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Working Standards for Water

Here is a description of the working standards that we use for d2H and d18O measurements of waters:

  • 18Onearzero: This working standard was prepared from one gallon of Trader Joe's Pure New Zealand. The water was spiked with 10% 18O labelled water to get it close to zero.

  • 2Hnearzero: This working standard was prepared from one gallon of Trader Joe's Pure New Zealand. The water was spiked with D2O.

  • PNZ: This is Trader Joe's Pure New Zealand bottled water

  • Dasani: This is Dasani bottled water

  • MSW: This is Trader Joe's Mountain Spring Water

  • DMSW: This is distilled Trader Joe's Mountain Spring Water

  • DSW-ANT: This is a blend of distilled Trader Joe's Mountain Spring Water and antarctic ice water

  • ANT: This is antarctic ice water graciously given to us by Tyler Coplen's group at USGS

 

Working Standards for d18O measurements

Working Standard d18O vs VSMOW () Std Error ()*
18Onearzero+ 4.09 0.07
PNZ -6.6 0.07
Dasani+ -7.99 0.06
MSW -14.5 0.08
DMSW -23.3 0.06
DSW-ANT -33.5 0.05
ANT+ -49.70 0.04

*n = 7 to 9

+ calibrated in 2005

The raw data for the 18O working standard calibrations is here in excel format. No drift was observed here so no drift correction was performed on this data. If you use the raw data in the second worksheet then you can recalculate the values for the standards and check them against the ones shown in the table above. If you have questions about how to go through the data, please feel free to contact the lab manager.

 

Working Standards for d2H measurements:

Working Standard d2H vs VSMOW () Std Error ()*
2Hnearzero+ -5.5 0.4
PNZ -37.4 0.4
Dasani+ -63.7 0.3
MSW -108.0 0.3
DMSW -136.6 0.2
DSW-ANT -256.2 0.2
ANT+ -393.5 0.5

*n = 7 to 9

+ calibrated in 2005

 

All working standards are calibrated against VSMOW and SLAP. GISP is run with the calibration as an accuracy check.

 

The raw data for the 2H working standard calibrations is here in excel format. It seems that we didn't do so great a job sealing some of these vials as several apparently had no H2 in them. A drift correction was used here but drift was insignificant in the end. The precision of the measurements was slightly improved with the drift correction, however, it did not change the actual final measured values. If you use the raw data in the second worksheet then you can recalculate the values for the standards and check them against the ones shown in the table above. If you have questions about how to go through the data, please feel free to contact the lab manager.

 

Working standards are stored in amber 240mL Qorpak bottles with the polyseal cap. When a new working standard bottle is opened for use, the entire contents is transferred to 5mL glass ampoules in 5mL aliquots and flame sealed. For any given analysis multiple working standards are used (two to bracket the samples and at least one with a midway value as a check of measurement accuracy and precision). The working standards are spread throughout the sequence so as to minimize effects of instrumental drift.

 

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Page last updated: June 19, 2007

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