DETERMINATION OF PURGEABLE ORGANICS




   IN SEDIMENT USING A MODIFIED




    PURGE AND TRAP TECHNIQUE





        David N. Speis

                                         XW'r

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DETERMINATION OF PURGEABLE  ORGANICS  IN  SEDIMENT

   USING A MODIFIED PURGE AND  TRAP TECHNIQUE
                               DAVID N.  SPEIS
                               U.S.  ENVIRONMENTAL  PROTECTION  AGENCY
                               REGION II
                               EDISON, NEW JERSEY   08817

                               OCTOBER 10, 1980.

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         DETERMINATION OF PURGEABLE ORGANICS IN SEDIMENT
1.    Scope and Application

     1.1    Thi's method is desiqned to determine volatile organics
           trapped in sediment that are capable of beinq thermally
           desorbed from the sediments and deposited by a carrier
           gas onto a porous polymer tran.

     1.2    This method can be used to determine oriority pollutant
           puraeables as listed in Table 1.

     1.3    This purae and tran techniaue is  preferably used with
           gas chromatography/mass soectrometry but can be used with
           electron capture gas chromatography.

2.    Summary of Method

     2.1    An aliauot of sediment is nlaced  into a hyno vial  and
           sealed.  The vial is attached to  the thermal purge
           modification of-a purge and trap  apparatus.  The volatile
           organics are thermally desorbed from the sediment and
           transferred to a porous polymer tran using an inert gas.
           When thermal desorption is complete, and all volatile
           organics have been transferred to the trap, the trap is
           backflushed with the inert purge  gas and rapidly heated,
           desorbing the concentrated organics to the inlet of the
           gas chromatograph.  The mixed volatile organics are
           chromatographically separated and analyzed using a mass
           spectrometer or electron capture  detector to provide
           gualitative data and quantitative information.

3.    Interferences

     3.1    The analytical system must be demonstrated to be free from
           interferences as demonstrated throuqh the analysis of an
           orqanic free blank.  Extremely contaminated samples may
           contain compounds that chromatoaranhically mask compounds
           of interest.  This can be especially serious if the masking
           compounds contain interferinq ions.

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     3.2   Cross Contamination

           3.2.1   Cross contamination can occur in the analytical
                   system when extremely contaminated samples are
                   analyzed.  An organic free water blank should be
                   analyzed after the analysis of a contaminated
                   samnle to insure that cross contamination does not
                   occur.

           3.2.2   Cross contamination can occur via diffusion during
                   transportation or storaae of contaminated samples.
                   A trio blank should accompany samnle vials throughout
                   the entire survey process.  This blank should be
                   analyzed with the reaular samples to monitor possible
                   cross contamination.

4.    Apparatus and Materials

     4.1   Sampling Eauinment

           4.1.1   Teflon-coated stainless steel spatula (methanol-
                   rinsed, oven-dried at 105  C).

           4.1.2   40 ml screw cap vial  (deterqent-washed and dried;
                   105° C oven).

           4.1.3   Teflon-backed silicon septum (detergent-washed
                   and dried; 105  C oven)

     4.2   Analytical Equipment

           4.2.1   Purge and trap device capable of meeting specifi-
                   cations outlined in Federal Register Method 624,
                   (Sec. 4.2) with modification for sediment purging
                   consisting of a variably heated sand trap as
                   illustrated in Figure 1.  This device consists of
                   a 250 ml sand-filled  beaker wrapped with heating
                   tape.  A 15 ml septum vial is connected in series,
                   using 1/16" I.D. stainless steel tubing with the
                   purge gas line and organic free water trap.

           4.2.2   Gas chromatograph (capable of meeting Federal Register
                   Method 624 specifications (see Table 2).

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           4.2.3   Mass spectrometer/Data System capable of meeting
                   Federal Register Method 624 specifications.

           4.2.4   Stainless steel soatula.

           4.2.5   10 ul syringe.

5.    Reagents

     5.1    Commercially available puraeable priority pollutant
           standard solution consisting of compounds listed in  Table 1.

     5.2    Commercially available surroaate standards (pure)  diluted
           to a concentration capable of delivering 500 ng of standard
           with a normal injection size.

     5.3    "Oraanic Free" distilled water.  "Oroanic Free" or "Reaaent
           Free" water can be generatedpby passing distilled water
           through a bed of Tenax G.C.  ' and activated charcoal.

6.    Sample Collection and-Preservation

     6.1    Samples are collected in 40 ml sampling vials with teflon-
           Backed silicon septa lining the vial  caps.  The vials
           should be filled to capacity to minimize the amount  of
           headspace.  A methanol-rinsed stainless steel spatula
           is used for sample collection.

     6.2    Samples should be.shipped and stored at wet ice temperature.
           Samples must be analyzed within one week of collection.

7.    Sample Extraction and Analysis

     7.1    Weigh 2-3 qrams of a sediment sample into a Pierce (or
           equivalent) 15 ml Hypo vial".  Quickly seal the vial  with
           a teflon-backed silicon septum (a maximum of 6 grams of
           sediment may be used if the sample is sandy and appears
           to be uncontaminated.)

     7.2    Inject 2 ul of three internal standards (to be used  for
           matrix affects monitoring).  The compounds are bromo-
           chloromethane, 2-bromo-l-chloropropane, and 1.4-dichloro-
           butane at a level of 250  ng/ul.   Inject the internal
           standards directly into the sediment using a 10 microliter
           syringe.

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7.3   Adjust the temperature of the sand bath to 110° C + 2.0 C.

      NOTE:  Sand bath temperatures above 110° C may cause excess
             water vapor to enter the GC/MS system.  This will be
             immediately noticeable by monitoring the recovery
             of bromochloromethane.  Monitor the sand bath
             temnerature after each analysis.

7.4   Fill the FLO trap with 5 ml of reaaent free H20.  Attach
      the 15 ml nyno vial to the purge and trap modification
      as indicated in Figure l,.usina a sharpened piece of S.S.
      tubing to pierce the septum of the sample vial.  Immerse
      the vial into the sand bath.

7.5   Purge and Tran

      7.5.1   Heat the sample for 20 minutes while purging at
              a rate of ^0 ml/min.

      7.5.2   At minute 20 - turn filament on.

      7.5.3   At minute 20 - begin 4 minute Tenax trap desorption.

      7.5.4   At minute 21 - start data collection.

      7.5.5   At minute 22 - begin temperature programming GC oven.

      7.5.6   At the completion of the desorption phase, vent
              the trap for a minimum of 10 minutes.

      7.5.7   Drain the H~Q from the trap and rinse with reaaent
              free H20.

7.6   Gas Chromatography

      7.6.1   Use columns as indicated in Federal Register
              Method 624, Table 2.

7.7   Additional Purge Parameters

      Purge gas:  Helium UHP

      Trap Dimensions:  1/8 in O.D. x 25 on long

      Trap Sorbent:  Tenax G.C. 60/80 mesh-- (15 cm), type 15
                     silica gel 35/60 mesh - (8 cm).

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     7.8   Mass Spectrometer - caoable of scanning from 20 to 260 amu
           in 7 seconds or less at 70 electron volts (nominal), and
           producing a mass spectrum which meets the criteria in
           Table 4 from 50 nanograms of n-bromofluorobenzene (BFB)
           when this material is introduced into the mass spectrometer
           either by syrinae injection into the gas chromatograph or
           throuah the purae and trao system.   Alternatively, the
           mass spectrometer must be capable of producing a mass
           spectrum which meets the criteria in Table 3 from 50
           nanoarams of decaf!uorotriphenyl phosohine (DFTPP, also
           known as bis (perfluorophenyl) phenylphosphine) when this
           material is introduced into the mass spectrometer by
           syrinae injection into the gas chromatoaranh and using one
           of the columns recommended in  Method 625, Federal Register.
           The criteria in Tables 3 and 4 are comoatible, and a
           spectrometer meeting the criteria in Table 3 (DFTPP) will
           also meet the criteria in Table A (PFB).  The mass
           spectrometer must be interfaced with a aas chromatograoh
           designed for packed-column chromatography.  It is recommended
           that the interface between the end of the chromatoaraphic
           column and the ion source of the mass spectrometer be
           constructed with deactivated glass or glass-lined materials.
           However, the GC/MS interface can use any-separator, transfer
           line, or other interface part, orovided it is demonstrated
           that the system gives acceptable and reproducible mass
           spectra of all the compounds listed in Table 1 at the
           specified limits of detection, and that all  other performance
           criteria included in this section are achieved.

           7.8.1   If the system performance criteria are not met,
                   the instrument must be retuned and rechecked
                   until the criteria are met.  No samples shall be
                   analyzed until the performance criteria are met.

8.   Qualitative and Quantitative Determination

     8.1   To identify a compound, obtain the background subtracted
           mass spectrum of the compound  of interest.  The criteria
           below must be met for an identification.

           8.1.1   All of the ions that are present above 10% relative
                   abundance in the 70 ev (nominal) electron
                   ionization spectrum of an authenic sample of the
                   comnound (or library spectrum) must be present
                   in the experimental-spectrum with agreement to
                   plus or minus 10% of the base oeak abundance.

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      8.1.2    If the reference ion's abundance is 30%,  allowable
              limits on the relative intensity of the samole's
              ion would be 20-40%.

      8.1.3    The unknown peak should be within +_ 30 seconds
              and all  references to scan numbers should be
              deleted because variable times may be used for
              a  complete scan.

              Structural isomers that have very similar mass
              spectra can be explicitly identified only if the
              resolution on the GC column between the isomers
              in a standard mix is acceptable.  Otherwise,
              structural isomers are identified as isomeric
              pairs.

              Acceptable resolution is achieved if the  depth
              of the valley between the oeaks, measured from
              the smallest peak, is  50% of the smaller peak
              height.

8.2   Primary ions listed in Table 5 should be used for
      quantisation.   Primary ion interferences can be avoided
      by using secondary ions for auantitation.

8.3   External Standard Calibration

      Concentrations of identified ourgeable organics may be
      calculated using a single point calibration.  This
      techniaue  should be used after response vs. concentration
      linearity  has  been proven for the compound to be
      calculated.  Use Eguation 1 for this calculation.
      Equation 1.              (A)(B)
              A = Micrograms Standard
              B = Area of the unknown
              C = Area of Standard
              D = Kilograms Sample

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                             Bibliography
1.   Federal  Register,  Volume 44,  No
    December 3, 1979.
233, pg. 69532 - 69539.
2.  Determination of Purgeable Organics  in  Sediments.   D.N.  Speis.
    Hydrocarbons and Halogenated Hydrocarbons  in  the Aquatic
    Environment,  Plenum Press, New York, NY   1980,

3.  Bellar, T.A., Lichtenberg, J.J., and Kroner,  R.C.   Deter-
    mining Volatile Organics  in Microgram per  Liter levels by
    Gas Chromatography.  Journal  American Water Works Association,
    Volume 66, No. 12, December 1974.

4.  Sediment Sampling for Volatile  Organics.   U.S. Environmental
    Protection Agency, Environmental  Monitoring and Support
    Laboratory.  Cincinnati,  Ohio.   August  2,  1977.

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                             TABLE 1
CHLOROMETHANE



BROMOMETHANE



VINYL CHLORIDE



CHLQROETHANE



DICHLOROMETHANE



TRICHLOROFLUOROMETHANE



1,1- DICHLOROETHYLENE



1,1- DICHLOROETHANE



TRANS L, 2 - DICHLORETHYLENE



CHLOROFORM



1,2- DICHLOROETHANE



1,1,1- TRICHLOROETHANE



CARBONTETRACHLORIDE



BROMODICHLOROMETHANE



1,2- DICHLOROPROPANE



1,3- DICHLOROPROPENE



TRICHLOROETHYLENE



BENZENE



DIBROMOCHLOROMETHENE



1,1,2- TRICHLOROETHANE



BROMOFORM



1, 1, 2, 2 - TETRACHLOROETHANE



TETRACHLOROETHYLENE



TOLUENE



CHLOROBENZENE



ETHYLBENZENE

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                                    TABLE 2
                     GAS  CHROMATOGRAPHY OF  PURGEABLE ORGANICS
                                   •'RETENTION TIME  (MIN)      LIMIT OF DETECTION 3
    COMPOUNDS                          :~~          (ug/kg)
                                   Col . 1  '   Col . 2 2
CHLOROMETHANE-
BROMOMETHANE
VINYL CHLORIDE
CHLOROETHANE
METHYLENE CHLORIDE
TRICHLOROFLUOROMETHANE
1,1-DICHLOROETHYLENE
1,1-DICHLOROETHANE
TRANS-1 ,2-DICHLOROETHYLENE
CHLOROFORM
1,2-DICHLOROETHANE
1,1,1-TRICHLOROETHANE
CARBON TETRACHLORIDE
BROMODICHLOROMETHANE
1,2-OICHLOROPROPANE
1,3-DICHLOROPROPANE
TRICHLOROETHYLENE
DIBROMOCHLOROMETHANE
BENZENE
1,1,2-TRICHLOROETHANE
BROMOFORM
1,1,2 ,2-TETRACHLOROETHANE
TETRACHLOROETHYLENE
TOLUENE
CHLOROBENZENE
ETHYL BENZENE
BROMOCHLOROMETHANE 4
2-BROMO-l-CHLOROPROPANE 4
1,4-DICHLOROBUTANE 4
ACROLEIN
ACRYLONITRITE
1.50
2.17
2.67
3.83
5.25
7.18
7.92
9.30
10.08
10.68
11.40
12.60
13.02
13.65
14.92
15.22
15.80
16.48
16.30
16.52
19.23
21.62
21.67
24.79
24.18
29.03
8.48
-
17.50
9.10
9.65
1.43
1.87
2.30
2.60
3.37
4.43
4.80
5.43
5.93
6.20
6.77
7.60
-7.93
8.40
9.60
9.90
10.50
10.90
10.97
11.03
13.63
16.27
16.83
18.20
19.53
21.70
4.90
12.27
16.83
-
-
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
_
_
-
-
-
   Eight ft. stainless steel column (1/8 in. OD x 0.1 in. ID) packed with 1%
   SP-1000 coated on 60/80 mesh Carbopack B preceded by a 1 ft. stainless steel
   column [1/8 in. OD x 0.1 in. ID) packed with 1% SP-1000 coated on 60/80 mesh
   Chromosorb W. (A glass column (1/4 in. OD x 2 mm ID) may be substituted).
   Carrier gas helium at 40 ml/min.  Temperature program: 3 min isothermal  at
   45°C, then 8°/ min to 220°, hold at 220° for 15 minutes.
2
   Eight ft. stainless steel column (1/8 in. OD x 0.1 in. ID) packed with 0.2%
   Carbowax 1500 coated on 60/80 mesh Carbopack C preceded by a 1 ft. stainless
   steel column (1/6 in. OD x 0.1 in ID) packed with 9% Carbowax 1500 coated on
   60/80 mesh-Chromosorb W.  A glass column (1/4 in. OD x 2 mm ID) may be substituted.
   Carrier gas: helium at 40 ml/min.  Temperature program: 8 min. isothermal at
   6.0°C then 8°/min to 160°, hold at 160 until  all  compounds elute.

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3
   This is a minimum level at which the entire system must give recognizable
 .  mass spectra and acceptable calibration points.
4
   Internal Standard.
                                    TABLE 3


                    DFTPP KEY  IONS AND ION ABUNDANCE CRITERIA
          MASS                                 ION ABUNDANCE CRITERIA

            51                                 30-60% of mass 198

            68                                 less than 2% of mass 69
            70                                 less than 2% of mass 69

           127                                 40-60% of mass 198

           197                                 less than 1% of mass 198
           198                                 base peak, 100% relative abundance
           199                                 5-9% of mass 198

           275                                 10-30% of mass 198

           365                                 greater than 1% of mass 198

           441                                 less than mass 443
           442                                 greater than 40% of mass 198
           443                                 17-23% of mass 442

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                         TABLE 4


 p-BROMOFLUOROBENZENE KEY IONS AND  ION ABUNDANCE CRITERIA	


MASS                                 ION ABUNDANCE CRITERIA

 50                                  15-40% of the base peak
 75                                  30-60% of the base peak
 95                                  base peak, 100% relative abundance
 96                                  5-9% of the b,ase peak
173                                  less than 1%'of the base peak
174                                  greater than 50% of the base peak
175                                  5-9% of mass 174
176                                  greater than 50% of the base peak
177                                  5-9% of mass 176

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                                     TABLE 5
                    CHARACTERISTIC  IONS OF VOLATILE ORGANICS
      COMPOUNDS
El IONS
PRIMARY ION
CHLOROMETHANE-
BROMOMETHANE
VINYL CHLORIDE
CHLOROETHANE
DICHLOROMETHANE
TRICHLOROFLUOROMETHANE
1,1-OICHLOROETHYLENE
1,1-OICHLOROETHANE
TRANS-1,2-DICHLOROETHYLENE
CHLOROFORM
1,2-DICHLOROETHANE
1,1,1-TRICHLOROETHANE
CARBON TETRACHLORIDE
BROMODICHLOROMETHANE
1,2-OICHLOROPROPANE
1,3-OICHLOROPROPENE
TRICHLOROETHYLENE
BENZENE
DIBROMQCHLOROMETHANE
1,1,2-TRICHLOROETHANE
BROMOFORM
1,1,2,2-TETRACHLOROETHANE
TETRACHLOROETHYLENE
TOLUENE
CHLOROBENZENE
ETHYL BENZENE
BROMOCHLOROMETHANE
2-BROMO-l-CHLOROPROPANE
1,4-OICHLOROBUTANE *
50,52                             50
94,96                             94
62,54                             62
64,66                             64
49,51; 84,86                      84
101,103                          101
61,96,98                          96
63,65; 83,85; 98,100              63
61,96,98                          96
83,85                             83
62,64; 98,100                     62
97,99; 117,119                    97
117,119,121                      117
83,85; 127,129                    83
63,65; 112,114                    63
75,77                             75
95,97; 130,132                   130
78                                78
127,129; 206,208                 129
83,85; 97,99; 132,134             97
171,173,175; 250,252; 254,256    173
83,35; 131,133; 166,168           83
129,131; 164,166                 164
91,92                             91
112,114                          112
91,106                            91
49,51; 128,130                   128
77,79,156                         77
55,90,92                          55
  Internal Standard.

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                                              F J G I! R F   J.
PURGE  GAS  INLET   WO ML/MIN)
15 ML SEPTUM SEALED VIAL
 2-5 GMS WET SEDIMENT
      HEATED SAND  (110° C)
                                      1/16" STAINLESS STEEL TUBING
                                                                       PURGE EFFLUENT TO TENAX/SILICA GEL TRAP
                                                                             15 ML SEPTUM SEALED CENTRIFUGE TUBE
                                                                  5 ML REAGENT FREE WATER

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               PREPARATION OF SPIKED SEDIMENT SAMPLES FOR ANALYSIS





A pre-selected sediment was heated to 600°C in a muffle furnace to remove any


volatile organic compounds.  The muffling also activated the surface of the sediment


to produce a matrix that would bind organics.






Five grams of the sediment were weighed into a 15 ml  hypo vial.  A solution of


purgeable organics (Table 1) was prepared in water so that 2 ml of this solution


would deliver the desired quantity of each organic.  Two ml  of water was sufficient


to thoroughly wet the sediment sample without floating it.  Five replicates of each


spike are prepared along with 2 unspiked sediment blanks.  The samples are sealed


with aluminum seals and teflon-lined silicon septa.  After sealing, the spiked


samples were placed in a 5°C refrigerator and equilibrated for 16 hours before
                                  >.

analysis.





The levels of the spikes for the listed compounds were:  2ng; lOng; 20ng; 40ng;


80ng.





The attached table contains nanograms recovery,  % recovery and standard deviation


(% recovery) for each compound in the 5 spike levels.  Correlation coefficient has


been calculated for each compound over the spiking range.





Conclusions:  Recoveries were linear and reproduceable over  the concentration


range of 10-80 ng.   Quantitative recoveries  for  amounts  lower than lOngs are er-


ratic.   Qualitative determinations are possible  for some compounds at the 2ng level.

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The average recovery in the linear range was 75-80%.








The Internal Standard, bromochloromethane,  is an excellent indicator of potential



trouble caused by excess water vapor carried into the GC/MS that has not condensed



in the reagent free water trap.  When recoveries are less than  80%,  the analyst



can expect a 20-60% reduction in the recovery of 1,2-dichloroethane, 1,1-dichloro-



ethane, chloroform, 1,1-dichloroethylene and 1,2-trans dichloroethylene.  These



compounds elute under the broad chromatographic peak caused by  water.

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1
SPIKED COMPOUNDS
"HLOROHETHANE
BROMOMETHANE
•INYL CHLORIDE
HLOROETHANE
.ETHYLENE CHLORIDE
i R I CHLOROTR I FLUOROMETHANE
1 ,1-DICHLOROETHYLENE
i,l-DICHLOROETHANE
:RANS 1 ,2-DICHLOROETHYLENE
:HLOROFORM
i ,2-DICHLOROETHANE
1 ,1,1-TRICHLOROETHANE
JARBON TETRACHLORIDE
'.ROMODICHLOROMETHANE
' ,2-DICHLOROPROPANE
1 ,3-DICHLOROPROPENE
RICHLOROETHYLENE
jIBROMOCHLOROMETHANE
ENZENE
1,1,2-TRICHLOROETHANE,
iROMOFORM
,1,2,2-TETRACHLOROETHANE
HRACHLOROETHYLENE
ULUENE
ILOROBENZENE
HYLBENEZENE

INTERNAL STANDARDS
::-OMOCHLOROMETHANE
BROMO-1-CHLOROPROPANE
4-DICHLOROBUTANE

'
* NOT RECOVERED
** IN SCANS V 2. SEC.
2 NG 10 NG 20 NG 40 NQ 80 NG
**
R.T.
43
56
69
78
101 1
133
144
163
178
186
203
J28_
238
252
288
297
315
327
329
331
409
488
505
546
586
651


147
368'
505



.
NG
REC.
*
*
*
*
*
8.9
*
5.0
7.0
7.4
*
12
2.1
1.7
3.2
*
2.4
1.9
3.2
*
2.6
*
*
0.5
1.8
2.3









NOTE 1: EXCESS WATER JflftPOR IJNTERFE
NOTE 2: EXTERNAL CONT^INATIJON >
II 1
%-
REC.





448

250
350
327

602
106
86
161

121
98
162

128


26
89
[Ti2


122
104
83




RENCE
200%

"SD
W





no

18
61
62

47
12
15
_19_
12
25
33

86


18
8.1
10


20
9
25













_ ..__




















	






NG
REC.
8.3
9.7
8.8
6.5
5.6
4.4
6.7
6.7
6.9
7.8
7,5.._
7.4
7.4
6.9
8.4
4.9
8.4
7.3
6.3
7.0
7.5
5.9
7.7
8.9
6.4
6.3











	
%
REC.
83
97
88
65
56
44
67
67
69
78
75
74
74
69
84
49
84
73
63
70
75
59
77
89
64
63


95
97
92







SD-
(X)
10
7.2
13
14
12
6.3
13
17
2.3
4.8
16 .._
8.9
7.7
10
_6.2. .
9.4
6.9
9.0
17
8.8
14
3.9
5.3
7.3
6.9
3.9


17
8.1
27
	






	










	




f





	
	
	





~N(T"
REC.
23.1
24.8
2
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SPIKED COMPOUNDS
CHLOROMETHANE
BROHOMETHANE
VINYL CHLORIDE
CMLOROETHA'NE
METHYLENE CHLORIDE
TR I CHLOROTR I FLUOROMETHANE
1,1-DICHLOROETHYLENE
1.1-DICHLOROETHANE
TRANS 1 ,2-DICHLOROETHYLENE
CHLOROFORM
1 ,2-DICHLOROETHANE
1,1,1-TRICHLOROETHANE
CARBON TETRACHLORIDE
BROMOD I CHLOROMETHANE
1 ,2-DICHLOROPROPANE
1,3-DICHLOROPROPENE
TRICHLOROETHYLENE
DIBROMOCHLOROMETHANE
BENZENE
1,1,2-TRICHLOROETHANE
BROMOFORM
,1,1,2,2-TETRACHLORQETHANE
TETRACHLOROETHYLENE
TOLUENE
CHLOROBENZENE
CTUVI ncwCTrNF


INTERNAL STANDARDS
3ROMOCHLOROMETHANE
2-BROMO-l -CHLOROPROPANE
M-TnaiLOROBUfANE


* NOT RECOVERED
** IN SCANS V 2. SEC.
NOTE 1: EXCESS WATER '
NOTE 2: EXTERNAL CONT/

2 NG '
**
R.T.
43
56
69
78
101
133
144
163
178
186
203
228
238
252
288
297
315
327
329
331
409
488
505
546
586
651

147
368
505



I\POR I
«NATI

NG ;
REC.
*
*
*
*
*
8.9
*
5.0
7.0
7.4
*
12
2.1
1.7
3.2
*
2.4
1.9
3.2
*
2.6
*
*
0.5
1.8
2.3


	




NTERFE
ON >

%
REC.


448
250
350
327
602
106
86
161

121
98
162

128


26
_89
112

122
104
83




RENCE
200%

SD
(*)

*
110
18
61
62
47
12
15
10

12
25
33

86
18
8.1
1C
20
9
25

















m '
REC.
8.3
9.7
8.8
6.5
5.6
4.4
6.7
6.7
6.9
7.8
7.5 _
7.4_
7.4
6.9
8.4
4.9
8.4
7.3 j
6.3
7.0
7.5
5.9
7.7.
8.9
6.4
6.3



	




10 NG 20 NG 40 NQ 80 NG
' %
REC.
83
97
88
65
56
44
67
67
69
78
75
74
74
69
84
49
84
73
63
70
75
59...
77_ .
89
64
63

95
97
92




SD -
(X)
10
7.2
13
14
12
6.3
13
17
2.3
4.8
16
8.9
7.7
10
6.2
..M.
6.9
9.0
17
8.8
14
3.9
5.3 .
7.3
6.9
3.9
17
8.1
27
-- - -

















_.. -.


-
-- —
~m-
REC.
23.1
24.8
20.4
25.4
15.3
21.3
18.0
17.8
16.7
18.6
17.8
16.9
15.3
16.0
18.3
13.7
16.2
14.2
23
16.4
13.6
15.4
16.5
16.5
15.9
15.8





~

-f-
REC.
116
124
102
127.._
J.L..
106
90
89
83
93
89
84
76
80
92
68
81
71
113
82
68
-77_
83
83
80
79


113
105
100

	
	
3D
%
8.1
14
11
13
15
15
6.3
6.5
7.2
5.2
6.5
5.2
8.5
6.4
6.8
3.4
8.6
7
7.6
9.7
10
20
8.5
8.2
6.4
8.2


3.4
2.9
13
—

	



























. _. .

	
NG
REC.
51.8
46.5
42.4
37.5
24.4
NOT
32.3
35
NOT
32.5
33.8
31.8
30.9
30.8
32.4
27.1
30.9
29.8
28.6
29.5
28.0
28.7
30.7
25.4
29.2
28.8






._ . ..
't
REC.
132
116
106
94
61
: 2
81.1
87.5
E 1
69
85
79
77
76
81
68 _
77
74
71
74
70
72
77
64
73
72


90
101
102



SD
%
13
8.4
3.8
13
3.9

2.3
2.1
27
2.9
4.4
2.3
7.5
3.3
7.1
5.9
4.2
6.1
7.2
6.2
9.6
3.1
12
3.8
4.6


27
7.1
11
-


	



- -












	


	
	








NG
REC.
72.7
61.0
59.9
50.8
51.4
82. 8
67.1
56.8
62.2___
62.7
64.5
74.1
BO. 3
74.5
70. 4_
56.6
78.7
59.4
66.0
51.5
52.9
18.1
59.9
51.2
55.5
51.4


	


	




%
REC.
91
77
87
76
77
103
84
84
78
77
81
93
01
93
88
71
99
87
83
77
79
60
88
77
81
80


73
74
60

	


	
SD
%
13
15
2.4
20
17
37
20
29
32
35
31
1.3
3.3
'24
18 _
21
12
33
10
35
41
33
7.6
8.8
13
8.0


24
18
28

	




^,=,,

_..









	
















	




CORR
CO-E
.9659
.9508
.9916
.9725
.9928
.9971
.9988
.9986
.9994
,9985
•9990
.9975
.9924
,9960
9984
9996
9935
9968
9831
9992
9980
9917
9978
mi.
9982
9990


	

___, 	


LATIO
Fieri


	 	






_:'-_„:

	

	



•




	
	
	



T:;. v_
11 '•'•';

	







.... — i












	 ~


— „,
"' '^'-' '
— - —'

-------