unpopular opinion: most of what gets said here about HPLC is guesswork
Posting this as a discussion rather than a claim: unpopular opinion: most of what gets said here about HPLC is guesswork. Retention time shifted 0.4 minutes and I assumed the worst. It was the column temperature. Gave the same trace to two people I trust and got two integrations about a point apart. That was the most…
report the method or do not report the number
Ran a blank after a high-concentration injection and found the carryover I had been calling an impurity.
system suitability before you believe any number on the run
Bought a second-hand instrument and learned more in six months of fixing it than in three years of reading traces.
a shoulder is not an impurity until you can resolve it
A shoulder that does not baseline-resolve cannot be quantified honestly. You can report it as an unresolved shoulder, which is useful information, or you can develop the method until it resolves.
baseline choice is a decision, not a measurement
A shoulder that does not baseline-resolve cannot be quantified honestly.
Adding one practical thing — run the blank. It answers this before anyone has to argue about it.
What did system suitability look like on that sequence?