Electronic Resource
Oxford, UK
:
Blackwell Publishing Ltd
Freshwater biology
13 (1983), S. 0
ISSN:
1365-2427
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
SUMMARY. Methods for determination of low levels of biogenic silica (0.2–0.4 mg SiO2) in aqueous samples after digestion with three wetalkaline extraction procedures compared favourably in both precision of replicates and recovery of silica utilized by diatoms in budgeted cultures. Leaching samples with 0.2 M NaOH for 10–15 min at 100°C was the least time consuming procedure. Also interference from silicate minerals was lower for this method than leaching with either 0.5 or 5% Na2CO3 for 2 h at 85°C. The use of filters to concentrate samples enables detection of low levels of biogenic silica with colorimetric procedures. Polycarbonate filters are recommended in preference to cellulose acetate or polyvinyl chloride filters for sample collection. Time-course experiments are recommended for establishing digestion times and determining the presence of mineral silicate interference. Wet-alkaline digestion methods are recommended for routine analysis of biogenic silica in suspended matter in preference to infra-red analysis, alkaline fusion and hydrofluoric acid/nitric acid methods.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2427.1983.tb00658.x
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