Below is a list of reference materials (often referred to as "standards") used at IsoLab. With respect to Internationally recognized reference materials, this page is for convenience. Best to double check against a more authoritative body such as the Commission on Isotopic Abundances and Atomic Weights (CIAAW). Another good resource is GeoReM, a Geological and Environmental Reference Material database. International reference materials are typically purchased from NIST or IAEA.

View a table of informal survey results conducted through IsoGeoChem to obtain reasonable estimates of δ15N and δ13C values for the NIST1547 Peach Leaves material:

View a table of all laboratories that have measured O2 gas from a compressed cylinder originating from Praxair in Seattle, Washington, the results they obtained, and information provided about their reference materials:

Reference Materials for Carbonate δ13C δ18O

These reference materials are used with our Kiel device as well as for our clumped isotope method.
Reference Materialδ13C VPDB (‰)δ18O VPDB (‰)Material
NBS19 1+1.95-2.2limestone
LSVEC 1-46.6 lithium carbonate
IAEA-603+2.47-2.37calcium carbonate
C2 8-48.99-16.47calcium carbonate
CQS2-2.15-15.34calcium carbonate
C64-2.05-15.54calcium carbonate

Reference Materials for Nitrate δ15N δ18O Δ17O

These reference materials are use with our bacterial denitrifier method.
Reference Materialδ15N Air N2(‰)Δ17O VSMOW (‰)δ18O VSMOW (‰)Material
IAEA-NO-3+4.72-0.2+25.32potassium nitrate
USGS32 6+180+25.4potassium nitrate
USGS34-1.8-0.1-27.78potassium nitrate
USGS35+2.5+21.6+56.81sodium nitrate
USGS34 / 35mix+0.45+10.75USGS34 / USGS35 50:50 mixture

Reference Materials for Sulfate Δ17O

These reference materials are used with our silver sulfate pyrolysis method. Their creation was published in:

Schauer AJ, Kunasek SA, Sofen ED, Erbland J, Savarino J, Johnson BW, Amos HM, Shaheen R, Abaunza M, Jackson TL, Thiemens MH, Alexander B. (2012). Oxygen isotope exchange with quartz during pyrolysis of silver sulfate and silver nitrate. Rapid Communications in Mass Spectrometry 26. doi: 10.1002/rcm.6332.

More details on the recipe can be found in this Sulfate Oxygen Standards - 2009 blog post.

Reference MaterialΔ17O VSMOW (‰)Material
sulf-A 0.0Silver sulfate (Ag2SO4 off the shelf
sulfα 50.9sodium sulfate
sulfβ 52.0sodium sulfate
sulfε 57.0sodium sulfate

Reference Materials for Solid δ13C δ15N δ34S

These reference materials are used with our carbon, nitrogen, and sulfur elemental analysis methods.
Reference Materialδ13C VPDB (‰)δ15N Air N2(‰)δ34S VCDT (‰)Material
IAEA-N-1 6 +0.43 ammonium sulfate
NIST 8540-32.15 polyethylene foil
NIST 8542-10.45 Sucrose
USGS40-26.39-4.52 L-glutamic acid
USGS41+37.63+47.57 L-glutamic acid
NIST 15474-25.99+1.98 peach leaves
GA1-28.3-4.6 glutamic acid
GA2-13.7-5.7 glutamic acid
Salmon-21.311.3 Bristol Bay Sockeye
MAL-26.5-0.4+8.3Malachite Lake Sediment
IAEA-S-1 2 -0.3silver sulfide
IAEA-S-3 -32.55silver sulfide
NBS-127 +21.1barium sulfate
Ag2S +17.60silver sulfide
ZnS -32.31zinc sulfide
BaSO4 +4.59barium sulfate

Reference Materials for Water δD δ18O 17Oexcess

These reference waters are used with all of our water isotope composition methods as well as for the creation of various carbon dioxide reference gases.
Reference MaterialδD VSMOW (‰)17Oexcess VSMOW (permeg)δ18O VSMOW (‰)Material
VSMOW 3000Vienna Standard Mean Ocean Water
VSMOW2 3000Vienna Standard Mean Ocean Water
GISP-189.725-24.78Greenland Ice Sheet Precipitation Water
GRESP-257.8 -33.39Greenland Summit Precipitation
SLAP 3,7-4280-55.5Standard Light Antarctic Precipitation Water
SLAP2 3,7-427.50-55.5Standard Light Antarctic Precipitation Water

USGS53+40.2 +5.47USGS Lake Shala Distilled Water
USGS50+32.8 +4.95USGS Lake Kyoga Water
USGS PR-1.3 -1.52USGS Puerto Rico Water
USGS A1 -395 -50.02USGS Antarctic Water
USGS45-10.3 -2.238USGS Biscayne Aquifer Drinking Water
USGS47-150.2 -19.804USGS Lake Louise Drinking Water

RW-18.52 +5.15Rebecca Water - Evaporatively enriched Seattle Water
KD0.65-30Kona Deep - drinking water
KD2 Kona Deep - Drinking Water 2nd Batch Courtesy of Popp Lab
HW Hawaii Water - Popp Lab Distilled
PW-42.1230-6.88Pennsylvania Water
SW-75.6333-10.55Seattle Water - UW Johnson Hall Distilled
SW2-77.9633-10.85Seattle Water - Johnson Hall Distilled 2nd batch
BW-156.8713-20.01Beth Water - ITASE / Seattle Water mixture
AW0 Antarctic Water - zero batch frozen carboy
AW-231.54 -29.79Antarctic Water - 1st batch
WW-268.3025-33.82WAIS Water - West Antarctic Ice Sheet (WAIS) Water
CW-265.95 -33.64Colorado Water - WAIS Divide Core (WDC06A) Water NICL 2009
TDW-309.49 -38.76Taylor Dome Water
WGW-318.8214-39.77WAIS Glacial Water - WDC06A Water Last Glacial Time Period
SVW-316.59 -41.13Seattle Vostok Water - mixture
SPS-365.0115-46.96South Pole Snow - core packing snow
SPS2-365.2015-47.07South Pole Snow - 2nd Batch
SPG-435.31-11-55.39South Pole Glacial - SPIce Core Last Glacial Time Period, homogenous with INSTAAR
VW-439.240-56.61Vostok Water

Reference Material - O2 Gas Laboratory Comparison

O2 gas from a compressed cylinder originating from Praxair in Seattle, Washington.

Here is a table of all laboratories that have measured this gas, the results they obtained, and information provided about their reference materials. The ± symbol indicates standard deviation. 17O excess was calculated as (ln (δ17O/1000 + 1) - 0.528 × ln(δ18O/1000 + 1) ) × 1,000,000 and are in units of permeg.
Laboratory Numberδ17O (‰)δ18O (‰)17O excess (per meg)Reference Gas δ17O (‰)Reference Gas δ18O (‰)
1-4.52 ± 0.023 -8.55 ± 0.052 4.24 23.70 46.13
2-4.45 ± 0.022 -8.60 ± 0.017 100.51 unk unk
3-4.32 ± 0.009 -8.26 ± 0.015 48.38 -7.02 -13.38
4-4.21 ± 0.068 -8.08 ± 0.092 66.06 12.53 24.56
5-4.17 ± 0.044 -7.89 ± 0.025 7.20 8.84 17.56
6-4.4918 -8.555 34.6 0 0

Reference Material - NIST1547 Peach Leaves

In January of 2009, we surveyed the IsoGeoChem email listserv for δ15N and δ13C values of the NIST1547 Peach Leaves material. The specific inquiry to the IsoGeoChem email listserv can be found here. Information about this material beyond this page can be obtained from the NIST domain. A direct link to the formal certificate from the NIST page for this material is here as a pdf. If you would like to add yourself to this anonymous survey, please contact us. The mean and standard deviation for δ15N and δ13C for the survey are emphasized in the first row of the table below. Please note, some submissions are individual samples, some are previously conducted surveys and represent a compilation.

This table shows the results from the IsoGeoChem email listserv survey of δ15N and δ13C values for the NIST1547 Peach Leaves material. The summary values below are in no way accepted by the community but simply represent values obtained during routine analysis.
Anonymous Lab NumberAverage δ13C vs VPDB (‰)Standard Deviation δ13C (‰)Sample Size δ13CAverage δ15N vs AirN2 (‰)Standard Deviation δ15N (‰)Sample Size δ15N
Survey-25.990.18 1.980.21
3-25.890.13 1.890.15
5 2.000.097
8-25.880.06 2.250.23
9-25.790.14 1.720.08
11-25.80 1.90
13-26.50 1.80
14 2.200.085
16-26.30 22.100.043
19 1.800.2010
20-25.970.12 1.870.13

Reference Material Footnotes

  1. exact values defining the VPDB delta scale
  2. exact value defining the VCDT delta scale
  3. exact values defining the VSMOW delta scale
  4. NOT accepted, Lithium carbonate acid fractionation not well known, this value assumes calcium carbonate acid fractionation
  5. Schauer et al. Rapid Commun. Mass Spectrom. 2012, 26, 2151-2157. DOI: 10.1002/rcm.6332
  6. interim consensus values used for AirN2 scale normalization
  7. Schoenemann et al. Rapid Commun. Mass Spectrom. 2013. DOI: 10.1002/rcm.6486
  8. C2 is Merck Suprapur Calcium carbonate product number 1020590050 (50 g bottle)
Last updated: 2023-03-03 08:30:24