Table 4. Properties of four detergent solutions.1
Recommended (%) conc's, for
% phosphate
Type of
pH of
different water temps
Detergent
(as P)
detergent
1% sol.
Cold
Warm
Hot
1†
Alconox
7.3
anionic
9.5
1
1*
1†
Liquinox
0
anionic
8.5
1
1*
23*†
Detergent 8
0
nonionic
11.0
35
23*
2†
Citranox
0
**
2.52
2
2**
1
Information provided by Alconox, Inc.
* Recommended rinse temperature
† For hard-to-remove contamination, use higher concentrations
** Citranox is a blend of organic acids, anionic and nonionic surfactants, and alkolamines.
which type of nonphosphate or laboratory deter-
Variations in methodology
gent to select. Presumably it was thought that if
Mickam et al. (1989) compared the decontami-
the detergent removes similar contaminants from
nation procedures of several state and federal reg-
similar types of surfaces in the laboratory, it
ulatory agencies and found that these procedures
ought to work in the field. ASTM Method D-5088-
were highly variable. Following is a discussion of
90 (ASTM 1990) recommends using a nonphos-
some (but not all) of the variations that have been
phate detergent and refers to Alconox and Liqui-
found.
nox by name. Several other methods also refer to
While most methods did not stipulate how
Alconox. However, according to the manufactur-
aqueous cleaning was to be conducted (i.e., soak-
er, Alconox is not phosphate-free. Several other
ing, scrubbing with a brush, or using a high-pres-
detergents (Liquinox, Citranox, and Detergent 8)
sure washer), a few methods [ASTM 1990, U.S.
made by the same manufacturer (Alconox, Inc.)
EPA Region IV 1991, and according to Mickam et
are phosphate-free. Table 4 summarizes the char-
al. (1989) older procedures for Alabama and Penn-
acteristics of these detergents. All four of them
sylvania] did recommend using a brush during
can be used for soaking, brush cleaning, ultrason-
the cleaning process. In the past, a few state agen-
ic cleaning, and flow-through cleaning in place
cies have also recommended using either steam
(as would be used for a pump), but only Deter-
cleaning [California, New Jersey, and New York
gent 8 is recommended for spray cleaning. The
according to Mickam et al. (1989)], or a power
manufacturer recommends two phosphate-free
washer [Maryland and New Jersey according to
detergents, Liquinox and Detergent 8, for clean-
Mickam et al. (1989)] either to remove gross con-
ing equipment that will be used for environmen-
tamination or for equipment used for collecting
tal sampling and testing.
samples to be analyzed for organic contaminants
Typically, the acid rinse is dilute (0.1 N) hydro-
(California). Region IV of the U.S. EPA also rec-
chloric or nitric acid. Most protocols do not rec-
ommended steam cleaning when necessary (U.S.
ommend this step unless inorganic species are
EPA Region IV 1991). In addition, several research
going to be analyzed. Recommended organic sol-
studies (Bryden et al. 1986, Matteoli and Noonan
vents vary with the particular protocol but typi-
1987, Fink and Boyajian 1989) have used steam
cally include acetone, hexane, or methanol. Obvi-
cleaning to clean sampling equipment, and a pa-
ously, any organic solvent that is used as a rinsing
per by Brice and Kelley (1991) recommended us-
agent should not be one of the target analytes or
ing a high-pressure sprayer.
interfere with chemical analyses. In addition, the
Brice and Kelley (1991) give one of the most
waste decontamination fluids need to be disposed
descriptive and extensive protocols for aqueous
of properly and should be containerized, at least
cleaning of sampling devices. They recommend-
until it can be determined if the waste is hazard-
ed the following cleaning procedure for lightly
ous. Clearly, it is advantageous to find the most
contaminated equipment: 1) remove particles us-
effective decontamination method that generates
ing a low-volume, high-pressure sprayer, 2) scrub
the least amount of hazardous waste.
in a phosphate-free detergent solution and rinse
8
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