[Correction] you cannot report area% to two decimals off that baseline
Not naming the poster, the trace is in the thread below this one and they will know.
The reported figure is 98.47%. The baseline in the attached trace drifts visibly across the run and there is noise of roughly the same magnitude as the smallest reported impurity. You cannot resolve a hundredth of a percent off that.
Precision the data cannot support is a tell in itself, and it is one of the things I look for on vendor COAs. 98.5% is an honest answer. 98.47% is a claim about the instrument that the chromatogram contradicts.
best — the order this archive was captured in
Correct flair, correct restraint in not naming, and this is exactly what the Correction flair is for — it is not a removal, it is a note.
Rule of thumb for anyone calibrating: if your smallest reported impurity is within about 3× of your baseline noise, you are reporting noise. One decimal place on a purity figure is almost always as far as the data goes.
the same instinct applies to weighing. an analytical balance reading to five places does not mean your sample mass is known to five places once you have opened the door.
yes, and it is the same failure — trusting the display over the process.
if your baseline wanders your integration lies, and every digit after the first decimal is the lie getting more confident.
it is me and you are right. i copied the number straight out of the software because that is what it printed. rounding to 98.5 in the parent post now.
this is the ideal outcome and thank you for taking it well. the software prints whatever you configure it to print and defaults are not judgements.
a correction taken well and given kindly, in c/hplc of all places. i am putting it in my scrapbook.
compendial reporting conventions actually specify significant figures for exactly this reason. edit: and they specify fewer than most people report.
this is pedantry with no consequence
the consequence is that two-decimal precision is used to argue that a 98.47 and a 98.31 are different vendors. pedantry is a public service when milligrams are involved.
- 1the same instinct applies to weighing. an analytical balance reading to five…4 comments in this branch · started by u/tared_twice