Monona Rossol on sat 5 sep 98
---------- Forwarded message ----------
From: Gavin Stairs
To: CLAYART@LSV.UKY.EDU
Subject: Re: Cobalt Poisoning (fwd)
----------------------------Original message----------------------------
At 09:06 AM 03/09/98 EDT, you wrote:
>----------------------------Original message----------------------------
In an analysis, trace simply means that the analyst got an indication that
the substance was present, but could not determine the amount, because it
was less than the sensitivity limit of his apparatus. So, that means that
"trace" has no definite quantitative meaning. It could be 1% or it could
be a part per billion or less. If you are reading "trace" off a list of
other analyses, you can sometimes get an indication of what the limit is by
looking at the other small amounts, but this is not always as good as you
may think, since sensitivities vary according to species. Best is if the
analyst records the amount as <1ppm, or something like that. Sometimes the
sensitivity may be stated elsewhere. Gavin
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"Trace" as it applied to nutrients like cobalt does have a definite
meaning and is unrelated to the sensitivity of the analysis. The following is
from Hawley's Chemical Dictionary.
"Trace element (micronutrient). An element essential to plant and animal
nutrition in trace concentration, i.e., minute fractions of 1% (1000 ppm or
less)."
Monona
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