Biomedical Engineering Reference
In-Depth Information
Fig. 7.5.
Transition interval of pH indicators.
A
amber,
b
blue,
c
colorless,
g
green,
o
orange,
pk
pink,
p
purple,
r
red,
v
violet,
y
yellow
buffer should be near the pH which is to stabilize, and the
concentration of the buffering substance should not be too low.
For instance, a 10-mM Tris buffer pH 7.4 is mostly ineffective.
-
A special problem is the dilution of buffer stock solutions. Es-
pecially if diluted by orders of magnitude, and if neutral salts,
such as sodium chloride or potassium chloride, are added, and
if the diluted buffer is used at temperatures far of its calibration,
thepHofthebuffer,aswellasitscapacity,changesdramati-
