Compound-Specific Stable Isotope Analysis (CSIA)

Tips for Fatty Acid Methyl Ester (FAME) Analysis


Tips for Sample Preparation
We recommend shipping samples dry; shipment of solvents requires handling as dangerous goods and incurs additional shipping fees. If shipping samples in solvent, please do not overtighten your vial caps. Samples leak out of vials with over-tightened caps. Turn caps until snug, but not so far that septa start to pucker.

We recommend using an internal standard (e.g. c19:0) if you intend to account for extraction efficiency in concentration data. Please avoid the use of small chain FAMEs, as we often use these compounds as internal standards for calibration of isotope-ratio measurements.

Please inspect your data upon receipt of data report. We provide the identification of a large number of FAMEs, however we also report data for all detectable, yet unidentified, peaks. This allows you to decide which data to keep and which ones to discard. Very small peaks (< 1 V-s) may have biased values that should be ignored, especially when closely eluting to much larger peaks. Further, when large peaks are not fully resolved, the δ13C or δ2H measurement for each approaches the average of the two peaks. This is because the IRMS measurements take place on the combustion/pyrolysis products (CO2/H2) following chromatography and cannot fully discern the CO2/H2 from either peak.

 

Quality Assurance

Every SIF data report contains results for a range of calibrated quality assessment reference materials that were co-measured with the project. However, as for all analyses, we recommend that clients submit a quality assurance material to allow for their own monitoring of batch-to-batch variation over time and consider the submission of sample duplicates[1]. Ideally, these QA materials should be similar to the sample materials you intend to measure. Requirements for material preparation are the same as those for all sample materials.


Scheduling
The queue for CSIA at the SIF often extends several months. We recommend that you contact us about your sample submission as early as possible to expedite your project analysis.
 

Supplies

Manufacturer / Part#

Description

 Unit

National Scientific / C4000-2W

Screw-Thread Vials 9-425, 2 mL Amber with ID Patch

100/PK

National Scientific / C4000-53B

Blue Screw Caps, Red PTFE/White Silicone/Red PTFE

100/PK

National Scientific / C4010-630

Poly-spring Glass Inserts 300 µL

100/PK

National Scientific / C4012-25

Storage rack for 50 vials, polypropylene, without lid

EACH

National Scientific / C4011-25

Storage rack for 100 vials, polystyrene, with lid

EACH

Agilent / 5182-0716

Screw-Thread Vials, Large Opening, 2 mLAmber with Write-On Spot

100/PK

Agilent / 5182-0716

Screw-Thread Vials, Large Opening, 2 mL

100/PK

Agilent / 5182-0724  

Green Screw Cap, PTFE/Silicone/PTFE  

100/PK

Agilent / 5181-1270

Micro-volume Inserts, Borosilicate Glass, Conical with Polymer Support Feet

100/PK

Agilent / 5181-3377

Micro-volume Inserts, Borosilicate Glass, Flat Bottom

500/PK

Microliter / 09-1400

Conical Bottom Vials, Clear, 1.8 mL

100/PK

 

References
[1] Jardine, T.D. & Cunjak, R.A.. 2005. Analytical error in stable isotope ecology. Oecologia. 144: 528. doi: 10.1007/s00442-005-0013-8