We are using Chem Station and it spits out 5 decimal places for the peak area! I have always rounded that to three for my own reporting purposes. however, I am now doing some method validation and want to know what the regulatory take is on hese numbers. The actual final results won't change since my total areas are fairly high (100mAU*sec).
Thanks!

Remember, significant figures of final results should not be more than the least number of significant figures used throughout. For example, if you use a 5.00 ml pipet to dilute the solution to 50.00 ml, your final answer should not be more than three significant figures. But this might be four if you use a 10.00 ml pipet to dilute to 100.00 ml.

I view area counts as a kind of intermediate calculation and carry all insignificant digits to the end and round once - less checking. Of course anything past one or two insignificant digits is useless and could be rounded or truncated.

I think replicate injections of standards would tell you where the least significant digit was, of course this could vary run to run. One sequence might produce 0.5% RSD and another 0.05%. I guess you could take the instrument specification for precision as the limit and round accordingly(1% for the 1100). Then again, it pretty much just dosen't matter.

As far as siggy figgies go, how about the "real-world" approach that 2 SF for the final result (talking well-behaved HPLC analysis here)is never enough, since we can prepare and analyze better than than the >1% "steps" allowed between a "99" and a "100 result? Likewise, 4 SF is always too much, since we can't reliably distinguish between a "100.0" and a "100.1" considering sample prep, injector precision, integration, etc. So what's left, since 2 SF is too few and 4 SF is too many? Do we really want to jump a SF when the allowable precision of the reported result becomes lower than the cumulative imprecision of our analysis? Messy.
Also, I agree w/ Tom - Round once at the end, if possible.
And I wouldn't assume a 10 mL pipet is 10.00 since its tolerance is +/- 0.02 mL