Definition - What does Buffer mean?
A buffer, within the context of drug testing, is an aqueous solution that can neutralize small amounts of an added acid or base. This neutralizing effect maintains the stability of the solution's pH and inhibits bacteria growth depending on the type of sample. A buffer may also be called a pH buffer, a fluid buffer, or a hydrogen ion buffer.
SureHire explains Buffer
A buffer is used in chemical processes when a stable pH range is needed. When a buffer is present, acids or bases can be added to the solution in limited amounts without upsetting the solution's pH balance. Each buffer will have a limited range in which it is effective. Whether or not a buffer is used and how it is used depends on the type of sample. For example, oral fluids are less acidic and more prone to bacteria growth than urine samples.