A versatile instrumental approach in intermodular alternating current polarography has been developed which enables phase-selective measurement to be made at variable frequency differences and amplitude. A phase-selective detector acting as a balanced modulator is used to generate the required reference signal by multiplying the two sine waves frequencies. The sum frequency terms are filtered out from the response leaving the frequency difference or intermodular component as the reference signal. The development of the new instrumental approach has allowed the theoretical response for a range of intermodular polarographic and voltammetric techniques to be verified. A comparison with phase-selective second harmonic ac polarography using equivalent instrumentation shows that the background current is relatively large in the intermodular method. On this basis, and for instrumental reasons, it is therefore concluded that second harmonic techniques are superior to the related second-order intermodular methods.
|Number of pages||6|
|Publication status||Published - 1 Dec 1976|