Hi,
I need to do a protein test. The prac calls for protein sticks which are quite expensive. I've had a go at making a Biuret solution. This soln tested negitive for egg white. Something wrong there. The other recipe that I have requires the students using a NaOH solution of a too high molarity. Can anybody help please?
For my next question.... How do others label their dropper bottles. I am using paper labels and contact but am finding that the labels are in need of constant replacement.
Thanks all
Noela
Protein test solution
Hi Noela,
try thison
Biuret solution
For one liter:
1.5 g cupric sulfate pentahydrate (CuSO4 5 H2O)
6.0 g sodium potassium tartrate tetrahydrate (NaKC4H4O6 4 H2O).
Dissolve these in 500 ml of H2O. Add 300 ml of 10% NaOH. Add water to make total volume of 1 liter. Store in a plastic bottle protected from light.
10% NaOH is only 2.8M
try thison
Biuret solution
For one liter:
1.5 g cupric sulfate pentahydrate (CuSO4 5 H2O)
6.0 g sodium potassium tartrate tetrahydrate (NaKC4H4O6 4 H2O).
Dissolve these in 500 ml of H2O. Add 300 ml of 10% NaOH. Add water to make total volume of 1 liter. Store in a plastic bottle protected from light.
10% NaOH is only 2.8M
Cheers Jazz
Protein Testing - Biuret Reagent
Hi All,
Another alternative for Biuret Reagent can be found on the Regional Technician Group's website http://www.rtg.wa.edu.au/solution/probsoln.htm#biuret under problems and solutions:
This website has many good tips!
Here is the info I have copied from the RTG website:
"Protein Testing - modified Biuret Reagent
Protein testing using Millon's Reagent and the Sakaguchi Test (which contains 1-naphthol) are potentially hazardous for High School student use. The alternative Biuret Test can also be hazardous as some recipes call for high concentrations of caustic reagents (4M sodium hydroxide or 6M potassium hydroxide). The following is a safer alternative:
Reagent 1 - 'Strong Alkali Solution' - (1M sodium carbonate solution is sufficient)
Reagent 2 - 'Dilute Copper Sulfate Solution' (0.1M copper-II-sulfate solution)
Method: To a small sample of the material under test, add 1 eye-dropper full of strong alkali solution and 1 drop of dilute copper sulfate solution. The solution will turn violet in the presence of protein or will remain pale blue in the absence of protein.
Thanks to Carole Peters - PEAC (Primary Science) for this one."
I inherited a set up with 1M NaOH and 0.1M CuSO4 and it works well!
Regards
Teresa
Another alternative for Biuret Reagent can be found on the Regional Technician Group's website http://www.rtg.wa.edu.au/solution/probsoln.htm#biuret under problems and solutions:
This website has many good tips!
Here is the info I have copied from the RTG website:
"Protein Testing - modified Biuret Reagent
Protein testing using Millon's Reagent and the Sakaguchi Test (which contains 1-naphthol) are potentially hazardous for High School student use. The alternative Biuret Test can also be hazardous as some recipes call for high concentrations of caustic reagents (4M sodium hydroxide or 6M potassium hydroxide). The following is a safer alternative:
Reagent 1 - 'Strong Alkali Solution' - (1M sodium carbonate solution is sufficient)
Reagent 2 - 'Dilute Copper Sulfate Solution' (0.1M copper-II-sulfate solution)
Method: To a small sample of the material under test, add 1 eye-dropper full of strong alkali solution and 1 drop of dilute copper sulfate solution. The solution will turn violet in the presence of protein or will remain pale blue in the absence of protein.
Thanks to Carole Peters - PEAC (Primary Science) for this one."
I inherited a set up with 1M NaOH and 0.1M CuSO4 and it works well!
Regards
Teresa
Hi Noela
Answering your second question. We use paper printer labels, (Avery DL24) covered with three overlapping strips of general sticky tape. We have tried spray coating and contact and this seems to be the best and easiest. They do need replacing at intervals but are quite easy to remove with a single sided razor blade. Hope this is of some help.
Diana
Answering your second question. We use paper printer labels, (Avery DL24) covered with three overlapping strips of general sticky tape. We have tried spray coating and contact and this seems to be the best and easiest. They do need replacing at intervals but are quite easy to remove with a single sided razor blade. Hope this is of some help.
Diana
Protein test solution
Greetings,
The simplest form of protein I have used is gelatin and we have had no failures. Weigh out 10 g gelatin. Gradually add this to 500 ml of boiling water, stirring continuously as you do so. Make up to 1 litre.
We previously used peptone but it does not store well and starts to smell - stink actually!! Also gelatin is easy to source.
As reagents we use 4M (can use 2M) NaOH and 0.8M Copper Sulfate (5g/25mls). Since these are in dropper bottles and are supplied in very small quantities we have had no safety concerns.
Regards,
Robbie
The simplest form of protein I have used is gelatin and we have had no failures. Weigh out 10 g gelatin. Gradually add this to 500 ml of boiling water, stirring continuously as you do so. Make up to 1 litre.
We previously used peptone but it does not store well and starts to smell - stink actually!! Also gelatin is easy to source.
As reagents we use 4M (can use 2M) NaOH and 0.8M Copper Sulfate (5g/25mls). Since these are in dropper bottles and are supplied in very small quantities we have had no safety concerns.
Regards,
Robbie
