I have to wash glassware before culturing bacteria in LB media with different concentration of heavy metals. This is suggested in some literature as it will not allow the metal particles to adhere to the walls of glassware. I have come across 3 acidic solutions and need suggestions on which one to use and for how long?
1) Chromic acid ( I am trying to avoid it ) + I want to know if it will affect the studies when I culture bacteria with chromium
2) 1 N HNO3 ( overnight soaking + rinsing the glasswares 5 times with deionised water
3) 20% HNO3 + 10% HCl
Currently I have tried the second option.
The idea is to not allow the metal particles adhere to glass surface ( first use glassware). However, other answers are also welcome. Answers for after use washing were also very good
The best way of washing glasses to remove both organic and inorganic material is washing in a solution containing 50% Methnol+50% HCl. Put your glasswares in the solution for an hour and then rins with Deionized water.
I think your idea is to remove heavy metal contaminants from glass ware. HNO3 acid is good enough to remove them since you use LB. I assume you autoclave LB and glass ware after cleaning then add heavy metals to the medium.
I used the below Acid preparation for contaminated glasswares (Bacteria, fungus, heavy metal etc.) 13.75 ltr
Weigh 375 g K2Cr2O4 and dissolve in 1.25 ltr MQ water
Arrange 2 buckets of ice and two tubs of ice
Wear proper gloves and eye protecting goggles
Add the dissolved potacium di chromate in 12.5 ltr conc. H2SO4
Pour slowly and keep stirring with a steel rod until it gets fully dissolved
Keep in the acid tank and use for acid wash. It is reusable for several weeks, depending on the quantity of glass wares you clean.
Sock your glassware overnight in it.
Rinse with water and dry in oven.
Ready to use.
+++
We do use Potassium dichromate + sulphuric acid solution as given by Ranjan.. Its too good to clean all kind of glass wares.
what are the ratio of chromic acid to sulfuric acid used in cleaning : is it 1: 10 or what
thanks . what the concentration of chromic acid and sulfuric acid
250ml of Sulphuric acid + 750 ml of Distilled water and 100 gm of Potassium Dichromate
I find that I also need answer to a similar question. I want to test serum iron levels by colorimetry and I need to wash the test tubes to remove residual iron (and other heavy metals that absorb around same wavelength as iron). Is 10% HCL solution sufficient?
Dear Dr Patil,
If you are using virgin glassware (ie the one not used before) your choice of the second option is the best.
Only if the glassware has sticky substance left from earlier use that chromic acid would be needed to clean it.
With best regards,
Sincerely,
Abbasi
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