All waste methanol from the rinses should be
12. DATA ANALYSIS AND
disposed of according to Federal, state and local
CALCULATIONS
regulations.
The absorbance data are converted to picric acid
All acidmethanol mixtures should be treated
concentration in the sample by the following for-
separately as required by Federal, state and local
mula:
regulations.
g/L picric acid =
daily response factor (g/L-ABS unit)
16. REFERENCES
(Final ABS 0.5 Initial ABS).
Thorne, P.G. and T.F. Jenkins, "Development of
This is based on a 2-L subsample of water using
a Field Method for Ammonium Picrate and Picric
the dilutions specified in the PROCEDURE. Any
Acid in Soil and Water," Special Report 95-20, USA
dilution that was required to bring the eluent into
Cold Regions Research and Engineering Labora-
the linear range of the initial calibration should be
tory, Hanover, N.H.
included in the calculations using the following
formula:
17. TABLE AND FLOW DIAGRAM
g/L picric acid =
daily rf (g/L-ABS unit)
TABLE B1. Preparation of calibration solutions from
[(Final ABS df) 0.5 (Initial ABS/df)]
the 10-mg/L working standard.
Volume of
Volume of
where rf is the response factor and df is the dilu-
working STD
water
Conc.
tion factor.
(g/L)
Solution
(mL)
(mL)
A
0
2000
0.0
13. METHOD PERFORMANCE
B
5
1995
25
C
10
1990
50
D
20
1980
100
The method was tested on 34 well waters. The
E
40
1960
200
field method indicated no picrate contamination
above the detection limit. This result was con-
firmed using HPLC.
WATER SAMPLE
14. POLLUTION PREVENTION
All containers of organic solvents and extrac-
Vacuum Filter Through Anion Disk
tion solutions should be keep capped to prevent
evaporation. A large tray should be used under
Rinse Disk with Methanol
the work area to contain any spilled solvents.
Elute with H2SO4 Methanol
15. WASTE MANAGEMENT
Obtain Initial ABS (400 nm)
All solid waste contaminated with solvents, acid
and extracted chemicals should be disposed of
Dilute with Water
according to Federal, state and local regulations.
This includes extraction disks, glass fiber filters,
Obtain Final ABS (400 nm)
pasteur pipets and eluent test tubes.
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