文档介绍：usp中缓冲溶液和标准溶液的详细配制方法
BUFFER SOLUTIONS
The pletion of many Pharmacopeial tests and assays
requires adjustment to or maintenance of a specified pH by the addition
of buffer solutions. In pH measurements, standard buffer solutions are
required for reference purposes. For convenience, the preparation of
these solutions is in some instances described in the sections in which
their use is specified; ., five separate phosphate buffers are
described under Antibiotics -- Microbial Assays <81>, and several
miscellaneous single-purpose solutions are described in the individual
monographs.
A solution is said to be buffered if it resists changes in the
activity of an ion on the addition of substances that are expected to
change the activity of that ion. Buffers are substances binations
of substances that impart this resistance to a solution. Buffered
solutions are systems in which the ion is in equilibrium with substances
capable of removing or releasing the ion.
Buffer capacity refers to the amount of material that may be added to
a solution without causing a significant change in ion activity. It is
defined as the ratio of acid or base added (in gram-equivalents per
liter) to the change in pH (in pH units). The capacity of a buffered
solution is adjusted to the conditions of use, usually by adjustment of
the concentrations of buffer substances.
Buffers are used t