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Home Q & A Board Laboratory Help Upper-Year Courses
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SMG SMG
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9 years ago
Hi. I am currently working on alpha amylase inhibition assay using DNS reagent.
As the first step I am preparing the DNS reagent and testing it with glucose to ensure that the DNS reagent is prepared in a correct way.
After boiling the mixture of glucose and DNS reagent, I don't see any colour change. I prepared DNS reagent using the following steps:
Dissolve 1g of 3,5 dinitrosallicylic acid in 20mL 2M NaOH. Then add slowly 30g sodium potassium tartrate and dilute to a final volume of 100mL using distilled water. .
Please advice on the procedure to prepare DNS reagent. thank you
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#1
Educator
9 years ago
I think the problem lies in boiling the DNS. To prepare it correctly, about 1g of DNS is dissolved in 50ml of distilled water. To this solution add about 30g of sodium potassium tartarate tetrahydrate in small lots, the solution turns milky yellow in colour. Then add 20ml of 2N NaOH, which turns the solution to transparent orange yellow colour. The final volume is made to 100 ml with the distilled water. This solution is stored in an amber coloured bottle.
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