There is a USEPA standard on this I believe, but I am having trouble finding it. Our lab washes dishes and we place dried dishes in the HCl acid bath to remove contamination but focus especially on phosphorus removal. We need to have the volume of the bath increased a bit (it is about 6L).
Hi Colleen, Taking a guess the concentration is probably 5% v/v, but this is not as important as having two baths that alternate between 'clean' and 'dirty'. Testing the 'dirty' bath to decide when to retire it and refill it with clean acid. The baths need to have lids and be inside a constantly running fume hood, Paul.
Dear Colleen, use chromic acid solution prepared by dissolving 100 g potassium dichromate in 250 ml distilled water. Slowly add 250 ml sulfuric acid and make the volume to one litre by adding 500 ml D water. Then rinse the glass ware with D. W. If the glass ware is new, it should be soaked in 1 percent solution of HCl before washing
With respect Sunita, chromic acid may be effective but I discourage its use because Cr is an environmental toxin, Paul
Thanks for your answers! I will use an HCl bath (still deciding on the concentration to keep) and also soak new glassware in HCl, as we just got some.