Run stops with Mass spec fault during acquisition: 16384

Mass Spec faults can be decoded in tune. Status, MS Error Codes, type the error, <enter>, and this is what shows for 16384

The GC may have shut down the MS if GC detector, temperature, pressure, or flow setpoints have not be reached. The MS will remain in standby until the problem is fixed or the APG cable is disconnected.

The simplest test is to remove the syringe and try a sequence of a few vials without it.  If it works, it's related to the injection. If it doesn't, it's probably related to a method setpoint.  Are you running Splitless or a Pulsed Splitless injection and the inlet is struggling to get to the initial pressure?

Any beeps on the GC?

Mass Spec faults can be decoded in tune. Status, MS Error Codes, type the error, <enter>, and this is what shows for 16384

The GC may have shut down the MS if GC detector, temperature, pressure, or flow setpoints have not be reached. The MS will remain in standby until the problem is fixed or the APG cable is disconnected.

The simplest test is to remove the syringe and try a sequence of a few vials without it.  If it works, it's related to the injection. If it doesn't, it's probably related to a method setpoint.  Are you running Splitless or a Pulsed Splitless injection and the inlet is struggling to get to the initial pressure?

Any beeps on the GC?

This was helpful. I had not used Status: MS Error Codes before. So that's a new tool for me.

Even more helpful, is realizing that the problem did not originate with the MS!

The method is a 10:1 split injection. There is elevated temperature and flow in the post-run, but this has worked in the past. It _could_ be part of the problem because combing through the logs, I have seen this:

ACQ5975 Run started 22:12:50 07/11/2024
7890 Front inlet pressure not ready Run Time 0.00 22:20:50 07/11/2024
METHOD Acquired CO24193A_05_L3.d 22:23:53 07/11/2024
7890 The run was stopped by the GC's Stop button or 22:28:22 07/11/2024
Stop input.

Although it says the Run Time is 0.00, this has occurred as it starts the post-run, as evidenced by being exactly 8 minutes after the injection, and the data not being written for another 3 minutes. That the GC's "stop button" isn't pressed for another 5 minutes makes me wonder if it thinks it is taking too long to cool down?

I have tried many things without resolution. Best case, it will run 2-4 samples and then the GC will cause it to stop. I say GC because of the message above, but it is ultimately because the MS decides to go to standby.

Thank you for your assistance,
Matt

In Windows Explorer underneath your RUN_METHOD_Example.M subdirectory is a file called acqmeth.txt. Please upload it.

10:1 split is very low if the column flow is typical GC/MS 1.2 ml/min.  The total flow should never be lower than 20 ml/min and the inlet pressure should never be <5psi for reasonable pressure/flow control.  These both can happen with too low total flow/too low split ratio, and too short/too wide a column at too low an oven temperature.

On the GC edit parameters page, there are the GC Calculators.  I use the Vapor Volume and Pressure/Flow Calculator quite often.

The method is for headspace analysis. It was originally intended to have cryotrapping, but it has been modified to work without it, but I believe that the 10:1 was also used in the reference method.

The split flow does drop to zero momentarily when it transitions to the post-run, so that could cause issues. We are leaning towards the GC network card though, since the errors do not always occur at that time.

I came back in to the office to look up "The run was stopped by the GC's Stop button or Stop input." since this occurs at times when I would not expect the GC to be communicating anything. 

AcqMeth.txt:

https://drive.google.com/file/d/1qfDcDVCxLqR_dExKGCwStSzw-64xViE2/view?usp=sharing

(reply is hung up in moderation, presumably due to the attachment)

Recommendations.

Increase the oven temperature equilibration time to 1.0 to 1.5 minutes or longer. It takes time for the 250° oven final temperature sheetmetal to cool all the way down and become stable for the next run.  If the temperature is making it to 30° C for 0.2, it might go ready but then might go not ready again as the temperature hasn't sufficiently settled down.

30° C oven start temperature is very difficult to achieve in most laboratories. There's enough extra heat from the inlet and transferline that below 35° to even 37° C is tough at some places. If you really need to start that low you may have to use oven cryo. 

The liner recommended for headspace only runs is the 1.5 mm i.d. one - 18740-80200 | Agilent (1 pk), 5183-4709 | Agilent (5 pk), 5183-4710 | Agilent (25 pk).  The sample does not need expansion volume so the low 140µL volume keeps the peaks a bit narrower than a larger one.

Please set the MS transferline temperature to 230° C...to match the MS Ion Source.  That might aid source thermal stability.

1.9328 ml/min column flow is higher than optimal for the ion source and higher linear velocity than optimal with the 20m×250µm×0.18µm column.  The orthogonal ion source works best between 0.8 to 1.4 ml/min of helium flow.  Lowering the column flow may improve your sample's peak shapes.

Are you getting at least 10 scans across your earliest eluting peaks?  If not, you may need to change the A/D from 2^3 down to 2^2 ...that will reduce the averaging and may result in slightly increased visible noise, but better peak quantitation.

That method is from Wed Jan 19, 2011 ?

Oh, that is the wrong method then! Thanks for pointing out the date.

However, that is about when the instrument was delivered, so apparently they never used the cryotrap? (I assumed that it had been used, and then dropped when they stopped using the SPME fiber)

Here it is, as updated:

INSTRUMENT CONTROL PARAMETERS: GCMS5975
------------------------------------------

C:\msdchem\1\methods\cdcvoc2023.M
Thu Feb 16 13:40:35 2023

Control Information
------- -----------

Sample Inlet : GC
Injection Source : Manual
Mass Spectrometer : Enabled

Injection Location: Front

No Sample Prep method has been assigned to this method.

Oven
Equilibration Time 0.2 min
Max Temperature 260 degrees C
Slow Fan Disabled
Oven Program On
30 °C for 0.55 min
then 45 °C/min to 93 °C for 0 min
then 4 °C/min to 112 °C for 0 min
then 40 °C/min to 164 °C for 0 min
Run Time 8 min
3 min (Post Run) 240 °C

Sample Overlap
Sample overlap is not enabled

Front SS Inlet He
Mode Split
Heater On 150 °C
Pressure On 9.32 psi
Total Flow On 24.261 mL/min
Septum Purge Flow On 3 mL/min
Gas Saver On 15 mL/min After 7 min
Split Ratio 10 :1
Split Flow 19.328 mL/min

Thermal Aux 2 {MSD Transfer Line}
Heater On
Temperature Program On
150 °C for 0 min
Run Time 8 min

Column #1
Restek 49914Rtx-VMS
260 °C: 20 m x 250 µm x 0.18 µm
In: Front SS Inlet He
Out: Vacuum

(Initial) 30 °C
Pressure 9.32 psi
Flow 1.9328 mL/min
Average Velocity 61.424 cm/sec
Holdup Time 0.54268 min
Flow Program On
1.9328 mL/min for 0 min
Run Time 8 min
3 min (Post Run) 2.75 mL/min

Signals
Test Plot Save Off
50 Hz
Test Plot Save Off
50 Hz
Test Plot Save Off
50 Hz
Test Plot Save Off
50 Hz

GERSTEL MPS Headspace Injection

SYRINGE SETTINGS
Syringe : 2.5ml-HS
ITEX : not used - use these parameters if it becomes 'used'
Syringe Temperature : 100 'C
Flush Time : 180 s

SAMPLE PREPARATION
Headspace : from Incubator

Incubator : Agitator
Incubation Temperature : 75 'C
Incubation Time : 5.00 min
Agitator On Time : 5 s
Agitator Off Time : 1 s
Agitator Speed : 500 rpm

SAMPLE PARAMETERS
Inj. Volume : 1000.0 uL
Inj. Speed : 1000.00 uL/s
Pullup Delay : 10 s
Fill Volume : 2500.0
Fill Strokes : 0
Fill Speed : 100.00 uL/s
Pre Inj. Delay : 0 s
Post Inj. Delay : 0 s
Inj. Penetration : 45.00 mm
Sample Tray Type : VT32-10
Vial Penetration : 22.00 mm

MULTIPLE HEADSPACE SAMPLE ENRICHMENT (MHSE) AND/OR PRESSURIZE
Pressurize : not used - use these parameters if it becomes 'used'
MHSE Inj. per Run : 1

MS ACQUISITION PARAMETERS

General Information
------- -----------

Tune File : lomass.u
Acquistion Mode : Scan

MS Information
-- -----------

Solvent Delay : 1.50 min

EMV Mode : Gain Factor
Gain Factor : 1.00
Resulting EM Voltage : 1400

[Scan Parameters]

Low Mass : 35.0
High Mass : 171.0
Threshold : 800
Sample # : 3 A/D Samples 8
Plot 2 low mass : 35.0
Plot 2 high mass : 240.0

[MSZones]

MS Source : 230 C maximum 250 C
MS Quad : 150 C maximum 200 C

END OF MS ACQUISITION PARAMETERS

TUNE PARAMETERS for SN: US10423623
-----------------------------

Trace Ion Detection is OFF.

EMISSION : 34.610
ENERGY : 69.922
REPELLER : 29.788
IONFOCUS : 90.157
ENTRANCE_LE : 28.500
EMVOLTS : 1364.706
Actual EMV : 1400
GAIN FACTOR : 0.96
AMUGAIN : 2188.000
AMUOFFSET : 123.000
FILAMENT : 1.000
DCPOLARITY : 0.000
ENTLENSOFFS : 18.573
MASSGAIN : -496.000
MASSOFFSET : -37.000

END OF TUNE PARAMETERS
------------------------------------

END OF INSTRUMENT CONTROL PARAMETERS
------------------------------------