Sample Collecting Instructions and Information

For small samples, 11 mL glass vials with Polyseal caps are available from RSIL in boxes of 144 units.

For sample amounts as small as 0.5 mL , please contact RSIL.

Container that prevents evaporation of water.

HDPE 20-mL scintillation vial with Polyseal cap, Wheaton 986706, available from RSIL

Sample should be dried and powdered to between 100 and 200 micrometer to ensure isotopic homogeneity.

Maximum sample amount of calcite is 0.5 g. For sample amounts as small as 0.02 g, contact RSIL.

250 mL glass bottle with Polyseal cap or if concentration is low, 1-L bottle with Polyseal cap

Do not field rinse bottle. Fill bottle to overflowing. Decant about 20 mL of sample. With a 5 or 10-mL plastic syringe having a 15-cm Tygon tube on its end, withdraw a syringe full of ammoniacal strontium chloride (see below) and discard to clean out any carbonate in the syringe. Transfer 5 to 20 mL ammoniacal strontium chloride to sample bottle and cap immediately.

Ammoniacal strontium chloride preparation: Dissolve 500 g of SrCl₂ 6H₂O reagent in a standard 4–pound NH₄OH reagent bottle (or 4 to 1 ratio of NH₄OH to SrCl₂). Let stand for 2 days. Decant the clear reagent into clean glass field reagent bottle. Always use the clear reagent in the upper part of the field reagent bottle. Minimize head space in reagent bottles because air contains carbon dioxide, which can precipitate as solid strontium carbonate in field reagent bottle.

HDPE 20-mL scintillation vial with Polyseal cap, Wheaton 986706, available from RSIL

Sample should be dried and powdered to 100 to 200 micrometer to ensure isotopic homogeneity. No treatment, preservation, or special shipping requirements.

Concentration of N in sample must be at least 1 mg/g; concentration of C in sample must be at least 1 mg/g. Total amount of N in sample must be at least 0.15 mg; total amount of C in sample must be at least 0.15 mg. Maximum sample amount is 1 g.

Contact RSIL

Contact RSIL

Contact RSIL

Contact RSIL

Collected on anion exchange resin (Amberlite IRA-400 (RN(CH3)3 + Cl^-) ordered from RSIL ($35 each). Rinse with 50 mL DI water before use.

Sulfate and sulfide concentration should be determined in the field before sample collection. Each sample that contains < 20 mg/L sulfate should be collected on anion exchange resin, chilled, and maintained at 4 deg C until shipped. Fill a 10-L bucket with sample and acidify with 1M HCl to pH of 3 to 4. With a rate of 0.4 liter/minute, pump with a peristaltic pump sufficient sample through resin to collect 20 to 40 mg of sulfate. Resin capacity is such that it can easily accommodate 4 L water having a sulfate concentration of 10 mg/L, or 8 L of 5 mg/L, or 20 L of 1 mg/L. If the water contains sulfide, the collection should be fast to avoid possible oxidation by oxygen in air of the sulfide to sulfate.
1M HCl can be prepared by adding 40.4 mL of 38% commercial HCl solution to 500 mL of DI water.

Contact RSIL

Contact RSIL

32 oz (1 L) polyethylene bottle (Q35FLD at One-Stop Shopping)

Sulfate and sulfide concentration should be determined in the field. Each sample that contains > 20 mg/L sulfate should be filtered by a 0.4 µm polycarbonate membrane filter. Sample should be collected in a maximum of 1-L glass or plastic bottle. For sulfate concentration less than 20 mg/L, use 1949. A sample that contains > 0.01 mg/L sulfide or has a sulfate/sulfide ratio < 40 should be stripped of its sulfide in the field.

Contact RSIL.

Contact RSIL

HDPE 20-mL scintillation vial with Polyseal cap, Wheaton 986706, available from RSIL

Sample should be dried (or frozen) to prevent biological reaction of nitrogen-bearing species during storage or transport to laboratory. No special shipping is required.

Concentration of nitrate in sample must be at least 1 mg/kg as N. Total amount of nitrate in sample must be at least 0.02 mg as N. Maximum sample amount is 30 g. For samples containing atmospheric nitrate, the bacterial method may overestimate the delta N-15 values by as much as 1 to 2 per mill. For samples that may contain more than about 20 percent atmospheric nitrate, users should collect samples with a minimum of 0.4 mg of N and contact RSIL about methods to avoid this problem.

For samples containing nitrite, the bacterial method will determine the N isotopic composition of the nitrate + nitrite, but the O isotopic composition may be incorrect. If nitrite concentrations are known to be significant, they should be provided to RSIL.

If nitrate concentration is too low or insufficient nitrate is provided, the RSIL will attempt an isotopic analysis, but may not be successful. The sample submitter will be charged for the full cost of the analysis. Sample submitters with laboratory capabilities may want to dissolve nitrate from sediments themselves and confirm that the nitrate concentration is sufficient prior to submitting the dissolved nitrate sample for isotopic analysis. The following procedure is suggested. Approximately 30 mg of solid sample is placed in a 150-mL beaker and 80 mL of DIW (deionized water) is added; the sample and water are stirred well and allowed to sit overnight covered. The sample is then filtered and rinsed several times with 10-mL aliquots of DIW, not to exceed more than 300 mL of water in total. An aliquot is submitted for determination of nitrate concentration--LC 1979 is recommended. The remaining sample is frozen. If LC 1979 indicates that the concentration is greater than 0.03 mg/L as N, the frozen sample is submitted on ice to the RSIL for isotopic analysis.

16 oz (500 mL) polypropylene bottle, 89 mm cap, Q413FLD (bottle) and Q422FLD (cap) at One-Stop Shopping

Sample should be dried (or frozen) to prevent biological reaction of nitrogen-bearing species during storage or transport to laboratory. No special shipping is required.

Concentration of ammonium in sample must be at least 0.2 mg/kg as N. Total amount ammonium in sample must be at least 0.2 mg as N. Maximum sample amount is 1 kg.

32 oz (1 L) polyethylene bottle (Q35FLD at One-Stop Shopping)

Concentration of ammonium in sample must be at least 0.2 mg/kg as N. Total amount of ammonium in sample must be at least 0.2 mg as N. Maximum sample amount is 1 L.

4 oz (125 mL) amber polyethylene bottle, untreated (Q33FLD or Q405FLD in One-Stop Shopping). It is recommended that conical insert Polyseal caps be used with these bottles. Secure the caps with Parafilm or electrical tape to prevent leakage.

Field rinse bottle. Filter sample through 0.2 μM filter, fill the bottle only ¾ full. Freeze sample to prevent biological reaction of nitrogen-bearing species during storage or transport to laboratory. Alternatively, samples can be preserved by adding reagent-grade NaOH or KOH to achieve a pH greater than 10, but not higher than 11.95 (typically 1 “pellet” per 125-mL bottle). Label the bottles to indicate if hydroxide has been added. Submitter must provide concentration of nitrate in sample with an accuracy of ±10 percent or better before sample can be analyzed. A “<” value is not acceptable. LC 1975 can be used for samples with concentrations above 0.06 mg/L as N. LC 1979 can be used for samples with concentrations less than 0.06 mg/L. If concentration provided is not accurate to within ±10 percent, the normal accuracy of the technique cannot be achieved. The submitter will be contacted to see if an additional isotopic measurement should be made (at additional expense to the submitter.) Samples should be held until nitrate concentration is available. Ship on ice or at 4 deg C if not preserved.

Concentration of nitrate in sample must be at least 0.03 mg/kg as N. The minimum sample amount is 30 mL.  Maximum sample amount is 125 mL. For samples containing atmospheric nitrate, the bacterial method may overestimate delta N-15 values by as much as 1 to 2 per mill. For samples that may contain more than about 20 percent atmospheric nitrate, users should contact the RSIL..

For samples containing nitrite, the bacterial method will determine the N isotopic composition of the nitrate + nitrite, but the O isotopic composition may be incorrect. If nitrite concentrations are known to be significant, they should be provided to RSIL.

HDPE 20-mL scintillation vial with Polyseal cap, Wheaton 986706, available from RSIL

Sample should be dried and powdered to 100 to 200 micrometer to ensure isotopic homogeneity. No treatment, preservation, or special shipping requirements.

Concentration of C in sample must be at least 1 mg/g and/or concentration of N in sample must be at least 1 mg/g. Total amount of C in sample must be at least 0.15 mg and/or total amount of N in sample must be at least 0.15 mg. Maximum sample amount is 1 g.