time (Table 1). After removing the test pieces from
room-temperature detergent water wash with a
the initial test solution, the test solutions were
DI water rinse vs. a hot water detergent wash
sampled and analyzed for analyte loss (sorption).
with a hot DI water rinse (Table 1). We selected
100C for the hot wash and rinse to simulate
After allowing time for desorption, the vials con-
taining the deionized water were also sampled
steam cleaners and hot water washing systems.
and analyzed. In each instance, an aliquot was re-
moved from each 40-mL vial using a Pasteur
Fourth VOC study--Effect of solvent rinsing
pipet and transferred to an autosampler vial (1.8
The purpose of this study was to determine if
mL), which was filled to capacity so there was no
solvent rinsing enhanced removal following a hot
headspace, and capped.
water detergent wash and a hot DI water rinse.
Analytical determinations were performed us-
Two solvents were selected: methanol, a relative-
ly polar solvent, and hexane, a relatively nonpo-
ing reversed-phase high-performance liquid
lar solvent (Table 1).
chromatography (RP-HPLC). A modular system
The protocol differed in this and subsequent
was employed consisting of a Dynatech LC-241
autosampler with a 100-L injection loop, a Spec-
VOC experiments in that only the PTFE test piec-
es that were exposed to the test solution for 24
tra Physics SP8810 isocratic pump, a Spectra
Physics SP100 variable wavelength UV detector
hours and allowed to desorb for 24 hours were
used in this study (Table 1). The reason we did
set at 210 nm, and a Hewlett Packard 3396 series
this was because the previous experiment dem-
II digital integrator. Separations were obtained on
a 25-cm 0.46-cm (5-m) LC-18 column (Supelco)
onstrated that a detergent water wash removed
all traces of the contaminants from the other test
by eluting with 65/35 (V/V) methanol/water at
1.5 mL/minute. The detector response was ob-
pieces (i.e., all the PVC and SS pieces, and the
tained from the digital integrator operating in the
PTFE pieces exposed for 10 minutes/10 minutes
peak height mode.
and 24 hours/10 minutes).
A set of primary standards (each 3000 mg/L)
was made in methanol. A combined standard
Fifth VOC study--Effect of
(300 mg/L) was made by pipeting a volume of
room temperature and oven drying
The purpose of this experiment was to com-
each primary standard into a volumetric flask
pare three treatments: 1) air drying at room tem-
containing methanol. These standards were kept
perature for 24 hours (with no washing in-
in a freezer. Each day, a series of aqueous stan-
volved), 2) hot water detergent wash with hot DI
dards was made by serially diluting the com-
water rinse followed by air drying for 24 hours,
bined standard with deionized water. These
working standards ranged in concentration from
and 3) hot water detergent wash with hot DI wa-
ter rinse followed by oven drying at 105C for 24
3.0 to 0.012 mg/L. The MDLs for the analytes
hours (Table 1).
were determined by the protocol described in the
Federal Register (1984).
Sixth VOC study--Effect of only oven drying
The purpose of this study was to determine
First VOC study--Effect of no treatment
whether oven drying was effective without using
In this study, we wanted to establish what lev-
any type of detergent washing or rinsing. After
el of contamination would be carried over to DI
blotting dry the contaminated test pieces, the test
water blanks if the three materials (PVC, SS, and
PTFE) received no decontamination treatment.
pieces received one of the following treatments:
1) no further treatment, 2) oven drying at 105C
for one hour, or 3) oven drying for four hours
Second VOC study--Effect of a water rinse
In this study, untreated samples were com-
(Table 1).
pared with test pieces that were briefly rinsed
The experimental protocol for contaminating
with DI water. This was done to reduce or elimi-
the test pieces differed in this study. Two 460-mL
nate any carryover of water droplets clinging to
wide-mouth glass jars were filled with test solu-
the test pieces (Table 1).
tion so there was no headspace. Eighteen pieces
of PTFE were placed in each jar, and the jars were
closed with Teflon-lined plastic screw caps. The test
Third VOC study--Effect of a
pieces in one jar were allowed to sorb for 24 hours
cold water wash and a hot water wash
In this study, we examined the efficiency of a
while those in the other jar sorbed for seven days.
6
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