United States
Environmental Protection
Agency
Environmental Monitoring and
Support Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S4-84-051 July 1984
4»EPA Project Summary
EPA Met
hod Study 17,
Method 607 — Nitrosamines
John D. Millar, Richard E. Thomas, and Herbert J. Schattenberg
This report describes the results
obtained and data analyses from an
interlaboratory evaluation of EPA
Method 607 (Nitrosamines). The method
. is designed to analyze for three nitrosa-
mines, N-nitrosodirr ethylamine, N-
nitrosodi-n-propylami ie, and N-nitro-
sodiphenylamine, in water and waste-
water. As tested here, the method
utilized three 60-mL extractions with
dichloromethane, cle anup/separation
on an alumina colurr n, and injection
into a gas chromatograph equipped
with a nitrogen-phosphorus detector.
The study design required the analyst
to dose six waters with each of six
mixtures of the three nitrosamines. The
six dosing levels represented three
Youden pairs, one each at a low, an
intermediate, and a high level. The six
waters used were a laboratory pure
water, a finished drinking water, and a
surface water, all collected by the
participant, and three] low-background
industrial effluents furnished by the
prime contractor. A total of 17 labora-
tories participated in t|he study.
The method was studied to estimate
the accuracy and precision that can be
expected, including effects on the
accuracy and precision of analysis of
different matrices. In addition, results
of method detection limit and analytical
curve studies and qualitative assess-
ments of the methJDd based upon
comments by the participating labora-
tories are included. I
This Project Summary was developed
by EPA's Environmental Montoring
and Support Laboratory, Cincinnati,
OH, to announce key findings of the re-
search project that is fully documented
in a separate report of the same title (see
Project Report ordering information at
back).
Introduction
EPA first promulgated guidelines
establishing test procedures for the
analysis of pollutants in 1973, following
the passage of the Federal Water Pollution
Control Act in 1972 by Congress. Pur-
suant to the amendment and publication
of these guidelines, EPA entered into a
Settlement Agreement—the Consent
Decree—which required the study and, if
necessary, regulation of 65 "priority"
pollutants and classes of pollutants of
known or suspected toxicity to the biota.
Subsequently, Congress passed the
Clean Water Act of 1977, mandating the
control of toxic pollutants discharged into
ambient waters by industry. ,,-•
In order to facilitate the implemeptation
of the Clean Water Act, EPA selected for
initial study 129 specif ic toxic pollutants,
113 organic and 16 inorganic. The
organic pollutants were divided into 12
categories based on their chemical
structure. Analytical methods were
developed by EPA for these 12 categories
through in-house and contracted research.
These analytical methods may eventually
be required for the monitoring of the 113
toxic pollutants in industrial wastewater
effluents, as specified by the Clean Water
Act of 1977.
As a logical subsequence to the work
that produced proposed EPA Method 607
(nitrosamines), an interlaboratory study
was conducted to test the validity of the
proposed method. This report describes
the work performed, presents the data
acquired, and gives the conclusions
drawn from the collaborative effort.
The three compounds undergoing
analyses in the interlaboratory study
were N-nitrosodimethylamine (NDMA),
N-nitrosodi-n-propylamine (NDPrA), and
N-nitrosodiphenylamine (NDPhA).
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The objective of this interlaboratory
study was to obtain information about the
accuracy and precision associated with
measurements generated by Method
607. This objective was met through the
use of statistical analysis techniques
designed to extract and summarize the
relevant information about accuracy and
precision from the data reported by the
participating laboratories. The statistical
techniques employed in the data reduction
process are similar to the techniques
suggested in the ASTM Standard Practice
02777-77.
The algorithms required to perform the
statistical analyses have been integrated
into a system of computer programs
referred to as IMVS (Interlaboratory
Method Validation Study). The analyses
performed by IMVS include several tests
for the rejection of outliers (laboratories
and individual data points), summary
statistics by concentration level for mean
recovery (accuracy), overall and single-
analyst standard deviation (precision),
determination of the linear relationship
between mean recovery and concentration
level, determination of the linear relation-
ship between the precision statistics and
mean recovery, and a test for the effect of
water type on accuracy and precision.
Procedure
The study design was based on Youden's
original plan for collaborative evaluation
of precision and accuracy for analytical
methods. According to Youden's design,
samples are analyzed in pairs where each
sample of a pair has a slightly different
concentration of the constituent. The
analyst is directed to do a single analysis
and report one value for each sample, as
for a routine sample.
In this study, samples were prepared as
concentrates in sealed glass ampules and
shipped to the analyst with portions of
final effluents from manufacturing plants
from three relevant industries. Each
participating laboratory was responsible
for supplying laboratory pure water, a
finished drinking water, and a surface
water, thus giving a total of six water
matrices involved in the study. The
analyst was required to add an aliquot
of each concentrate to a volume of water
from each of the six waters and submit
the spiked water to analysis. Three pairs
of samples were used. One pair contained
the substances at what was considered to
toe equivalent to a low level for the
industrial effluents; a second pair con-
tained the substances at an intermediate
level; and the third pair contained the
substances at a high level.
Before the formal study began, each
participant was sent a pair of ampules
(not one of the pairs used in the study)
for a trial analysis by Method 607. After
submitting data from these analyses to
SwRI, all participants met in Cincinnati to
discuss problems encountered during the
trial run.
Results and Discussion
The accuracy of the method could be
expressed as a linear function of the true
concentration. The regression equations
for accuracy are shown in Table 1.
The precision of the method could be
expressed as a linear function of the
mean recovery, both as single-analyst
and overall standard deviations. The
regression equations for ..precision, are _
also shown in Table 1.
The percent recovery of the method
was similar to that obtained during the
developmental phase. The method has an
extreme negative bias for IMDMA, nearly
quantitative recovery for NDPrA, and "a
moderate negative bias for NDPhA.
Percent recoveries at the midrange
concentration were from 36 to 43% for
NDMA, 84 to 102% for NDPrA, and 58 to .
67% for NDPhA.
The precision of the method was about
as expected for NDMA and NDPrA and
higher than expected for NDPhA. The
additional variability likely results from
the column elution procedure.
Six water types were used in this study:
laboratory pure, finished drinking, sur-
face, and three relatively interference-
free industrial effluents. No difference in
method performance was attributable to
the water type from which the analysis
was performed.
Verifying the activity of the alumina
and separating NDPhA from diphenyl-
amine proved to be a difficult step in the
analytical procedure and several labora-
tories were unable to achieve satisfactory
separation.
Data rejected from the study due to
missing results, values reported as below
the laboratory's detection limit, and
statistical outliers amounted to more
than 19% of the total analyses.
Conclusions and
Recommendations
The participating laboratories in this
study were able to obtain results with
Method 607 that were comparable to
those obtained during the single-labora-
tory evaluations conducted after method
development. The accuracy and precision
statements presented earlier apply only
to the range of concentrations studied
and should not be extrapolated beyond
those limits.
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Table 1. Accuracy and Precision Equations
Water type N-Nitrosodimethylamine
Range, ug/L 0.82-24.2
Laboratory pure
A ccuracy X = 0. 370* + 0. 06
Precision
Overall S = 0.25X+0.11
Single Analyst SR = 0.25X - O.O4
Finished Drinking
Accuracy X = O.37C + 0.23
Precision
Overall S = 0.23X + 0.23
Single analyst SR = 0. 16X +0.15
Surface
Accuracy X = 0. 42C + 0. 14
Precision
Overall S = 0.34X^0.17
Single analyst SR = 0.29X + 0. 15
Industrial Effluent 1
Accuracy X = 0. 38C + 0.17
Precision
Overall 5 = 0. 33X + 0.09
Single analyst SR =0.1 3X + 0.21
Industrial Effluent 2
A ccuracy X = 0. 35C + 0.13
Precision
Overall S =0. 33X + 0. 09
Single analyst SR = 0. 25X + 0. 03
Industrial Effluent 3
Accuracy X = 0.36C + 0.30
Precision
Overall S = 0.27X+0.21
Single analyst - SR = 0.28X + 0.07
*C-true concentration
X-mean concentration
John D. Millar, Richard E. Thomas, and Herbert J. Schattent
Southwest Research Institute, San Antonio, TX 78284.
Robert L. Graves and Edward L. Berg are the EPA Project Offi
-fy^ Nj-Nitrosodi-n-propylamine
1.22-26.7
*
X = O.96C -O.O7
S=0.21X+0.15
SR = 0. 15X + 0. 13
X = 0.84C - 0.02
S = 0.28X+0.05
SR=0.24X
X = 0.92C + 0.05
*
S=0.26X+0.24
SR=0. 16X + 0.24
•. ••>-•"-.» * - - - > - -• - •
X = 1.OOC + 0.21
S = 0.26* +0.39
SR = 0.18X+0.27
X = 0.860 + 0.21
S = 0.33X + 0.18
Sr = 0.26X - 0.04
X = 0.940 + 0. 14
S = 0.37X+0.25
SR = O.22X + O.44
erg are with the
cars (see below).
The complete report, entitled "EPA Method Study 17, Method 607 — Nitros-
amines, " (Order No. PB 84-207 646; Cost: $1O.OO, subject t
available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, V A 221 61
Telephone: 7O3-487-465O
The EPA Project Officers can be contacted at:
Environmental Monitoring and Support Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
•> change) will be
N-Nitrosodiphenylamine
8.22-54.8
X = 0.640 + 0.52
S=0.46X -0.47
SR = 0.36X - 1.53
X = 0.600-0.03
S = 0.37X+0.67
SR = 0.23X + 0.81
X = 0.620 -0.56
S = 0.32X+1.03
SR = 0.23X + 0.24
•-' • - • » - "'••» ' • —
X = 0.680 -0.44
S = 0.39X + 0.14
-SR = 0.34X - 0.83
"
X = 0.580 + 0.15
S = 0.42X+0.66
SR = 0.22X + 0.65
X = 0.620 + 0.54
S = 0.37X + 0.50
SR = 0.21 X + 0.21
ING OFI
U.S. GOVERNMENT PRINTING OFFICE; 1984 — 759-015/7757
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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