The same water samples were filtered at 0.45 µm and 0.02 µm, using respectively Whatman® membrane filters nylon and Whatman® Anotop® 10 syringe filters. The water samples were kept in plastic bottles, and iron and aluminium were measured using ICP-AES. Iron concentrations are, as it should, higher in 0.45 µm than in 0.02 µm filtered water. However, aluminium concentrations are higher in 0.02 µm filtered water.
How would you explain this result for the aluminium? Could a sample be contaminated and, if so, which one would it most likely be (0.45 µm or 0.02 µm) and where would the contamination come from? Could colloidal aluminium adsorb on the plastic bottle used for storage?
usually use 0.45 milli micron filtration. It is surprising in your case How get more aluminium value.
What is the turbidity? Did you digest the samples? - Could the samples have been switched? Did you re-run and confirm?
Thank you for your answers!
Turbidity was not measured but we measured 8-10 mg/L of suspended solids on average. No digestion was undertaken. For ICP-AES, samples were diluted 2x and acidified at 0.5% HNO3.
As iron concentrations seem to be correct, a switch of samples seems unlikely. Re-running the analysis is indeed maybe the best option!
Thanks again for the help!
- Badges
- Science topic
- Similar topics
- Control Systems Engineering
- Filtering