Forum - Recent Threads

RE: Recomended Flow on a GC

james_jenkins — Tue, 20 Apr 2021 12:00:14 GMT

Hi Michael1993,

Deans switch can be a little more complicated. Take a look at this presentation and you will see healthy flows in all states of use. https://www.agilent.com/cs/library/eseminars/Public/Deans%20Switch%20060711.pdf

Regards

James

Recomended Flow on a GC

mr.white — Wed, 29 Aug 2018 10:30:12 GMT

Hi,

We currently using 2 Columns in our GC.

1 for the analysis itself. And a second one, which is just there to minimize the maintenance of changing a column.

What are the recommended flow settings, for a column which isn't in use ?

I heard that u always should run it at low flow. But I am unsecure, how much would be the perfect Value.

GC transfer line high temperature alarm

Hanadyz — Sat, 17 Apr 2021 19:55:02 GMT

Hello there.

I encountered a problem in my GC HS 7964E twice. The instrument was on and ready for injection, but the transfer line was hot than usual, even more than the set temp.

The actual temperature was reading ''--------'' (blank) and an error message was displayed; "High temperature alarm". It was extremely hot to the touch, and I disconnected it from the instrument and waited till it was cool, then I reconnected it.

After that, I was trying to inject my samples, no peaks appeared at all, but peaks who are supposed to be of large areas appeared but with rather smaller areas.

For example, DMSO whose area is supposed to be ''20000'' was found to be only ''300''!

All other methods that I have in my lab were tried, but all of them were of the same results.

My opinion is that there is a doubt that when the transfer line got too hot, some part melted or broken and it was plugged due to that extreme high temperature.

Please advise. Thank you for your time.

RE: GC transfer line high temperature alarm

ishtiyaq — Mon, 19 Apr 2021 00:48:36 GMT

Either there is leak or loop is not filling properly with sample for low area.

And for too hot transferline, may be PC board or sensor is malfunctioning or faulty of headspace.

You can change column or trim the column from inlet and detector side.

If you are using FID then you can clean jet or do FID maintenance.

After this do injection and see area.

If still problem persist then problem is from headspace side and has to check complete sample flow path of headspace to see which part is faulty.

Like after equilibrium of vial, sample goes in loop and then by switching of valve, helium took sample from loop and goes to GC through transferline.

So all these need to check.

RE: 7697A Vials leaking error using Empower 3

ishtiyaq — Fri, 16 Apr 2021 19:27:10 GMT

You are using openlab chemstation or empower 3 for 7697a headspace.

If empwer3 then you have to contact waters.

7697A Vials leaking error using Empower 3

Seb99 — Fri, 16 Apr 2021 19:00:22 GMT

I am having an issue regarding the pressurization of my vials. I am using 10 ml vial and cap from Agilent. Leak rate always higher than my limit. Seems to be a known driver error when reading in Waters forums. To fix that problem without drivers upgrade, they propose to set the Fill modes of my vials to Constant Volume. Any idea what volume should I use to perform pressurize my vials?

RE: Recomended Flow on a GC

Michael1993 — Thu, 15 Apr 2021 19:48:00 GMT

appreciate this is 3 years old, but if youre still here, is this true for MSD with a deans switch?

RE: 8355 SCD high output

ishtiyaq — Thu, 15 Apr 2021 07:57:24 GMT

How old is column.

SCD is very sensitive towards column bleed.

Install any other column after conditioning then see baseline.

8355 SCD high output

jmbrummett — Wed, 24 Mar 2021 19:36:23 GMT

I operate an Agilent 8355 SCD. The baseline output that is stated in the manual is 150pA in a well stabilized system with an oven temperature of 50C. When not in use, the baseline output is around 500pA. I'm not sure if this is caused by the method I use/frequency of use or if there is an issue with the detector itself that needs to be addressed. Any thoughts on the cause of a high baseline output?

ALS on 8890 - configuration ?

Ting — Wed, 14 Apr 2021 04:26:47 GMT

Hello all,

Trying to figure out where or how to change ALS configuration on the touch pad from Front Injector to Back Injector and vice- versa?

Thanks,

Ting

RE: ALS on 8890 - configuration ?

Ting — Wed, 14 Apr 2021 19:13:18 GMT

ALS works fine as Front Injector - wire and connection is not the issue. thanks

RE: ALS on 8890 - configuration ?

ishtiyaq — Wed, 14 Apr 2021 19:11:01 GMT

And also share pic of led light of ALS to understand the problem..

RE: ALS on 8890 - configuration ?

ishtiyaq — Wed, 14 Apr 2021 19:08:16 GMT

What you are finding in inlet in above pic..can you share pic after clicking inlet..

RE: ALS on 8890 - configuration ?

Ting — Wed, 14 Apr 2021 18:58:29 GMT

ALS is stuck on Front Injector on the panel and on the GC. I need it to register as the Back Injector. Have tried both connections in the back, have rebooted multiple times - no success. In the 6890 - we were able to have the flexibility to choose Inj1 or Inj2 as front or back . I can't seem to find a way on these new fancy touch screens :)

RE: ALS on 8890 - configuration ?

ishtiyaq — Wed, 14 Apr 2021 18:53:33 GMT

Can you check ALS Led is light up or not.If wire of ALS is connected properly with GC from back side then after restarting the instrument, ALS should show in setting then service mode then set up..

RE: ALS on 8890 - configuration ?

Ting — Wed, 14 Apr 2021 18:47:49 GMT

Hi - thanks but there is no ALS option at the set up

RE: Hi, I'm having trouble with a signal buffer overflow. It's complicated so please see the details

gcbill — Wed, 14 Apr 2021 18:19:59 GMT

James,

I hope this works, as I'm having trouble getting back in to the community. The problem ended up being a printer. It was printing sometimes and not others, and something about the printer buffer not accepting more information was the GC buffer to become full. All I had to do was remove the printer as the default, and everything worked fine.

Best Regards
Bill

(Personal details removed by Moderator)

"james_jenkins" ---04/14/2021 02:08:12 PM---[http://www.agilent.com/] Agilent Community

Hi, I'm having trouble with a signal buffer overflow. It's complicated so please see the details

gcbill — Thu, 15 Oct 2020 22:39:45 GMT

The buffer overlow is causing our sequences to crash. Instruments are GCMS only (the GCs run fine). It also happens on a colleagues instruments across the building, and it doesn't seem to matter the age of the instrument, or software being used, just that it's an GCMS. The buffer overflow error itself displays in the software and on the GC control panel. The problem is intermittent. Some sequences run fine, others crash on the first sample. Most of the time it overflows between 4-6am after about 6 samples. But not at an exact time like a scheduled task interference. Our IT and our service company both say there's nothing wrong on their end. No IP conflicts, no network outages, nothing physically wrong with the instruments or computer. I'm at a loss. The start of this did occur after a tropical storm caused a power outage, but I wouldn't think the network card would fail *sometimes*. We didn't install any updates or change configurations recently, and it was working fine previously. I'm thinking of trying a system restore, but would like to avoid it. Any thoughts?

What range of carrier gases is possible?

memfarmer — Sun, 28 Oct 2018 00:45:36 GMT

I'm wondering just how exotic I could get with GC (or GC-MS) carrier gases. For example, could I run pure methane, or carbon monoxide or carbon dioxide, or syngas (CO + H2)? I'm much less concerned with chromatographic efficiency than I am with things like filament lifetime, or on the GC, how the FID detector would respond. Thanks!

RE: What range of carrier gases is possible?

james_jenkins — Wed, 14 Apr 2021 18:14:06 GMT

Hi memfarmer,

The inlet electronic pressure control (EPC) modules are calibrated for up to 4 carrier gases: Split/Splitless capillary (SS), Purged packed (PP), Programmable temperature vaporization (PTV), Multi-Mode (MM), and cool on-column (COC) are calibrated for Helium, Hydrogen, Nitrogen, and Argon methane 5%. Volatiles inlet VI is calibrated for only Helium and Hydrogen.

The issues with non standard gases is complex, in GCMSD, anything with a mass higher than helium can block ionization, effectively a roadblock for signal.

Regards

James

RE: 8355 SCD high output

jmbrummett — Wed, 14 Apr 2021 17:55:12 GMT

No, not yet. I called Agilent service for assistance but they never called me back. I thinking part of it has to do with the temperature program I have for my analysis method but the output is still high even when not running. I've changed the hydrogen and oxygen recently (the tanks last a long time) and that did not fix the issue. I've also changed the inner ceramic tube and that did not fix the issue either. There isn't much troubleshooting information available out there for this instrument which is kind of a bummer.

RE: 8355 SCD high output

james_jenkins — Wed, 14 Apr 2021 17:48:48 GMT

Hi jmbrummett,

Were you able to resolve the issue?

Regards

James

RE: ALS on 8890 - configuration ?

ishtiyaq — Wed, 14 Apr 2021 06:01:56 GMT

Hi,

You can configure from touch screen by going in setting option.

RE: Column trimming and bake out.

ishtiyaq — Tue, 13 Apr 2021 20:20:21 GMT

Yes..Tips and tricks work based on environment and situation also.

But there is always pros n cons..if succeed then okay otherwise what is recommended in manual, has to follow.

I am happy that you succeed to use instrument without vent...

Column trimming and bake out.

Agnes — Tue, 13 Apr 2021 10:09:03 GMT

Hello Everyone,

I'm very new and don't have much experience in troubleshooting the GC-MS so I need your help. I'm operating on Agilent 7890B and 5977 MSD. Recently I've noticed very big baseline noise. I have changed the inlet septum and liner, which helped a little bit, but not enough. I suspect that contamination might be already in the column so I would like to trim the column and bake it out. Could you please let me know how should I prepare the GC and MSD for this process? I know that I have to cool the oven and inlet to room temperature, but what about the MSD and gas flow? Should I vent the MSD (the column is connected directly to MSD), and what about the carrier gas (He), should I close the cylinder?

If someone would be able to help, I will appreciate this a lot.

Thank you.