Welcome to the Environmental Isotope Laboratory
(Effective July 15, 2023, we have had to implement a price increase)
About Our Lab
Staff and students in the Environmental Isotope Laboratory employ naturally-occurring stable and radioactive isotopes as well as major and trace element compositions in research into a variety of questions in the fields of hydrology, ecology, paleoclimate and geology. We are honored to continue traditions established by the founders of this lab, the late Professors Austin Long and Paul Damon.
Study areas have historically spanned the globe. Research problems include locations and extent of groundwater recharge, paleohydrology and paleoelevation of evolving mountain ranges, sources of sedimentary basin brines, past solar activity inferred from high-precision radiocarbon measurement on tree rings, origin and evolution of evaporites, methods development in isotope paleohydrology and paleosalinity studies, and extensive work in isotope dendrochronology and isotope studies of cactus spines (acanthochronology).
Recent hydrologeologic studies have revealed sites of recharge in Tucson Basin, and the extent of migration of 1960s precipitation in local aquifers. The sources of municipal groundwater supplies in El Paso and Ciudad Juarez have been established, and the isotope effect of large reservoirs has been used in conjunction with groundwater flow modeling to map recharge beneath the Rio Grande. Tritium in precipitation in southwestern North America has been mapped, and the future usefulness of tritium in groundwater studies has been evaluated.
Stable isotope research in ecology, biology, and climatology include studies of natal habitat and life history for endemic fish in the Gulf of California, pre-dam salinity and flow conditions of the Colorado River and its delta, sourcing marine shell from archaeological settings in the southwest, bird and human migration, the pre-human-impact status of river systems, and the use of saguaro spine geochemistry as a record of past rainfall.
Research facilities in the Environmental Isotope Laboratory include a conventional radiocarbon dating laboratory capable of high-precision analyses, a tritium analysis laboratory for natural environmental levels of tritium, and four stable isotope mass spectrometers equipped for analysis of C,H, N, O and S isotopes in a variety of geological, hydrological and biological materials. Additional equipment associated with the lab includes a LGR laser system for analysis of O and H isotopes in water, two micromilling systems, and a cathodoluminescence microscope unit.
David Dettman - Director, Research Scientist
Christopher Eastoe - Co-director, Staff Scientist (Retired)
Xiaoyu Zhang - Research Scientist
Zhennan Wang - Research Scientist
Benjamin McElhaney - Electronic Technician
Please forward requests to Laboratory information email GEOS-EIL@arizona.edu
Todd E. Lange: +1 (520) 621-8341
Dr. Xiaoyu Zhang: +1 (520) 621-1638
The data repository page is currently under contstruction.
Services
Service analyses for internal and external users include measurement of natural levels of tritium in water, stable isotope analyses of water, carbonates, brines, sulfide and sulfate minerals.
The Radiocarbon Laboratory has closed.
Analytical Service Rates
| Material | Measurement | Rate | Precision (1S) | Notes |
|---|---|---|---|---|
| WATER | dD and d18O | $44.00 | 1.0‰, 0.1‰ | A |
| WATER | dD or d18O | $28.00 | A | |
| Water (>200g/l salt) | dD and d18O (activity) | $66.00 | 2.0‰, 0.2‰ | |
Water DIC | Tritium d13C | $248.00 $42.00 | Detection limit 0.5 TU, or 1.3 pCi/L for 9X enrichment 0.2‰ | A B |
| S (aqueous) | d34S | $24.00 | 0.2‰ or better | D |
| S (aqueous) | O18 in S | $31.00 | 0.4‰ or better | |
| ORGANICS | d13C | $14.00 | 0.1‰ or better | |
| d13C and [C] | $17.00 | |||
| d15N | $14.00 | 0.2‰ or better | ||
| d15N and [N] | $17.00 | |||
| d13C and d15N | $21.00 | C | ||
| d13C d15N [C] [N] | $23.00 | C | ||
| d18O | $26.00 | 0.4‰ or better | ||
| dD | $33.00 | 2‰ | ||
| SEDIMENTS | d13C | $21.00 | 0.1‰ or better | A |
| d13C and [C] | $23.00 | |||
| d15N | $21.00 | 0.25‰ or better | A | |
| d15N and [N] | $23.00 | |||
| d13C + d15N | $29.00 | A, C | ||
| d13C d15N [C] [N] | $33.00 | A, C | ||
| MINERALS | ||||
| carbonates | d13C and d18O | $20.00 | 0.08‰, 0.1‰ | |
| carbonates | ∆638 or ∆47 | $250.00 | 0.02‰ | A, E |
| hydrous minerals | dD | $33.00 | 2.5‰ | A |
| sulfates, sulfides | d34S | $24.00 | 0.2‰ or better | D |
| sulfates | d18O | $31.00 | 0.4‰ | |
| nitrates | d15N | $21.00 | 0.25‰ or better | D |
We have a $25 fee for the return of coolers or samples after analysis.
- Simple sample identification systems (e.g. AB-1, AB-2…..) save us time, and reduce the likelihood of errors.
- For large sample sets, please send by e-mail an Excel spreadsheet listing the samples in a logical order.
- Prices quoted do not include extra sample preparation such as drying, powdering, separating from filters, carbonate removal.
- Please tell us if we are handling hazardous samples.
- Payment can be made with check, bank wire transfer, or credit card
- Payment in US$ only
- Please request a credit card form if you plan to pay by card
Department of Geosciences
1040 E. Fourth St., Room 208
University of Arizona
Tucson, AZ 85721-0077
Analytical Method Descriptions
d15N and d13C, as well as carbon and nitrogen content were measured on a continuous-flow gas-ratio mass spectrometer (Finnigan Delta PlusXL) coupled to an elemental analyzer (Costech). Samples were combusted in the elemental analyzer. Standardization is based on acetanilide for elemental concentration, NBS-22 and USGS-24 for d13C, and IAEA-N-1 and IAEA-N-2 for d15N. Precision is better than ± 0.10 for d13C and ± 0.2 for d15N (1s), based on repeated internal standards.
d18O and d13C of carbonates were measured using an automated carbonate preparation device (KIEL-III) coupled to a gas-ratio mass spectrometer (Finnigan MAT 252). Powdered samples were reacted with dehydrated phosphoric acid under vacuum at 70°C. The isotope ratio measurement is calibrated based on repeated measurements of NBS-19 and NBS-18 and precision is ± 0.1 ‰ for d18O and ±0.08‰ for d13C (1sigma).
∆638, or ∆47 (carbon dioxide clumped isotope ratio) is measured using an automated carbonate preparation device (developed in house) coupled to an isotope ratio laser spectrometer (Aerodyne dual-laser monitor). Powdered samples are reacted with dehydrated phosphoric acid under vacuum at 70°C. The clumped isotope measurement is calibrated in both the Carbon Dioxide Equilibrium Scale (CDES) reference frame and InterCarb-Carbon Dioxide Equilibrium Scale (I-CDES) reference frame, and the precision is ± 0.01 ‰ S.E. for ∆638. The temperature calibration is based on 51 synthetic carbonates equilibrated at 6°C to 1100°C.
References:
d D was measured on a continuous-flow gas-ratio mass spectrometer (Thermo Electron Delta V). Samples were combusted at 1400 °C using an ThermoQuest Finnigan TCEA (Thermal combustion elemental analyzer) coupled to the mass spectrometer. Standardization is based on a linear calibration curve obtained by measuring three materials -- NIST SRM 8540 (-65.7‰), IAEA CH7 (-110.3‰) and our house standard benzoic acid (-87.6‰) in each set of analyses. Precision is better than ± 2.5 per mil on the basis of repeated internal standards.
Samples were equilibrated with ambient water vapor in laboratory air with tracer standards (swan feather). They are then dried with P2O5 for at least 6 hours.
d D was measured on a continuous-flow gas-ratio mass spectrometer (Thermo Electron Delta V). Samples were combusted with excess C at 1400 °C using an ThermoQuest Finnigan TCEA (Thermal combustion elemental analyzer) coupled to the mass spectrometer. Standardization is based on the calibrated house standard benzoic acid (-87.6‰) and Hexatriacontane (-247, University of Indiana) in each set of analyses. A value of 1.120 is used for the fractionation between water vapor and exchangeable hydrogen in calculating the non-exchangeable dD value. Precision is better than ± 2.5 per mil on the basis of repeated internal standards.
d D and d18O were measured on a gas-source isotope ratio mass spectrometer (Finnigan Delta S). For hydrogen, samples were reacted at 750°C with Cr metal using a Finnigan H/Device coupled to the mass spectrometer. For oxygen, samples were equilibrated with CO2 gas at approximately 15°C in an automated equilibration device coupled to the mass spectrometer. Standardization is based on international reference materials VSMOW and SLAP. Precision is 0.9 per mil or better for d D and 0.08 per mil or better for d18O on the basis of repeated internal standards.
d34S was measured on SO2 gas in a continuous-flow gas-ratio mass spectrometer (ThermoQuest Finnigan Delta PlusXL). Samples were combusted at 1030 deg. C with O2 and V2O5 using an elemental analyzer (Costech) coupled to the mass spectrometer. Standardization is based on international standards OGS-1 and NBS123, and several other sulfide and sulfate materials that have been compared between laboratories. Calibration is linear in the range -10 to +30 per mil. Precision is estimated to be ± 0.15 or better (1s), based on repeated internal standards.
d13C of DIC was measured on a continuous-flow gas-ratio mass spectrometer (ThermoQuest Finnigan Delta PlusXL) coupled with a Gasbench automated sampler (also manufactured by Finnigan). Samples were reacted for > 1 hour with phosphoric acid at room temperature in Exetainer vials previously flushed with He gas. Standardization is based on NBS-19 and NBS-18 and precision is ±0.30‰ or better (1sigma).
d18O of sulfate was measured on CO gas in a continuous-flow gas-ratio mass spectrometer (Thermo Electron Delta V). Samples were combusted with excess C at 1350 °C using a thermal combustion elemental analyzer (ThermoQuest Finnigan) coupled to the mass spectrometer. Standardization is based on international standard OGS-1. Precision is estimated to be ± 0.3 per mil or better (1s), based on repeated internal standards.
Tritium was measured by liquid scintillation spectrometry on samples that were first distilled to remove non-volatile solutes, and then enriched by electrolysis by a factor of about 9. Enriched samples were mixed 1:1 with Ultimagold Low Level Tritium (R) cocktail, and counted for 1500 minutes in a Quantulus 1220 Spectrometer in an underground counting laboratory at the University of Arizona. The detection limit under these conditions is 0.6 TU. Standardization is relative to NIST SRM 4361C, and water from Agua Caliente Spring in Tucson basin is used to determine background.
d18O of cellulose was measured on a continuous-flow gas-ratio mass spectrometer (Thermo Electron Delta PlusXL). Samples were combusted with excess C at 1350 °C using a thermal combustion elemental analyzer (ThermoQuest Finnigan) coupled to the mass spectrometer. Standardization is based on international standards IAEA601, IAEA602 and OGS-1. Precision is estimated to be ± 0.3 per mil or better (1s), based on repeated internal standards.
d15N was measured on bulk residual salt from the gentle evaporation of water to dry; this represents bulk DIN of the sample. Measurements were made using a continuous flow gas-ratio mass spectrometer (Finnigan Delta PlusXL) coupled to an elemental analyzer (Costech). Samples were combusted in the elemental analyzer. Standardization is based on IAEA-N-1 and IAEA-N-2 for d15N. The IAEA standards were used to calibrate d15N of the laboratory working standard, acetanilide. Precision is better than ± 0.2 for d15N (1s), based on repeated internal standards.
