Patent ID: 8183046

Claim:
A composition made by a method comprising: selecting a pH of the composition, the composition having a pH of 6 to 8; selecting a first buffer with a negative temperature coefficient, the first buffer comprising HEPES or BisTrisPropane; selecting a second buffer with a positive temperature coefficient, the second buffer comprising potassium phosphate; and forming the composition comprising the first buffer and the second buffer; wherein the composition does not comprise a pH-indicator dye, the composition has an average temperature coefficient ΔpH/ΔT(T a ,T b )≦1×10 −3 pH-unit/K for T a =253 K and T b =273 K, or T a =273 K and T b =293 K and the HEPES or BisTrisPropane comprises 25-60 mole percent of the sum of the first and second buffers, and potassium phosphate comprises the remainder mole percent of the sum of the first and second buffers.