Biological buffering agents are of great significance in biochemical research. They are widely used in immunoblotting, biochip and biological hybridization, in vitro diagnosis, biomedicine and other industries.
The biobuffer system contains dozens of varieties. Typical varieties such as Tris, HEPES, etc. This article will introduce the most common variety of the Tris buffer advantages and use matters needing attention.
Tris tromethamine is a kind of buffer salt widely used in the biomedical field, the full name of trIS (hydroxymethyl) aminomethane, chemical formula C4H11NO3, white crystalline particle, CAS No. : 77-81-1, 25°C pKa 8.06, often used in protein or nucleic acid buffer, the effective range is usually between pH 7.0 and 9.2.
Tris is used to grow protein crystals under different pH conditions. Tris is also one of the main components of protein electrophoresis buffer. It forms a buffer system with glycine in electrophoresis buffer to stabilize pH during electrophoresis. In addition, Tris is an intermediate in the preparation of surfactants, vulcanization promoters and some drugs. Tris is also used as a titration standard.
Common Tris buffers are Tris-HCl buffer, TRis-phosphate buffer and a variety of derived buffers, such as TBS, TE, etc.
1. Tris alkali is strong, so you can only use this buffer system to prepare a wide range of pH buffer from acid to alkaline, a wide range of applications;
2. Tris buffer has little interference on the biochemical process and does not precipitate with calcium, magnesium and heavy metal ions;
3. Tris has high solubility in water and is inert to many enzymes;
4. High buffering capacity of Tris, strong buffering capacity between pH7.5-9.0;
5. Tris buffer is widely used and plays an important role in biochemistry, molecular biology, in vitro diagnosis, cosmetics, coatings and other fields.
1. Tris buffer pH value is greatly affected by temperature, △pKa / ℃ = -0.031, for example: 4℃ buffer pH = 8.4, 37℃ pH = 7.4, so must be prepared at the use of temperature, room temperature preparation of TRIS-HCl buffer can not be used for 0℃ ~ 4℃.
2. The pH value of Tris buffer is greatly affected by the concentration of the solution. When the buffer is diluted ten times, the change of pH value is greater than 0.1
3. Tris reacts with various molecules to a certain extent, including RNase inhibitors, aldehydes, enzymes, DNA and common metals such as Cr3+, Fe3+, Ni2+, Co2+ and Cu2+, etc., which can play an inhibitory role in some systems. The interaction with other components should be considered in the preparation process.
4. Tris buffer is easy to absorb CO2 in the air, and the prepared buffer should be tightly sealed;
5. Tris buffer has a certain interference effect on some pH electrodes, so it is necessary to use electrodes compatible with Tris solution;
6. Tris buffer is not suitable for the determination of diquinolinic acid (BCA);
7. Inhalation, ingestion and skin absorption of Tris may cause injury. Wear gloves and goggles when operating;
8. When used as a protein buffer, if mass spectrometry is required for subsequent work, Tris is not suitable, and it is better to switch to another buffer that can be tolerated by the mass spectrometer.
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