I'm sorry I said bad.
Ex:
... the retention time is about 1.3 minute... etc etc
There have been some opinions so far, and I'm sorry we can't be more precise as to what "about" would mean here. When someone gives a value "about" or "approximately", instead of giving a quantitative range, what they (
should) mean is "it doesn't really matter how much."
In this case, the retention time is about 1.3. If the run time is 5 minutes, then you should see the peak in the first third of the run. The real concern is if the peak comes out much sooner or much later, then there is something wrong with the system. The thing is, if you run a standard made of pure substance first, you will know what the correct elution time will be for your system. Once you know that, it won't matter that the description was "about." You'll know exactly when to expect it.
When I do a titration, I often add "about one or two drops of indicator". So what if I add 1/2 or 1/4 of a drop? That's not possible, so no on e worries about it. What if I add 3 or 4 drops? Nothing bad happens. So what if I add 5 mL. Well that may ruin the titration. But I know better than to do that.