IsoLab - Reference Materials

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.

Carbonate δ¹³C δ¹⁸O
Nitrate δ¹⁵N δ¹⁸O Δ¹⁷O
Sulfate Δ¹⁷O
Solid δ¹³C δ¹⁵N δ³⁴S
Water δD δ¹⁸O ¹⁷O_excess

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:

NIST1547 Peach Leaves

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:

O₂ Gas Laboratory Comparison

Reference Materials for Carbonate δ¹³C δ¹⁸O

These reference materials are used with our Kiel device as well as for our clumped isotope method.
Reference Material	δ¹³C VPDB (‰)	δ¹⁸O VPDB (‰)	Material
NBS19 ¹	+1.95	-2.2	limestone
LSVEC ¹	-46.6		lithium carbonate
NBS18	-5.01	-23.01	carbonatite
IAEA-603	+2.47	-2.37	calcium carbonate
C1	+2.54	-0.42	marble
C2 ⁸	-48.99	-16.47	calcium carbonate
CQS2	-2.15	-15.34	calcium carbonate
C64	-2.05	-15.54	calcium carbonate
Coral	-2.14	-4.50	aragonite

Reference Materials for Nitrate δ¹⁵N δ¹⁸O Δ¹⁷O

These reference materials are use with our bacterial denitrifier method.
Reference Material	δ¹⁵N Air N₂(‰)	Δ¹⁷O VSMOW (‰)	δ¹⁸O VSMOW (‰)	Material
IAEA-NO-3	+4.72	-0.2	+25.32	potassium nitrate
USGS32 ⁶	+180		+25.4	potassium nitrate
USGS34	-1.8	-0.1	-27.78	potassium nitrate
USGS35	+2.5	+21.6	+56.81	sodium nitrate
USGS34 / 35mix	+0.45	+10.75		USGS34 / 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 Material	Δ¹⁷O VSMOW (‰)	Material
sulf-A	0.0	Silver sulfate (Ag₂SO₄ off the shelf
sulfα ⁵	0.9	sodium sulfate
sulfβ ⁵	2.0	sodium sulfate
sulfε ⁵	7.0	sodium sulfate

Reference Materials for Solid δ¹³C δ¹⁵N δ³⁴S

These reference materials are used with our carbon, nitrogen, and sulfur elemental analysis methods.
Reference Material	δ¹³C 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	-21.3	11.3		Bristol Bay Sockeye
MAL	-26.5	-0.4	+8.3	Malachite Lake Sediment
IAEA-S-1 ²			-0.3	silver sulfide
IAEA-S-3			-32.55	silver sulfide
NBS-127			+21.1	barium sulfate
Ag₂S			+17.60	silver sulfide
ZnS			-32.31	zinc sulfide
BaSO₄			+4.59	barium sulfate

Reference Materials for Water δD δ¹⁸O ¹⁷O_excess

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 Material	δD VSMOW (‰)	¹⁷O_excess VSMOW (permeg)	δ¹⁸O VSMOW (‰)	Material
VSMOW ³	0	0	0	Vienna Standard Mean Ocean Water
VSMOW2 ³	0	0	0	Vienna Standard Mean Ocean Water
GISP	-189.7	25	-24.78	Greenland Ice Sheet Precipitation Water
GRESP	-257.8		-33.39	Greenland Summit Precipitation
SLAP ^3,7	-428	0	-55.5	Standard Light Antarctic Precipitation Water
SLAP2 ^3,7	-427.5	0	-55.5	Standard Light Antarctic Precipitation Water

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

RW	-18.52		+5.15	Rebecca Water - Evaporatively enriched Seattle Water
KD	0.65	-3	0	Kona Deep - drinking water
KD2				Kona Deep - Drinking Water 2nd Batch Courtesy of Popp Lab
HW				Hawaii Water - Popp Lab Distilled
PW	-42.12	30	-6.88	Pennsylvania Water
SW	-75.63	33	-10.55	Seattle Water - UW Johnson Hall Distilled
SW2	-77.96	33	-10.85	Seattle Water - Johnson Hall Distilled 2nd batch
BW	-156.87	13	-20.01	Beth Water - ITASE / Seattle Water mixture
AW0				Antarctic Water - zero batch frozen carboy
AW	-231.54		-29.79	Antarctic Water - 1st batch
WW	-268.30	25	-33.82	WAIS Water - West Antarctic Ice Sheet (WAIS) Water
CW	-265.95		-33.64	Colorado Water - WAIS Divide Core (WDC06A) Water NICL 2009
TDW	-309.49		-38.76	Taylor Dome Water
WGW	-318.82	14	-39.77	WAIS Glacial Water - WDC06A Water Last Glacial Time Period
SVW	-316.59		-41.13	Seattle Vostok Water - mixture
SPS	-365.01	15	-46.96	South Pole Snow - core packing snow
SPS2	-365.20	15	-47.07	South Pole Snow - 2nd Batch
SPG	-435.31	-11	-55.39	South Pole Glacial - SPIce Core Last Glacial Time Period, homogenous with INSTAAR
VW	-439.24	0	-56.61	Vostok 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 Number	δ¹⁷O (‰)	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 Number	Average δ¹³C vs VPDB (‰)	Standard Deviation δ¹³C (‰)	Sample Size δ¹³C	Average δ¹⁵N vs AirN₂ (‰)	Standard Deviation δ¹⁵N (‰)	Sample Size δ¹⁵N
Survey	-25.99	0.18		1.98	0.21
1	-26.03	0.21	50	2.00	0.10	10
2	-25.90	0.02	3	1.80	0.06	3
3	-25.89	0.13		1.89	0.15
4	-26.00	0.19	5	1.80	0.16	5
5				2.00	0.09	7
6	-25.90	0.05	12	2.40	0.22	12
7	-26.19	0.01	3	1.92	0.07	3
8	-25.88	0.06		2.25	0.23
9	-25.79	0.14		1.72	0.08
10	-25.93	0.07	475	1.92	0.14	407
11	-25.80			1.90
12	-26.03	0.16	10	1.98	0.27	10
13	-26.50			1.80
14				2.20	0.08	5
15	-25.90	0.05	12	1.90	0.23	12
16	-26.30		2	2.10	0.04	3
17	-25.90	0.03	5	1.90	0.02	5
18	-26.00	0.26	4	2.50	0.12	4
19				1.80	0.20	10
20	-25.97	0.12		1.87	0.13

Reference Material Footnotes

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

Last updated: 2023-03-03 08:30:24

Reference Materials for Carbonate δ13C δ18O

Reference Materials for Nitrate δ15N δ18O Δ17O

Reference Materials for Sulfate Δ17O

Reference Materials for Solid δ13C δ15N δ34S

Reference Materials for Water δD δ18O 17Oexcess