Only silver ions (Ag+) can kill bacteria, metallic Silver (Ag 0) is not able to kill bacteria or prevent bacteria from growth.
Spectroscopical methods detect the total silver content but cannot make statements how much of the silver is bioavailable.
Voltammetry is an electrochemical method for detection of trace elements in aqueous and non-aqueous media.
The bioavailable silver species (uncomplexed, unbound silver ions Ag+) which is also responsible for antimicrobial action is directly monitored.
This method was Validated by QualityLabs for testing antimicrobial silver products
Suitable sample material:
- Silver-Cosmetics (fluid or semi-fluid)
- Textiles, Suture, Fibers, (Non-)Woven
- Paint, Laquer, Coatings
- Impregnated material
- Medical Devices
- Specific detection of silver ions even in presence of other antimicrobials like Triclosan, Antibiotics, etc.
- biologically relevant concentrations can be determined in the nanomolar range (ppb)
The power of Voltammetry:
- Detection/Creation of elution profiles for certification of antimicrobial silver medical devices
- Estimation of product lifetime by monitoring silver ion release (silver release kinetics)
- Simulation of product ageing by means time lapse models
- Homogeneity of silver cosmetics (quality assurance)
- Total silver analysis in cosmetic formulations
- Correlation with Proliferation Assay data
How does it work?:
Ag+ is preconcentrated on a spinning electrode by reduction to metallic silver.
By applying a current the same silver is then stripped off the electrode.
The total current which was needed for stripping the electrode is proportional to the originally present number of silver ions.
How much sample material do we need?
- appr. 1 g for extraction (also depending on the silver concentration and the release behaviour of the sample)