How can i avoid precipitation in pbs?
when i solve salts separately then add to a bowel there is no precipitation but when i want to solved them in a bowel after adding 3th salts the salts started to precipitate while i did it before without any precipitation
Dear Fatemeh,
are you making a 10x PBS or 1x? It does occur to see some precipitates with 10x PBS when you store it at 4 °C, but it needs to dissolve at room temperature - or something went wrong.
I always use type I water (double distilled) for my solutions. Perhaps something is wrong with the salts concentration?
137 mM NaCl
2.7 mM KCl
10 mM Na2HPO4
1.8 KH2PO4
(see that there isn't any Ca2+ of Mg2+ components).
You need also to adjust 1x PBS pH to 7.4. Perhaps the pH is not contributing to the salt correct dissolution?
Dear
1. your phosphate might be too concentrate
2. high NaCl concentration
3. hard water and calcium phosphate will precipitate (you should use dd- water)
4. you can use HEPES buffer rather than PBS. HEPES would be very good.
Best
It might be because of
1. High concentration of components;
2. Low solubility of components at low temperature;
3. Change in pH of solution upon storage; or
4. Poor purity of each components
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