3. Pour carefully the ammonium molybdate tetrahydrate solution
to the acid solution, otherwise the solution turns white, milky
looking, and cannot be used.
4. It is critical to have proper training before running the analyzer.
This will depend on the system that you are using and it is
beyond the scope of this chapter to go into the details of the
operation of the instrument. We have used Thermo Scientific
Aquakem 250 analyzer for silica.
5. Calibration curve is prepared by plotting measured absorbance
of standards versus standard concentrations (linear regression).
6. Start each sample run with blank(s) and reference material to
verify proper operation of the instrument. Analyze samples in
sequences of max 20 samples followed by a blank and reference
material. Insert also standards in the sequence to test accuracy
and drift during the analytical runs.
7. Determine concentration in the sample by the slope of the
calibration curve. Reduce the absorbance of the blank from
the absorbance of the sample.
8. The method is very sensitive; so for diatom cultures you should
use a relatively little volume, just enough to see some color on
the filter.
9. At least one for each batch of samples to assess and correct for
laboratory contamination.
References
1. Hildebrand M, Davis AK, Smith SR, Traller JC,
Abbriano R (2012) The place of diatoms in the
biofuels industry. Biofuels 3(2):221–240
2. Bozarth A, Maier UG, Zauner S (2009) Diatoms in biotechnology: modern tools and applications. Appl Microbiol Biotechnol 82
(2):195–201
3. Armbrust EV (2009) The life of diatoms in the
world’s oceans. Nature 459:185–192
4. Martin-Je ´ze ´quel V, Hildebrand M, Brzezinski
MA (2000) Silicon metabolism in diatoms:
implications for growth. J Phycol 36:821–840
5. Round FE, Crawford RM, Mann DG (2007)
Diatoms: biology and morphology of the
genera. Cambridge University Press, Cambridge
6. Grasshoff K, Ehrhardt M, Kremling K (1999)
Methods of seawater analysis. Wiley-VCH Verlag Gmbh, Weinheim
7. Krausse GL, Schelske CL, Davis CO (1983)
Comparisons of three wet-alkaline methods of
digestion of biogenic silica in water. Freshwater
Biol 13:73–81
8. Koroleff F (1979) Methods for the chemical
analysis for seawater. Meri 7:1–60. (In Finnish)
9. Haeckel EHPA (1904) Kunstformen der Natur.
Bibliographisches Institut, Leipzig
Determining Dissolved and Biogenic Silica
101
to the acid solution, otherwise the solution turns white, milky
looking, and cannot be used.
4. It is critical to have proper training before running the analyzer.
This will depend on the system that you are using and it is
beyond the scope of this chapter to go into the details of the
operation of the instrument. We have used Thermo Scientific
Aquakem 250 analyzer for silica.
5. Calibration curve is prepared by plotting measured absorbance
of standards versus standard concentrations (linear regression).
6. Start each sample run with blank(s) and reference material to
verify proper operation of the instrument. Analyze samples in
sequences of max 20 samples followed by a blank and reference
material. Insert also standards in the sequence to test accuracy
and drift during the analytical runs.
7. Determine concentration in the sample by the slope of the
calibration curve. Reduce the absorbance of the blank from
the absorbance of the sample.
8. The method is very sensitive; so for diatom cultures you should
use a relatively little volume, just enough to see some color on
the filter.
9. At least one for each batch of samples to assess and correct for
laboratory contamination.
References
1. Hildebrand M, Davis AK, Smith SR, Traller JC,
Abbriano R (2012) The place of diatoms in the
biofuels industry. Biofuels 3(2):221–240
2. Bozarth A, Maier UG, Zauner S (2009) Diatoms in biotechnology: modern tools and applications. Appl Microbiol Biotechnol 82
(2):195–201
3. Armbrust EV (2009) The life of diatoms in the
world’s oceans. Nature 459:185–192
4. Martin-Je ´ze ´quel V, Hildebrand M, Brzezinski
MA (2000) Silicon metabolism in diatoms:
implications for growth. J Phycol 36:821–840
5. Round FE, Crawford RM, Mann DG (2007)
Diatoms: biology and morphology of the
genera. Cambridge University Press, Cambridge
6. Grasshoff K, Ehrhardt M, Kremling K (1999)
Methods of seawater analysis. Wiley-VCH Verlag Gmbh, Weinheim
7. Krausse GL, Schelske CL, Davis CO (1983)
Comparisons of three wet-alkaline methods of
digestion of biogenic silica in water. Freshwater
Biol 13:73–81
8. Koroleff F (1979) Methods for the chemical
analysis for seawater. Meri 7:1–60. (In Finnish)
9. Haeckel EHPA (1904) Kunstformen der Natur.
Bibliographisches Institut, Leipzig
Determining Dissolved and Biogenic Silica
101