CHM 4354 Lecture Notes - Lecture 3: Analyte, Internal Standard
11 Jul 2018
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Document Summary
No instrument, which has a detector, will produce concentration for you. The only thing they produce is some kind of detector response that is proportional to concentration. Direct measurement: mass, time, volume does not provide concentration. Indirect measurement: direct measurement + calibration: concentration is the result of a indirect measurement. Calibration: ascertain the relationship between [ ] in a sample and the response of the assay. External standard: analyzed separately from the replicate unknowns being tested. Usually use to produce a calibration curve (line): we make a solution of known concentration of standard, run them separately, measure their signal and draw a line between them (goal is a straight line). If the curve actually curves, you will be very wide off in your final concentration. Important to remember when using calibration curves with external standards, we always interpolate never extrapolate: limitations, if matrix is complicated, you get a lot of things coming with your target.
