Post by SassmanPost by David StonePost by analytical chemistryHi,
anybody has any experience with washing AND drying glassware for AA
analyses?
I would appreciate any tips on the matter.
The best answer probably depends on what you're interested in analysing,
and at what level. For example, you might get away with using a lab
dishwasher, or you might need to clean with chromic acid, then store
everything in 10% nitric acid until needed (i.e. never dry it).
For trace levels, use plastic containers. Some element can leach from
glassware and trace elements like to sorb to glass surfaces. All
dishware (plastic or glass) should be soaked in 10% nitric acid for at
least one hour, then rinsed thoroughly with DI water. Glassware can be
dried in an oven, but be sure that it is stored so that no dust or other
contamination can get in the container (ie. upside down).
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http://www.analyticalchem.com/
You can't automatically assume plastics won't contaminate
your solutions. Some plastics are made with
metal-containing catalysts that end up in the plastic. I've
seen fluorocarbon bottles that contaminated acid solutions
because there were fragments of metal and other impurities
in the polymer, some bifg enough to see with a microscope
and a few that could be seen without any magnifier.
A good rule for successful trace analysis is to trust nothing.