Stable Isotope Facility

Nitrate (NO₃) in Water Sample Preparation

For NO₃ in water preparation, please see the denitrifier articles in the references section. Water samples requiring preparation by the SIF should be filtered and shipped frozen in 30 - 60 mL Nalgene-type bottles. Samples requiring extensive handling by the SIF (e.g., filtering) will be charged an additional $5.00 fee per sample. Please provide a minimum of 10mLs of each water sample.

Accurate nitrate concentrations are required for all samples. Please specify if your concentration is NO3 vs. NO3-N, μM vs. mg/L, etc. If this information is not available, please allow the SIF to refer you to an analytical facility that can determine the concentration for you. Required minimum concentration is 1 μM NO3.

Analytical Precision

0.4 for 15N of NO3 in water
0.8 for 18O of NO3 in water

Please note: Samples will be stored by SIF for 3 months post-analysis and then discarded. Please review your results during this 3-month window.

Shipping
Headspace Vials: Headspace vials ship best when separated by cardboard dividers. Or individual vials should be wraped in foam sheet and grouped in ziplock bags with rubber bands. Make sure the samples are very secure; loose vials can shatter during shipping. These gas samples do not require refrigeration during shipping.

Unprepared Water Samples: Water samples for bacteria denitrification preparation by the SIF should be filtered and frozen in Nalgene-style or other freezable, screw-top container. Water samples should be shipped frozen and packaged in an insulated box with dry ice or blue ice blocks. Coolers will not be returned.

Please complete and submit the online Analysis Order Form and Sample List for your samples. Please include nitrate concentration for water samples for bacteria denitrification preparation by the SIF. Samples missing NO3 concentration information will be charged for reruns. Also, be sure to include a printed copy with your samples. The SIF uses this form to track your samples and to contact you regarding receipt of samples, data, and invoicing. For mixed analysis requests, we require the completion of a separate form for each type of analysis.

Recommended supplies for customer prepared NO3 headspace samples

Manufacturer / Part#	Description	Unit
Restek / 24685	20mL, 23 x 75mm, 20mm Crimp, Flat Base, autosampler vials	Pack of 100
Restek / 21761	20mm Aluminum Seals w/PTFE/Gray Butyl Rubber Septa	Pack of 100

Recommended supplies for unprepared NO3 in water samples

Manufacturer / Part#	Description	Unit
Wheaton / 209545	Leak-Resistant Wide-Mouth HDPE Bottles, 30mL, Natural w/ cap	Case of 72
Wheaton / 209546	Leak-Resistant Wide-Mouth HDPE Bottles, 60mL, Natural w/ cap	Case of 72
Wheaton / 209626	Leak-Resistant Wide-Mouth HDPE Bottles, 60mL, Amber w/ cap	Case of 72

References for NO₃ in Water

¹⁵N Analysis of NO₃ in water using Pseudomonas chlororaphis bacteria:

D. M. Sigman, K. L. Casciotti, M. Andreani, C. Barford, M. Galanter, and J. K. Böhlke. 2001. A Bacterial Method for the Nitrogen Isotopic Analysis of Nitrate in Seawater and Freshwater. Anal. Chem. 73: 4145 -4153.

Nitrogen and ¹⁸O Analysis of NO₃ in water using Pseudomonas aureofaciens bacteria:
K. L. Casciotti, D. M. Sigman, M. Galanter Hastings, J. K. Böhlke, and A. Hilkert. Measurement of the Oxygen Isotopic Composition of Nitrate in Seawater and Freshwater Using the Denitrifier Method. 2002. Anal. Chem. 74: 4905 -4912.