Neutralization Buffer A (for transfer to uncharged membranes), is supplied by HiMedia. It is available in the form of a colourless solution with a pH in the range of 7.3 to 7.5. Neutralization Buffer A is used for transfer of DNA bands from agarose gel to uncharged membrane (e.g. nitrocellulose) during Southern hybridization procedure. This buffer lowers the pH of DNA during the blotting process. If the DNA gel is de-purinated prior to alkaline or non-alkaline transfer, exclusion of the neutralization step prior to transfer can reduce signal. Without a neutralization step, depurination continues in the gel. Neutralization Buffer A is composed of 1M Tris and 1.5 M Sodium chloride and the pH is adjusted to 7.4. . It is advisable to store this product room temperature (15-25C).

Southern blotting, first devised by E. M. Southern in 1975, is one of the prime techniques in molecular biology. This procedure involves the transfer of DNA bands, usually restriction fragments, from agarose gel to a nitrocellulose or nylon membrane. If a nitrocellulose membrane is being used then the agarose gel is treated with Neutralization Buffer A after the denaturing step. This treatment is essential as DNA does not bind to nitrocellulose at a pH of greater than 9.0 and this Tris-containing buffer brings the pH back to proper binding environment. Neutralization Buffer A is mainly used to neutralize DNA agarose gels after the DNA denaturation in base step before transfer to nitrocellulose membranes.