United States
                    Environmental Protection
                    Agency
Environmental Monitoring and
Support Laboratory
Cincinnati OH 45268
                    Research and Development
EPA-600/S4-84-037 June 1984
4?EPA         Project Summary
                    EPA  Method  Study  26,
                    Method  613:
                    2,3,7,8-Tetrachlorodibenzo-p-
                    Dioxin
                    Fred D. Hileman, David E. Kirk, Thomas Mazer, Arthur D. Snyder, Beverly J.
                    Warner, and Carl R. McMillin
                      The experimental design and results
                    of  an interlaboratory study  for an
                    analytical method to detect 2,3,7,8-
                    tetrachlorodibenzo-p-dioxin in water
                    are  described  herein.  In USEPA's
                    Method 613,  water  containing an
                    internal standard  (labeled 2,3,7,8-
                    TCDD) is  extracted  with  methylene
                    chloride, concentrated, exchanged to
                    hexane, and then subjected to capillary
                    column gas  chromatography/mass
                    spectrometric (GC/MS)  analysis,
                    which allows for  separation   and
                    measurement  of the 2,3,7,8-TCDD
                    isomer in the extract. The method study
                    consisted of the replicate analyses of a
                    performance evaluation  sample  used
                    primarily for  determining  laboratory
                    competence for 2,3,7,8-TCD D specific
                    analyses and subsequent analyses of six
                    sample concentrations and a  blank in
                    six different  waters (42  samples).
                    Statistical analyses and conclusions in
                    this report are based on analytical data
                    obtained  by  eleven collaborating
                    laboratories.
                      Participating  laboratories were
                    selected  based  upon  technical
                    evaluation  of  proposals  and  upon
                    technical evaluation of proposals and
                    upon the analytical results of prestudy
                    samples. Data  obtained  from  the.
                    interlaboratory study  were analyzed
                    employing USEPA series of computer
                    programs known as the Interlaboratory
                    Method  Validation  Study   (IMVS)
                    system,  which  was designed to
                    implement the concepts recommended
                    in ASTM Standard D-2777.
  The statistical analyses included tests
for the rejection of outliers, estimation
of mean recovery (accuracy), estima-
tion  of  single-analyst  and  overall
precisions, and tests for the effects of
water type on accuracy and precision.'
  This Project Summary was deve/oped-
by EPA's  Environmental .Monitoring-/
and  Support Laboratory. Cincinnati,:
OH,  to announce key findings of the-'';
research project that isfullydocumen&"<'
ed in a separate report of the same'title f
(see  Project Report ordering in forma- ••
tion at back).       '    '  .   ' ' -•• '•-"'-

Introduction                 *  ,
  The analytical laboratories of the U.S.
Environmental  Protection Agency
(USEPA) gather water  quality data to
provide information on water resources,
to assist research activities, ancl to evalu-
ate pollution  abatement activities. The
success  of  these  pollution   control
activities, particularly when legal action
is involved, depends upon the reliability of •
the data provided by the laboratories.
  Under provisions of the Clean Water
Act, the USEPA is required to promulgate
guidelines establishing  test procedures
for the analysis of pollutants. The Clean
Water  Act  Amendments of  1977,
emphasize the control of toxic pollutants
and declare the 65 "priority" pollutants
and classes of pollutants to be toxic under.
Section 307(a) of the Act, This report is
one of a  series that investigates the
analytical  behavior  of selected  priority
pollutants and suggests a  suitable test

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 procedure for their measurement.  The
 priority pollutantto be analyzed by Method
 613 is 2,3,7,8-TCDD. The Environmental
 Monitoring  and  Support Laboratory—
 Cincinnati (EMSL) of the USEPAdevelops
 analytical methods and conducts a quality
 assurance (QA) program to maximize the
 reliability and  legal  defensibility of all
 water quality information  collected by
 USEPA laboratories.
   The responsibility f or QA is assigned to
 the Quality  Assurance  Branch which
 conducts   interlaboratory   method
 validation studies. This study reports the
 results of the  interlaboratory study on
 Method 613 (Study 26).
 Procedure
   Phase  I included preliminary method
 study  work  conducted  by  Monsanto
 Research Corporation to (1) evaluate the
 original Method 613 as published in the
 December 3, 1979 Federal Register; (2)
 determine the method's minimum detec-
 tion limit; and, (3) determine the storage
 stability of 2,3,7,8-TCDD/acetone solu-
 tions in ampuls over a 90-day period. Asa
 result of  the Phase I Study, Method 613
 was revised to  substantially  alter  the
 sample processing steps. These revisions
 are now included  in the version  of
 Method 613 as presented in test method
 manual,  "Method for Organic Chemical
 Analysis of  Municipal  and Industrial
 Wastewater," EPA-600/4-82-057, July
 1982.
   Phase  II  involved  the  selection  of
 participating  laboratories  that   could
 demonstrate satisfactory analytical
 results using their personnel and equip-
 ment. This selection was based partially
 on analysis of a performance evaluation
 sample of  mixed  tetrachlorodibenzo-p-
 dioxin isomers for 2,3,7,8-TCDD.
   Phase  III, the formal interlaboratory
 study, required analyses of 2,3,7,8-TCDD
 in six water types at each of six concen-
, trations (three Youden pairs) in addition
 to the analysis of all water blanks with no
 Spiked compound.  Each   participating
 laboratory then forwarded a report to
 Monsanto  Research  Corporation
 containing  all  data obtained,  and  a
 completed  questionnaire  covering
 specifics  on the analyses  including  the
 source of  distilled, tap  and  surface
 waters,  instrumentation  used,  GC
 conditions,  and  specific  problems
 encountered in the analyses.
   The final step in the study was a statis-
 tical analysis of all data by Battelle Col-
 umbus Laboratories,  Columbus,  Ohio,
 under USEPA Contract No. 69-03-2624
employing  USEPA's  IMVS  system  of
computer programs.

Results and Discussion
  The objective of this study was to char-
acterize the performance of Method 613
in terms of accuracy, overall precision,
single-analyst precision, and the effects
of water types on accuracy and precision.
Through statistical  analyses  of 396
analytical values, estimates of accuracy
and  precision  were  made; these are
expressed  as regression equations in
Table 1. The accuracy is  obtained  by
comparing the mean recovery to the true
values of the concentration. The average
percent recovery is 91% with  a range
from 86% to 96%.
  The overall relative standard deviation
(RSD) indicates the precision associated
with measurements generated by a group
of laboratories. The average percent rela-
tive  standard deviation is 21%  with a
range of 18% to 23%.
  The  relative single-analyst  standard
deviation  (RSD-SA)  indicates  the
precision  associated  within  a  single
laboratory relative to the mean recovery.
The  average percent relative standard
deviation for a single analyst is 1 6% with
a range of 13% to 18%.
  A statistical comparison of the effect of
the water types indicated no statistically
significant  differences between  water
types.
  Correct activation  of  the  alumina
column is critical. Overactivation causes
adsorption which results in incomplete or
no elution of TCDD from the column.
  Some  laboratories  experienced poor
recovery and  poor  precision  on  the
labeled compounds. As a quality control
measure, a second independent internal
standard or surrogate should be used to-
detect  possibje^errpr irj) knqwri^concen-
tration, evaporated  'concentration,"or
incomplete dissolution of standards.
  Six  of  the  eleven   laboratories
experienced little or  no  difficulty with
Method 613. In these cases, over 98% of
the data points were retained (4 outliers
out of  216 analyses). All data from  one
laboratory which used an incorrect inter-
nal standard were rejected. Of the remain-
Table  1.   Regression Equations for Accuracy and Precision 2,3,7,8-TCDD
          (Concentration Range 21-202 ppt)
       Water Type
                   2,3,7,8-TCDD
Distilled water
  Single-analyst precision
  Overall precision
  Accuracy

Tap water
  Single-analyst precision
  Overall precision
  Accuracy

Surface water
  Single-analyst precision
  Overall precision
  Accuracy

Wastewater 1
  Single-analyst precision
  Overall precision
  Accuracy

Wastewater 2
  Single-analyst precision
  Overall precision
  Accuracy

Wastewater 3
  Single-analyst precision
  Overall precision
  Accuracy	
                     SR = 0.13X + 1.29
                      S = 0.19X +0.28
                      X = 0.86C + 1.45
                     SR = 0.01X+ 7.78
                      S = 0.22X + 0.80
                      X =0.810 + 4.82
                     SR = 0.09X + 2.25
                       S=0.21X — 1.11
                       X = 0.80C + 3.93
                     SR = 0.25X — 4.41
                       S = 0.28X — 4.63
                       X = 0.940+ 1.03
                     SR = 0.06X + 2.71
                       S_ = 0.16X + 3.12
                       X = O.82C + 4.30
                     SR = 0.16X + 0.49
                      S_ = 0.20X + 0.01
                      X = 0.780+ 4.26
X = mean recovery
C = true concentration

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 ing four laboratories, 66% of the data
 were found to be outliers. In these cases,
 three problems were identified:

   (1) difficulty  with  alumina  cleanup
      {Laboratories 4 and 11).

   (2) no recovery on 12C13 internal stan-
      dard (Laboratory 6).

   (3) lack of sensitivity at low levels of
      TCDD  (Laboratory 8).

 Conclusions and
 Recommendations
   Method 613  is recommended for the
 analyses  of 2,3,7,8-TCDD in municipal
•and industrial wastewaters.
   To increase sensitivity, place the end of
 the column  as close to the ion source as
 possible.               	'_	
   the alumina column should be checked
 for proper activity. Overactivated alumina
 can cause  adsorption of 2,3,7,8-TCDD
 which is not eluted or incompletely el uted
 by the solvent eluent.
   Because  some laboratories  reported
 poor  precision  and  experienced
 interferences  with   the  labeled
 compounds, the use of a second internal
 standard or surrogate is recommended to
 detect errors in  known  concentration,
 evaporated concentrations or incomplete
 dissolution of standards.
F. D. Hileman, D. E, Kirk, T. Mazer, A. D. Snyder, B. J. Warner, andC. R. McMillin
  are with Monsanto Research Corporation, Dayton, OH 45407.
R. J. Wesselman is the EPA Project Officer (see below).
The complete report, entitled "EPA Method Study 26, Method 613, 2,3,7,8-
  Tetrachlorodibenzo-p-Dioxin,"(OrderNo. PB84-188879;Cost:$11.50, 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 Officer can be contacted at:
        Environmental Monitoring and Support Laboratory
        U.S. Environmental Protection Agency
        Cincinnati, OH 45268
                                 •ft U.S. GOVERNMENT PRINTING OFFICE; 1984 — 759-015/7717
                                                                                3:

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Environmental Protection
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