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Traces

Traces

(OP)

This is a general term much used in many disciplines. The common meaning being extremely small but detectable quantities.

If they are detectable, are they per se quantifiable ?  

Any contribution to the subject would be highly appreciated.

RE: Traces

I don't think so.
I think what is meant is we know it is there but it is just too small to be measured.
Hence I turn your question around and suggest that if it can be quantified, it isn't a trace.

There is a limit to the accuracy and resolution of instrumentation.

You may be confident that your instrument is detecting the presence of the "stuff" but have no confidence in the accuracy with which it quantifies that presence.

JMW
www.ViscoAnalyser.com

RE: Traces

(OP)

JMW, following your reasoning that a trace ceases to be a trace when it is quantified, measured contaminants such as 0.1 ng/L or 0.1 parts per trillion (ppt) of mercury in potable water, how should they be called if not traces ?

I was of the idea that it is the smallness of the concentration that defines whether a trace is a trace and not the actual measured value of the concentration. Please comment.

RE: Traces


Perhaps they can be better defined as "trace elements".

RE: Traces

I think of trace like a near-empty gas tank on a car.  There may be enough to move the needle, but not enough to tell you how far you'll get.

RE: Traces

I agree with jmw.  Although detected, the concentration recorded may be below calibration standards.  The results may however be difficult to legally defend.  Typically laboratories have a lower reporting limit below which point it becomes diffacult to repeat the analytical results, the reporting limit (RL) is similar to a detection limit (DL).  This is really common in chromatography.  Most labs don't like to report trace as it drives clients nuts and they end up spending way too much time explaining the results. Labs commonly report Non Detected (ND), <DL, or the quantified result.

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