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	Quality Assurance at RSIL (Site not responding. Last check: 2007-11-06)
		The Reston Stable Isotope Laboratory (RSIL) is an entity that produces hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope ratio analyses of water, rock, and biological samples for the operational and research components of the U.S. Geological Survey.
		The isotopic composition is reported to the sample submitter in per mill relative to VPDB on a scale such that NBS 19 calcium carbonate is +1.95 ‰ exactly.
		If the 1-sigma of nitrogen isotope ratios is greater than 0.25 ‰ (or the 1-sigma of oxygen isotope ratios is greater than 0.5 ‰), the unknowns are re-analyzed until the 1-sigma uncertainty of the result is better than 0.25 ‰ for nitrogen isotope ratios (or 0.5 ‰ for oxygen isotope ratios).
	www.isotopes.usgs.gov /Quality.htm (2371 words)

	[I] TERMS & DEFINITIONS IN NUCLEAR CHEMISTRY
		ISOTOPE EXCHANGE ANALYSIS A method of quantitative analysis based on the isotope exchange between isotopes of the element to be determined and other isotopes of this element in different valency state or in different molecules.
		ISOTOPE GEOLOGY Investigation of geological phenomena by means of stable and radioactive isotopes of elements and of changes in their abundance.
		ISOTOPE HYDROLOGY The study of the properties and distribution of water on the surface of the earth, in the soil and rocks, and in the atmosphere as measured using stable and radioactive isotopes and measurements of their abundances.
	www.radiochemistry.org /nomenclature/i.htm (1657 words)

	New study shows exposure to depleted uranium
		By measuring the relative abundances of different isotopes of uranium in the urine samples, the researchers were able to distinguish between natural and depleted uranium.
		The analysis of samples from Gulf War veterans was performed in collaboration with the Baltimore Veterans Affairs Depleted Uranium Follow-up Program, which is assessing, treating, and monitoring veterans who may have been exposed to depleted uranium during the war.
		As expected, the soldiers with embedded shrapnel had high concentrations of uranium in their urine, and the isotope analysis showed that it was depleted uranium, presumably being released into their bodies from the shrapnel.
	currents.ucsc.edu /03-04/01-19/uranium.html (758 words)

	Tracking with isotopes (Site not responding. Last check: 2007-11-06)
		But the hydrogen isotope deuterium also has a neutron, and is almost twice as heavy as the common hydrogen isotope.
		The goal was to compare isotopes in monarchs found in Mexico to the isotopic "signature" of various possible breeding grounds in Canada and the United States.
		Thus the isotopic content of wintering individuals is a good marker of the geographic origin of the monarchs.
	whyfiles.org /083isotope/2.html (715 words)

	Bone Chemistry
		Carbon and nitrogen isotope ratios in human bone may be used to reconstruct prehistoric diet because of differential fractionation, between certain plant groups, of atmospheric carbon dioxide during photosynthesis and of nitrogen during fixation or absorption.
		Stable carbon isotope analysis is particularly useful in New World dietary studies since maize is often the only C4 plant contributing significantly to human diets; its contribution to bone collagen and to bone apatite may be estimated by interpolation.
		The nitrogen isotope ratios for plants depend primarily on how they obtain their nitrogen - by symbiotic bacterial fixation or directly from soil nitrates - and these values are similarly passed along through the food chain accompanied by an approximately 2-3 positive shift for each trophic level, including between mother and nursing infant.
	luna.cas.usf.edu /~rtykot/Bone.html (2927 words)

	Isotope Dilution in Chemical Analysis
		An isotope dilution standard is an isotope of an element or a molecular compound labeled with an isotope.
		The Pb isotopes which are stable and occur naturally have atomic masses of 204 (1.4%), 206 (24.1%), 207 (22.1%), and 208 (52.4%) where the natural abundances appear in parenthesis.
		In the analysis of sub-ppm levels of lead (Pb) in supplements, errors from traditional approaches using ICPMS and GFAA can be 25% or more, characteristic of a trace analysis in a solid matrix.
	www.wcaslab.com /tech/isotope_dilution.htm (440 words)

	Stable Isotope Laboratory - Sample Submission Information (Site not responding. Last check: 2007-11-06)
		Isotope ratios are determined on a Micromass (formerly VG) SIRA Series II mass spectrometer.
		Analyses of carbon and oxygen isotopes in atmospheric CO2 or carbon isotopes in atmospheric methane are typically made from samples contained in 3-liter glass flasks with stopcocks and a 14/24-size ground glass joint.
		ANALYSIS TIME: Generally reference cylinders require analyses made over a period of weeks to verify the stability of the standard air before it can be released and ceritified for use.
	mysticplum.colorado.edu /groups/sil/sample.html (705 words)

	W.M. Keck Isotope Laboratory
		In particular, the ability to measure accurately the relative abundances of different stable isotopes of the same element in a sample is important to many researchers.
		Isotopic analysis of the layers in fish otoliths using this laser technique can yield clues about the different environments a fish lived in throughout its life.
		The Keck Isotope Laboratory is one of the core analytical facilities at UCSC, open to researchers in a variety of disciplines on campus and throughout the UC system.
	currents.ucsc.edu /03-04/06-28/lab.html (838 words)

	Isotope analysis -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-11-06)
		The distribution of (Click link for more info and facts about stable isotopes) stable isotopes and certain (Violent or severe weather (viewed as caused by the action of the four elements)) elements within a food web make it possible to draw direct inferences regarding diet, trophic level, and subsistence.
		Isotope analysis is a completely different technique from (A chemical analysis used to determine the age of organic materials based on their content of the radioisotope carbon-14; believed to be reliable up to 40,000 years) radiocarbon dating, which is used to measure the age of organic materials.
		To obtain an accurate picture of palaeodiets, it is important to understand processes of (Click link for more info and facts about diagenesis) diagenesis that may affect the original isotopic signal.
	www.absoluteastronomy.com /encyclopedia/i/is/isotope_analysis.htm (150 words)

	Carbon and nitrogen isotope analysis at the Colorado Plateau Stable Isotope Laboratory
		Carbon and nitrogen isotope analysis at the Colorado Plateau Stable Isotope Laboratory
		Isotope measurements are not affected by small weighing inaccuracies because their determination is not weight-dependent...
		An additional $3 per sample will be included for any other tasks that need to be performed by our lab prior to isotope analysis (e.g., sieving soils, pre-combustion of sediments to remove organics, acid-treatment to remove inorganic carbon, grinding samples to a fine powder, weighing samples, etc.).
	www4.nau.edu /cpsil/13c_15n_org.htm (1800 words)

	qa/qc
		Samples for automated isotope analysis are first weighed out into tin boats to the nearest 0.01 mg on a Mettler AE240 or a Sartorious micro electronic balance.
		The gas of interest is then introduced into the mass spectrometer for isotope analysis and the rest pumped away.
		The sample isotope ratio is compared to a secondary gas standard, whose isotope ratio has been calibrated to international standards.
	www.bu.edu /sil/quality.htm (741 words)

	Isotope analysis of closely adjacent minerals - Patent 4965209
		The relative abundance of carbon, hydrogen and oxygen isotopes in natural carbonates, such as limestones, dolomites, and the like and in hydrous minerals, such as clays and micas, can be used to provide information about whether hydrocarbons were present or were likely to be formed during mineral formation and about prevailing temperatures.
		According to yet a further aspect of the invention, a mineral sample comprising a plurality of minerals is moved relative to a laser beam, the laser beam is at least periodically caused to thermally pyrolyze portions of the sample, and the resulting gases are collected and analyzed.
		A tube 48 is in communication with ionization chamber 42 and provides a gas sample to the ionization chamber 42 for analysis from vacuum chamber 50 of microscope 52 having a laser 74 associated therewith to direct thermally pyrolyzing excitation onto a slide on stage 56 within the chamber 50.
	www.freepatentsonline.com /4965209.html (4536 words)

	DIALOG Dissertation Abstracts (Site not responding. Last check: 2007-11-06)
		The developed isolation and isotope analysis methods were then applied to environmental samples to validate the methods.
		Analysis of PAH concentration data and molecular ratios indicated that the PAHs were mostly pyrogenic in the Lake Union and petrogenic in the WQB.
		Compound specific isotope analysis using GC/C/IRMS provided clear evidences for the unique source of the PAHs and suggested that the PAHs in the Lake Union were likely produced during the coal gasification processes, which lasted for 50 years until 1956.
	aslo.org /phd/dialog/200312-5.html (403 words)

	Stable isotope practicum
		A sample's isotopic composition is measured by determining the ratios of the stable isotope masses being examined - in the case of this laboratory, 15N/14N or 13C/12C as appropriate.
		In stable isotope analysis, calibration is made against reference materials chosen to have an isotopic abundance and total-element composition (nitrogen or carbon content and carbon-to-nitrogen ratio) similar to the expected values range for the samples.
		An ideal soil or plant sample intended for natural abundance isotopic analysis at this lab would contain 200 micrograms total N and 800 micrograms total C. It may not, of course, be possible to provide both these ideal amounts in one sample.
	www.uga.edu /~sisbl/ratio.html (1422 words)

	WHOI Sea Grant: Education/Focal Points/Isotope Analysis
		One such technique currently used to identify the fate of waste-derived nutrients in coastal embayments is the application of stable isotope analysis of nutrients.
		The use of stable isotopes for examining food web relationships or for tracing the fate of nutrient sources relies on the assumption that different producers and/or different sources of nutrients have distinct ratios of the naturally occurring isotopes of a particular element.
		The relative contribution of two sources of nutrients, mixed in a sediment sample or assimilated by an organism, is estimated by calculating the weighted average of the stable isotope signature of the sample in respect to the two sources.
	www.whoi.edu /seagrant/education/focalpoints/isotope.html (1324 words)

	Corso & Brenna: Position-Specific Isotope Analysis (Site not responding. Last check: 2007-11-06)
		Position-specific measurements for the analysis of natural variability have been published but are generally limited because of laborious chemical degradation and separation steps prior to isotope ratio mass spectrometry (IRMS) analysis.
		Isotope labeling in the in the carboxyl, terminal, and methyl positions of methyl palmitate demonstrates the absence of rearrangement during activation and fragmentation.
		These data demonstrate that online pyrolysis 1) can produce highly reproducible carbon isotope ratios, 2) rearrangement induced by pyrolysis is negligible, 3) fractionation during pyrolysis is minor, and 4) facilitates calculations of isotope ratios of individual positions at precisions required for enriched tracer experiments and some natural abundance applications.
	www.people.cornell.edu /pages/jtb4/brennalab/brenp1.html (325 words)

	Stable isotope analysis is not at all related to water quality. (Site not responding. Last check: 2007-11-06)
		Stable isotope analysis is not at all related to water quality.
		Stable isotope analysis is not a measure of water quality; in fact, stable isotope analysis provides no information at all about water quality.
		The purpose of our scientific study is to determine the naturally occurring range of heavier isotopes in the surface waters and drinking waters of the United States.
	ehleringer.net /water/WaterQuality.html (309 words)

	Paleobiology: A paleoecological paradox: The habitat and dietary preferences of the extinct tethythere Desmostylus, ...
		Finally, the Sr isotope composition of marine organisms reflects that of the ocean and is relatively invariant when compared with values for animals from land.
		Sr isotope values for Desmostylus were similar to those for terrestrial, rather than marine, mammals, suggesting Desmostylus was spending time in estuarine or freshwater environments.
		Together, isotopic data suggest that Desmostylus was an aquatic herbivore that spent a considerable portion of its life foraging in estuarine and freshwater ecosystems.
	www.findarticles.com /p/articles/mi_qa4067/is_200310/ai_n9343275 (1202 words)

	Hybrid Project
		Portability, immediate results in the field, ability to detect hazardous metals and the usually hard-to-identify radioactive isotopes, are some of the characteristics Ames Lab researchers have brought together in a new analytical hybrid instrument for simultaneous multi-element identification.
		The narrow band width of diode lasers makes it possible to identify not only elements but isotopes, which are separate forms of the same element that are virtually impossible to distinguish with traditional portable methods.
		Clear identification of radioactive isotopes is particularly important since each one may pose a different environmental threat.
	www.etd.ameslab.gov /etd/technologies/projects/hybrid/index.html (550 words)

	ISGS - Stable Isotope Analysis for Hydrogen and Oxyget in Water
		The ISGS Isotope Geochemistry Laboratory employs water-zinc reaction for analyzing hydrogen/deuterium ratios in water samples.
		A Finnigan Mat Delta E isotope ratio mass spectrometer is used for isotopic analysis of light gases such as hydrogen, oxygen, CO
		Our precision is ± 0.1 per mil for oxygen isotopic analysis, and ± 1 per mil for hydrogen/deuterium analysis.
	www.isgs.uiuc.edu /isotope/stable.html (183 words)

	Carbon and Nitrogen Stable Isotope Literature
		Ambrose, S.H. Isotopic analysis of paleodiets: methodological and interpretive considerations.
		Craig, H. Isotopic standards for carbon and oxygen and correction factors for mass-spectrometric analysis of carbon dioxide.
		Thackeray, J.F., Henzi, S.P., and Brain, C. Stable carbon and nitrogen isotope analysis of bone collagen in Papio cynocephalus ursinus: comparison with ungulates and Homo sapiens from southern and East African environments.
	epswww.unm.edu /facstaff/zsharp/carbon_nitrogen_literature.htm (3201 words)

	12-Ion Microprobe Analysis
		In particular, stable isotope ratios can be used to constrain theories of fluid sources, pathways, and fluxes, mechanisms of mineral reaction and exchange, and thermal evolution.
		Commonly, analyses have been made of splits, prepared from much larger samples with the implicit assumption that measured compositions are representative of the sample as a whole and thus that samples are homogeneous at the centimeter scale or larger.
		The accuracy of stable isotope analysis by ion microprobe has been dramatically improved, and the difficulty and expense of analysis reduced in the past few years since the first reliable sub-per mil-precision data were obtained.
	www.geology.wisc.edu /zircon/new_tech/12.html (827 words)

	SOFIA - Open File Report - OFR 98-205 - Petrography, biostratigraphy, strontium-isotope analysis - Fakahatchee ...
		The unnamed formation is found from the bottom of the core at 227 ft to a depth of 40 ft.
		Seven samples were analyzed for strontium isotopes (table 6).
		Strontium-isotope analysis indicates an early Pliocene age with a margin of error that includes the latest Miocene and the late Pliocene.
	sofia.usgs.gov /publications/ofr/98-205/fakagate12.html (1217 words)

	Lehigh University Stable Isotope Laboratory
		The Stable Isotope Chemistry Laboratory at Lehigh University is equipped with a Finnigan MAT 252 isotope ratio mass spectrometer fitted with a dual-inlet bellows inlet system and two automated microvolumes for analysis of small gas aliquots.
		An on-line extraction system for analysis of small quantities of nitrogen in silicate minerals and fluid inclusions is also available.
		Isotopic characterization of Late Cretaceous to Eocene regional crustal fluid flow in the Northern Rockies (Idaho-Montana).
	www.lehigh.edu /~bdi2/silab.html (455 words)

	[No title] (Site not responding. Last check: 2007-11-06)
		Food web components of Lake Roosevelt, WA, were examined using carbon and nitrogen stable isotopes in an effort to determine the extent of pelagic versus benthic carbon in the diet of commonly occurring species in the lake.
		Isotopic data shows Lake Roosevelt to be primarily a pelagically driven system.
		Benthic primary producer carbon signatures were isotopically heavier than pelagic primary producer carbon signatures.
	abstracts.allenpress.com /esa/web2000/abstracts/GEO-3-74-22.html (244 words)

	A New Method of Trace-Isotope Analysis
		We have recently developed a widely applicable method, Atom Trap Trace Analysis (ATTA) [1], and demonstrated its feasibility by analyzing two rare isotopes in a natural krypton sample at the parts-per-trillion level.
		For isotope separation, ATTA relies on the fact that different types of atoms and molecules have different resonant frequencies.
		The atom trap is a wonderful isotope separator because it only traps atoms of a particular isotope when the laser frequency is tuned to its resonance position (see figure 4).
	dnp.nscl.msu.edu /current/atta.html (756 words)

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