phosphatebuffer磷酸盐缓冲液的配置
K. M. DeA ngelisupdated 1/15/2007phosphate bufferIn formati on from cshprotocols.org:Gomori buffers, the most com monly used phosphate buffers, con sist of a mixture of mon obasic dihydroge n phosphate and dibasic mon ohydroge n phosphate. By vary ing the amount of each salt, a range of buffers can be prepared that buffer well betwee n pH 5.8 and pH 8.0 (please see the tables below). Phosphates have a very high buffering capacity and are highly soluble in water. However, they have a number of potential disadva ntages:* Phosphates in hibit many en zymatic reacti ons and procedures that are the foun dati on of molecular cloning, including cleavage of DNA by many restriction enzymes, ligation of DNA, and bacterial tran sformatio n.* Because phosphates precipitate in etha nol, it is not possible to precipitate DNA and RNA from buffers that contain significant quantities of phosphate ions.* Phosphates sequester divale nt cati ons such as Ca2+ and Mg2+.0.5L of 1M K2HPO4 at 174.18g mo-1 = 87.09g0.5L of 1M KH 2PO4 at 136.09g mo-1 = 68.045gpreparati on of 0.1 M potassium phosphate buffer at 25Preparation of OJ M Potassium Phosphate Buffer at 2S°CVolume of 1 mVolume of 1 mKH2PO4 (ml)PHK2HPO4 (ml)励8.591.56.013286.86.219780.86.427.872.26638.161.9G849,75(X37.061.538.57.271.723.37.480.219.87.686.613.47.890.fi928.094,06JQDilute the cutnblird 1 M ilnck Lions Lo 1 liiirr with disLllkd HjO. pl I bi rHlruLatcd arrrKTiing td the Elendennn-Eiaiiiebakh equation:pH - pK + lop J (piolon a cceptor)1proknul 口norwhereat 25°C.