New buffers to improve the quantitative real-time polymerase chain reaction

Real-time PCR is a potent technique for nucleic acid quantification for research and diagnostic purposes, the wide dynamic range being one of the advantages over other techniques like the microarray. Several additives and enhancers have been studied to expand the PCR dynamic range in order to be more efficient in quantifying low quantities of nucleic acids, increase the yield and improve reaction efficiency. Shown here is that a combination of new buffers with the regularly used Tris buffer makes it possible to expand the real-time PCR dynamic range and to improve the efficiency and correlation coefficient. Mixing HEPES, TEA or MOPS with Tris was more efficient than Tris alone. It was also found that, if the pH value of the Tris buffer was calibrated with phosphoric acid instead of hydrochloric acid, then the dynamic range was significantly improved and low quantities could be detected and quantified more efficiently. Mixing more than one compound with the Tris buffer was also effective for expanding the dynamic range and increasing the efficiency and correlation coefficient in quantitative real-time PCR.