Angela Chang

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ENVIRONMENTAL ANALYTICAL CHEMISTRY

• Angela Chang
• Mausami Desai
• Katie Sovik

Winter 1999
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• PRINCIPLES
• To experience and practice a variety of
  techniques useful in analyzing natural
  environmental processes. This includes complex
  biological, chemical, geological, and physical
  phenomena.
• This laboratory utilizes some of the
  state-of-the-art instrumentation currently
  available, noting the accuracy of results that
  can be obtained.
• The focus is split between a lesson on
  instrumentation and results analysis.

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• OBJECTIVE
• This course specifically focuses on
  characterizing naturally occurring organic matter
  (NOM) because of its influence on the
  bioavailability and activity of pollution. The
  following analyses provide an introduction to
  important laboratory instrumentation while
  addressing a significant environmental material.

4
CONTENTS

• Characterization of Total Organic Carbon
• Capillary Electrophoresis
• Potentiometric Methods
• Glucosidic Proteinaceous Fractions of DOM
• DOM Fingerprinting by PY-GC-MS

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CHARACTERIZATION OF TOTAL ORGANIC CARBON
6
TOTAL ORGANIC CARBON

• OBJECTIVE
• Quantify overall organic carbon concentrations,
  and the dissolved and particulate fractions.
• This is a generalized starting point in analyzing
  naturally occurring organic matter. Subsequent
  procedures determine more specific
  characterizations of the types of organic
  material or carbon.

7
TOTAL ORGANIC CARBON ANALYSIS

• by Automated Carbon Analyzer
• (UV Persulfate Oxidation)
• by UV Spectroscopy

8
Automated Carbon Analyzer

• 2 STEP TOC ANALYSIS PROCEDURE
• Principals
• By UV persulfate oxidation the sodium persulfate
  and phosphoric acid reagents convert all organic
  matter ? CO2
• Measuring CO2 concentrations suggests organic
  carbon concentration
• The infrared absorbance detector measures and
  quantifies this CO2 as ppm total C

9
UV PERSULFATE OXIDATION

• REACTIONS
• Excitation by UV light produces the primary
  oxidants (sulfate and hydroxide radicals)
• S2082- ?v ? 2SO4- ?
• H20 ? v ? H OH?
• UV light also breaks down the organic material
  into radical functional groups.
• R ? v ? R?

10
UV PERSULFATE OXIDATION
The combination of these 2 types of radicals
oxidizes the organic matter releasing CO2. R?
SO4- ? H20 ? nCO2 ... ? Ultimately a
measure of the amount of CO2 produced
quantifies the TOC
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Dohrman DC-180 Carbon AnalyzerFlow Diagram
See next page for system operations explanation
12
System Operations

• A pump fills the pickup loop with sample
• Specific amounts of sample and acid are injected
  into the sparger
• Acidification with H3PO4 in the sparger strips
  the inorganic (IC) and purgeable carbon (PuOC)
  from the sample. Separation of these fractions
  is aided by a bubbling flow of O2(g)
• The nonparticulate organic carbon (NPOC)
  remaining in the liquid sample is sent to the UV
  reactor by another injection loop
• UV radiation and the persulfate reagents oxidize
  all organics in the sample

13
System Operations (continued)

• The CO2(g) and OH-?(g) are directed to the
  Gas/Liquid separator and bubbled with acidified
  water. A pH of 3 is maintained to aid the
  elimination of water from the CO2.
• The infrared absorbance of water significantly
  overlaps with our focus, CO2. The removal of
  water in an osmotic pressure dryer is thus
  important.
• In the Nondispersive Infrared Detector (NDIR) the
  absorbance of infrared radiation measures CO2.
• The computer calculates and displays this as ppm
  C.

14
Interferences

• There are 3 significant types of interferences
  related to the instrument procedure and
  components of the samples
• The incomplete removal of inorganic and purgeable
  carbon in the sparger
• The incomplete oxidation of the organic material
  in the UV reactor
• Chloride present in the sample absorbing UV
  radiation

15
Calibration Curvecounts (15,500 /-
102.4)conc - 540.6 /- 1213
16
Calibration

• 5 standards of known C-concentration were made
  from KHP (K-acid phtalate)
• These concentrations ranged from 1-20 ppm
• 2 blank samples were also analyzed and used to
  zero the calibration
• The error on the intercept is larger than the
  actual intercept estimate and insignificant with
  respect to the origin
• This intercept value can be disregarded
• Considering this was our first time doing error
  analysis, we included all error estimates in our
  calculations.

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Organic Carbon Calculations
Calculations are based on average values of
triplicate readings from the machine for each
sample
18
Organic Carbon Calculations

• Dissolved particles are defined as that smaller
  than 0.45 ?m by the filters used
• Suspended/colloidal materials ineffectively
  separated by filtration can thus be
  misrepresented as dissolved
• This is a possible explanation for the large DOC
  values, misleadingly close to the TOC
• The resultant small POC calculations suggest
  large amounts of colloidal material
• The error carried over from the total and
  dissolved carbon values is greatly amplified in
  the POC calculations making them essentially
  insignificant

19
TOC - Sheboygan River
Corporate PCBs
Kohler Company
20
TOC - Lake Depue
21
Trends

• Sheboygan River
• The organic carbon levels are greatest upstream
  of the PCBs input
• The Kohler Co. does not seem to effect the carbon
  levels
• Overall there is about a 2 ppm downstream
  decrease in TOC
• Lake Depue
• No seasonal effects on TOC are noted
• There is evidence that the lake is highly
  colloidal

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UV SPECTROSCOPY

• Principle Different compounds at certain
  wavelengths show unique and specific absorbances.
  The following methods attempt to quantify the
  fractions or concentrations of different types of
  organic matter from absorbance spectra.

23
UV SPECTROSCOPY

• Correlation methods in particular, have been used
  as estimates in characterizing
• Humidification
• Aromaticity
• TOC
• The UV-254 correlation with TOC useful for
  specific water types has continued to be
  mentioned and documented because of the
  simplicity of the procedure and the portability
  of spectroscopy equipment. Even though automated
  carbon analyzers are more widely accurate, this
  method has shown some advantages.

24
UV SPECTROSCOPY

• Transmittance is the fraction of incident light
  transmitted by a solution
• This cannot be measured directly in the lab due
  to reflective interferences with any container
  used to hold the sample
• Beers Law (For use with dilute solutions only)
• Absorbance - log T ?bc
• ? molar absorptivity L/molecm
• b the path length through the solution
• c concentration

25
Spectrophotometer
1 - D2 lamp 2 - Grating 1 3 - Entrance Slit 4 -
Grating 2 5 - Exit Slit 6 - Chopper 7 - Sample
Reference Positions 8 - Chopper 9 -
Photo Tube
26
Spectrophotometry

• Mirrors and gratings redirect and disperse the
  radiation
• The slits limit the radiation range allowing
  successively isolated wavelengths to be selected
• The rotating chopper wheels alternately direct
  the light beam through the sample and reference
• A distilled water reference is required to zero
  the interference effects of the cuvette
• Other Interferences include
• chloride absorbance
• particulate scattering
• non-absorbing organic material

27
Absorption Ratios Characterizations
Although negative values are useless, the ratios
developed have been used to characterize soil
type and degree of humidification
28
E4/E6 E2/E3 Ratios Humic Substances

• Constitute a large portion of the organic matter
  in soils
• Product of the degradation of plant and animal
  materials microorganism activity
• Aromatic
• acidic
• Hydrophilic
• Flexible Polyelectrolytes
• Lignin is the second most abundant polymer
  synthesized by plants and a structural unit for
  humics

29
Biochemistry Significance

• The aromatic building blocks of humic substances
  are connected by flexible low energy bonds
• Reactions and voids aggregate/trap other
  materials
• Metals ions and toxic organic pollutants are
  stabilized in complexes

30
Humidification Analysis E4/E6 E2/E3 Ratios

• Even though our results are inconclusive
• low E4/E6 ratios have been found to indicate a
  high degree of aromatic humic constituency
• High E4/E6 ratios indicate low aromaticity, or a
  high degree of aliphatic structure

E4/E6
Humic Acids
3.8 - 5.8
Fulvic Acids
7.6 - 11.5
31
Humidification Analysis E4/E6 E2/E3 Ratios

• Less data has been compiled for E2/E3 ratios and
  thus they are less reliable although certain
  characterizations have been documented

E2/E3
Strongly humic and oligotrophic lakes
4.0
Chlorolignin
4.2
5.7
Lignin
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Absorption Ratios Characterizations
33
Aromaticity

• Aromaticity of organic matter is a specific
  structural factor significant to interactions
  with pollutants, and their stabilization
• The higher the aromatic fraction of DOM, the
  higher the xenobiotic binding capacity
• A simple equation for Aromaticity has been
  developed that is dependant on molar absorptivity
  
• ? A/bc
• ? Aromaticity 0.05 ? 6.74
• Primary assumption all organic matter absorbs
  the same at any wavelength and that also absorbs
  as the KHP standard, i.e. the ? of all organic
  matter is the same. This assumption in actuality
  is not valid, as ? varies for different types of
  organic matter.

34
TOC Surrogate

• UV absorbance at 254 nm is documented as a widely
  used substitute for TOC
• We analyzed the filtered samples in the
  spectrophotometer and thus ultimately compared
  DOC approximations from the 2 methods

35
Non-Acidified Pseudo Calibration Curveabs
(0.01953 /- 0.002089)(ppm C) - 0.01740 /-
0.01393
36
Non-Acidified Pseudo Calibration Curve

• Only 3 standards solutions ranging from 5 - 20
  ppm C, and a blank were analyzed
• the standards were diluted from a KHP stock
• the samples were zeroed by the spectrophotometer
• the 10 ppm standard introduced error

37
TOC - Comparisons
The ppm C derived by the UV-254 correlation is
doubly overcompensated. Greater error values
must also be noted as a result of the limited
calibration.
38
TOC Comparisons - Sheboygan River
39
TOC Comparisons - Lake Depue
40
Note

• The effects of the colloidal particles noted in
  the POC calculations is greatly amplified in the
  UV-254 method
• The scattering action of the colloidal material
  is one explanation for high absorbance readings
  and the overcompensation for TOC
• It is common belief that UV persulfate oxidation
  and automated carbon analysis is the more
  accurate method in determining TOC
• Although this exercise allowed a realization of
  the potential advantages and real limitations of
  experimental procedures

41
CAPILLARY ELECTROPHORESIS
42
Capillary Electrophoresis

• OBJECTIVE
• Determination of concentration of specified ions
  in sample waters

43
Introduction

• Electrophoresis is the migration of ions in
  solution under influence of electric field. In a
  typical capillary electrophoresis (CE)
  application, use an electric field of 15-30 kV to
  separate the components inside a fused silica
  capillary tube.
• Since different solutes have different
  mobilities, they will migrate through the
  capillary at different speeds
• This gives the extraordinary resolution and
  separation of many ionic species.

44
Electrophoresis

• When an ion with charge q is placed in an
  electric field E, the force on the ion is
• F qE
• In solution, the other major force on the ion is
  the retarding frictional force fvep, where vep
  is the electrophoretic velocity and f is the
  coefficient of friction
• vep qE/f µepE
• The constant of proportionality between speed of
  ion and the applied electric field is
• µep
• µep is proportional to the charge on the ion and
  inversely proportional to the friction
  coefficient.

45
Electroosmosis

• The inside surface of the silica capillary is
  covered with silanol (Si-OH) groups which carry a
  negative charge above pH2
• These negative charges on surface induce cations
  to neutralize some of the surface charge
• The constant of proportionality between
  electroosmotic velocity (veo) and applied field
  is the electroosmotic mobility
• µeo
• A relationship for the electrophoretic effect is
  
• veoµeoE

46
Diagram Hydrodynamic Velocity Profile

• (a) Positive charges move toward cathode,
  absorbed on surface of glass
• (b) More dispersion created by velocity profile
  because pushed from middle

47
Apparent Mobility

• The apparent (or observed) mobility (?app) of an
  ion is the sum of the electrophoretic mobility of
  the ion and the electroosmotic mobility of the
  solution
• ?app ?ep ?eo
• For a cation moving in the same direction as the
  electroosmotic flow, the mobilities have the same
  sign and then ?app is greater than ?ep

48
Diagram Solute Mobilities

• (a) Optimize electrolyte conditions to make
  separation larger and force ions out of system
  faster
• (b) Use TTAB as reversal compound to separate
  anions out first
• (c) Sum of all ions out of sides of capillary

49
Diagram Apparatus

• Both ends of capillary placed into electrolyte
• Sample injected by siphon effect
• Insert capillary into vial and elevate
• After injection, vial returned to normal height
• Apply voltage of 15kV
• Ions migrate through electrolyte
• Indirect detection

50
Br-
SO42-
Cl-
NO3-
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Sample Data
57
Cl-
SO42-
NO3-
58
1. DASS 2. WDNR 3. RP 4. KCL 5. EP
59
Analysis

• NO3 drops significantly from May to November
• Cl- and SO4 increased overall in Lake Depue
• Cl- a bit higher along entire Sheboygan River
  compared to other ions

60
POTENTIOMETRIC METHODS
61
Potentiometric Methods

• OBJECTIVE
• Determination of
• acid/base properties of
• samples.

62
Alkalinity CT

• Representation of the buffer capacity of a water
  sample or the ability of the water to neutralize
  strong acid.
• Alk 2CO32- HCO3- OH- - H
• Measure of alkalinity due to carbonate system
• CT H2CO3 HCO3- CO32-

63
Computer Automated Titration SystemME-10 Analyzer

• Components
• Automatic burette
• Potentiometer
• Glass Electrode
• Windows Interface program controls ME-10
  Analyzer unit during titration and records data
  (volume additions and potential)
• Data analysis to determine the equivalent volumes
  and equilibrium constants

64
Titration System Setup
Glass Electrode (w/ reference electrode and ion
selective membrane)
Titrant
Computer
Sample mixer
Burette
65
Glass Electrode

• Measures pH
• The indicator electrode measures potential
  difference across a glass membrane between 0.1 M
  HCl and the sample solution.
• The glass electrode has two key components
• reference electrode
• ion selective glass membrane

66
Reference Electrode

• Within a tube in the indicator glass electrode
• The reference electrode contains a small volume
  of dilute HCl and AgCl. The Ag wire forms a
  reference electrode creating a link to the
  potential measuring device. This electrode should
  obey Nernst equation when constant temperature
  and ionic strength are maintained.
• The reference electrode provides a base potential
  from which changes in potential can be measured.

67
Ion Selective Membrane

• The ion selective glass membrane is sealed into
  one
• end of the glass tube.
• When hydrated, it allows for the interaction
  between singly charged cations (electric
  conductivity) in the glass and protons from the
  solution.
• H NaGl- ? Na HGl-
• More specifically when Na is low, conduction
  within the hydrated layer involves the movement
  of hydrogen ions by the following reactions
• H Gl- ? HGl- (between glass and sample
  solution)
• HGl- ? H Gl- (between internal solution
  and glass)

68
Typical Electrode System for Measuring pH
69
Measurement through Electrode

• The equilibrium position of these 2 reactions are
  determined by H in the solutions on the two
  sides of the membrane.
• The surface where greater dissociation occurs
  becomes negative w/respect to other surface with
  less dissociation.
• A boundary potential Eb develops across the
  membrane which is sensed by the analyzer and
  recorded by the computer.
• The potential change is recorded in mVolts along
  with the corresponding volume of acid added

70
Measurement through Electrode

• Since constant temperature and ionic strength are
  maintained, the system obeys the Nernst equation.
• Eb is Emv where
• Emv EG kT ln H
• EG Potential normal of the glass electrode for
  H1M
• Includes reference potential and
  corrects for
• departure from ideal behavior
• k R/F (R Gas constant, F Faradays
  constant)
• T Room temperature in Kelvin

71
Calibration of Electrode System

• Titrated solution of 5 mL 0.1 M KCl (to maintain
  ionic strength) and distilled water with 0.1 M
  HCl at T 22o C or 295 K
• Verifies Nernst Equation by obtaining linear
  relationship by plotting pH vs.. change in
  potential where pH is
• ln H ln (Vad tHCl)/(Vo
  Vad)
• Note tHCl HCL0.1M
• Theoretically under these conditions should be
• kT 58.54, the experimentally obtained value
  was
• kT 57.51 a variation of less than 2

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Error Sources in Potentiometric Method

• Variation in temperature of solution possibly due
  to constant stirring
• Variation in ionic strength
• The Eppendorf was not sealed properly and
• additions of KCL to samples may have varied
• Junction Potential Potential develops from the
  difference in composition between sample and
  titrant. This potential arises from the unequal
  distribution of cations and anions and the
  different rates at which the species migrate. As
  long as ionic strength is maintained this
  potential is reduced.

74
Gran Method

• Priniciple Graphical procedure based on
• knowledge that added increments of strong acid
• linearly increase H or decrease OH-,
  likewise
• added increments of strong base decrease H or
• increase OH-.
• A titration curve is obtained by plotting volume
  added vs. potential E in mV. In this lab strong
  acid is added to determine the alkalinity of our
  samples so we know that the lower part of the
  curve is composed of base, while the upper part
  of the curve is composed of acid.

75
Potentiometric Titration-DASS sample
200
180
acidic
160
140
120
100
80
60
V2 2.503/- 0.0159
40
mV
20
0
-20
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
3.2
3.4
3.6
3.8
4
-40
-60
-80
basic
-100
-120
-140
-160
V1 0.1204/-0.0074
Volume Added
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Gran Method cont.

• At the midpoint the base A- acid HA.
• All base is titrated at the endpoint or
  equivalence point of the titration and is
  represented by an inflection point.
• Thus, using this method, it is possible to
  determine the carbonate system equivalence
  points, assuming that the alkalinity of our
  samples is due to the carbonate system.
• Determine equilibrium constant for carbonate
  system

77
Gran Plots F1

• For volumes gt than the second equivalence point,
  volume v2
• H gtgt HCO3-, CO32-, and OH- together
• So the following relationship is true
• F1 (vo vad) H (vad - v2)tHCl
• Note tHCl HCL0.1M
• When plotted against vad, the function is linear
  beyond v2 so
• F1 0 for vad v2

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Gran Plots F2

• Between the first and second equivalence points
  volumes, v1 and v2
• H2CO3 gtgt H - CO32- - OH-
• HCO3- gtgt CO32- OH- - H
• Similarly the following relationship holds
• F2 (v2 - vad)H (vad - v1)K1
• F2 is linear for volumes less than v2 when
  plotted against vad and F2 0 for vad v1, with
  the slope of F2 K1 the equilibrium constant for
  
• H2CO3 ? HCO3- H

80
K 6.2512/-2.65E-3
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Alkalinity CT Results

• Determined by the following relationships
• Alk (v2 tHCl)/ v0 CT ((v2 -
  v1) tHCl)/ v0
• Alkalinity CT
• DASS 5.0007E-03 4.7601E-03
• WDNR 5.0060E-03 4.8310E-03
• RP 5.0271E-03 4.7971E-03
• KCL 5.0620E-03 4.8210E-03
• EP 5.0870E-03 4.8160E-03
• MAY 2.7100E-03 2.5910E-03
• NOV 4.4810E-03 4.2230E-03
• both are molar
  values M

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Analysis

• Sheboygan River Alkalinity increases moving
  downstream along the, while CT remains
  essentially constant varying around 4.8E-3 M
• Lake Depue Alkalinity and CT increase in the
  winter nearly doubling, most likely due to the
  course of productivity throughout the year

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GLUCOSIDIC PROTEINACEOUS FRACTIONS OF DOM
86
GLUCOSIDIC PROTEINACEOUS FRACTIONS OF DOM

• OBJECTIVE
• Qualitative analysis of simple sugars and amino
  acid fractions of DOM through colorimetric and
  fluorescence methods. These residuals of
  biological activity and decay are significant in
  determining COD.

87
GLUCOSIDIC FRACTION

• COLORIMETRY/SPECTROSCOPY
• Reaction of phenol and H2SO4 (Dubois reagents)
  with the samples breaks down complex sugars.
• The attachment of phenol to the reduced sugar
  monomers produces compounds of a stable yellowish
  color.
• Spectrometric measurement of the intensity of
  color quantifies the specific fraction of sugars.
  

88
Spectrometer
1 - D2 lamp 2 - Grating 1 3 - Entrance Slit 4 -
Grating 2 5 - Exit Slit 6 - Chopper 7 - Sample
Reference Positions 8 - Chopper 9 -
Photo Tube
89
Spectrophotometry

• Mirrors and gratings redirect and disperse the
  radiation
• The slits limit the radiation range allowing
  successively isolated wavelengths to be selected
• The rotating chopper wheels alternately direct
  the light beam through the sample and reference
• A reference sample is required to zero the
  interference effects of the cuvette.
• Other Interferences include
• particulates scattering
• non-absorbing organic material

90
GLUCOSIDIC CALIBRATION _at_ 480 nm
No distinction can be made between the 0 and 10
uM concentrations. Most of our data points fall
within this range. The calibration from this
method therefore does not lead to conclusive
results.
91
GLUCOSIDIC CALIBRATION _at_ 490 nm
92
GLUCOSIDIC RESULTS480 nm
As noted, all of our data points refer to
concentrations less than 10 uM with the exception
of samples EP and May. In general, this did not
provide us with useful data for analysis.
93
GLUCOSIDIC RESULTS490 nm
94
ANALYSIS

• The glucosidic fraction of TOC increases
  downstream in the Sheboygan River.
• The TOC values previously determined show a
  slight decreasing trend downstream.
• The Lake Depue fraction is higher in May than
  November.
• Using glucose as a representation of all other
  sugars is not a good quantitative method.

95
Total Hydrolyzable Free Amino Acids(Proteinaceous
Fraction)

• Samples reacted with OPA-MERC solution to bind
  with aromatic compounds, such as proteins
• Fluorometric measurement quantifies proteinaceous
  fraction

96
FLUORESCENCE

• The fluorometer energy source excites electrons
  of organic compounds bound to OPA-MERC
• High energy state is unstable
• As electrons return to a more stable ground
  state, visible light is emitted
• From the intensity of emitted light,
  proteinaceous fractions can be determined

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Fluorometer
98
Procedure
Procedure
Procedure

• Simple, low-cost, and easy to use
• Mercury lamp for fluorescence excitation
• Source beam split near source into a reference
  beam and a sample beam
• Both beams pass through primary filter
• Sample beam causes emission of fluorescent
  radiation

99
Proteinaceous Calibration
Like the glucosidic calibration the amount of
scattering within the data shows that this method
is unreliable at these concentrations.
100
Proteinaceous Results
No apparent trends are noted.
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DOM FINGERPRINTING BY PY-GC-MS
102
DOM FINGERPRINTING

• OBJECTIVE
• To characterize the constituents of dissolved
  organic matter, accomplished by breaking down the
  DOM through a 3-step process.

The data obtained in this procedure is based on a
wetland sample taken on August 6,1998
103
PY-GC-MS METHOD

• STEP 1 PYROLYSIS
• In an inert environment and at a controlled
  temperature, the organic matter from the
  concentrated water samples is thermally degraded
• Bonds within the OM are broken and rearranged
• Predictable and reproducible fragments form

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PY-GC-MS METHOD

• STEP 2 GAS CHROMATOGRAPHY
• The pyrolyzed fragments are drawn into the GC
  column
• The fragments migrate through the column by
  action of a He mobile phase flushing the system
• affinity to a stationary phase (the silica
  column) results in varied migrations rates for
  the different types of fragments

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Gas Chromatograph
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PY-GC-MS METHOD

• STEP 3 MASS SPECTROMETRY
• A detector senses when the organic matter
  fragments reach the end of the column
• This signal is plotted versus time producing a
  chromatogram
• Specific fragments can be identified by their
  characteristic retention times

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Chromatogram
1
1. Unknown aliphatic 2. Acetic Acid 3. Propanoic
Acid 4. Dimethyl-Propanedioic Acid 5. Butanoic
Acid 6. Hexanoic Acid 7. Butenoic Acid 8. Phenol
2
8
3
4
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7
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PY-GC-MS METHOD

• STEP 3 CONTINUED MASS SPECTROMETRY
• In the mass spectrometer the fragments are
  ionized
• An alternating current through the 4 poles of the
  mass spec separates the ionized fragments by
  their mass/charge ratios
• The mass spec plots the spectrum of the ionized
  fragments mass/charge ratio versus abundance

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Quadrupole Mass Spectrometer

• the fragments of the specific mass/charge ratio
  wanted at any one time pass between the rods
  without being neutralized
• the other fragments are neutralized by contact
  with the rod walls

110
PY-GC-MS METHOD

• STEP 3 CONTINUED MASS SPECTROMETRY
• The software program used in conjunction with
  this method performs an online library (NIST)
  search to match the mass spectra of a fragment to
  known compounds.
• The compounds detected in our sample
• unknown aliphatic butanoic acid
• acetic acid hexanoic acid
• propanoic acid butenoic acid
• dimethyl-propanoic acid phenol

111
Note

• If we had samples leftover to analyze, the
  PY-GC-MS method would have been beneficial in
  providing structural feature fingerprints serving
  as chemical markers within our samples. Trends
  may be depicted.
• Analysis methods can allow results comparisons
  with other methods. Such as with determination
  of the glucosidic fraction. PY-GC-MS analysis is
  enhanced when used in conjunction with data from
  other methods.

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Evaluation

• We have improved our laboratory skills
• Through this course we have gained an
  understanding of analytical methods currently
  being used in the environmental field
• We not only have a more comprehensive
  understanding of scientific terminology, we are
  capable of analyzing data in a more applicable
  way
• In previous laboratory courses, error analysis
  was not required. We have gained an
  understanding of how results are obtained and how
  error can limit their relevance

113
References

• C45 Winter 1999 Lab Manual
• Samuel Webb, Jill Kostel, Tanita Sirivedhin -
  technical advice
• Leary, Skoog. Principles of Instrumental
  Analysis
• Chen, Senesi, Schnitzer. Information Provided
  on Humic Substances by E4/E6 Ratios, Soil
  Science Society of America.
• Aiken, Chin, OLoughlin. Molecular Weight,
  Polydisperity and Spectroscopic Properties of
  Aquatic Humic Substances, Environmental Science
  Technology.
• Dean, Dobbs, Wise. The Use of Ultra-Violet
  Absorbance fo rMOnitoring the Total Organic
  Carbon Content of Water and Wastewater, Water
  Resources.
• Kukkonen. Effects of Lignin and Chlorolignin in
  Pulp Mill Effluents on the Binding and
  Bioavailability of Hydrophobic Organic
  Pollutants, Water Resources.