Aux EPC or PCM for Collision Gas 7890/7200

No.  There is a QTOF specific collision cell EPC module. The software needs to recognize it.

G3850-60039 | Agilent   EPC module

G3470-60550 | Agilent,  Fitting and 1/16" tubing to go from the EPC module to the QTOF CC 1/16" Swagelok connection.

Is the 7890 setup for the MS transferline heater/sensor connection?  Has that GC ever been run with a mass spec?

Is it a 7200A or 7200B ? What's the serial number?

It's a 7890A - it hasn't been run with a mass spec before but it has the correct aux heater connection and we removed the rebated hole for the transfer line and got everything set up and configured so it recognizes the transfer line and heats it. The 7200 was purchased from a reputable biotech liquidation auction company by itself as working and come to find out it was missing the entire transfer line module, the TOF gauge, the foreline gauge, the #3 turbo, half the foreline connections, and the #2 turbo had a lunched bearing. It's taken quite a bit of work but we've managed to get it running smoothly for uunder $10,000 in parts from Agilent and resellers, finally giving good signal, holding excellent vacuum, turbos are running extremely smooth/quiet/low current consumption, no errors etc. 

For now just to test everything out we've been able to run samples by feeding N2 to the collision cell directly via a manual Omega 0-6ml/min flow meter and everything seems to work fine, and we're getting good results so we were hoping to avoid having to spend another $3k on parts if at all possible but if that's the only way, I guess that's what we have to do. Thanks!

Richard987    A normal EPC module could probably supply the nitrogen to the collision cell but it's not tested, not supported, no one knows as it's never been done.  If you can run it now and MassHunter Acquisition isn't complaining it might work.

How long was it open to atmosphere?  I'm very surprised that the detector itself is functional.  They do not handle exposure to moisture well at all.  I keep track of the GC QTOF systems in North and South America, that's why I asked the model and serial number. 

Yeah, that's what I thought as well but the AUX EPC flow controllers only are capable of pressure regulation, not flow correct? The problem we were having was since the outlet is connected to the collision cell under vacuum, and since the n2 flow is so tiny, the EPC measures -14 psi. And since there is no way to set the EPC for flow rate only pressure 0-100, it throws an error and gives up. I experimented with using it in a reverse pressure regulator configuration with output weldment as the N2 input and the normal input going out to the flow cell, which fixes the negative pressure issue but since the PID loop is set to open when the pressure is low and close when it's high, it does the reverse of what's needed and the firmware update program only gives a few predefined options for PID - I don't believe there's any way to modify the PID settings directly without directly editing of the PID setting XML files, and they consist of eeprom memory locations not human editable variables from the looks of it)

That's why I was asking if an AUX PCM might work since I believe they have flow sensors as well as pressure, correct? Mass hunter methods seem pretty flexible in configuration of different modules so even if it didn't directly recognize it was collision cell gas, it could still be set up manually. 

As for the 7200, the serial is US1247H001, model G3850-64201, and I believe it was at atmospheric for at LEAST a year (I can look Monday but I believe the last service sticker was from 2021 and it was purchased mid January 2024, so it's somewhere between 7 months and 2.5 years at atmospheric (with no TOF turbo or blanking plate, just a wide open hole, and a Kimwipe blocking the opening for the missing transferline. It was probably stored in a lab from whenever it was vented (sometime post 2021- late 2023) then moved to an auction warehouse in RI, then to the lab here in Farmington CT).

We haven't run a real tune or calibration yet (just manual calibration checking bbackground and signal from the EI calibrant, and quick autotune reports and water/air reports) but it's pretty low noise and descent signal so far. The source is definitely very dirty and needs a good clean which we're doing Monday, and the only issue we're having at the moment is o2 and n2 spikes.

We initially had an extremely small air leak somewhere - small enough that the system got to 10-5/10-6 qused/TOF from atmosphere in less than 2 hours (with a DS-602 foreline pump FWIW) and 10-7/10-8 overnight, but we were getting peaks at 28 & 32, so I cleaned and regressed all the o rings and tightened all the clamps, bolts and screws which significantly dropped the signal but somehow there are still peaks at 28 & 32 but instead of 4 to 1 they are EXACTLY equal - and I mean to the decimal: precisely 3,497,070.0 counts each with collision gas off and the transferline blocked. If you introduce some n2 to the transferline, the oxygen peak drops off and the nitrogen picks up but then when you stop they both go right back to 3,497,070.0 within maybe 15-20 seconds. I leak tested every seal, joint and fitting with nitrogen to look for leaks, but nothing, even when bagging the entire 7200 and purging with n2. So I'm hoping it's just source contamination but if you have any other ideas, please let me know. 

Yeah, that's what I thought as well but the AUX EPC flow controllers only are capable of pressure regulation, not flow correct? The problem we were having was since the outlet is connected to the collision cell under vacuum, and since the n2 flow is so tiny, the EPC measures -14 psi. And since there is no way to set the EPC for flow rate only pressure 0-100, it throws an error and gives up. I experimented with using it in a reverse pressure regulator configuration with output weldment as the N2 input and the normal input going out to the flow cell, which fixes the negative pressure issue but since the PID loop is set to open when the pressure is low and close when it's high, it does the reverse of what's needed and the firmware update program only gives a few predefined options for PID - I don't believe there's any way to modify the PID settings directly without directly editing of the PID setting XML files, and they consist of eeprom memory locations not human editable variables from the looks of it)

That's why I was asking if an AUX PCM might work since I believe they have flow sensors as well as pressure, correct? Mass hunter methods seem pretty flexible in configuration of different modules so even if it didn't directly recognize it was collision cell gas, it could still be set up manually. 

As for the 7200, the serial is US1247H001, model G3850-64201, and I believe it was at atmospheric for at LEAST a year (I can look Monday but I believe the last service sticker was from 2021 and it was purchased mid January 2024, so it's somewhere between 7 months and 2.5 years at atmospheric (with no TOF turbo or blanking plate, just a wide open hole, and a Kimwipe blocking the opening for the missing transferline. It was probably stored in a lab from whenever it was vented (sometime post 2021- late 2023) then moved to an auction warehouse in RI, then to the lab here in Farmington CT).

We haven't run a real tune or calibration yet (just manual calibration checking bbackground and signal from the EI calibrant, and quick autotune reports and water/air reports) but it's pretty low noise and descent signal so far. The source is definitely very dirty and needs a good clean which we're doing Monday, and the only issue we're having at the moment is o2 and n2 spikes.

We initially had an extremely small air leak somewhere - small enough that the system got to 10-5/10-6 qused/TOF from atmosphere in less than 2 hours (with a DS-602 foreline pump FWIW) and 10-7/10-8 overnight, but we were getting peaks at 28 & 32, so I cleaned and regressed all the o rings and tightened all the clamps, bolts and screws which significantly dropped the signal but somehow there are still peaks at 28 & 32 but instead of 4 to 1 they are EXACTLY equal - and I mean to the decimal: precisely 3,497,070.0 counts each with collision gas off and the transferline blocked. If you introduce some n2 to the transferline, the oxygen peak drops off and the nitrogen picks up but then when you stop they both go right back to 3,497,070.0 within maybe 15-20 seconds. I leak tested every seal, joint and fitting with nitrogen to look for leaks, but nothing, even when bagging the entire 7200 and purging with n2. So I'm hoping it's just source contamination but if you have any other ideas, please let me know.