In article <4fvgku$mci$1 at mhafc.production.compuserve.com>,
74267.2135 at CompuServe.COM says...
>>I would like to know the relative advantages and disadvantages of
>large volume sampling of water and the differences of
>centrifugation vs filtration on the detectability of substances.
>Please forward me any thoughts or references.
>I am presently preparing sampling of rivers and would like to
>choose between different matrices.
There is no one answer to your question. The problem is highly parameter
dependant. For inorganic cation water quality parameters filtration is
normally employed. It should be done at the time the sample is
collected. Carbonate should be done by titration immediately upon
collection. Extrapolated carbonate values are meaningless. Previously
filtered samples should never be filtered again in the laboratory. What
are your objectives? What are your parameters of interest? Organic
materials in low concentrations are a problem. One has to consider
substrate composition and partitioning problems.
You should probably start with the literature. Water Supply papers from
the GS are a good place to start.