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Core Facility for Ecological Analyses

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The facility offers analyses of liquid, gas, and solid samples for nutrients.  Facility personnel prepare standards and quality control samples for all analyses. Researchers are expected to process samples for the listed analyses in separate laboratories.  Below is a list of the analytes and sample types for each instrument housed in the facility.

Please contact us about how to prepare your samples or if you have any questions regarding the sample requirements (e.g., preservation, sample amount, labeling requirements, etc.) for each analysis.

Inorganic N and P

OI Analytical Flow Solution IV (OI Analytical Corp., College Station, TX, USA). This instrument is for filtered liquid samples only: water, soil extracts, or digests.  This instrument can analyze: ammonium (NH4+), nitrite + nitrate (NO2-/NO3-), nitrite only (NO2-), orthophosphate (PO43-), and total N and/or P following persulfate digestion.  Inorganic N and P concentrations are calculated from the standard curve based on elemental concentrations and should be reported as NO3-N, NH4-N, and/or PO4-P.

Preparation requirements: Samples must be filtered through a 0.4 μm membrane prior to analysis.  We recommend using polycarbonate membranes to filter samples as Whatman filters can contain ammonium.

Submission requirements:  Each sample must be labeled with a date, investigator name, project name, ID system, and background solution (e.g. 2 N KCl or H2O).

TOC, TC and/or TN

Shimadzu TOC-L/TNM-L (Shimadzu Corp., Kyoto, Japan). This instrument is for filtered liquid samples only: water or extracts. This instrument can analyze: Total Organic Carbon (TOC), Total Carbon (TC), and Total Nitrogen (TN). The primary configuration uses a high salt combustion tube, for samples such as 0.5 M K2SO4 soil extracts. The instrument must be reconfigured with a standard combustion tube for water samples.

Preparation requirements: Samples must be filtered through a 0.4 μm membrane prior to analysis.  We recommend using polycarbonate membranes to filter samples as Whatman filters can contain ammonium.

Submission requirements:  Each sample must be labeled with a date, investigator name, project name, ID system, and background solution (e.g. 0.5 M K2SO4 or H2O).

Total CN, CHN, CHNS and/or O

Thermo Flash 2000 CHNS/O Elemental Analyzer (CE Elantech Corp., New Brunswick, NJ, USA). This instrument can analyze solid or liquid samples (requiring special preparation) for percent carbon (C), nitrogen (N), hydrogen (H), sulfur (S), or oxygen (O) using dry combustion followed by gas chromatography.  The primary configuration of the instrument is for CN.  The instrument must be reconfigured to analyze samples for H, S, and O, so separate samples must be submitted for the desired configuration: CN, CHN, CHNS, or O.

Preparation requirements:  Solid samples must be dried and ground to a fine powder.  We recommend using a mixer mill (“ball-grinder”) or mortar and pestle to achieve a powder-like consistency (spice/coffee grinders and Wiley mills are not adequate for sample homogenization).  Samples must be weighed on a microbalance (00.000 mg) into a tin capsule.  Capsules should be condensed to a “square-like” package to prohibit sample rolling, spilling and to remove excess air from the sample.   It is recommended that tin capsules are purchased directly from CE Elantech.  Samples should be housed in well-plates or individual vials.

Contact the facility for appropriate weights to use.  The following are general guidelines for plant tissues and soil:

  • Percent CN in solid samples: Appropriate sample weights are determined by the percent of the element in the sample (e.g., soil with %C < 10% use 40.000-80.000 mg; organic soils like peat use ~10.000 mg; plant tissue use 5.000-10.000 mg).
  • Percent CHN/CHNS in solid samples:  Approximately 2.000 mg
  • Percent O in solid samples:  Approximately 2.000 mg

Other types of solid samples include filter papers and animal tissues, please contact us for more information.

Liquid samples can be analyzed by placing absorbent in the foil cup and pipetting in a small amount of liquid sample.  The tin cup must then be sealed.  Please contact us for more information.

Submission requirements:  Each sample plate must be labeled with a date, investigator name, project name, ID system, and type of sample.  Corresponding weights for each sample must be submitted.  The facility will prepare standards and checks.

Gas Analyses: CO2 and N2O

Shimadzu GC-8A and GC-2014 (Shimadzu Corp., Kyoto, Japan). These instruments are for gas samples only.

These instruments can analyze nitrous oxide (N2O) and high concentrations of carbon dioxide (CO2).  The GC-2014 contains an electron capture detector (ECD) and the GC-8 contains a thermo-conductivity detector (TCD).  Both instruments require manual injection and there is a 7 minute sample run time.  Contact the facility if you wish to analyze samples for these gases.

Chlorophyll a, Rhodamine Water Tracing, or Chromophoric Dissolved Organic Matter

Trilogy 7200 Fluorometer (Turner Designs, San Jose, CA, USA). This instrument is for liquid samples only, either water or extract solutions.   Contact the facility for use of this instrument.