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There is NO good buffer with phosphate for pH = 4.5, because pKa-value's differ too much from 4.5: pKa = 2.13 and 7.21 for H3PO4 and H2PO4- respectively.
A good alternative would be Acetic acid / Acetate in molar ratio of about 2 : 1, because pK(acetic acid) = 4.77 .
More precisely you can use the formula, based on the Henderson-Hasselbalch equation:
log[acid]/[conjug.base] = = 4.77 - 4.5 = 0.27
or
[acid]/[conjug.base] = 10(pKacid -pHbuffer) = 100.27 = inv.log(0.27) = 1.82
Doing the same for a H3PO4 / H2PO4- buffer, this results in
[H3PO4/H2PO4-] = 10(pKacid -pHbuffer) = 10(2.13-4.5) = inv.log(-2.37) = 4.3*10-3
or for H2PO4-/HPO42- buffer, this results in [H2PO4-/HPO42-] = 10(7.21-4.5) = 102.71 = inv.log(2.71) = 5.1*102
Both ratio's are far beyond values for optimal buffercapacities: 0.1 < ratio < 10
What else can I help you with?
How do you prepare phosphate buffer of pH 7.5?
To prepare a phosphate buffer of pH 7.5, you can mix appropriate amounts of monosodium phosphate and disodium phosphate in a ratio that will achieve the desired pH. Adjust the pH using either phosphoric acid or sodium hydroxide, depending on whether you need to increase or decrease the pH. Make sure to use a pH meter to accurately adjust the pH to 7.5.
What is the pH of disodium phosphate?
The pH of disodium phosphate is around 9-9.5. It acts as a buffer in solution, helping to maintain a stable pH level.
How do you prepare 20 mM citrate phosphate buffer of PH 7?
10ml of 0.4M Citric acis solution 90 ml of 0.4M sodium phsophate dibasic solution 12.22g NaCl (tomake 150mM ionic solution) or 6.38g to make 100mM ionic strength. make up volume upto 2000ml with water. You should not need to pH this buffer . :)
What is difference with the concentration of phosphate buffer?
The difference in concentration of a phosphate buffer refers to the amount of phosphate salts present in the buffer solution. This concentration can affect the buffering capacity and pH of the solution. A higher concentration of phosphate buffer will provide greater buffering capacity and more resistance to changes in pH compared to a lower concentration.
What is the difference between phosphate buffer and phosphate buffered saline?
Phosphate buffer is a solution containing a mixture of dibasic and monobasic sodium phosphate used to maintain a stable pH. Phosphate buffered saline (PBS) is a buffer solution containing phosphate salts, sodium chloride, and sometimes potassium chloride used in biological and chemical research to provide a stable environment for cells. PBS is a specific type of phosphate buffer solution that is isotonic and mimics the pH and osmolarity of biological fluids.
How to prepare phosphate buffer pH 5.8?
To prepare a phosphate buffer solution at pH 5.8, mix the appropriate amounts of monosodium phosphate (NaH2PO4) and disodium phosphate (Na2HPO4) in water. The exact ratio will depend on the desired buffer capacity. Adjust the pH by adding small amounts of acid or base as needed, and then confirm the pH using a pH meter.
How do you prepare phosphate buffer of pH 7.5?
To prepare a phosphate buffer of pH 7.5, you can mix appropriate amounts of monosodium phosphate and disodium phosphate in a ratio that will achieve the desired pH. Adjust the pH using either phosphoric acid or sodium hydroxide, depending on whether you need to increase or decrease the pH. Make sure to use a pH meter to accurately adjust the pH to 7.5.
How do you prepare a 0.055M sodium phosphate buffer pH7.2?
To prepare a 0.055M sodium phosphate buffer at pH 7.2, mix sodium dihydrogen phosphate (NaH2PO4) and disodium hydrogen phosphate (Na2HPO4) in the correct proportions. The exact concentrations of NaH2PO4 and Na2HPO4 needed to achieve pH 7.2 will depend on the specific buffer system and temperature. It is recommended to use a buffer calculator or consult a buffer table to determine the appropriate ratio of the two components to achieve the desired pH.
How do you prepare phosphate buffer PH 6.8?
dissolve the 12 g of crystals of sodium phosphate in water to make 1oo ml
How do you prepare 0.05M Phosphate buffer of pH 6.8?
To prepare a 0.05M phosphate buffer of pH 6.8, you would need to mix a specific ratio of monosodium phosphate and disodium phosphate in a certain volume of water. The exact amounts can be calculated using the Henderson-Hasselbalch equation or by using online calculators. Adjust the pH using small amounts of acid or base as needed.
How do you prepare 0.5 M phosphate buffer pH 7.0?
To prepare 0.5 M phosphate buffer pH 7.0, dissolve the appropriate amounts of monobasic potassium phosphate and dibasic potassium phosphate in water. Adjust the pH using either dilute HCl or NaOH, while continuously checking with a pH meter until pH 7.0 is reached. Dilute to the desired final volume with water if needed and ensure that the final pH is within the acceptable range.
How do you prepare 50 Mm phosphate buffer of pH 7?
To prepare a 50 mM phosphate buffer of pH 7, you would need to calculate the correct ratio of monobasic potassium phosphate and dibasic potassium phosphate to achieve the desired pH. You can then mix the appropriate amounts of each salt in distilled water, adjusting the pH as needed with additional acid or base. Finally, make up the volume to reach a final concentration of 50 mM.
How do you prepare phosphate buffer pH 7.4 using potassium dihydrogen orthophosphate?
To prepare a phosphate buffer pH 7.4 using potassium dihydrogen orthophosphate, you would mix potassium dihydrogen orthophosphate with disodium hydrogen phosphate in appropriate proportions to achieve the desired pH. The specific ratio needed will depend on the concentrations desired and the Henderson-Hasselbalch equation. It is important to use a pH meter to confirm the pH of the buffer after preparation.
How do you make a sodium phosphate buffer solution of pH 6.8?
To prepare a sodium phosphate buffer solution of pH 6.8, mix the appropriate amounts of monosodium phosphate (NaH2PO4) and disodium phosphate (Na2HPO4) in water. Adjust the ratio of the two components to achieve the desired pH using a pH meter or a buffer calculator.
What is the PH of the phosphate buffer?
The pH of a phosphate buffer solution depends on the ratio of monobasic to dibasic phosphate ions present. For example, a mixture of NaH2PO4 and Na2HPO4 can create a buffer with a pH around 7.2-7.6, depending on the concentrations of each salt used.
How I can prepare 5 mM phosphate buffer?
To prepare a 5 mM phosphate buffer, first calculate the amount of monosodium phosphate (NaH2PO4) and disodium phosphate (Na2HPO4) needed based on their respective molecular weights. For example, to make 100 ml of solution, dissolve 0.190 g of NaH2PO4 and 0.281 g of Na2HPO4 in distilled water. Adjust the pH to your desired range, typically around 7.4, by adding small amounts of acid or base.
What is the lambda max of paracetamol at pH 6.8 phosphate buffer?
The lambda max of paracetamol typically occurs around 243 nm in a pH 6.8 phosphate buffer.
