Silver
Precise rapid tests for water and waste water samples
Silver is a soft ductile metal that has the highest electrical conductivity of all the elements and the highest thermal conductivity of all metals. It is a rare element accounting for only about 0.079 ppm of the earth’s crust. Like copper, it is one of the coinage metals.
As pure metal, silver is too soft, and therefore it is mainly used in alloys (typically with copper). Like copper, silver has germicidal effects, which is why silver is of interest for medical devices (tablets, ointments, silver foil) as well.
Furthermore, silver is used in photo developing. Fixation is the final process in the development of films and photos. Here, excess silver halides are washed out from the photo layer. Regular control of the silver content of such fixation baths is therefore meaningful and necessary.
Our Silver Products
| Product | Range | REF | Order | |||||
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| Silver test paper | > 20 mg/L Ag+ | 90732 |
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| Ag-Fix test sticks |
0 · 0.5 · 1 · 2 · 3 · 5 · 7 · 10 g/L Ag+ pH 4 · 5 · 6 · 7 · 8 |
90741 |
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| NANOCOLOR® Silver 3 | 0.20 - 3.00 mg/L Ag+ | 985049 |
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| QUANTOFIX® Silver | 0 · 1 · 2 · 3 · 5 · 7 · 10 g/L Ag+ | 91350 |
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Reaction Basis
Silver ions react with an indicator to form a blue dye. Poorly soluble or complexed silver compounds such as silver bromide, chloride, iodide, cyanide, or thiocyanate are not included in the determination.
Sample preservation
After adjusting the pH value to 1–2 with nitric acid, the sample can be preserved for storage for up to 1 month (storage vessel: PE or glass bottle).
Tips & tricks
- Decomposition
- Poorly soluble or complexed silver compounds such as silver bromide, silver chloride, silver iodide, silver cyanide or silver thiocyanate are not covered by the determination. For the determination of these compounds, decomposition with NANOCOLOR® NanOx Metal (REF 918 978) must be performed prior to analysis.
- Sea water suitability
- The method is not suitable for the analysis of sea water.
- pH
- The pH of the sample must be between 3 and 9. If necessary, adjust the pH with nitric acid or sodium hydroxide.
- Interferences
- Various metal ions such as Pb2+ or Al3+ interfere with the test. The concentration from which on interference is to be expected is specified in the instruction leaflets.
- Further interfering ions are listed in the instruction leaflets.
- Performance of the test
- Lower silver concentrations (0.08 to 0.50 mg/L Ag+) can be determined by using 50-mm semi-micro cuvettes (REF 919 50).
- Turbidity
- Turbid solutions must be filtered prior to the determination of dissolved silver; turbidity leads to incorrect results: For coarsely dispersed turbidities, use qualitative filter paper (e.g. MN 615), for moderately dispersed turbidities, use glass-fiber paper (e.g. MN 85/70 BF) or or membrane filtration set GF/PET 0.45 μm, for finely dispersed turbidities, use membrane filtration kit 0.45 μm or GF/PET 0.45 μm.
