Phosphate buffer, sometimes referred to with slight variations as the “Sorensen buffer,” remains a widely employed resource in biology. Scientists recognize its essential role as it offers robust buffering capacity and allows for pH adjustment within the range of 5.8 to 8.
Phosphate buffer closely resembles certain components found in extracellular fluids, rendering it one of the most physiologically relevant among commonly used buffers. It poses no threat to cell viability, demonstrating its non-toxic nature. Minimal pH fluctuations occur with temperature shifts, ensuring stability. Storing it at 4°C maintains its stability for several weeks.
On occasion, it may precipitate when exposed to calcium ions during fixation. It tends to form precipitates with uranium acetate and reacts with lead salts. Additionally, precipitation may occur during dehydration with ethanol, making acetone dehydration a preferred alternative.
Given its critical role, it remains susceptible to contamination (thus, it should be stored at 4°C). High molar concentrations of 0.4M and above effectively prevent bacterial growth even at room temperature. We recommend obtaining 0.4M stock solutions and conducting necessary dilutions during experiments. This practice helps minimize the risk of contamination that can occur after a few days, reducing the concentration to 0.1M.
We carefully select our products for their purity. The 0.1M concentration is sensitive and should be stored in the refrigerator at 4°C. If cloudiness appears, it may indicate contamination. Our solutions are hermetically sealed under neutral gases like argon, effectively eliminating oxygen to prevent bacterial proliferation. Upon opening the bottle, please note the date, as exposure to air can lead to bacterial growth.