5973N tune issues

Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.

66 posts Page 5 of 5
MSCHemist wrote:
Sadly I ended up having to replace the calibration valve after all. 2 weeks later it starting plugging up during tunes and I tried again using some methylene chloride then methanol and baking it at 68 deg C. It then began flooding the mass spec with insane amounts of PFTBA during the tune.
That little capilary tube in there is supposed to be pretty breakable. Pity that bit is not a user replaceable part vs the whole valve assembly.
LALman wrote:
Good to know it really was just the detector and that you did not have to buy a side board. Speaking of turbo pumps, we got our 5973 in 2004 and about 7 years later had to get the turbopump rebuilt. Then we had to rebuild it again 2 years later in 2013. I hope I can get 10 years out of this one. Mine is a BOC Edwards standard turbo.

Edits: I went and looked this up in the maintenance log. Our turbopump failure rate has been worse than I remembered.
Just an update, I had my Edwards 70 standard turbopump die after a series of closely spaced power failures. An hour long one on May 23 then a series of power failures May 24 killed it off. I had a UPS on the 5973 but it only had battery for about 10 minutes. It was mainly to protect from spikes. So at least this last pump lasted 8 years.

Thanks to Benhutchinson dropping a hint a while back; I got help from Great Lakes Technical Services (GTLS). Geoff at GTLS was super helpful over the phone with support. First overnighting a turbo controller and finally after memorial day overnighting me a used Edwards EXT255 and all the parts I might need that might also have failed. Now 5973 is easily hitting 1.1E-5 at 1mL/min on helium.
LALman wrote:
Now 5973 is easily hitting 1.1E-5 at 1mL/min on helium.


Good vacuum.

Mine always hits that creepy vacuum of 6.6E-6

I think it is possessed!
The past is there to guide us into the future, not to dwell in.
Mine seems to jump around some. Air and water is less than 2%. Over the weekend vacuum will drop to 9.6E-6 but one run will bring it back up to ~1.1E-5. I do ramp my run from 1mL/min to 1.5mL/min just after BFB. Also, the Tekmar 3000 with Vocarb trap does dump a lot of water even with the moisture trap on the Tekmar and splitting 40:1.
LALman wrote:
Mine seems to jump around some. Air and water is less than 2%. Over the weekend vacuum will drop to 9.6E-6 but one run will bring it back up to ~1.1E-5. I do ramp my run from 1mL/min to 1.5mL/min just after BFB. Also, the Tekmar 3000 with Vocarb trap does dump a lot of water even with the moisture trap on the Tekmar and splitting 40:1.


I have seen it happen with purge and trap, if it sets a while the rough pump oil will "dry out", then after a few runs it will reach a new equilibrium with the moisture and affect the vacuum a little. We just throw on a few extra blanks to get the instrument warmed up on Monday morning after it sits for the weekend or maybe longer.
The past is there to guide us into the future, not to dwell in.
I lead off with a "BFB" that I never use for two reasons. (1) I get a fairly large tetrahydrofuran peak that accumulates on the trap overnight. (2) Also, as you say, it settles the inlet system into a steady state and confirms there is no carryover from the final sample of the previous night. The CCV seems to come out more consistently than if it is the lead off sample.
66 posts Page 5 of 5

Who is online

In total there is 1 user online :: 0 registered, 0 hidden and 1 guest (based on users active over the past 5 minutes)
Most users ever online was 1117 on Mon Jan 31, 2022 2:50 pm

Users browsing this forum: No registered users and 1 guest

Latest Blog Posts from Separation Science

Separation Science offers free learning from the experts covering methods, applications, webinars, eSeminars, videos, tutorials for users of liquid chromatography, gas chromatography, mass spectrometry, sample preparation and related analytical techniques.

Subscribe to our eNewsletter with daily, weekly or monthly updates: Food & Beverage, Environmental, (Bio)Pharmaceutical, Bioclinical, Liquid Chromatography, Gas Chromatography and Mass Spectrometry.

Liquid Chromatography

Gas Chromatography

Mass Spectrometry