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15th
Continuous Flow-IRMS Workshop Sunday June 28th
through Wednesday July 1st 2009 Cornell University,
Ithaca, NY, United States |
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Workshop Abstracts Sunday, June 28th, 2009 TC/EA--Running in a multi-use environment: high
backgrounds, incompatible samples, and why did the baseline just do that? G. Olack Yale University, New
Haven, Connecticut, USA Abstract The TC/EA is a useful tool
in a stable isotope mass spectroscopy laboratory. However, like many instruments, it can be
rather fun to keep running. We’ll go
over some of the common modes of failure, what they look like, and how to fix
them. Different reactor set ups, their
uses and promises and pitfalls will be discussed. The varied sample types, nitrates,
phosphates, sulfates, organics, waters and even silicates, can also pose
unique challenges, and we’ll go over some rules of thumb. Some useful articles (not required
reading): Kornexl, Gehre, Hofling, and Werner, 1999, Rapid Commun. Mass
Spectrom. 13, 1685-1693. Werner, 2003, Isotopes Environ. Health Stud., 39/2
85-104. Vennemann, Fricke, Blake, O’Neil, and Colman, 2002, Chemical Geology, 185,
321-336. LaPorte, Holmden, Patterson, Prokopiuk, and Eglington 2008, J. Mass Spectrom. DOI 10.1002/jms.1549. Outline: 1. Overview. 2. Parts is parts. Cleaning, repairing, and finding the bits
you need. A. TC/EA repairs: i. Solid state relay. ii. Thermocouple. iii. Capping the wires. iv. Heating element (spiral cut silicon carbide). v. New collar. B. Reactor packing. i. Standard flow--solid samples ii. He from the bottom. iii. Running with liquids. a. cold weld b. injections. iv. Is it dead yet? v. Finding/making replacement parts C. Trapping and diverting flow. i. Valco valve before GC. ii. Cold and acid traps. D. Conflo III i. Stickiness everywhere--residue from Silver
phosphate runs. ii. Cleaning the flow controller valve. iii. Now you’ve done it--replacing the open
split tube. E. Things that make you go hmmm...(I haven’t
played with these) i. Moly-be-what??? Who needs glassy C. ii. Low flow: higher sensitivity and
backgrounds. iii. Trapping your peak--how can it help? 3. Applications--is this the real world? A. Phosphates, sulfates, nitrates and
silicates--oh my. i. Sample preparation--if we have time. ii. Dry, Ca free. iii. Phosphates after sulfates suck, sulfates
after phosphates phine. iv. PTFE with silicates--what we see. v. Maybe we should just dilute the N2. B. Hydrous minerals. i. Adventitious water? ii. Hydrogen
works--oxygen, not so much. iii. Stepped heating--ok, not in the TC/EA. C. Liquids. i. cold weld. ii. injections. D. Organic samples. i. Cooler temperatures, nickel too. ii. What’s exchangeable? 4. Numbers versus data. A. Waiting for the baseline to settle. B. High baseline--scale compression. C. Didn’t wait long enough. D. Storm front moved in. E. How many standard runs? F. How many replicates? 5. Free form....(oops, no time left) Monday, June 29th 2009 Keynote Address The Emergence of Isoscapes as Tools for Studying
Large-scale Processes J. West Texas A&M University, College
Station, Texas, USA Abstract Since the
discovery of isotopes and the development of precise instrumentation capable
of measuring small differences in isotope abundances, a variety of
disciplines have studied the spatio-temporal distributions of isotope ratio
variation in natural systems. The interest in understanding this variation arises
because of the wealth of information about spatially-distributed Earth system
processes available in these isotopic records. The recent and continuing
development of analytical tools for isotope analysis, in particular
continuous-flow isotope ratio mass spectrometry (CF-IRMS) methods and other
approaches such as laser spectroscopy, have led to lead to dramatic increases
in the availability of light stable isotope ratio data, significantly
expanding the questions and systems that can now be studied in detail. In
addition, an abundance of spatially-explicit datasets have emerged from
Earth-observing instruments, and computer and software developments continue
to supply critical cyberinfrastructure for exploring spatial variation in
isotope ratios and its application to questions across a spectrum of
scientific domains. In part due to these technological advances, spatially
explicit maps of isotopic variation, or isoscapes, are being developed by a
growing number of research groups and applied to new questions as our
understanding and capacity to measure stable isotope ratio variation
increases. In addition, commonalities in how isoscapes are developed and the
need for large, often internationally-distributed sampling networks have led
to the identification of isoscapes as an exciting platform for better
interaction across disciplinary boundaries where that interaction can advance
understanding. Taking examples from my and colleagues’ work, I will discuss
approaches to the use of isoscapes to address questions in forensics,
biogeochemistry, and hydrology and insights obtained within each area. I will
also highlight recent efforts to enhance understanding within and across
disciplines that I believe will improve the ability to produce isoscapes and
the utility of these tools for addressing important questions in the Earth
sciences and beyond. Multicollectors in Isotope Ratio MS A. Hilkert and
C.B. Douthitt Thermo
Fisher Scientific, Bremen, GER Abstract One
of the basic features in Isotope Ratio MS is the simultaneous collection of
all ion beams required in an isotope ratio application. The use of more than
one collector enhances the precision of the measurement due to the constant
acquisition of all ions over time. This also ensures the correlation of data
points collected at the same time in both dual inlet and continuous flow
applications. IRMS
and with it the multicollection started with the setup of two faraday cups
for collection of masses 44 and 45 in CO2. This was followed by
the addition of a third collector for mass 46 to allow the correction of the
interfering 12C17O16O ion on mass 45 via the
18O information plus the relation between 18O and 17O. With
the extension to gases like N2, O2, SO2 and
H2 but also triggered by the invention of the continuous flow
application with its fast delivery of more than one gas universal collector
arrangements were required. A
prerequisite for extended universal collectors was the development of new
electronics for signal amplification and data collection. Today simultaneous
detection of 10 ion beams on a wide focal plaine, an enhanced dynamic range
of 50 V on each preamplifier plus computer controlled switching of the
amplifier gains allow tailored collector systems for many different applications
and isotope ratio ranges. The
pros and cons of various collector configurations and their contribution to
the development of new applications will be discussed. New Product Update from Elementar and Isoprime
Elementar Americas, Inc., Mount Laurel, New Jersey, USA Abstract Elementar purchased the
assets of GV Instruments gas IRMS business from Thermo Fisher in February
2008 and formed Isoprime Ltd. One of
the anticipated benefits of this transaction was increased product
development resources. This first 18 months of
cooperative development has resulted in the release (or soon release) of 4
new products for use in IRMS determinations.
These new products of Elementar and Isoprime will be reviewed. Isotech Laboratories, Inc. Who we are, what we do,
and what's new and...exciting? T. Coleman Isotech Laboratories, Inc., Champaign,
Illinois, USA Abstract Isotech Laboratories, Inc.
is the largest commercial stable isotope laboratory in the U.S. (perhaps the
world?). Located in Champaign, Illinois, Isotech, specializes in natural gas
analysis, but also provides analyses of waters, solids, oils, liquids, etc. We also currently operate 2 satellite
facilities in Cairo, Egypt, and Rio de Janiero, Brazil with a 3rd coming
online later this year in Perth, Australia.
Another important aspect of the analytical business is ensuring the
acquisition of quality samples. To
help clients with this process Isotech also manufactures sampling equipment
which supplements our analytical business, including the IsoTube(r),
IsoJar(r), and IsoBag(r), as well as the new IsoPak(tm), IsoTube(r)
AutoLoader(tm) and IsoTube AIM Chip(tm) (Automatic IsoTube Marking). A new laser-based, field-deployable analyzer for
laboratory-class stable isotope measurements in water P.
Gupta1, D. Noone2, J. Galewsky3, C. Sweeney4,
N. Saad1, and B.H. Vaughn2 1Picarro, Inc., Sunnyvale, California, USA 2University of Colorado, Boulder, Colorado, USA 3University of New Mexico, Albuquerque, New Mexico,
USA 4National Oceanographic and Atmospheric
Administration-Earth System Research Laboratory, Boulder, Colorado, USA Abstract Details are presented of a
new isotopic water analyzer that incorporates an evaporator system, allowing
isotopes in liquid water samples as well as in water vapor from ambient air
to be measured by the same instrument with precision rivaling that of conventional
IRMS. The measurements require no sample preparation and the same analyzer
can measure both δ18O and δD in water simultaneously.
Importantly, vapor measurements are made in-situ, in real time, obviating the
need for flask sampling. The results of field trials and laboratory
measurements show that this analyzer is ideal for precise, accurate
measurements with extremely low drift, in widely varying environmental
conditions. In the laboratory as well as in field settings, the analyzer can
achieve precisions better than of 0.3‰ for δD and 0.05‰ for δ18O,
previously reserved for dedicated, laboratory-based IRMS systems. These
results demonstrate that this laser based isotope analyzer, employing
wavelength scanned cavity ring down spectroscopy (WS-CRDS) is among the most
remarkably simple and reliable tools available to scientists for water
isotope studies. It enables real-time, continuous measurements of water vapor
in ambient air as well as measurement of waters from precipitation, ice
cores, ground water and many surface waters, facilitating our greater
understand of hydrology, meteorology and more recently, global climate
change. Latest advances in isotope studies using laser
spectroscopy: High Frequency, Increased Precision, and New Applications M. Gupta Los Gatos Research, Mountain View, California, USA Abstract We will present our latest advances in using
Off-Axis Integrated Cavity Output Spectroscopy (Off-Axis ICOS) to measure δ18O
and δD of water. System improvements have increased the sample
throughput to 90 unknowns per day with a measurement precision of better than
± 0.17 ‰ and ± 0.32 ‰ for δ18O and δD respectively. Moreover,
repeated measurements further improve the precision as expected, enabling the
quantification of 23 unknowns per day with δ18O and δD precisions
exceeding ± 0.08 ‰ and ± 0.23 ‰ respectively. Data from a recent field
deployment using high-frequency measurements will be presented. Other isotope
applications will also be discussed. Advances in
Compound Specific Isotope Analysis: Scope and Requirements on automated
multi-element irm-GC/MS D. Juchelka, A. Hilkert, and M. Krummen Thermo Fisher Scientific, Bremen, GER Abstract Compound specific isotope analysis (CSIA) by coupling GC has made
great advances in the last 20 years which has significantly increased the
range of applications of continuous flow isotope ratio MS. In 2008 a new
concept for an automated multi-element irm-GC/MS has been introduced, which
incorporates more automated functionalities and tools for optimization and
system monitoring. With the ability of analysis of the main bioelements and their major
isotopes 13C, 15N, 18O and 2H a
comprehensive scientific approach can be accomplished by irm-GC/MS. Multiple
isotope methods can be established switching between different operating
modes. Today’s requests are still related to the improvement of the overall
sensitivity and precision but also to high throughput and ease of use. The
overall performance of GC applications is given by GC resolution, background
correction, conversion efficiency and transfer rates. Scope and requirements on this technique will be addressed with respect to the dynamic range, precision and
accuracy together with the requirements on sample size. Examples for
multi-element and multi-compound isotope analysis will be shown. The analysis of compounds
with high molecular weight, high polarity and thermal instability by
irm-GC/MS is limited. The introduction of irm-LC/MS has enlarged the range of
applications towards these compound classes. Although this technique is still
limited to 13C/12C ratio determination, new key
applications have already been covered. Inherent restrictions from the
conversion technology in the liquid phase require more focus on the HPLC
applications and techniques. GC and LC techniques will be briefly compared and
factors influencing the overall performance will be discussed. Detection of endogenous steroid doping by carbon
isotope ratio analysis J.T. Brenna Cornell University,
Ithaca, New York, USA Abstract Endogenous steroids such
as testosterone or dehydroepitestosterone (DHEA) are taken as exogenous
substances for performance enhancement. The doses perceived to be effective
maintain the overall urinary concentrations within the broad normal range.
Masking substances are often employed to foil tests that normalize for
steroids that normally co-vary with the active steroid. Since commercial sources of steroids are
usually synthesized from C3 plant materials, and the steroid precursor
cholesterol is synthesized ultimately from a mixture of C3 and C4 plants,
carbon isotope ratio (CIR) analysis can be used to detect doping. We review
the principles and practice of IRMS analysis of testosterone and DHEA testing
with reference to a recent high profile case. Poster Session Abstracts Assessment of animal starvation by continuous
flow-IRMS: quantification of nutritionally-important stable isotopes in the
hair of starved dogs. H.R. Tran and A. Carpi CUNY John Jay, New York, New York, USA Abstract As animal anti-cruelty
laws become increasingly prominent, the complexity of the cases being
presented to U.S. courts requires a more rigorous analysis of data and
evidence. This project examines animal
starvation and aims to develop a method to determine a time-course profile of
the starvation event based on sequential analysis of δ13C and
δ15N concentrations measured by continuous flow-IRMS in the
hair of recovering Pit Bull Terriers as well as their food source. While diagnosis of starvation is currently
done through medical means, there does not exist a method for determining the
duration of the starvation event.
Stable isotope analysis can be used to monitor the dietary changes to
which an animal may be subjected. In
an anabolic state dietary proteins are incorporated into the hair and as a
result 15N and 13C concentrates in body tissues and
hair at roughly 3-5% and 2-3% respectively above that of their food
source. In a catabolic state, δ13C
values are expected to show a decline while δ15N are expected
to show an initial decline followed by an increase as muscle, which is
already δ15N enriched, is broken down and used for
energy. It is hoped that sequential
analysis of hair will reveal these changes, which can then be correlated with
hair growth rates to determine a timeframe for the starvation event. Limits and Possibilities for Subsistence and
Climate Reconstruction Based on Organic and Inorganic Oxygen Isotopes in
Vertebrate Calcified Tissues K. Kirsanow,1 I. Barnes,2
and N. Tuross1 1Harvard University, Cambridge,
Massachusetts USA 2Royal Holloway University of London,
Egham, Surrey, UK Abstract We report on the oxygen
isotopic composition in two different populations: 1) experimental rodent cohorts that vary in
their location of birth, domicile and in the isotopic composition of their
drinking water, 2) late Pleistocene mammoths recovered from known latitudes. The ability to assess
differences in the local hydrology and drinking water δ18O is
limited by at least two factors: the compression
of the meteoric water oxygen isotopic values in both inorganic and organic
animal tissues and the influence of food δ18O values in
consumer tissues. Data from
experimental rodent populations indicate that different tisses and tissue
fractions are differentially sensitive to different δ18O inputs, and that values from both apatite
and collagen can be affected by complex dietary inputs in ways that obscure
drinking water oxygen isotopic values. In spite of these limitations there is
a robust relationship in the mammoth population between the organic oxygen
values in collagen and the latitude of origin. Improvements to Nafion traps to reduce
water-induced error in the measurements of
carbon isotopic ratios from carbon dioxide gas. P. Higgins University of Rochester,
Rochester, New York, USA Abstract It has long been known
that water contamination can result in errors in isotope ratio measurements.
Leckrone and Hayes (1998) further showed specifically how water can induce
error in carbon isotopic values when using continuous-flow mass spectrometry.
They demonstrated that effective water removal from the gas stream was
necessary, and that this could be accomplished by simply keeping the Nafion
water traps cooled to approximately 0°C. At SIREAL, the most common
materials analyzed are carbonates and bioapatites. While specifications, and
professional consensus, were that errors on carbon isotopic values should be
lower than those for oxygen, the opposite was typically observed at SIREAL.
Water contamination was suspected due to high ambient humidity in the
laboratory (typically 60% during the summer) and the potential for adsorbed
water in the samples (which often contain clay). The typical temperature of
the Nafion traps was about 26°C. These Nafion traps are located adjacent to a
gas chromatograph oven held at about 100°C, which have an external
temperature around 70°C. An external water chiller connected to a copper hard drive cooling block was installed below the Nafion water traps and insulated. The mechanics of the cooling system will be shown in this presentation. During analyses, the water traps are now typically between 6 and 0°C. Precision on carbon isotopic values for typical samples improved, while those for pure carbonate standards were unaffected, showing that perhaps a large part of the error observed from carbonates run at SIREAL results directly from adsorbed water in the samples themselves. Integration of Stable Isotope Mass Spectrometry in
an Undergraduate Research Environment:
Hamilton College EMSI Initiative G. Rahn, M. Crocker, B.
Wegter, and E. Domack Hamilton College, Clinton,
New York, USA Abstract In March of 2008, the
Hamilton Antarctic and Environmental Isotope Lab was born. This lab was established to provide stable
isotope mass spectrometry results for sediments, particulates, soils and
biogenic carbonate in order to support paleoenvironmental studies. Both combustion EA and Gas Bench inlet
techniques are used in the generation of weight % and d isotopic values for Carbon and Nitrogen
results. This poster will outline the
steps taken in the set-up of the lab, the procedures used for the analysis of
samples and the statistical monitoring of QC sample data generated
concomitantly with actual samples to ensure the reporting of precise and
accurate data. Presentation of results
from Antarctic sediment cores demonstrates the validity of the procedures put
in place. Variations of sulfur isotope ratios in a single
lichen thallus: a potential historical archive for sulfur pollution M. Yun,1, 2 M.A.
Wadleigh,1 and B. Mayer3 1Memorial University,
St. John’s, Newfoundland, CAN 2University of Manitoba, Winnipeg, CAN 3University of Calgary, Calgary, Alberta, CAN Abstract Fruticose lichen samples
were collected from an oil refinery area in Come-By-Chance, Newfoundland,
Canada, where significant changes in the atmospheric sulfur (S) content and
the isotope composition had occurred during the lifetime of the lichens. In
addition, lichen samples were obtained from two coastal areas, where little
anthropogenic S activities had occurred during the lifetime of the lichens.
Total S concentrations and 34S values were determined on
lichen segments of varying age by EA combustion of the lichen material
followed by CF-IRMS in order to evaluate whether they constitute historical
archives recording changes in atmospheric S pollution with time. Old segment
samples collected near the oil refinery had significantly higher δ34S
values (1.0 to 2.5‰ higher) and lower S concentrations whereas young segment
samples were characterized by lower δ34S values and higher S
concentrations. This is consistent with an increase of anthropogenic S with
lower S isotope ratios in the atmosphere in the vicinity of the
Come-By-Chance oil refinery during the lifetime of the lichens. No noticeable
differences in both δ34S values and S concentrations were
observed between old and young segment samples from two coastal background
areas, suggesting no changes in the S pollution history in these areas. These
results indicate that old lichen segments appear to preserve the isotope
ratios of pre-industry atmospheric S while young segments record present
atmospheric S isotope ratios. Therefore, under certain circumstances, lichen
thalli may record changes of atmospheric S pollution over time and hence
constitute a suitable historical archive for biomonitoring. Automated methods for analysis of ∆17O
of nitrate and sulfate at micromole and sub-micromole levels S. Kunasek, A. Schauer, D.
Allman, D. Gleason, E. Sofen, H. Amos, and B. Alexander University of Washington, Seattle, Washington, USA Abstract The measurement of the
triple oxygen isotope composition (16O, 17O, 18O,
where ∆17O ≈ d17O –
0.52 ´ d18O)
of nitrate and sulfate in aerosol, rain, and snow samples provides a new
means of elucidating the importance of various oxidation pathways in
atmospheric nitrate and sulfate formation. We describe the development of
automated methods for the analysis of ∆17O of nitrate and
sulfate at micromole and sub-micromole levels, using pyrolysis of silver
salts (AgNO3 and Ag2SO4) in a continuous
flow isotope ratio mass spectrometer system.
We also present quantitative results of several methods for removal of
sample organics, which can otherwise interfere with liberation of O2
by pyrolysis. Separation of aqueous sample anions and conversion to AgNO3
and Ag2SO4 are automated using an ion chromatograph
interfaced with a cation exchange column and fraction collector. Pyrolysis of
AgNO3 and Ag2SO4 and isotopic analysis of
the evolved O2 are automated using a temperature conversion /
elemental analyzer (TC/EA), 5A molecular sieve packed gas chromatography
column, a Conflo open-split interface, and an isotope ratio mass spectrometer
(MAT253) with helium as the carrier gas. For mmole sample sizes, this method provides
precision (1s) better than ±0.4‰ for nitrate and ±0.3‰ for
sulfate, based on repeated analyses of the international reference standard
USGS-35 (NaNO3, ∆17O = 21.6‰) and inter-lab
calibration standards (UCSD Standard #8, #9, Na2SO4, ∆17O
= 1.3‰, 2.4‰, respectively). For sub-mmole sample sizes (50 nmol – 1 mmol), we use the TC/EA coupled to a Gas Bench with
5A molecular sieve cryofocusing traps followed by a 5A molecular sieve
capillary column. Samples smaller than 1 mmole are influenced by (1) non-sample O2,
with ∆17O = 0 ‰, generated from Ag2O produced
during drying of AgNO3 and Ag2SO4 salts and
(2) absorption of as much as 15 nmoles of O2 by Ag in the TC/EA.
Both of these processes affecting sub-mmole samples necessitate further characterization.
Automation of methods for analysis of ∆17O of nitrate and
sulfate and reduction of sample sizes will enable critical improvements in
atmospheric and ice core sampling. Compound-Specific Hydrogen Isotope Forensics of
Lightly Refined Petroleum Products Y. Wang Zymax Forensics, Escondido, California, USA Abstract Compound-specific hydrogen
isotope forensics were conducted for lightly refined petroleum products
collected from a subsurface plume of non-aqueous-phase liquid and two
suspected sources, the underground storage tanks, by GC-TC-IRMS. Samples were
collected and stored in sealed vials at low temperature (<0oC)
until isotope analyses. The accuracy and
reproducibility of the hydrogen isotopic analyses were evaluated routinely
using laboratory isotopic standards. The accuracy of hydrogen isotope
measurements had been evaluated using standards with off-line measured δD values. The online and offline measured
values were in excellent agreement (difference <±2 ‰). The precision of
the GC-TC-IRMS was routinely checked by an injection of laboratory isotopic
standards after every nine sample injections. At least three runs were
conducted for each sample. The standard
deviation obtained for these isotopic standards during the course of
analyzing a sample sequence were <±1.5 ‰. Complete match of
molecular abundances between the leaking products and source of underground
storage tank was difficult due to the rapid change in compositions once
gasoline entered the groundwater. The identification of the leakage origin
was achieved successfully with our established analytical methodology,
further assisted by various statistic methodologies, e.g., dissimilarity
coefficients, which were calculated using isotope results as well as
molecular indices. The results have demonstrated the effectiveness of the
combined isotope and molecular approaches for point source identification.
Hydrogen isotope ratios of different petroleum products are excellent tracers
for the sources of petroleum products in the natural environments as they
could be extremely different with a range of several hundred per mils. Performance evaluation of the Isoprime mass
spectrometer/ Elementar vario MICRO cube for 15N and 13C
analyses. P. Brooks1, M.
Seed2, and T. Dawson1 1University of California, Berkeley, California, USA 2Isoprime, Cheadle Hulme, UK Abstract A performance evaluation
of an Isoprime mass spectrometer interfaced with an Elementar vario MICRO
cube elemental analyzer (EA) was conducted. Sensitivity, linearity, and
precision for simultaneous analysis of Nitrogen (δ 15N )
and carbon (δ 13C) stable isotope ratios using a range of
environmental standards of different sizes, CN ratios, and isotope
composition was the goal. The Elementar vario MICRO
cube uses a temperature programmed desorption (TPD) column and 120 position
zero blank auto sampler. Helium flow
rate was 200 mL/min and cycle time for N and C analysis of 7 minutes. The Isoprime IRMS was programmed to
automatically peak jump between N2 and CO2 with no need for peak centering.
CO2 was automatically
diluted to 10% of original CO2/He eluting from the EA. The analysis was
calibrated with 3.8 to 4.2 mg NIST 1547 peach leaves every 6 samples but with
less than a variation of ±0.1
δ 13C and ±
0.1 δ 15N over an 80-sample analysis. This drift with time was so small that
correction standards every 12 samples would have been more than sufficient. NIST 1547 peach leaves
showed no sample size dependence for C over a range of 0.63 to 4.72 mg
at –25.97 ± 0.02 δ 13C . NIST 1547 peach leave were linear from 3 to
297 ug N in the capsule, after correction with a dual mixing model as
described by Fry et al. 19921. Other sample material had
a similar large linear range with size and did not appear to be affected by their
C/N ratio. Results of for different
standard materials are shown below:
±
is standard deviation Reference cited: (1) Fry B.
et al.; Anal Chem. 1992, 64, 288 –291 Evaluation of different syringes for analysis of
18O and HD in water using an LGR liquid-water isotope laser. P. Brooks and T. Dawson University
of California, Berkeley, California, USA Abstract The LGR liquid-water laser
normally uses a 1.2 uL Hamilton syringe #203185/01 for automated
analysis. Recent batches (2009) of
this syringe appear to have significantly poorer performance than earlier
batches used for development of current analysis methods. Therefore alternate
syringes were evaluated for performance.
Since the Hamilton 10uL syringe #80300 works well for 1 uL injection
with the Thermo H/Device, is used with an LGR laser (William Rugh, EPA
Corvallis Oregon, personal communication), and costs only US$19 compared to
about US$100 for the 1.2 µL syringes, 10 µL syringes were evaluated. All
tests were done with the standard CTC Combi PAL auto sampler and 0.9 mL of
sample or standard in the recommended MicroLiter Analytical Supplies, Inc
#10-1200 2 mL vials and #10-0040W caps.
The LGR software was set to 10 fill strokes and a inject 480 nL
injection volume. With a 10 µL syringe
this results in about a 2 µL injection.
Syringes tested are shown below.
A consistent injection volume of ±3% is recommended for best performance. In 312 injections, good is <3
injections, promising is <10 injections, and poor is >20 injections outside the ±3% range.
Unfortunately the software
does not allow the #80300 syringes to be pumped back and forth vigorously to
remove the air bubble inherent in 10µL liquid syringes, so the sample was
always injected with an air bubble. Since
this was the case, #80300 syringes were greased and had a more promising
performance. Then gas tight syringes
were tested and failed until the LMK syringe was tested. This has good performance and, with
greasing, appears to have potential for a long life. Results of ongoing LMK
syringe tests will be presented Measurements of SO and SO2 in a Thermo
Scientific Delta V multi-collector system and the determination of sulfur
isotopes: A new method D.A. Fike1 and
J. Burdett2 1Washington University, St. Louis, USA 2Thermo Fisher Scientific, San Jose, California, USA Abstract The measurement of δ34S
from SO2 has always posed the problem of how to determine how much
of the measured 66SO2 is actually from 18O. In the past, there has been no way to
separate the 18O from the 34S. One solution has been to measure the
molecular ion, SF5+.
However, the process of converting sulfate and sulfide samples to SF6
involves special handling of fluorine.
Thus historically, the measurement of SO2 and the problems
it presents has been the more conventional method. SO2, when ionized yields SO as a
secondary ion. Advances of the
collection of ionized gases in the isotope ratio mass spectrometer equipped
with a multi-cup collector system over the past few years have allowed us to
simultaneously measure SO and SO2 molecular ions. Differences in the 50/48 ratios and the
66/64 ratios, in turn, allow us to determine how much of the measured ions
are derived from 18O. Now
we are able to resolve the isotopic composition of these various components
of SO2, including δ34S, δ33S, δ
36S, δ 17O and δ18O, by multiple
collection techniques and determinations from different methods. These recent developments demonstrate that
the SO2-SO approach may be a suitable alternative to account for
the effects of oxygen in SO2 analysis of sulfates and sulfides. Tuesday June 30th, 2009 Stable isotope applications using the Isoprime Ltd.
product range R. Sutka Elementar Americas, Inc., Mount Laurel, New Jersey, USA Abstract The Isoprime mass
spectrometer is a high performance and flexible instrument for C, H, N, O and
S analyses. The collector arrays can
be customized with up to 10 collectors with bespoke head amplifiers for
applications such as CO2 isotopologues requires additional
collectors and large sample sizes.
Applications development work at Isoprime Limited has led to solutions
for compound specific oxygen, improved methods for running carbon and nitrogen
isotopic analyses and data from GC-IRMS-MSD coupling. In addition, data on the Isoprime and vario
MICRO cube combination demonstrates that it is a high performance solution
for C, N and S isotopes. Compound specific isotope analysis of essential
fatty acids to determine feeding strategies on coral reefs M.A. Teece1 and
D. Lirman2 1 SUNY-ESF, Syracuse, New York, USA 2 RSAMS, University of Miami, Miami, Florida, USA Abstract Scleractinian (hard)
corals form the framework of coral reefs and they are dying at an alarming
rate under currently changing oceanic conditions. As water conditions change,
corals must adapt and one method of adaptation is to change their feeding
habits and strategies. In this complex relationship between an invertebrate
coral animal and its symbiotic algae (= zooxanthellae), a rapid transfer of
nutrients and energy occurs. The
sources of these nutritional compounds including essential fatty acids and
proteins will change as the coral adapts its feeding strategies. Invertebrates such as
corals require essential fatty acids for growth and reproduction and can
obtain them either through direct feeding on zooplankton and particulates, or
through translocation from their symbiotic zooxanthellae. We are using compound specific isotope
analysis of specific essential and non-essential fatty acids as a molecular
tool to discern feeding behaviors of individual corals in the ocean. Comparative analyses of symbionts and hosts
from two coral species, namely Porites
astreoides and Montastrea faveolata,
which grow in close proximity on reefs in the Florida Keys, USA revealed
considerable differences in feeding behavior. Using a mass balance approach
and the isotopic composition of specific fatty acids, we show that corals can
adapt their feeding strategies in the presence of higher prey abundance or
higher light availability. This
isotopic approach provides a much needed tool to determine feeding behaviors
and adaptation mechanisms in a closely coupled symbiotic relationship that is
difficult to determine using any other techniques. Coupling of Comprehensive 2D Gas Chromatography
(GCxGC) to Isotope Ratio Mass Spectrometry (IRMS) H.J. Tobias, G. Sacks, Y.
Zhang, and J.T. Brenna Cornell University,
Ithaca, New York, USA Abstract Traditional gas
chromatography (GC) has insufficient resolution to separate many components
in complex mixtures without prior sample cleanup. Comprehensive 2D-GC (GCxGC) has
substantially greater chromatographic peak number capacity, making it more
suitable to intricate samples.
Generally GCxGC employs two chromatographic columns with different
solid phase properties operating in tandem, where the first column separates
normally (~30-60 min) and the second column separates cryogenically focused
slices from the first column very rapidly (~2-10 seconds). There are many challenges to interfacing
GCxGC to IRMS, such as the preservation of narrow peak shapes required for
the fast GC separation in the second column which dictates interface
configuration limitations, and the reconstruction of “sliced up peaks” for
precise isotope ratio calculation.
These issues and their solutions will be discussed. Out of this World – Measuring Stable Isotopes on
the Red Planet J. Stern NASA Goddard Space Flight
Center, Greenbelt, Maryland, USA Abstract The Mars Science
Laboratory (MSL) Mission, to be launched in 2011, will have an unprecedented
set of tools to make in situ stable
isotope measurements of Martian atmospheric gases as well as CO2
evolved from Martian regolith. As part
of the Sample Analysis at Mars (SAM) instrument suite, a Tunable Laser
Spectrometer (TLS) will be used to measure 13C/12C
isotope ratios of both CH4 and CO2, as well as 16O/17O/18O
isotope ratios of CO2 and H2O, and D/H in H2O. Some of the most interesting data will come
from combustion of Martian regolith, which will give bulk d13C
data for Martian soil. To optimize and
“ground truth” these measurements, we are working on coupling a combustion
cell to a cavity ringdown spectrometer (LGR CO2 isotope analyzer)
for bulk carbon isotopic analysis. We
will test our system using Mars analog soils that have already been analyzed
for bulk d13C using conventional laboratory EA-IRMS. Limitations of Gas Chromatography Combustion
Isotope Ratio Mass Spectrometry in Doping Control K. Goodman Sciancis LLC, Cambridge,
Massachusetts, USA Abstract Gas Chromatography
Combustion Isotope Ratio Mass Spectrometry (GC/C/IRMS) is a highly optimized
technique that can measure the variation of carbon isotope ratios resulting
from natural processes. Carbon that
comprises endogenous testosterone is derived from the diet and typically has
a higher delta value (greater 13C content) than exogenous or synthetic
testosterone. Enrichment differences
between metabolic precursors and products are used to identify cases where a
doping violation has occurred. Several factors can affect
the accuracy and precision of the GC/C/IRMS measurement, especially when
applied to the analysis of compounds derived from a complex and variable
biological matrix. This presentation
describes the limitations of the technique and identifies procedures to
improve the robustness and reliability of the analysis. Alternatives in δD, δ18O Water Isotope Analysis W.
Rugh, K. Rodecap, and J.R. Brooks Environmental Protection
Agency, Corvallis, Oregon, USA Abstract A brief review is given of
current methods used for the analyses of δD and δ18O in
natural water. The methods are
compared using a “Consumers Guide” approach to their relative strengths and
weaknesses. We also present an
in-depth “test drive” of an Off Axis Integrated-Cavity Output
Spectrometer, (Los Gatos Research DLT-100). Modifications allowed us
to interface our own A200S Auto-sampler, providing us with the flexibility of
programmed selection of up to nine different injection methods. A thermocouple vacuum gauge was installed
between the vacuum pump and inlet valve to monitor residual vapor pressure
before injections. The integrity of
pre-injection vacuum is critical for the quantitative vaporization and transfer
of the injected water into the laser cavity. The vacuum gauge was useful for
runtime monitoring, as well as troubleshooting. We evaluated the use of post injection
solvent rinse/vacuum drying to reduce memory effects between samples. We also investigated the relationship
between injection volume and isotope ratio by sequential method selection
with eight different volumes.
Dependence on injected sample volume, and drift over time affected
ratio measurements during analysis. We
have created a function to normalize the ratio to sample volume, and used a
symmetrical standard placement technique to correct for drift. With the combination of these techniques,
our overall precision is +/- 0.3 for δD, and +/- 0.2 for δ18O. Cobbling Together a System for Measuring Rare
Sulfur Isotopes: Trials and
Tribulations of a Tormented Trio C.H. Moore, S.A. Studley,
and S.A. Young Indiana University,
Bloomington, Indiana, USA Abstract The rare isotopes of
sulfur, 33S and 36S, are being measured more and more
frequently in rocks because of their possible use in differentiating rocks
older than about 2.2 billion years from those that are younger. Additionally, there is mounting evidence
that some microbial processes may cause anomalous fractionation of these
isotopes. For several years at the
Stable Isotope Research Facility at Indiana University we have been
developing a system for analyzing rock samples for these isotopes. A number of attempts were made using
different methods that were ultimately abandoned because of the inability to
acquire reproducible data. As it turns
out, these methods may not have been faulty in themselves but were perceived
to be so because of problems with the mass spectrometer that did not show up
(or were not noticed) when running standard SO2 (EA-Conflo) samples. These problems included: 1) unstable
voltages caused by machining residue in the source, 2) wide discrepancies in
data values due to changes in peak centering, and 3) a relatively subtle user
error in peak evaluation that did not always manifest itself. We will discuss these problems and our
solutions in some detail. Ultimately, a systems
design that utilizes off-line SF6 gas generation using purified fluorine gas,
cleaning of the SF6 gas via gas chromatography and introduction of the clean
SF6 gas to a MAT 252 mass spectrometer via a modified Conflo II was
adopted. Because of problems in the
mass spectrometer that are still unresolved, a variety of test mechanisms
were built into the design. The design
of the systems will be discussed along with some of the problems encountered. We have been generating
useable δ33S data for several months now, and we will present
our data for standards IAEA S1, IAEA S2, IAEA S3, and 2 internal reference
samples and compare them with data in the literature. Corrections to errors in the data that are
introduced by the gas generation system and the gas chromatography process
will also be discussed. Uniform Isotopic Standards for Gas Chromatography
Combustion Isotope Ratio Mass Spectrometry of Steroids Y. Zhang, H.J. Tobias, and J.T. Brenna Cornell University, Ithaca, New York, USA Abstract Carbon Isotope Ratio (CIR)
analysis of urinary steroids using Gas chromatography combustion isotope
ratio mass spectrometry (GCC-IRMS) is a recognized test to detect illicit
doping with synthetic versions of normally endogenous steroids such as
testosterone. However, there are currently no universally used steroid
isotopic standards (SIS). We developed a protocol to prepare isotopically
uniform steroids for use as a calibrant in GCC-IRMS. These SIS can be
analyzed under the same conditions as used to analyze steroids extracted from
urine. Two separate SIS containing a mixture of steroids were created and
coded CU/USADA 33-1 and CU/USADA 34-1.
CU/USADA 33-1 contains 5α-androstan-3β-ol acetate, 5α-androstan-3α-ol-17-one
acetate, 5β-androstan-3α-ol-11,17-dione acetate and 5α-cholestane. CU/USADA 34-1 contains 5β-androstan-3α-ol-17-one, 5α-androstan-3α-ol-17-one, and 5β-pregnane-3α,
20α-diol.
Each mixture was prepared and
dispensed into a large set of ampoules using a protocol carefully designed to
minimize isotopic fractionation and contamination. The ampoules were
subsequently flame sealed. A natural
gas reference material, which is traceable to the international standard NIST
RM 8559, was used to calibrate the SIS.
Eight ampoules were randomly selected from both SIS CU/USADA 33-1 and
SIS CU/USADA 34-1 batches for analysis by GCC-IRMS. The absolute d13CVPDB and the ∆d13CVPDB values
measured for the steroids in both CU/USADA 33-1 and CU/USADA 34-1 indicate uniformity of steroid isotopic composition
within measurement reproducibility among the ampoule sets prepared. The calibration principles developed here
apply to all GCC-IRMS standards. Using CF-IRMS Applications for monitoring pollution
on Mexican Coral Reefs D. Baker Cornell University, Ithaca, New York, USA Abstract Developing nations are
challenged with balancing economic growth and environmental health. The
Mexican state of Quintana Roo is among the most rapidly developing coastal
zones on the planet, driven by tourism. With it’s proximity and dependence on
the Meso-American Barrier Reef, it’s surprising that little is known about
the impacts of development on nearshore reef ecosystems. Specifically, sewage
contamination to local aquifers is a critical issue. Wastewater treatment
systems are rare and generally remove solids while discharging high
concentrations of nutrients and bacteria. These discharges pose a threat to
human health and reef corals, arguably the keystone to the tourism industry. Here, we utilize cost-effective monitoring tools
(stable isotope analyses and Enterococcus
assays) to test for the presence of sewage-derived nitrogen in groundwater
inputs to coastal marine waters proximal to developed and undeveloped
localities in Quintana Roo. d15N values of the sea fan coral Gorgonia ventalina sampled from
developed coastlines were enriched (up to 3.6 ‰) relative to undeveloped
areas. Furthermore, d15N values from corals sampled along a transect parallel
to shore were correlated with Enterococcus
counts, suggesting that the source of nitrogen assimilated by corals was of
human origin, and not a result of denitrification. We stress that these
metrics provide a means to relate development to ecosystem decline in regions
where traditional water quality monitoring is not feasible. Simple
electronic gizmos that make your life easier.
Or the art of expressing your lazyness via electrons. P. Middlestead and G. St-Jean University of Ottawa, Ontario, CAN Abstract An electronic control box was designed to be attached to a Conflo
interface. This box allows users to
control up to four actions in a given method. Two applications using this device are explained:
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