Transcript Gas Chromatography/Mass Spectrometry Analysis (GC/MS) Fundamentals and Special Topics Zbigniew ‘Bernie’ Wilk, Ph.D. Russell Confer, M.S. Office of Quality Assurance New Jersey Department of Environmental Protection.

Gas Chromatography/Mass
Spectrometry Analysis
(GC/MS)
Fundamentals and Special Topics
Zbigniew ‘Bernie’ Wilk, Ph.D.
Russell Confer, M.S.
Office of Quality Assurance
New Jersey Department of Environmental Protection
Gas Chromatography/Mass Spectrometry
• GC/MS Overview
50 min.
• the nuts and bolts of how GC/MS works
– Break
• GC/MS Analysis Special Topics
10 min.
50 min.
• Chromatograms & Peak Integration
• TICs & MS Libraries, Interferences
– Break
• Dioxins and PCB Analyses
• GC/High Resolution Mass Spectrometry
10 min.
50 min.
Gas Chromatography/Mass Spectrometry
•
Introduction
–
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Organic Analysis Overview
History
The wide world of Mass Spectrometry
How it all works
Tuning/Calibration
•
Break
•
Gas Chromatography/Mass Spectrometry (GC/MS)
–
–
–
–
From Chromatograms to final report
Mass Spectrometry Libraries and Compound Identification (TICs)
Proper and Improper Peak Integrations - Manipulating Results
Dealing with Interferences
•
Break
•
- Dioxin and PCB Analyses Using GC/High Resolution Mass Spectrometry
–
–
–
–
–
Review of EPA Methods
Why High Resolution Mass Spectrometry
High Resolution Mass Spectrometry Fundamentals
Dioxin and PCB Analysis Methods Highlights
Comparing PCB Methods 1668A to 8082 - Aroclors or Congeners.
Gas Chromatography/Mass Spectrometry
(GC/MS)
Gas
Chromatography

Separates mixture of pollutants
so each can be identified individually
Mass
Spectrometry
=
Gas Chromatography Mass Spectrometry
A Chemical Analysis Technique
combining two instruments to provide for
powerful separation and identification
capabilities
Identifies (detects) pollutant molecules
based on their molecular weight or mass
Gas Chromatography/Mass Spectrometry
The mass spectrometry results at a
resolving power of 10,000 indicate that
isobaric interferences exist that make the
chlorine ion intensities inconsistent with
their natural isotopic abundance at the
molecular ion.
WHAT THE MASS SPECTROMETRIST SAYS
The mass spectrometry results blah,
blah, blah, blah, blah, blah, blah, blah,
blah, blah, blah, blah that make the
chlorine blah, blah, blah, blah, blah,
blah, blah, blah, blah, blah, blah, blah,
blah, blah, blah, blah.
WHAT THE AVERAGE PERSON HEARS
Historical Timeline of GC/MS
1952
Martin and Synge
Nobel Prize
Chromatography

1900
1906
Sir J.J. Thompson
Nobel Prize for
discovery of electron
1979
USEPA Publishes
Wastewater Methods
Under Clean Water Act
EPA Born
1942
First Commercial
Mass Spectrometer
1971
USEPA Purchases 6
Finnigan GC/Mass Specs
2000
GC/MS
LC/MS
ICP/MS
Dates of Historical Note
•
•
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•
•
•
•
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1906 - Sir J.J. Thomson (Cambridge) gets Nobel Prize for the discovery of the
electron.
1930 - Aston uses MS to study isotopes
1942 - first commercial magnetic mass spectometer
1952 - Martin and Synge win Nobel Prize for Chromatography
1959 - Gas Chromatography interfaced to Mass Spectrometer
1968 - Finnigan Corp. delivers first Quadrupole GC/MS
1969 - Finnigan Corp. delivers first Quadrupole GC/MS with computer
1970 - USEPA is born
1971 - USEPA purchases 6 Finnigan GC/MS systems
1972 - Federal Water Pollution Control Act (CWA) is passed
1976 - Hewlett Packard introduces fully computerized GC/MS system
1976 - RCRA Enacted
1979 - USEPA publishes wastewater methods under CWA
1983 - Development of LC/MS interface by Vestal et. al.
Various Forms of Mass Spectrometry
• A whole range of possibilities/permutations
Sample Introduction
Ionization
Mass Separator
Detector
Gas Chromatography
EI (electron impact)
Quadrupole
Liquid Chromatography
Electrospray
CI (chemical ionization)
Ion Trap
discrete dynode
NCI negative CI
Time-of-Flight(TOF)
photo-optical
FAB(fast atom bombardment) Sector(BE, EB, EBE)
image current
n
API (atmospheric pressure)
FTMS (MS )
LIMS (laser ionization)
Ion Mobility
FI/FD (field desorption)
Triple Stage Quadrupoles (MS/MS)
MALDI (matrix assisted laser Hybrid Combinations (Q-TOF, BEQ)
desorption ionization)
Particle Beam (PB/LC/MS Interface)
Thermospray (TSP/LC/MS Interface)
Atmospheric Pressure Ionization (API/LC/MS)
ETC.
channeltron
GC/MS
• Great For the Analysis of Organics
• Gas Chromatography Analysis Requirement
– Organics to be analyzed must be VOLATILE or at least
Partially VOLATILE .
• First 30 years of EPA have concentrated on relatively volatile organics
• Next 30 years?
Polar and Non-Volatiles?
LC/MS?
Broad Range of Organic Compounds
(How many are there?)
Chemical Abstracts Service
16, 000, 000
(based on CAS #’s as of 1998)
NIST Organic MS Database
approx. 150,000
Federal Pollutant Database
approx 700
e.g.
Most Organic Analyses:
approx. 10 to 80 compounds in one analysis
Classification of Organic Compounds
Boiling Point
Polarity *
Technique
Ionic
high
high
HPLC, HPLC/MS
NonVolatiles
high
high
HPLC, HPLC/MS
SemiVolatiles
medium
low-medium
GC; GC/MS; HPLC
Volatiles
low
low-medium
GC; GC/MS
* Increasing polarity = Increasing solubility in water
Survey of GC/MS Methods
(by Program)
– SDWA
» EPA 500 series
e.g. 524.2, 525
– Clean Water Act
» EPA 600 and 1600 series
e.g. 624, 625, 1624,
1625, 1666
– RCRA (Solid and Hazardous Waste)
» EPA 8000 series
e.g. 8260, 8270
– CERCLA (Superfund)
» OLMO contracts
– Clean Air Act
» TO (Toxic Organics) series
e.g. TO-14, TO-15,
TO-17
(Some ASTM and Standard Methods are also EPA approved)
Principles of Gas Chromatography – Mass Spectrometry
Advantages
- high sensitivity
excellent detection limits. Typically low ppb to high ppt
- high selectivity
identification is based on two parameters not one
(retention time and mass spectrum must match standard)
selects analyte of interest with very high confidence
- Speed
typical analysis takes from 1/2 hour to approx. 1 hour
analysis can contain upwards of 80 and more pollutants
Disadvantages
- higher capital cost (approx. $ >85 K vs. $15 K for GC)
- higher maintenance (time, expertise and money)
- for optimum results requires analyst knowledgeable in both
chromatography and mass spectrometry
The Analytical Process - GC/MS is Last Step
Data Received by
DEP
Sample Site
Contaminated Site
5.6 ppb
Monitoring Well
Permittee Effluent
Benzene
Drinking Water Facility
Laboratory Side
Sample Analysis
Sample
Preparation
Sample
Clean-Up
(optional)
Determinative Step
•Gas Chromatography (GC)
•Gas Chromatography/Mass Spectrometry
(GC/MS)
•High Pressure Liquid Chromatography (HPLC)
The Analytical Process
(It all starts with Sample Preparation)
Sample Analysis
Determinitive Step
Sample
Sample
Preparation Clean-Up
(optional)
•Gas Chromatography (GC)
•Gas Chromatography/Mass Spectrometry
(GC/MS)
•High Pressure Liquid Chromatography (HPLC)
Purge and Trap
Liquid-Liquid Extraction
Sonication
Solid Phase Extraction (SPE)
Soxhlet Extraction
(not an exhaustive listing)
Sample Preparation Techniques
 Preparation - v.v. important first step
1)
2)
used to separate organic contaminants from
their environmental matrix (e.g. groundwater
or soil)
used to concentrate the contaminants
 Typical Preparation Techniques include:
 Purge and Trap, LLE, Soxhlet, LSE (Sep Paks,
Cartridges)
Purge and Trap
(Aqueous and Soils / Volatiles Preparation)
Courtesy of Environmental Conservation Laboratories, Inc.
Liquid/Liquid Extraction
(Separatory Funnel)
(Aqueous Samples / Semivolatiles Analysis)
Courtesy of Environmental Conservation Laboratories, Inc.
Sonication
(Soils, Solids / Semivolatiles)
Courtesy of Environmental Conservation Laboratories, Inc.
Solid Phase Extraction
(Aqueous / Semivolatiles)
Sample
Cartridge
Courtesy of Stanford Laboratory
Soxhlet Extraction
(Soils, Solids / Semivolatiles)
Courtesy of Environmental Conservation Laboratories, Inc.
Sample Clean-Up Techniques
 Clean-Ups - used if interferences are a problem
 stand alone methods are available
 also procedures written into some methods
 these are often optional and choices often rest with analyst
and is dependent on the sample
 Examples of typical clean-up procedures include:
 Alumina, Silica, Flourisil, Gel Permeation
Chromatography, Acid Wash etc.
Sample Clean-Up Techniques from SW-846
(stand alone methods strictly for cleanups)
•
Analytes of Interest
Methods
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Aniline & aniline derivatives
Phenols
Phthalate esters
Nitrosamines
Organochlorine pesticides & PCBs
Nitroaromatics and cyclic ketones
Polynuclear aromatic hydrocarbons
Haloethers
Chlorinated hydrocarbons
Organophosphorus pesticides
Petroleum waste
All base, neutral, and acid
priority pollutants
3620
3630, 3640, 8041a
3610, 3620, 3640
3610, 3620, 3640
3610, 3620, 3630, 3660, 3665
3620, 3640
3611, 3630, 3640
3620, 3640
3620, 3640
3620
3611, 3650
3640
Gas Chromatography – Mass Spectrometry
(Operational Description)
Introduction System - Gas Chromatography
Ionization
Mass Separation
Mass Spectrometer
Mass Detection
Data System
Gas
Chromatography
Ionization
Source
Mass
Analyzer
Particle
Detector
Vacuum System - approx. 10-6 torr
Dedicated
Data System
Gas Chromatography
• Powerful Analytical Chemistry technique
used to separate and identify organic
compounds from mixtures.
– One requirement:
• organics must be volatile or semivolatile
• any very polar, non volatile or ionic compounds in sample will
not be detected
Gas Chromatography
Columns
• Packed
• Capillary
Cross section
THE CHROMATOGRAPHIC PROCESS - PARTITIONING
(gas or liquid)
MOBILE PHASE
Sample
out
Sample
in
STATIONARY PHASE
(solid or heavy liquid coated onto a solid or support system)
Parameters Affecting Separation
Temperature Control
Isothermal
Gradient
240
200
Temp (deg C)
Column Type (Phase)
Polar (DB-1701
NonPolar (DB-1)
Phase Thickness
Column Dimensions
160
120
80
40
0
0
10
20
30
Time (min)
40
50
60
Phases
Chromatograms - 551.1
Same Organic Mixture – Different Capillary Columns
Instrumentation - Detectors
Destructive
• Mass Spectral (CI/EI) [625]
• Flame Ionization (FID) [604]
• Nitrogen-Phosphorus (NPD) [8141A]
• Flame Photometric (FPD) [8141A]
• Electrolytic Conductivity (Hall/ELCD) [502.2]
Non-Destructive
• Thermal Conductivity (TCD)
• Electron Capture (ECD) [551.1]
• Photo Ionization (PID) [502.2]
How Mass Spectrometry Detectors Works
All “Organic Molecules” are made up of combinations of atoms
containing Carbon and Hydrogen
In addition to Carbon and Hydrogen, other elements are frequently a part of
a molecule to provide a variety of chemical and physical properties (e.g.
Oxygen, Nitrogen, Chlorine, Fluorine, etc.)
Molecular weights can be calculated knowing the elemental composition of a
molecule.
Mass Spectrometry analyzes (identifies) organic
molecules according to their molecular and fragment
weights.
How Mass Spectrometry (Mass Analysis) Works
(Use Table to Calculate Molecular Weights)
Element
Symbol
Nomi
nal
Mass
Exact
Mass
Abundanc
e
Hydrogen
H
D or 2H
1
2
1.00783
2.01410
99.99
0.01
C
C
12
13
12.0000
13.0034
98.91
1.09
N
N
14
15
14.0031
15.0001
99.6
0.37
O
O
18
O
16
17
18
15.9949
16.9991
17.9992
99.76
0.037
0.20
F
19
18.9984
Si
Si
30
Si
28
29
30
27.9769
28.9765
29.9738
92.28
4.70
3.02
P
31
30.9738
100
32
33
34
31.9721
32.9715
33.9679
95.02
0.74
4.22
Cl
Cl
35
37
34.9689
36.9659
75.77
24.23
Br
Br
79
81
78.9183
80.9163
50.5
49.5
12
Carbon
13
14
Nitrogen
15
16
Oxygen
Fluorine
17
28
Silicon
Phosphorus
29
32
Sulphur
S
S
34
S
33
35
Chlorine
37
79
Bromine
81
100
Isotopes
Calculating Molecular Weight (Mass)
Element
Carbon(C)
Hydrogen(H)
Chlorine(Cl)
Fluorine (F)
Oxygen(O)
Nitrogen(N)
atomic mass (amu)
12
1
35
19
16
14
H
H
H
C
C
C
H
H C C C H
H
C
H C
C
C
C
N
H
H
H
Benzene
(C6H6)
6 x 12 = 72
6x1 = 6
MW = 78 amu
amu - atomic mass units
Pyridine
(C5H5N)
5 x 12 = 60
5x1 = 5
1 x 15 = 15
MW = 79 amu
Gas Chromatography – Mass Spectrometry
(Operational Description)
Introduction System - Gas Chromatography
Ionization
Mass Separation
Mass Spectrometer
Mass Detection
Data System
Gas
Chromatography
Ionization
Source
Mass
Analyzer
Particle
Detector
Vacuum System - approx. 10-6 torr
Dedicated
Data System
The Ionization Process
(Electron Impact)
Neutral molecules are converted into Ions (charged particles)
-
e
+
Neutral Molecule
+.
Molecular
‘Ion’
-
+ 2e
(70 Electron Volts)
Fragment Ion 1
Fragment Ion 2, etc.
.
H
H
-
e
*
+
C
C
+
H
C
H
H
C
C
C
H
H C C C H
H C C C H
H
H
Mass Analysis can only work for charged species - not for neutrals.
-
+ 2e
GC/MS - Mass Analysis
Wavelength Separation
Continuous Light
Mass Separation
(quadrupole)
m
4V
z = qr22
Ions

Principles of Gas Chromatography/Mass Spectrometry
(NIST Library Mass Spectra for Benzene)
H
m/z 78
Abundance (Signal)
Benzene
H
C
C
C
H
H C C C H
H
78 amu
mass/charge (m/z) ------>
Principles of Gas Chromatography/Mass Spectrometry
Abundance (Signal)
(NIST Library Mass Spectra for Pyridine)
m/z 79
H
H
C
C
Pyridine
H C
C
C
N
H
H
79 amu
mass/charge (m/z) ------>
One More Example for o-Xylene
(Fragment Ions contain Useful Information)
Element
Carbon(C)
Hydrogen(H)
Chlorine(Cl)
Fluorine (F)
Oxygen(O)
Nitrogen(N)
H
mass
12
1
35
19
16
H
H
C
C
C
C
H
H
C
C
C
Xylene
(C8H10)
H
8 x 12 = 96
10 x 1 = 10
MW = 106
H
C
H
14
H
H
Molecular Ions can break down into smaller fragments
.
.
H
H
H
H
C
C
C
C
C
C
C
+
H
H
H
H
H
H
C
H
m/z 106
H
H
H
C
C
C
C
C
H
m/z 91
+
H
H
H
C
C
.
+
H
C
C
H
H
C
C
C
C
H
m/z 77
Principles of Gas Chromatography/Mass Spectrometry
(NIST Library Mass Spectra for Xylene)
mass
12
1
35
19
16
14
H
H
H
C
C
C
C
C
C
C
H
H
H
C
H
H
Abundance (Signal)
Element
Carbon(C)
Hydrogen(H)
Chlorine(Cl)
Fluorine (F)
Oxygen(O)
Nitrogen(N)
H
mass/charge (m/z) ------>
H
o-Xylene
(C8H10)
8 x 12 = 96
10 x 1 = 10
MW = 106
What Does GC/MS Data Look Like?
Abundance (Signal)
GC/MS Chromatogram of a 4 Component Mixture
Retention Time ------>
What Does GC/MS Data Look Like?
Abundance (Signal)
GC/MS Chromatogram of a 4 Component Mixture
Retention Time ------>
What Does GC/MS Data Look Like?
GC/MS Chromatogram From EPA Method 524.2 Analysis
Abundance (Signal)
*
Retention Time ------>
Courtesy of the NJDHSS Laboratory
What Does GC/MS Data Look Like?
Reviewing of Mass Spectra
6.99 min.
Abundance (Signal)
*
Retention Time ------>
m/z 78
mass/charge ------>
What Does GC/MS Data Look Like?
Reviewing of Mass Spectra
6.77 min.
Abundance (Signal)
*
*
Retention Time ------>
m/z 78
mass/charge ------>
1,1-dichloropropene/carbon tetrachloride
Difficult Mass Spectra
usually
• Mass Spectrometry does not always provide an easily
interpretable compound identification: e.g. MTBE
• use of mass spectral libraries for ID determination
• use of manual interpretation techniques
• use of alternate MS and other techniques
100
73
MTBE MW= 88
O
50
15
29
27
31
41
57
39
45
55
79
0
10
20
30
40
(ma inlib ) Pro p a ne, 2-metho xy-2-methyl-
50
60
70
80
90
100
Mass Spectral Interpretation Procedures
• GC/MS Interpretation Procedures
• Identify Molecular Ion if present
• Evaluate any Isotopic Observations
• Use Isotopes to calculate probable carbon #s for Molecule and/or
fragments
• Review all losses observed to determine substructures
• Review major fragments
• Hypothesize a molecular structure consistent with above observations
– Must Confirm Hypothesis with additional data.
•
•
•
•
•
Typically chemical ionization MS
High resolution mass spectrometry
Infra Red Spectroscopy
Nuclear Magnetic Resonance Spectrometry
Obtaining a pure standard and confirming mass spectra with unknown
GC/MS Summary
• Powerful analytical tool combining the separation capability of Gas
Chromatography and the identification capability of Mass Spectrometry.
• Provides for a higher level of confidence in the identification of organics
(Both retention time AND the mass spectrum are used).
• Capable of analyzing upwards of 80 pollutants in one analysis.
•
Typical Detection Limits (Aqueous) are in low ppb and high ppt
range.
• Appropriate calibrations and controls must be performed before any
samples can be analyzed.
GC/MS Analysis
(Special Topics)
• From Raw Data Chromatograms to final report
• Proper and Improper Peak Integrations – Data Processing
• Dealing with Interferences
• Mass Spectrometry Libraries and Tentatively Identified
Compounds (TICs)
GC/MS Data Processing
Important to Review Peak Integration
Chromatogram
(maximum
information content)
GC/MS
Final Report
GC/MS Data Processing
Important to Review Peak Integration
• Calibrations and quantitation of organics all rely
on correct chromatographic peak integrations
Standards (Ax/Ais)----->Response Factors----->Sample Quantitation
A
x
Ais
NJDEP
OQA
OCTOBER 2002
Manual Integration
FOR GC/MS
Definition
A Manual Integration is any editing of the
area of integration by the chemist. Manual
integration is a perfectly acceptable,
scientifically valid, analytical technique
used to accurately reflect the area of a peak
when auto-integration fails.
A Manual Integration is not a way to
compensate for an improperly
maintained instrument. Manual
integrations are not to be used in lieu
of establishing appropriate integration
events using the analytical system
software.
Manual integration may be done in the
following cases where the automatic
integrator has:
•
•
•
•
•
•
•
•
failed to integrate a peak or part of a peak
integrated one peak as two peaks
integrated the wrong peak out of two similar peaks
not integrated from baseline to baseline
integrated a peak due to an elevated baseline
integrated a negative peak
integrated a peak beyond baseline resolution (too much area)
Any additional situations in which the auto-integrator fails to perform
properly and/or consistently
Manual integrations are NOT to be
performed for the sole purpose of making a
calibration curve, ICV,CCV, &/ or a QC
check sample (LCS, MS, surrogate, etc.)
pass acceptance criteria.
History
Most of the software programs used for chromatography
are capable of quantitating, using either peak area or peak
height and employ mathematical algorithms related to the
slope of the response to detect the beginning and end of
peaks.
History
Due to the complex nature of some sample matrices, the
ability to manually adjust an incorrect integration became
necessary. This flexibility is necessary in the production
of quality data.
Much of this process is based on analyst judgment. Each
peak must be evaluated and adjusted when necessary.
However, this flexibility has led to several instances of
improper laboratory activities.
IMPROPER INTEGRATIONS
According to the EPA Region 5’s SOP on manual
integrations, inappropriate integration is any
integration, either automated or manual, which
excludes area associated with the target peak or
includes area not reasonably attributable to the
target peak, such as area due to a second peak or
excessive peak tailing due to a noisy baseline.
CORRECT INTEGRATIONS
This is an example of proper integrations when several peaks
are not completely resolved (i.e., the response does not return
to the baseline between peaks). The lowest point between two
points, the valley, is selected as the appropriate start and stop
points.
CORRECT INTEGRATIONS
•
•
Peaks with slight interferences either just prior to or
immediately after the target peak.
In these cases, part of the automatic integration may
include the interfering analyte. The following
integration techniques may be employed:
TYPES OF IMPROPER INTEGRATIONS
Peak shaving is the common term for unjustifiably
excluding area when integrating a chromatographic
peak.
Almost all of us would agree that cutting a peak in half
horizontally or vertically is unjustified. But what to do
about the in between cases? How can judgment be
applied correctly when integrating peaks?
TYPES OF IMPROPER INTEGRATIONS
•
Baseline addition or subtraction
Do not add or subtract from the baseline. Another
example of an incorrect manual integration
TYPES OF IMPROPER INTEGRATIONS
Poor sensitivity. Signal is not 3 times the background.
WHY IS THIS HAPPENING?
•Cost factors
•Level of Expertise factors
•Unethical Behavior
Cost Factors
•
The price paid is often not sufficient to
cover the costs of producing the product.
•
The client should not accept low bids
without considering the quality factor.
•
This is a free market economy - ‘Let the
buyer beware’ or ‘You get what you pay
for’.
Level of Expertise Factors
•
Some laboratories have let their most
experienced staff go.
•
Lack of understanding regarding the
fundamentals of analytical chemistry at
both the laboratory and data user levels.
•
Thinking that the computer will always
give you the correct answer.
Why Unethical Behavior Occurs
•Real or perceived pressures
•Lack of ethics education and awareness
•Lack of management oversite and review
•Lack of knowledge or confidence in appropriate
ways to solve problems
Prevention
Efforts should be made during method
development to include the best instrument
parameters that allow for automatic integration
by the data system in most cases.
However, regardless of the sophistication of the
software, instances occur when the automated
software does not integrate a peak correctly.
Prevention
The failure of the software to appropriately
integrate a peak is usually obvious from visual
inspection of the chromatogram (at an appropriate
scale). Electronic review of analytical raw data is
essential in detecting improper activities.
The use of proper documentation protocols should
be established to allow manual integrations to be
reviewed during data validation.
DOCUMENTATION
All data must be integrated consistently in
standards, samples and QC samples. Integration
parameters, both automated and manual, must
adhere to valid scientific chromatographic
principles. Manual integration is employed to
correct an improper integration performed by the
data system and must always include
documentation that clearly states the reason
manual integration was performed.
Proper documentation is vital when conducting
manual integrations. The following is an example
documentation requirement:
Print the improperly integrated peak. initial, date
and provide a reason on the original for the manual
integration. Perform the necessary manual
integration. Print the manually integrated peak,
initial and date. Submit the manual integration data
along with the original automatic integration data as
part of the final data package.
GENERAL OBSERVATIONS
The fundamental principle of quantitative integration is
that samples should be integrated in the same style
chosen for integrating calibration standards.
If properly documented and conducted in a scientifically
defensible manner, manual integrations are perfectly
acceptable.
WHAT CAN LABS DO TO PREVENT
IMPROPER ACTIVITIES
Develop a detailed standard operating procedure that
includes examples and documentation requirements.
Enforce a zero tolerance policy for any improper
activities.
Have all analysts sign an ethics statement.
Electronically review random data files.
Questions?
GC/MS Interferences
• What are Interferences?
– Any compound or mixture of compounds that elutes at
the same time as the compound of interest. Therefore
the compound of interest can not be properly identified
or quantified.
• EPA Office of Water Says:
• “Stating that ‘the sample couldn’t be analyzed’ is
not sufficient and will not be accepted as
justification for a claim of matrix interference.”
Interferences in GC/MS Analysis
• Problems they cause
• quantitation accuracy of targets may be negatively
impacted
• can make identification of target among interferences
difficult or impossible
• if dilution is required, may raise detection limits
above required regulatory limits.
Interferences - What do they look like
(Example 1)
interferences
Extract could only be concentrated to 5 mls.
Interferences - What Do They Look Like
(Example 2 )
- Can only concentrate to 5 mls.
- diluted extract 1:5
- total dilution factor = 25x
a - Napthalene
b - dimethyl phthalate
c - diethyl phthalate
d - di-n-butyl-phthalate
a
b c
d
Interferences - What Are They
(Example 2)
1,3-dichloro-2-propanol
(a chlorinated alcohol)
1-methyl, 2,4-diisocyanato benzene
(a diisocyanate)
Interferences - What Can Be Done
(Example 2)
•
Analyze Base/Neutrals and Acid Fractions Separately - may isolate
interferences into fraction of less interest
•
Perform GPC Analysis to remove any potential high molecular weight
interferences
– may help for samples that can only be blown down to 5 mls.
– no guarrantee that GC or GC/MS analysis is seeing all of the sample
•
Perform Appropriate CleanUps
– methods exist for cleaning up samples so that analytes of interest can be analyzed
•
GPC and Cleanups can be performed on the same sample.
•
Identify interferences and clean up waste stream
– permittee likely has most intimate knowledge of their own waste stream.
– Additional non-EPA method testing may be appropriate to identify interferences.
Clean-Up Techniques from SW-846
(stand alone methods strictly for cleanups)
•
Analytes of Interest
Methods
•
•
•
•
•
•
•
•
•
•
•
•
Aniline & aniline derivatives
Phenols
Phthalate esters
Nitrosamines
Organochlorine pesticides & PCBs
Nitroaromatics and cyclic ketones
Polynuclear aromatic hydrocarbons
Haloethers
Chlorinated hydrocarbons
Organophosphorus pesticides
Petroleum waste
All base, neutral, and acid
priority pollutants
3620
3630, 3640, 8041a
3610, 3620, 3640
3610, 3620, 3640
3610, 3620, 3630, 3660, 3665
3620, 3640
3611, 3630, 3640
3620, 3640
3620, 3640
3620
3611, 3650
3640
Interferences in GC/MS Analysis
•
From the EPA OCPSF (Organic Chemicals, Plastics and Synthetic Fibers) rule’s
Guidance on Evaluation, Resolution, and Documentation of Analytical
Problems Associated with Compliance Monitoring
– “Stating that ‘the sample couldn’t be analyzed’ is not sufficient and will
not be accepted as justification for a claim of matrix interference.”
– EPA provides for flexibility in wastewater methods and allows use of
cleanups etc provided method QA/QC are met.
• As per Fed Reg. 49 FR 43234
• Department can require additional work to be performed to get at an
accurate number. Not just take the easy way out and say interferences
are present.
• Alternate methods
• use of clean-up procedures
Mass Spectral Libraries
• What are mass spectral libraries?
– A compendium of electron impact mass spectra collected
from a variety of sources
• Why are they important?
– Identifying non-target or tentatively identified
compounds (TICs), relies exclusively on these libraries
Mass Spectral Libraries
• Why are they important - cont.?
– Site Remediation for example typically requests:
» VOAs + 10 TICs
» BNs + 15 TICs
» frequently drinking water methods
– If TICs are found, proper identification is very important
» may need correct ID for remediation
» may need to provide data to County Health Dept and Owners
of Potable Well (as in BUST)
Mass Spectral Libraries
• Why are they important - cont?
– Waste Water Permitting:
» some industries indicate that interferences are present which
preclude them analyzing the sample to permit detection limits
» Identification of interferences can be used to determine what
options for cleanup may exist. Interferences may also be
environmentally unfriendly compounds that may need to
reviewed.
– Bureau of Safe Drinking Water
» BSDW reporting form has ability to enter TIC observations
from a laboratory.
Mass Spectral Libraries
• How many libraries are there?
• NIST/NIH/EPA Mass Spectral Library
– NBS 75K
– NIST ‘98
– NIST ‘02
• Wiley Mass Spectral Library
• Combination Wiley/NIST
• Custom Libraries
– industry specific
– proprietary
Mass Spectral Libraries
 For NIST75K Library –
 Approx 50,000 Mass Spectra
 Approx 25,000 Replicates
 This library is very old
 Not very well reviewed
 Variety of Sources not well filtered.
Labs should NOT be using this!
Mass Spectral Libraries
 For NIST98 Library - (a 75% increase over NBS75K
library)
 107,886 Compounds
 107,829 Chemical Structures
 129,136 Spectra
 21,250 Replicate Spectra
 13,205 Compounds with Replicate Spectra
 93 Average Peaks per Spectrum
 78 Median peaks per Spectrum
 75% Increase in coverage from high quality sources
Labs should be using at least this revision!
Mass Spectral Libraries
 For NIST98 Library
(where does this 75% increase come from?)
 Mass Spectra from other sources were added in
 Chemical Concepts - including Prof Henneberg's industrial
chemicals collection
 Georgia and Virginia Crime Laboratories
 TNO Flavors and Fragrances
 AAFS Toxicology Section, Drug Library
 Association of Official Racing Chemists
 St. Louis University Urinary Acids
 VERIFIN & CBDCOM Chemical Weapons
Mass Spectral Libraries
• For NIST ‘02 Library - 35% increase in coverage over NIST 98
Library
• 27,750 Replicate Spectra
from high quality sources
• 147,198 Compounds with Spectra
• 18,598 Compounds with Replicate Spectra
• 147,194 Chemical Structures
• 111 Average Peaks/Spectrum
• 174,948 spectra
• 98 Median Peaks/Spectrum
Mass Spectral Libraries
• Comparison of NIST/NIH/EPA Libraries - different
revisions
NBS75K
NIST98
NIST ‘02
Total Spectra
75, 000
129,136
174,948
Total Replicates
20,000
21,250
27,750
Mass Spectral Libraries
• Wiley Registry of Mass Spectral Data - 7th
Edition
– the world's largest reference database of over
250,000 Electron-Impact mass spectra
• Wiley Library may or may not include NIST library
• Wiley contains mass spectra that are not as well reviewed.
• Still very useful, if NIST library comes up short.
Why MS Library Version is Important
(example)
Air Analysis Example from 1996 (TO-14)
• Samples consistently showed large peak in the analysis but
compound could not be identified by library.
• Library search result was so poor, even a good quality TIC
could not be obtained.
• At the time the NBS75K library was the only one available.
– Pre 1998
• Requested Chromatogram and Mass Spectrum to evaluate
Mass Spectral Libraries
(example of why version of library is important)
Mass Spectral Libraries
(example of why version of library is important)
Mass Spectral Libraries
(example of why version of library is important)
Mass Spectral Libraries
(example of why version of library is important)
Synonyms
•1,1-Dichloro-1-fluoroethane
• Ethane, 1,1-dichloro-1-fluoro• Freon 141
Mass Spectral Libraries
• Library Search Against NIST 98 Library
produced an excellent hit.
Best Hit
NBS75K
81
100
Cl
Freon 141
F
50
45
61
26
35
31 37
Cl
63
83
101
0
10
20
30
40
50
(ma inlib ) 1,1-Dichlo ro -1-fluo ro etha ne
60
70
80
90
100
110
120
130
Best Hit
NIST98
Summary
Mass Spectral Libraries
• Identities of non-target compounds (TICs)
may be dependent on the version of library
being used.
• Most laboratories still use NBS75K library.
• Be aware that other libraries exist.
Dioxins and PCB Analysis
Using
GC/High Resolution Mass Spectrometry
(actually high resolution gas chromatography/high resolution mass spectrometryHRGC/HRMS)
Overview
• Review of EPA Dioxins and PCB structures & methods
• Typical Mass Spectrometry Instrumentation
• Why High Resolution Mass Spectrometry?
• High Resolution Mass Spectrometry (MS) Overview
• Use of Isotopically Labeled Targets
• Comparison of ‘PCB congener’ and Aroclor methods
• Toxicity Equivalents (TEQs) and TEFs
Dioxin/Furans/PCBs
(Chemical Structures)
Dioxin Analysis Target Compounds
• Both 1613 and
8290 analyze for
these 17
“Dioxins and
Furans”
• Drinking water
regulates only
the 2,3,7,8TCDD
PCB Terminology
•
•
•
•
•
•
•
PCBs (can mean anything)
Aroclors (mixture of PCBs)
PCB Congeners (209 individual)
‘Dioxin-Like’ PCBs
Coplanar PCBs
WHO PCBs - a list of 12 specific PCBs
Homologs (all congeners having same # of chlorines
attached)
More PCB Terminology
•
BZ/IUPAC
Congener
Number
Prefix to Chlorobiphenyl
•
PCB-77
3,3',4,4'-Tetra-Chlorobiphenyl
•
PCB-81
3,4,4',5-Tetra-
•
PCB-105
2,3,3',4,4'-Penta-
•
PCB-114
2,3,4,4',5-Penta-
•
PCB-118
2,3',4,4',5-Penta-
•
PCB-123
2,3',4,4',5'-Penta-
•
PCB-126
3,3',4,4',5-Penta-
•
PCB-156
2,3,3',4,4',5-Hexa-
•
PCB-157
2,3,3',4,4',5'-Hexa-
•
PCB-167
2,3',4,4',5,5'-Hexa-
•
PCB-169
3,3',4,4',5,5'-Hexa-
•
PCB-189
2,3,3',4,4',5,5'-Hepta-
a total of 209 PCB congeners e.g. PCB 1 ---> PCB 209
Still More PCB Terminology
• ‘PCBs as Arochlors’
– no longer referring to individual PCBs
– Arochlors are complex mixtures
• Often designated ‘Aroclor XXXX’
– e.g Aroclor 1242
– on average, this molecule contains 42 % by weight of Chlorine
Method Overview
• Dioxin Analyses
– EPA Method 1613B1 - For drinking water and waste water use
– EPA Method 8290 - for SHW samples
• ‘PCB Congener’ Analysis Methods
– EPA Method 1668 - Revision A
– can be used for all matrices
–
–
dated December of 1999
contains all 209 possible PCB congeners
– EPA Method 8082 - usually used for Aroclors - SHW Samples
– has the option to perform limited set of 19 congeners
– can be modified to do other congeners
1
as old NPDES permits requiring dioxin analyses by 613, they will be reissued with
requirement for 1613B
Method Overview
• ‘PCB as Aroclors’ Analysis Methods
» EPA Method 508 and 608 - for Drinking and Wastewater
» EPA Method 8082 - solid and hazardous waste samples use
» all of these are GC/ECD techniques
Dioxin and PCB Analysis
(Why analyze for them?)
Dioxins and PCBs have been shown to be
toxic at varying levels.
• e.g. Drinking Water MCLs (NJ State Standards)
– 2,3,7,8-T etra C hloro D ibenzo D ioxin (TCDD)
– 3 x 10-5 ppb
– PCBs
– 0.5 ppb
or
0.00003 ppb
Why did EPA choose GC/High Resolution
Mass Spectrometry to analyze for Dioxins
and PCBs?
– MCLs for these compounds are very low
– Need sensitive method(s) capable of low detection limits
– Provide a high level of confidence in compound identification
– Need to minimize effect of interferences
How Does GC/High Resolution Mass
Spectrometry Accomplish These Criteria?
1) Need for Very High Identification Certainty/Minimize
Interferences
– High Resolution Mass Analysis
– Use of Chlorine Isotope Masses
• two masses for each target
• Isotope Ratios must meet theoretical value
2) Need for very low detection limits
– Combination of High Voltage Operation and Selected Ion
Monitoring Scan (SIM)
– Concentrate sample to ul range instead of ml.
Nominal and Exact Masses for Common Elements
Element
Symbol
Nomi
nal
Mass
Exact
Mass
Abundanc
e
Hydrogen
H
D or 2H
1
2
1.00783
2.01410
99.99
0.01
C
C
12
13
12.0000
13.0034
98.91
1.09
N
N
14
15
14.0031
15.0001
99.6
0.37
O
O
18
O
16
17
18
15.9949
16.9991
17.9992
99.76
0.037
0.20
F
19
18.9984
Si
Si
30
Si
28
29
30
27.9769
28.9765
29.9738
92.28
4.70
3.02
P
31
30.9738
100
32
33
34
31.9721
32.9715
33.9679
95.02
0.74
4.22
Cl
Cl
35
37
34.9689
36.9659
75.77
24.23
Br
Br
79
81
78.9183
80.9163
50.5
49.5
12
Carbon
13
14
Nitrogen
15
16
Oxygen
Fluorine
17
28
Silicon
Phosphorus
29
32
Sulphur
S
S
34
S
33
35
Chlorine
37
79
Bromine
81
100
What is High Resolution Mass Spectrometry
• High Resolution Mass Spectrometry is capable of obtaining mass
spectra and measuring masses to approximately the fourth decimal
place.
322
100
320
C12H435Cl4O2
MW = 319.896542
Cl
O
Cl
Cl
O
Cl
50
C12H437Cl135Cl3O2
257
194
74
MW = 321.8936
50 62
160
97
85
113
122
144
187
287
229
0
50
80
110
140
170
(ma inlib ) 2,3,7,8-Tetra chlo ro d ib enzo -p -d io xin
200
230
260
290
320
Specialized MS Instrumentation
VG70-250SE High Res. MS
HP5973 Low Res. MS
What is Mass Resolution?
Very Simply - The ability to distinguish between
different masses.
e.g. Can we distinguish mass 78 from 79?
Can we distinguish between mass 78.003 and 78.004?
A quantitative approach to determining how well we can distinguish
different masses is called ‘Resolving Power’. Different than
chromatographic resolution.
Resolving Power
by definition:
Resolving Power(R.P.) = m/m
ppm = R.P. / 1 x 10
6
a resolving power of 10,000 = 100 ppm
***All High Resolution EPA Methods use an R.P. of 10,000***
Calculation of Mass Resolution
Resolution Example
we’re asked to separate a three component gas mixture
containing
carbon monoxide
nitrogen
ethylene
Calculating Molecular Weights
nominal mass
carbon
monoxide - CO
nitrogen - N2
ethylene - C2H4
accurate mass
1 x 12 = 12
+ 1 x 16 = 16
28
1 x 12.0000 = 12.0000
+ 1 x 15.9949 = 15.9949
27.9949
2 x 14 = 28
28
2 x 14.0031 = 28.0062
28.0062
2 x 12 = 24
+ 4x 1= 4
28
2 x 12.0000 = 24.0000
+ 4 x 1.0078 = 4.0312
28.0312
What Resolution Do We Need to See
All 3 Components?
carbon
monoxide - CO
1 x 12.0000 = 12.0000
+ 1 x 15.9949 = 15.9949
27.9949
nitrogen - N2
2 x 14.0031 = 28.0062
28.0062
ethylene - C2H4
2 x 12.0000 = 24.0000
+ 4 x 1.0078 = 4.0312
28.0312
0.0113
0.025
What Resolution Do We Need to See
All 3 Components? (cont’d)
nominal
mass
CO
N2
C2H4
28
28
28
exact
mass
 mass
Resolving Power
Needed (m / m)
27.9949
0.0113
2,478
0.0250
1,120
28.0062
28.0312
- Need at least 2,500 to see all three components.
Low and Medium Resolution Mass Spectra
of Ternary Mixture
Applications to Dioxins/PCB Congener Analyses
(2,3,7,8-TetrachloroDibenzoDioxin (TCDD))
Calculation of Mass for 2,3,7,8-TCDD Analysis
2,3,7,8-TCDD
C
H
Cl
O
37
Nominal Mass
12 x 12 = 144
4x 1 = 4
4 x 35 = 140
2 x 16 = 32
320
Cl = 36.9659
C12H4Cl4O2
Exact Mass
12 x 12.000000 = 144.000000
4 x 1.007825 = 4.031300
4 x 34.968853 = 139.875412
2 x 15.994915 = 31.989830
C12H435Cl4O2
319.896542
C12H437Cl4O2
321.8936
Table From EPA Method 1613B
m/z 320 & 322
Same Calculation for PCB Congeners
360
100
HexaChloroBiphenyl
C12H4Cl6
50
290
145
109
37 49
61
218
127
74
98
163 180
204
0
30
50
70
90
110 130 150
1,1'-Biphenyl, 3,3',4,4',5,5'-hexachloro-
C
H
Cl
37
Nominal Mass
12 x 12 = 144
4x 1 = 4
6 x 35 = 210
358
Cl = 36.9659
170
190
210
254
324
240
230
250
270
290
310
330
350
Exact Mass
12 x 12.000000 = 144.000000
4 x 1.007825 = 4.031300
6 x 34.968853 = 209.813118
C12H435Cl6
357.844418
C12H437Cl137Cl3O2
C12H437Cl237Cl2O2
359.8415
361.8385
From Table 7 of EPA Method 1668A
m/z 360
362
364
Isotope Ratio QA/QC Requirements
(from EPA 8290)
(same as 1613B & 1668A)
 15 %
Common Chemical Interferences in the GC/MS determination
of 2,3,7,8-TCDD
Selected Ion Monitoring - Better DLs
(Sector Instruments Use Voltage Scanning for Accuracy)
322
100
Full Scan
Detect all masses
over a given scan
range.
e.g. m/z 100-500
Cl
O
Cl
Cl
O
Cl
50
74
50 62
97
85
113
160
187
143
257
194
50
80
110
140
170
(ma inlib ) 2,3,7,8-Tetra chlo ro d ib enzo -p -d io xin
287
229
0
200
230
260
290
322
100
SIM
Look only for
masses relevent
to targets
320
Cl
O
Cl
Cl
O
Cl
50
74
50 62
97
85
113
160
143
187
287
229
0
50
80
110
140
170
(ma inlib ) 2,3,7,8-Tetra chlo ro d ib enzo -p -d io xin
257
194
200
230
260
290
320
High Resolution MS Advantages
• Enhanced Identification Capabilities
– Ability to analyze exact masses provides for better identification
capability over LRMS
– Detecting multiple isotopes (chlorine) adds yet another level of
confidence in compound identification
– Eliminates or minimizes interferences in ‘dirty’ samples
– Cleanups are the rule not the exception
• Enhanced Sensitivity
– High Resolution Mass Spectrometers operate at High Voltage (8
KV)
– Voltage Scanning Selected Ion Monitoring (SIM)
– Concentration of Sample down to ul as opposed to ml’s.
Approximate Method Detection Limits
Depends on Matrix
• Method
Aqueous
Other
• Method 1668
5-300 ppq
1-25 ppt
• Method 1613B
• Method 8290
3 ppq
1 ppt
10 ppq
1 ppt
Disadvantages of HRMS
• high capital cost ( approx. $400,000)
• higher maintenance
• maint. contract  8% of purchase price annually.
• skilled staff required
• analysis costs high
•  $1,000 /analysis
• special facility requirements
• Vibration
• Footprint is large
•Temp/Humidity Control
• Special Power Requirements
Use of Isotopic Labeling
• Methods 1613B, 8290 and 1668A all make
use of Isotopic Labeling
•
13
37
C and Cl labeled target compounds are
used for quantitation (internal standards are
also used)
Use of Isotopic Labeling
• Methods 8290 - Dioxins/Furans
– 9 out of the 17 targets are labeled
• Methods 1613B - Dioxins/Furans
– 15 out of 17 targets are labeled
• Methods 1668A - PCB Congeners
– 27 out of 209 are labeled.
Benefits of Isotopic Labeling
• Isotopically labeled target compounds will behave
identically to targets of interest.
– If targets are lost during processing, labeled standards
will also be lost. Corrects for recovery  100%
– Provides for more accurate quantitation of targets.
• Isotopically labeled target compounds elute
seconds prior to target of interest
– Enable analyst to readily identify the target
– If interferences are present, this is extremely helpful
• This too increases ID accuracy
Sample Chromatogram
(showing Isotopically Labeled Standards)
Sample Chromatogram
(Typical Raw Data Page – Dioxins - HxCDD)
Target
HxCDD
Labeled
HxCDD
Interfering
Compounds
Lock Mass
Check Channel
PCB Congener Analysis vs. Aroclor Analysis
(pros)
•
The toxicity of PCBs is very congener specific
– measurement on an Aroclor basis may not accurately reflect toxicity.
•
Identification of a PCB is more definitive. Interferences are more easily
detected.
•
Quantitation of individual congeners is more accurate than estimating
Aroclors
•
Composition of weathered, degraded and metabolized PCB mixtures can
be measured and interpreted easier using congener vs. Aroclor analysis
•
Aroclor concentrations can be estimated using congener concentrations
(depending on the list of congeners being analyzed for)
PCB Congener Analysis vs. Aroclor Analysis
(cons)
•
Very high cost (typically greater than $1,000
•
TEFs are not available for all congeners
– World Health Organization (WHO) has a list of 12 TEFs
•
Comparability among laboratories
– labs vary in how they perform PCB congener analysis
• different labs may use different columns (different coelutions)
• PCB congener ID comparability
– no good PE samples are available (some SRMs)
– there is a “NIST Intercomparison Exercise for Organic Contaminants in the
Marine Environment”
• cost $2500 for two matrices
Comparison of EPA Method 8082 and
1668A
• 8082
–
–
–
–
–
–
DLs
Cost $75 - $300
Aroclor Using GC/ECD
May not meet DQOs.
Aroclor analysis may over or underestimated PCB concentrations.
Does not measure individual congeners but rather relies not a pattern
recognition
– Aroclor analysis may severely underestimate toxicity.
• 1668A
– PCB Congeners using GC/HRMS
– Detection Limits
– Cost > $1,000
EPA Method 1668A Misnomers
• All 209 congeners are analyzed for, BUT
– Does not provide quantitative values for each of the 209 individually
– Not all 209 are quantitated in the same manner.
• Multipoint vs. single point calibration
• Not all 209 congeners are chromatographically resolved
– about 130 congeners are fully resolved
– everything else is reported as coelutions
• Analyzed under low voltage conditions
– not at 70 eV (Typically 30 - 40 eV)
Proficiency Evaluation (PE) Samples for Dioxin
and PCB Analysis
• PE samples for 2,3,7,8-TCDD - Available
• PE Samples for Aroclors - Available
• PE samples for PCB congeners - NOT AVAILABLE
• For congeners
– SRMs are available from NIST
– Some standards available from CIL, Wellington, others?
– Still a problem
• none of the above contain all of the WHO PCBs - presumably the most important
ones.
• Need to go with a reliable lab
Dioxins and PCB Analysis
Hold Times
•
From 1613B Dioxins
– 8.4.1 There are no demonstrated maximum holding times associated with
CDDs/CDFs in aqueous, solid, semi-solid, tissues, or other sample matrices. If
stored in the dark at 0-4°C and preserved as given above (if required), aqueous
samples may be stored for up to one year. Similarly, if stored in the dark at <10°C, solid, semi-solid, multi-phase, and tissue samples may be stored for up to
one year.
– 8.4.2 Store sample extracts in the dark at <-10°C until analyzed. If stored in the
dark at <-10°C, sample extracts may be stored for up to one year.
•
From 1668A PCB Congeners
– 8.5.1 There are no demonstrated maximum holding times associated with the
CBs in aqueous, solid, semi-solid, tissues, or other sample matrices. If stored in
the dark at 0-4 EC and preserved as given above (if required), aqueous samples
may be stored for up to one year. Similarly, if stored in the dark at <-10 EC,
solid, semisolid, multi-phase, and tissue samples may be stored for up to one
year.
Reporting Dioxin and PCB Data Results
Two Approaches
1) Provide a quantitative value for each target compound
2) Report a single number – a Toxicity Equivalent
–
This approach used frequently for Risk Assessment purposes,
Dioxins/Furans/PCBs are often combined together as a Toxic
Equivalent Quantity (TEQ)
–
To calculate TEQ, need to use Toxic Equivalency Factors
•
(TEFs)
TEFs and TEQs
Toxic Equivalent Quantity (TEQ)
• Over the years, researchers have
determined the relative toxicities for a
variety of different compounds with the
most toxic 2,3,7,8-Tetrachlorodibenzodioxin
- being assigned a toxic equivalency
TEFs and TEQs
TEF for 2,3,7,8-TCDD = 1
• TEF = Toxic Equivalency Factors. A
method of weighting the toxicity of
individual dioxin/furan/coplanar PCB
compounds, as compared to 2,3,7,8TCDD.
TEFs and TEQs
1994 WHO TEFs(1)
1997 WHO TEFs(2)
Humans/Mammals
Fish
Birds
•
PCB-77
0.0005
0.0001
0.0001
0.05
•
PCB-81
--
0.0001
0.0005
0.1
•
PCB-105
0.0001
0.0001
<0.000005
0.0001
•
PCB-114
0.0005
0.0005
<0.000005
0.0001
•
PCB-118
0.0001
0.0001
<0.000005
0.00001
•
PCB-123
0.0001
0.0001
<0.000005
0.00001
•
PCB-126
0.1
0.1
0.005
0.1
•
PCB-156
0.0005
0.0005
<0.000005
0.0001
•
PCB-157
0.0005
0.0005
<0.000005
0.0001
•
PCB-167
0.00001
0.00001
<0.000005
0.00001
•
PCB-169
0.01
0.01
0.00005
0.001
•
PCB-170
0.0001
--
--
--
•
PCB-180
0.00001
--
--
--
•
PCB-189
0.0001
0.0001
<0.000005
0.00001
Calculating TEFs and TEQs
Conc. M DL
•
DIOXINS
OCDD
1234678-HpCDD
123478-HxCDD
123678-HxCDD
123789-HxCDD
12378-PeCDD
2378-TCDD
FURANS
OCDF
1234678-HpCDF
1234789-HpCDF
123478-HxCDF
123678-HxCDF
234678-HxCDF
123789-HxCDF
12378-PeCDF
23478-PeCDF
2378-TCDF
TEF
TEQ
ng/kg
ng/kg
ng/kg
5500
410
nd
10
8.8
nd
nd
10
5.0
2.5
5.0
5.0
4.8
0.75
1E-04
0.01
0.1
0.1
0.1
1
1
0.550
4.100
0.125
1.000
0.880
2.400
0.375
130
39
nd
nd
nd
nd
nd
nd
nd
nd
10
5.0
3.1
4.1
1.8
1.0
0.94
0.61
2.7
2.90
1E-04
0.01
0.01
0.1
0.1
0.1
0.1
0.05
0.5
0.1
0.013
0.390
0.016
0.205
0.090
0.050
0.047
0.015
0.675
0.145
Calculating TEFs and TEQs
Conc. MDL
ng/kg
•
COPLANAR PCB'S
1 3,4,4',5-TCB (#81)
170
2 3,3',4,4'-TCB (#77)
12
3 3,3',4,4',5-PeCB (#126)
19
4 3,3',4,4',5,5'-HxCB (#169)
nd
5 2,3,3',4,4'-PeCB (#105)
1000
6 2,3,4,4',5-PeCB (#114)
71
7 2,3',4,4',5-PeCB (#118)
2300
8 2',3,4,4',5-PeCB (#123)
93
9 2,3,3',4,4',5-HxCB (#156) 280
10 2,3,3',4,4',5'-HxCB (#157) 71
11 2,3',4,4',5,5'-HxCB (#167) 500
12 2,3,3',4,4',5,5'-HpCB (#189) 47
TEF
ng/kg
4.0
0.0001
4.0
0.0001
4.0
0.1
4.0
0.01
4.0
0.0001
4.0
0.0005
4.0
0.0001
4.0
0.0001
4.0
0.0005
4.0
0.0005
4.0
1E-05
4.0
0.0001
TOTAL TEQ
TEQ
ng/kg
0.017
0.001
1.900
0.020
0.100
0.036
0.230
0.009
0.140
0.036
0.005
0.005
13.574
Summary
• PCB Congener Data can be obtained by two
methods: EPA Method 8082 and 1668A.
• GC/High Resolution Mass Spectrometry provides
for the analysis of compounds with excellent
identification capability and sensitivity.
• PPQ detection levels can only be achieved using
GC/High Res Mass Spectrometry