An optimal buffer system is critical for the performance of successful PCR. VWR® Taq DNA Polymerase kits generally include two different buffers, Key Buffer and Extra Buffer, which are suited for different PCR needs. All buffers contain Tris and 15 mM MgCl₂ (1,5 mM MgCl₂ final concentration). Additional MgCl₂ for easy optimisation is included in a separate vial.

Key Buffer: Key Buffer (NH⁴⁺) gives a superior amplification signal (high yield) and minimises the need for optimisation of the Mg²⁺ concentration or the annealing temperature in most primer-template systems.

Extra Buffer: Extra Buffer is the traditional potassium (K⁺) buffer. Extra Buffer promotes high specificity. Careful optimisation of primer annealing temperatures and Mg²⁺ concentrations may be required.

Combination Buffer: Combination Buffer is a proprietary mixture of K⁺ and NH⁴⁺. It combines high specificity with good product yield and high tolerance to optimisation of primer annealing temperatures and Mg²⁺ concentrations due to its balanced ammonium-potassium formulation.

Buffers for GC-rich templates: Combined with VWR® TEMPase the GC buffers promote excellent amplification results with targets of varying degrees of GC content. This confirms that the choice of buffer is crucial for any successful amplification.