Ascorbic acid colorimetric analysis using the Murph
y Riley method.
DI-extracted PBC Inc soils were
analyzed by ascorbic acid colorimetry (Murphy Riley
).
16
To prepare samples, 4.0 mL Reagent B (Table 1) an
d 19.0
mL DI water was added to 2.0 mL of each extract. S
tandards consisting of 5.0 mL of each standard P so
lution (0.1
ppm to 1.0 ppm P), 4.0 mL Reagent B, and 16.0 mL DI
water and a 0.0 ppm P standard consisting of 4.0 m
L
Reagent B and 21.0 mL DI water were also prepared.
Samples were allowed 30 minutes for color developm
ent.
The absorbance of the samples and standard solution
s at 882 nm was measured with a Perkin Elmer Lambda
25
UV/VIS spectrometer.