Sonoelectroanalytical Detection of Ultra‐Trace Arsenic

The electroanalytical detection of arsenic on a gold electrode is investigated in the presence and absence of ultrasound. It is found that under quiescent conditions a detection limit of 1.8×10 −7 M is achievable using a 120 seconds accumulation period. Applying optimised ultrasound during the accumulation period was found to reduce the limit of detection to 1×10 −8 M from using a deposition period of 60 s at −0.5 V, while increasing the sensitivity by a factor of 15. The methodology was tested on a river sample containing significant copper contamination and electrode passivating organic materials. This technique provides promise for ‘in the field’ measurements due to the electrode‐depassivating effects of ultrasound.