Question

Is phosphate buffer a good buffer to be used in the laboratory?

Answer 1

Might be as phosphate buffer is used in dissolution !

Answer 2

Is there any drawbacks to this? Cos I really have no idea:/

Answer 3

hmm... Gomori buffers, the most commonly used phosphate buffers, consist of a mixture of monobasic dihydrogen phosphate and dibasic monohydrogen phosphate. By varying the amount of each salt, a range of buffers can be prepared that buffer well between pH 5.8 and pH 8.0. Phosphates have a very high buffering capacity and are highly soluble in water. However, they have a number of potential disadvantages:

* Phosphates inhibit many enzymatic reactions and procedures that are the foundation of molecular cloning, including cleavage of DNA by many restriction enzymes, ligation of DNA, and bacterial transformation.
* Because phosphates precipitate in ethanol, it is not possible to precipitate DNA and RNA from buffers that contain significant quantities of phosphate ions.
* Phosphates sequester divalent cations such as Ca2+ and Mg2+.

Answer 4

Generally, we use something called phosphate-buffered saline in biochemistry, molecular biology, and cell biology labs for two reasons:

1. Phosphate buffers such as PBS (phosphate buffered saline) are isotonic to our cells.
isotonic means that both solutions have equal osmotic pressure.
Also, phosphate buffers are non-toxic, which is a relief to those who work with dangerous chemicals daily.

Finally, phosphate buffer can be used to neutralize substances that carry a net charge.

Answer 5

This is done so that certain laboratory procedures can take place close to physiological pH

Answer 6

Are they the best buffers when added with an acid like HCl?

Answer 7

Phosphate carries a negative charge, which means that it can neutralize molecules that carry a positive charge (such as a select few amino acids)

HCl is a bit too strong too strong an acid to be added to most buffers.

Answer 8

But I would imagine that phosphate buffers have a wide-enough buffering zone that can withstand the addition of diluted HCl (since the stock solution is so strong)

Answer 9

Is ph 9 within the buffering zone? If the buffer drops by 0.10 for every drop of HCl acid, is it considered a good buffer?

Answer 10

I think pH 9 is just outside of the buffer zone for a phosphate buffer

Answer 11

Okay, thanks so much for your help!

Answer 12

You're looking at a range between 6.4 and 8.4 for a phosphate buffer (+/- 1 pKa)

Answer 13

That's alright ! : )