Change in retention Times after changin computer clock time

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

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Has anyone experienced the following:

We have 2 older Agilent 1200 HPLCs, purchased last year at auction. They each have identical PCs running ChemStation software, Rev. B.04.03 [16]. They are "stand-alone" systems, so there is no communication between the systems and they are not connected to the internet or any network/routers, etc.

We run 2 completely different analytical methods, 1 on each system, for the analysis of completely different compounds, and the retention time is has been highly reproduceable (16.5 min. for compound A on LC-1, 17.7 min. for compound B on LC-2). We recently made a computer clock adjustment for each PC (time of day was off by 1 hour at purchase for each of them). After the adjustment, the retention time for each analyte was off by about 5 minutes, each system, and the ratio of the change (current vs. original RT) was about the same for each system, (ratio = 1.3).

As strange as this sounds, can a computer clock time-of-day change affect the way ChemStation calculates retention time? Decades ago I had a similar problem using British-made computers, whose internal clocks were set for 50 Hz British AC power (60 Hz of course in the US) (We are a laboratory operating in the USA).

Thanks for any insights about this weird problem.
It would be interesting to know what happens if the computer clock is changed back to the original setting.
Changing system time of PC shouldn't have any impact on retention times.
I would check RT clock of PC for accuracy. IMHO PC clock is responsible for assigning retention times for peaks.
3 posts Page 1 of 1

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