United States
Environmental Protection
Agency
Environmental Monitoring
and Support Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S4-84-078 Nov. 1984
«»EPA Project Summary
EPA Method Study 28,
PCBs in Oil
Susan M. Sonchik and Richard J. Ronan
The full report describes the experi-
mental design and the results of the
U.S. Environmental Protection Agency
(USEPA) Method Study 28 for two
analytical methods to detect polychlo-
rinated biphenyls (PCBs) in oil. In this
study, the methods were used to
analyze for four PCB Aroclors {1016,
1242, 1254, and 1260), 2-chlorobi-
phenyl (2-MCB), and decachlorobi-
phenyl (DCB). The first method
consists of diluting the oil in hexane and
analyzing by gas chromatography using
an electrolytic conductivity detector in
the halogen mode. The second method
consists of diluting the oil in hexane,
cleaning/separating with sulfuric acid
extraction or with column chromatog-
raphy, and analyzing by gas chromatog-
raphy using an electron capture detec-
tor. Four oil types were tested in this
study: capacitor fluid, hydraulic fluid,
transformer oil, and waste oil.. Each.oil
was spiked with six concentration levels
of PCBs that constituted three Youden
pairs. Capacitor fluid was spiked with
Aroclor 1016, hydraulic flulid with
Aroclor 1242 and 2-MCB, transformer
oil with Aroclor 1260 and DCB, and
waste oil with Aroclor 1254.
Statistical analyses and conclusions
presented in the full report are based on
analytical data obtained by 18
participating laboratories and two
volunteer laboratories. The two
methods are assessed quantitatively
with respect to their expected precision
and accuracy. In addition, aspects of
the methods, such as sample stability
and methods detection limits, are
discussed.
This Project Summary was developed
by EPA's Environmental Monitoring
and Support Laboratory. Cincinnati,
OH, to announce key findings of the
research project that is fully document-
ed in a separate report of the same title
(see Project Report ordering
information at back).
Introduction
In 1976, polychlorinated biphenyls
(PCBs) became regulated substances
under the U.S. Toxic Substances Control
Act (TSCA, PL 94-496). In support of
Section 6 (e)(1) of TSCA, Final Rules Pre-
scribing Requirements for Disposal and
Marking of PCBs in PCB-Containing
Materials, an interlaboratory study was
conducted for two test procedures for the
analyses of PCBs in oil. The PCBs studied
were Aroclor 1016, Aroclor 1242,
Aroclor 1254, Aroclor 1260, 2-MCB and
DCB.
The interlaboratory study involved the
analyses of four PCB-spiked oil types by
20 laboratories and was conducted
between September. 1981 and December
1981. The method evaluated in this study
is described in the USEPA Draft Method
"The Analysis of Polychlorinated
Biphenyls in Transformer Fluid and
Waste Oils" (revised June 1981).
Procedure
The study 'was patterned after
Youden's non-replicate plan for
collaborative evaluation of analytical
methods, in which samples are analyzed
in pairs, each member of a pair having a
slightly different concentration of the
constituent of interest. The analyst is
directed to conduct a single analysis and
to report one value for each sample, as for
a normal routine sample. Samples of
three Youden pairs used in this study
contained low, medium, and high con-
centrations of the PCBs, 2-MCB, and DCB,
spiked into four different oil types and
then analyzed.
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Prior to the interlaboratory method
study, participants were familiarized with
both the study design and the analytical
procedure through a preliminary study
involving analyses of two oil samples
spiked at mid-level concentrations
following prescribed instructions. After
resolving method interpretation and ana-
lytical problems, participating laborato-
ries were supplied with the test materials
required by the formal collaborative study
and instructed to begin the analyses.
Statistical analyses of the data were
performed using the Interlaboratory
Method Validation Study computer pro-
gram, which was developed at Battelle's
Columbus Laboratories for USEPA. The
program is designed to output the raw
data in tabular form and compile summary
statistics including:
• Number of data points
• True value
• Mean recovery
• Accuracy as percent relative error
• Overall standard deviation
• Overall percent relative standard
deviation
• Single-analyst standard deviation
• Single-analyst percent relative
standard deviation
The overall standard deviations
indicate the dispersion expected among
values generated from multiple
laboratories. The single-analyst standard
deviations indicate the dispersion
expected among replicate determinations
within a single laboratory.
Results and Discussion
The data collected during this interlab-
oratory study were statistically analyzed
in order to establish the relationship
between accuracy and the true concen-
tration, and between precision and the
mean recovery. Those relationships are
summarized by the linear regression
equations presented in Table 1.
The final rules under the U.S. Toxic
Substances Control Act prescribe a
concentration of 50 mg/kg of PCB in oil
for disposal and marking. Therefore, this
value (except for DCB) was substituted
into the respective regression equations
and the accuracy and precision compared
for the HECD and ECD methods.
Percentage recoveries for all PCBs/oils
averaged approximately 84 percent for
both detection systems. The overall and
single-analyst standard deviation
approximated 10.0 and 7.0 mg/kg,
respectively, for both detection systems.
Percentage recoveries of DCB in
transformer oil were unusually high for
the HECD and ECD methods and were
attributed to data submitted from four
laboratories on three of the six ampules.
Subsequent recalculation without their
data resulted in the following regression
equations:
HECD X= 1.02C+0.05
S = 0.39 X + 0.00
Sr = 0-12 X +0.08
ECD X = 1.01 C + 0.00
S = 0.37 X + 0.03
Sr = 0.06 X + 0.08
Conclusions and
Recommendations
Based upon the results of the
interlaboratory study for PCBs in oils, it is
concluded that:
• At a concentration level of 50 mg/kg,
the HECD and ECD methods gave
comparable results.
• Outlier tests rejected 19 percent of
the data from 20 laboratories.
• The HECD and ECD methods in
general gave a pronounced negative
bias for recovery.
• The minimum detection level for the
ECD method is consistently lower
than for the HECD method.
Some laboratories had difficulty
integrating the DCB peak area, especially
at concentrations approximating 0.4
mg/kg. It is recommended that the oven
temperature be optimized to provide the
Table 1. Summary of Accuracy and Precision Regression Equations
Oil/PCB
X, mg/kg
S, mg/kg
Sr, mg/kg
Capacitor Fluid/1016 (33-492 mg/kg)
HECD X = 0.86T + 1.21
ECD X = 0.81T+3.10
Hydraulic Fluid 1242 (39-492 mg/kg)
HECD ~X = 0.89T- 4.28
ECD X = 0.92T-5.87
Hydraulic Fluid/2-MCB (41-1O18 mg/kg)
HECD ~X = 0.977 - 13.00
ECD X = 0.88T - 5.35
Transformer Oil/1260 (32-392 mg/kg)
HECD
ECD
X_ = 1.02T - 2.62
X = 1.04T - 4.46
Transformer Oil/DCB* (0.37-16.6 mg/kg)
HECD
ECD
X = 1.63T - 0.20
X = 1.26T - 0.09
Waste Oil/1254 (46-461 mg/kg)
HECD
ECD
X = 0.84T - 2.00
X = 0.95T - 7.02
S = 0.23X + 0.90
S = 0.35X- 2.70
S = 0.12X. + 2.50
S = 0.13X + 5.45
S = 0.16X + 1.74
S = 0.32X + 2.42
S = 0.15X + 5.97
S =
S = 0.74X - 0.14
S = 0.55X- 0.06
S = 0.17X^6.28
S = 0.12X + 3.29
Sr. = 0.09X + 4.98
Sr = 0.24X- 1.86
Sr = 0.08X^ + 3.29
Sr = 0.11X- 0.67
Sr = 0.13X -0.40
Sr = 0.24X + 0.73
Sr = 0.11X +3.50
Sr = 0.04X + 1.89
Sr = 0.12X + 0.08
Sr = 0.39X - 0.07
Sr = 0.09X + 5.59 '
Sr = 0.09X + 2.07
X = Mean Recovery.
S = Overall Method Precision.
Sr = Single-Analyst Method Precision.
T = True Value for the Concentration.
* = See recalculated regression equations in text.
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best peak geometry to assure the best
accuracy and precision for the HECD and
ECD methods.
AM. SonchikandR. J. Ronan are with Versar, 'inc., Springfield, VA 22151
Edward L Berg and Robert L. Graves are the EPA Project Officers (see below)
Incomplete report. entitled"EPA Method Study 28,'PCB's in Oil," (Order No PB
85-115178; Cost: $8.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650 '•
The EPA Project Officers can be contacted at:
Environmental Monitoring and Support Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
U.S. GOVERNMENT PRINTING OFFICE; 1984 — 559-016/7849
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