Green alternative methods for voltammetric analysis in different water matrices

Stripping voltammetry uses electrochemical sensors for the determination of heavy metal ions in different types of samples. These can include boiler feed water, drinking water, sea water, beverages, and even industrial samples like plating baths.

Low detection limits (between μg/L and ng/L), the possibility to distinguish between different oxidation states (e.g., As(V) and As(III)) as well as between free and bound metal ions, and low costs of ownership combined with quick results (approximately 10–15 minutes) make stripping voltammetry attractive for both stationary and mobile applications.

To meet legal regulations and to eliminate the use of metallic mercury (Hg), Metrohm has developed Hg-free alternatives for heavy metal determination. An overview of these alternative methods is given in this White Paper.

WHY MERCURY-FREE?

The term «mercury-free» means that no metallic mercury is used in the analysis. In fact, for several years, the hanging mercury drop electrode (HMDE) was used extensively for voltammetric determination of heavy metals [1]. The mercury electrode is ideally suited for trace metal determination due to its high sensitivity, wide cathodic polarization range, and the automatically renewable and reproducible electrode surface [2]. Despite its unique properties for electroanalysis, mercury is toxic and can accumulate in living organisms. To reduce the detrimental effect of metallic mercury on the environment and to replace it during the voltammetric determination of heavy metals, Hg-free sensors are required.