[Question] is 94.2% actually fine or am I being sold a rounding error
The claim in the title is exactly the claim I am making: is 94.2% actually fine or am I being sold a rounding error. Nothing implied beyond it. Figures up front so nobody has to dig: 94.2%. Gave the same trace to two people I trust and got two integrations about a point apart. That was the most educational afternoon…
How old is the column and roughly how many injections has it seen?
What wavelength, and what was the gradient?
Careful — you are treating retention time as identity. Two things can co-elute and the trace will not tell you.
That is area percent, not mass percent. The trace cannot give you the second one.
LC-MS for identity, UV for relative quantity
Carryover from a previous high-concentration injection looks exactly like a small impurity. The blank injection is four minutes and it removes the ambiguity entirely.