Sensitivity Enhancements in Stripping Voltammetry from Exposure to Low Frequency Sound

Attempts to improve the sensitivity of trace analyses in voltammetry have been investigated by exposure to sound, ultrasound and stirring. It is found that audible sound in the low frequency range, of about 100 Hz is very effective for this purpose, with an increase of the signal up to about 300%, without any significant increase of the corresponding noise level. Ordinary stirring has to be avoided during the voltammetric scanning due to the low reproducibility when stirring takes place. A sound exposure, however, can be performed during the entire measure-ment, and this explains the increased sensitivity. Further it is concluded that sound, exposed close to the resonant frequency, has improvement effects at least comparable of stirring, thus all mechanical stirring can be avoided. Compared with audible sound, the use of ultrasound seems not to give optimum conditions, possibly due to cavitation that decreases the reproducibility, the formation of radicals, and the increase of the temperature. Moreover, the simplicity of using audible sound makes this analytical method potentially attractive.