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Cleaning/disinfecting labware
Which of the following are the best cleaning/disinfecting agents, if ‘best’ means that the compound/solution is most effective at killing germs or if it is very cost-effective or have some other features that makes it better such as no white streaks after application?
Sodium metabisulphite solution in distilled water
Isopropanol (70%)
Hydrogen Peroxide (3/6/9/12%)If you use another cleaning solution and think it beats the compounds listed above, let me know!
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17 Replies
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in my experience 70% IPA is best, as it’s effective, easy to handle, evaporates readily, and doesn’t leave oxidising/reducing/odoriferous residues
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Many thanks. 70% IPA solution it is.
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5 percent formalin will do some better if required high level of disinfectant.
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Formaline is obsolete in many countries because, well, it’s formaline.For thorough disinfection, go with hydrogen peroxide which leaves no traces and won’t harm neither your health nor the environment. -
Hydrogen peroxide vs IPA 70%? Does the HP evaporate quickly?
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No, Hydrogen peroxide does not evaporate as quickly as IPA. It evaporates like water.
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In that case I think I’ll stick with IPA. Far less hassle and less hydrogen peroxide on my gloves/hands when cleaning.
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I know hydrogen peroxide is better at killing biofilms, but I think day-to-day maintenance with IPA would go a long way.
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I use 70% iso at home and at work. Hydrogen peroxide is only for cleaning really nasty stuff like the black algae which form in the edges around the bathtub.
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I use 70% ethanol but I use safety precautions and don’t hang around to get drunk by inhaling it.
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Pharma said:I use 70% iso at home and at work. Hydrogen peroxide is only for cleaning really nasty stuff like the black algae which form in the edges around the bathtub.
I have this black stain problem on the edges around my bathtub. Great to know that hydrogen peroxide could work. Do you recommend something better for this job? How do you recommend I go about using HP to remove the stains? Rubbing/swiping small amount using cloth? Do I leave it in after it has been rubbed/swiped or do I simply rinse with water after, say, 5 mins?
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So I looked for some hydrogen peroxide online and found 3/6/9/12% solutions in ultrapure water. Would a 3% solution be enough for removing the sealant which turned black in colour?
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I usually go overkill and use 30% in a spray bottle (and regularly have to evacuate the bathroom because air gets unbreathable). Not to recommend for the average (= non-suicidal) user.When there’s also limescale involved, I mix pure formic acid with 30% H2O2 which results in performic acid (cool name!), a very aggressive oxidating acid. Might actually remove old joint sealer too if you’re not careful. BTW, do that only with open windows and be prepared to RUN THE HELL OUTA THERE
.A more reasonable attempt would be 10% (3% won’t do much in time) on a piece of cloth or a sponge, rub it on and just leave it till dry. Ammonia 10% also works great for that black stuff but it stinks and I use it only on (ex-)white walls with acrylate based paint. -
Thanks a lot Pharma. I had no clue that the black stains could be removed. I’ve bought some 9% HP solution and will try that by rubbing it in with a cloth or sponge. If that doesn’t work, I’ll try the ammonia solution too. Just to be on the safe side, even with the 9% HP solution, I think it might be best for me to still leave the bathroom door open and left unused for about an hour.
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Update: 9% HP solution was very effective at removing stains from the porous material between the bathroom tiles but almost totally ineffective at removing any stains from the rubber sealant lining the bathtub. Instead of making performic acid, I think I may just remove the rubber sealant and apply a new sealant over the area. This conversation has somehow turned about household cleaning haha. Back to cosmetic metalware, I’ve run out of rubbing alcohol so I’ll see how 9% HP works for now. Let’s see if it’s also able to remove scent that just seems to stick my stainless steel pitchers.
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Pharma said:Formaline is obsolete in many countries because, well, it’s formaline.For thorough disinfection, go with hydrogen peroxide which leaves no traces and won’t harm neither your health nor the environment.
The only fear I have is when I suspect that there might be residue amounts of hydrogen peroxide on glassware which could affect my next batches in the same glassware.
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Once it’s dry, it’s dry, don’t worry
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