triplicate with each batch of samples analyzed. Ensure sufficient
quantities of the standard are available for QC charting over
multiple analyses.
2. All microalgal biomass samples should be freeze-dried/lyophilized
before analysis. Care must be taken to ensure a representative and
ground/homogenized (particle size <1 mm) sample is taken for
analysis. Limit sample contact with oxygen, heat, and moisture to
lessen the possibility of lipid degradation. Storage of samples
should ideally be in an inert (nitrogen) atmosphere and at least at
À20
C.
3. Dry samples in vials overnight in a 40
C oven under vacuum.
After drying, take a final weight to calculate the moisture-free
sample amount. Allow samples to cool in a desiccator under
vacuum before recording a final weight. If no vacuum oven is
available, samples can be stored overnight in a vacuum desiccator prior to analysis, given that a corresponding moisture measurement is available the same day for that material. Refer to
Determination of Total Solids and Ash in Algal Biomass procedure for moisture measurement [15]. Because moisture content can be variable in samples, it is important to correct for
moisture and report FAME content on a dry weight basis.
4. If using a digital dry block for heating, regularly check the
temperature of each block using a certified thermometer as
the heating coils used in these systems can fail over time.
5. Do not worry about capping the sample vials as you add the
internal standard; the C13:0ME will remain with the biomass,
even if the hexane evaporates.
6. Recap the C13:0ME vial after adding to all samples; it will be
needed for standard preparation.
7. It is advisable to add all reagents in sets of ten samples, and then
cap. Once an analyst is comfortable with the method, reagents
can be added to 50 samples before capping. The key is to avoid
excess solvent evaporation during preparation.
8. The block must be at temperature before adding samples. Once
the reagents have been added to the samples, the samples must
be heated. Do not allow samples to sit around as this may affect
the reaction.
9. If the rest of the procedure cannot be completed on the same
day, cooled samples may be stored overnight (no longer than
24 h) in a freezer (À20
C). Always store vials upright.
10. This can be done without removing the vial caps by using a
small hollow-core needle to penetrate the cap while adding the
hexane with the syringe through a second hole in the cap. Be
sure the opening in the hollow-core needle faces away from the
direction of the added hexane to avoid hexane being expelled
back up through the needle.
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S. Van Wychen and L.M.L Laurens
quantities of the standard are available for QC charting over
multiple analyses.
2. All microalgal biomass samples should be freeze-dried/lyophilized
before analysis. Care must be taken to ensure a representative and
ground/homogenized (particle size <1 mm) sample is taken for
analysis. Limit sample contact with oxygen, heat, and moisture to
lessen the possibility of lipid degradation. Storage of samples
should ideally be in an inert (nitrogen) atmosphere and at least at
À20
C.
3. Dry samples in vials overnight in a 40
C oven under vacuum.
After drying, take a final weight to calculate the moisture-free
sample amount. Allow samples to cool in a desiccator under
vacuum before recording a final weight. If no vacuum oven is
available, samples can be stored overnight in a vacuum desiccator prior to analysis, given that a corresponding moisture measurement is available the same day for that material. Refer to
Determination of Total Solids and Ash in Algal Biomass procedure for moisture measurement [15]. Because moisture content can be variable in samples, it is important to correct for
moisture and report FAME content on a dry weight basis.
4. If using a digital dry block for heating, regularly check the
temperature of each block using a certified thermometer as
the heating coils used in these systems can fail over time.
5. Do not worry about capping the sample vials as you add the
internal standard; the C13:0ME will remain with the biomass,
even if the hexane evaporates.
6. Recap the C13:0ME vial after adding to all samples; it will be
needed for standard preparation.
7. It is advisable to add all reagents in sets of ten samples, and then
cap. Once an analyst is comfortable with the method, reagents
can be added to 50 samples before capping. The key is to avoid
excess solvent evaporation during preparation.
8. The block must be at temperature before adding samples. Once
the reagents have been added to the samples, the samples must
be heated. Do not allow samples to sit around as this may affect
the reaction.
9. If the rest of the procedure cannot be completed on the same
day, cooled samples may be stored overnight (no longer than
24 h) in a freezer (À20
C). Always store vials upright.
10. This can be done without removing the vial caps by using a
small hollow-core needle to penetrate the cap while adding the
hexane with the syringe through a second hole in the cap. Be
sure the opening in the hollow-core needle faces away from the
direction of the added hexane to avoid hexane being expelled
back up through the needle.
210
S. Van Wychen and L.M.L Laurens