observed at frequencies approaching those which may be used for measuring the conductivity of the bulk solution itself. Meas urement of the dielectric behavior at low frequencies therefore allows a clear characterization of the response of these layers. Furthermore , the results indicate that it may be advisable to measure the frequen cy dependent behavior in order to ensure that the response at the freq uency used for conductance measurements is not influenced by the prese nce of electrode layers.