Chromatography Forum

Hi everybody

I'm new to this forum, and also new to the thrilling world of chromatographs. We're having an issue with the GC/MS/MS in our lab, and the most experienced staff cannot find a solution. It seems to be a communication issue between the computer and the MC. We have a Varian 1200 Quadrupole MS/MS, and in the software we get this message "saw host DSP interrupt" (in the quadrupole window...see the link for a picture)...Has anyone experienced a similar problem? Any suggestion? Thanks a lot in advance!

http://img41.imageshack.us/img41/1357/81942069.jpg

Sorry, I meant 'MS' (not MC!)

Is this your first time connecting this instrument, or is this an all-of-a-sudden development? It looks like it's connected - it shows that it's vented, and you seem to have voltage readbacks for all the various zones. What do you think you should be seeing? Are you all of a sudden missing the GC? If you click Instrument-->Configuration, do you see your modules in the upper part of the screen, or in the "Available Modules" list at the bottom of the screen, or not at all? If you click Windows-->Instrument Status, do you see any indication that you are not connected to the instrument, or if there are any faults associated with the connections/modules?

Hi!

Thanks a lot for your reply. Well, this is my first experience with thsi instrument, but it has been working for a while, and giving a lot of trouble in my lab...

I get some feedback from a really good technician working for Agilent in Spain. Thanks to his indications, now we know that the problem is not in the mother board or related to any connection. Apparently, we have this issue in the power supply...We measured the volts between two specific test points (TP 2 and TP 27, on communication side). It should be 5 V (or a close value), but the real one is 4.55 V... Values below 4.65 indicates a problem in the power supply. Now that we know this, we're just wondering if we should buy a new one, or if this can be fixed, maybe withe the help of an electrician used to work with this type of boards.

Again, thanks for your answer!

I had this problem a while ago the power supply didn´t work right check if the voltage is right. its very easy to change the part and it costs about 900 euro when you order it over agiland

Hi!

Thanks a lot for your answer. Indeed, it was the power supply, but we managed to re-adjust the voltage in the power board, and the communication was restored. Anyway, a new issue has appeared, since now we're not able to carry out a succesful auto-tune...The instrument passess the coarse tune with no apparent problems! Does anyone have experienced similuar issues with the autotuning? We need some clues, please!

Ruben

Are you getting any sort of error message associated with the inability to autotune? If you do an electronics diagnostic test, are there any errors?

Yes, indeed! I attach below the info on the tune file:


Exact Measured Peak Relative Peak Valley Resolution
mass mass height height width
(amu) (amu) (mV) (%) (amu @ 50%) (% of iso) (m/delta-m)
18.0 19.2 12.666 34.424 4.00 0 5
Warning: the peak is very wide and mass shifted!
28.0 28.1 5.565 15.125 2.54 17 11
Warning: the peak is very wide!
69.0 68.9 22.284 60.564 0.96 71 72
219.0 218.5 36.794 100.000 4.00 6 55
Warning: the peak is very wide and mass shifted!
502.0 502.2 11.477 31.192 4.00 0 126
Warning: the peak is very wide and mass shifted!

(Detector = 1820 V)

Tuning of quad 1 in positive mode had the following error(s):
Problem with fine resolution of m/z 502.0 (Time limit exceeded.)
Problem with fine resolution of m/z 219.0 (Time limit exceeded.)

-----------------------------------------------------------------------------------------------

Tune report for Varian Quadrupole Mass Spec

Time: 11:01:37 Tune file: FC-43 EI (Tuned on 18 Mar 2013)

Ionization mode:EI Scan Optimization: Standard GC (Fixed detector)

Exact Measured Peak Relative Peak Valley Resolution
mass mass height height width
(amu) (amu) (mV) (%) (amu @ 50%) (% of iso) (m/delta-m)
18.0 17.3 12.365 66.927 2.13 0 8
Warning: the peak is very wide and mass shifted!
28.0 30.4 5.936 32.131 3.09 13 10
Warning: the peak is very wide and mass shifted!
69.0 68.9 18.475 100.000 0.85 100 81
219.0 218.9 8.672 46.937 0.92 36 237
502.0 501.1 6.074 32.878 4.00 17 125
Warning: the peak is very wide and mass shifted!

(Detector = 1820 V)

Tuning of quad 3 in positive mode had the following error(s):
Problem with fine resolution of m/z 18.0 (Valley too high.)

28 absolute size (mV - EDR on)
- Limit 20.0 - Measured 0.0
- OK!
28/32 Ratio
- Air 3.5:1 - Measured 0.0:1
- OK! - Not indicative of Air
28/18 Ratio
- Limit 1.2:1 - Measured 0.0 :1
- OK!

- No significant leak detected -
- OK -

I'm sorry, I forgot that you're running this as a GCMS. I'm running it as an LCMS, and the tune operation is quite a bit different. However, I would think that the coarse tune has actually not been successful, being that you seemingly aren't finding the O2, N2, or H2O masses, and the masses you are finding are "very wide and mass shifted". Maybe I'm wrong, it's happened before. Have you verified you have adequate PFTBA calibrant in the vial?

From my hardware manual:

Source Pressure is too high (>50mTorr in EI mode).
• Check that the carrier gas flow is 1-2 mL/min. If pressure pulse is enabled
on the GC, the column flow increases, causing the source pressure to be
higher than normal while the pulse is enabled.
• Check that the correct (EI) ion volume is installed.• Check that the column is correctly installed into the transfer line. If the
column is too far away from the ion volume, the source pressure is high.
NOTE: If solvent flush is enabled, the source pressure will rise significantly (up
to 10Torr) during the beginning of an EI analytical run, but should start dropping
before the filament turns on. This is normal functioning in solvent flush mode
when using EI ionization.
To check the solvent flush setting, open System Control and click on
Configuration> Options > Advanced MS Options. This window displays the
EI Solvent Flush as either ‘enabled’ or ‘disabled’. Enable solvent flush to
minimize the solvent baseline caused by solvent accumulation in the CI line
when running in EI mode.

Source pressure is too low (<10mTorr in EI mode).
• Check that the GC carrier gas flow is 1-2mL/min.
• Check that the column is correctly installed into the transfer line. If the
column is too far into the source, the source pressure will be low.

No peaks or small peaks.
• Check that the standard was prepared correctly.
• Scan Ms with cal gas on to check MS sensitivity. If no or low cal gas (FC-
43) peaks:
• Check/refill cal gas bulb.
• Check that the scan range includes cal gas ions (e.g. 60-550).
• Check for leaks.
• Replace or clean the ion volume.
• Raise the detector voltage.
• Clean the source and hexapole and retune the instrument.
• Retune the instrument.
• Replace the filament.
• Replace the Electron Multiplier (detector).

Thanks a lot for your help!

We've try many possibilities, also following our manual. Anyway, I think it might be better if I upload more detailed information regading the steps we have followed + some pics:

1. Run a coarse tune and then autotune. There is a red warning on the readback window as to the 5V. At this time, the detector has not passed the calibration and this autotune was done under a fixed detector voltage. In fact, at first, the peaks were really bad. We even could not see the 18, 28. I kept on doing the autotune, and the results improved.

http://imageshack.us/a/img542/3038/clipimage002pf.jpg
[url=http://imageshack.us/photo/my-images/54 ... 002pf.jpg/]


Hardware diagnostics report for Varian Quadrupole Mass Spec

Time: 10:56:56

No errors detected. Proceeding with autotune.

Tune report for Varian Quadrupole Mass Spec

Time: 11:11:04 Tune file: FC-43 EI (Tuned on 1 Apr 2013) (2)

Ionization mode:EI Scan Optimization: Standard GC (Fixed detector)

Exact Measured Peak Relative Peak Valley Resolution
mass mass height height width
(amu) (amu) (mV) (%) (amu @ 50%) (% of iso) (m/delta-m)
18.0 18.0 8.691 42.998 0.68 100 27
28.0 27.9 3.550 17.562 0.76 100 37
69.0 69.0 20.213 100.000 0.64 100 107
219.0 219.0 12.250 60.603 0.97 65 226
502.0 502.6 7.134 35.296 4.00 15 126
Warning: the peak is very wide and mass shifted!

(Detector = 1660 V)

Tuning of quad 1 in positive mode had the following error(s):
Problem with fine resolution of m/z 502.0 (Time limit exceeded.)

-----------------------------------------------------------------------------------------------

Tune report for Varian Quadrupole Mass Spec

Time: 11:16:45 Tune file: FC-43 EI (Tuned on 1 Apr 2013) (2)

Ionization mode:EI Scan Optimization: Standard GC (Fixed detector)

Exact Measured Peak Relative Peak Valley Resolution
mass mass height height width
(amu) (amu) (mV) (%) (amu @ 50%) (% of iso) (m/delta-m)
18.0 18.0 12.248 78.869 0.68 100 27
28.0 28.0 4.173 26.872 0.80 52 35
69.0 69.0 15.529 100.000 0.75 93 93
219.0 219.0 9.579 61.685 0.97 25 226
502.0 502.4 3.140 20.223 2.67 2 188
Warning: the peak is very wide and mass shifted!

(Detector = 1660 V)

Tuning of quad 3 in positive mode completed.

28 absolute size (mV - EDR on)
- Limit 20.0 - Measured 0.0
- OK!
28/32 Ratio
- Air 3.5:1 - Measured 2.8:1
- OK! - Not indicative of Air
28/18 Ratio
- Limit 1.2:1 - Measured 0.3 :1
- OK!

- No significant leak detected -
- OK –


2. Then the detector has passed the calibration. Using the extended dynamic range of the detector, the autotune gave bad results.


http://imageshack.us/a/img850/2893/clipimage003h.jpg

Hardware diagnostics report for Varian Quadrupole Mass Spec

Time: 11:19:39

No errors detected. Proceeding with autotune.

Tune report for Varian Quadrupole Mass Spec

Time: 11:41:56 Tune file: FC-43 EI (Tuned on 1 Apr 2013) (3)

Ionization mode:EI Scan Optimization: Standard GC (EDR)

Exact Measured Peak Relative Peak Valley Resolution
mass mass height height width
(amu) (amu) (mV) (%) (amu @ 50%) (% of iso) (m/delta-m)
18.0 19.0 0.003 53.559 0.68 100 28
Warning: the peak is mass shifted!
28.0 28.9 0.001 16.111 0.88 83 33
Warning: the peak is mass shifted!
69.0 69.6 0.003 47.734 0.69 100 101
Warning: the peak is mass shifted!
219.0 219.0 0.005 100.000 1.68 0 130
Warning: the peak is very wide!
502.0 501.0 0.001 12.649 2.28 16 220
Warning: the peak is very wide and mass shifted!

(Detector = 1560 V)

Tuning of quad 1 in positive mode had the following error(s):
Problem with fine resolution of m/z 502.0 (Time limit exceeded.)
Problem with fine resolution of m/z 219.0 (Time limit exceeded.)
Problem tuning m/z 69.0
Problem tuning m/z 28.0
Problem tuning m/z 18.0

-----------------------------------------------------------------------------------------------

Tune report for Varian Quadrupole Mass Spec

Time: 11:54:49 Tune file: FC-43 EI (Tuned on 1 Apr 2013) (3)

Ionization mode:EI Scan Optimization: Standard GC (EDR)

Exact Measured Peak Relative Peak Valley Resolution
mass mass height height width
(amu) (amu) (mV) (%) (amu @ 50%) (% of iso) (m/delta-m)
18.0 18.0 0.006 100.000 0.67 100 27
28.0 28.0 0.002 29.840 0.71 75 39
69.0 69.0 0.003 47.843 0.78 69 88
219.0 218.9 0.002 27.128 0.72 38 303
502.0 502.6 0.001 11.732 4.00 8 126
Warning: the peak is very wide and mass shifted!

(Detector = 1560 V)

Tuning of quad 3 in positive mode completed.

28 absolute size (mV - EDR on)
- Limit 20.0 - Measured 0.0
- OK!
28/32 Ratio
- Air 3.5:1 - Measured 0.0:1
- OK! - Not indicative of Air
28/18 Ratio
- Limit 1.2:1 - Measured 0.0 :1
- OK!

- No significant leak detected -
- OK -


3. But a following autotune tried to improve.


http://imageshack.us/a/img819/1789/clipimage004wv.jpg

Hardware diagnostics report for Varian Quadrupole Mass Spec

Time: 11:57:27

No errors detected. Proceeding with autotune.

Tune report for Varian Quadrupole Mass Spec

Time: 12:20:41 Tune file: FC-43 EI (Tuned on 1 Apr 2013) (4)

Ionization mode:EI Scan Optimization: Standard GC (EDR)

Exact Measured Peak Relative Peak Valley Resolution
mass mass height height width
(amu) (amu) (mV) (%) (amu @ 50%) (% of iso) (m/delta-m)
18.0 18.2 0.002 67.355 0.62 96 29
28.0 28.0 0.001 39.577 0.65 71 43
69.0 68.9 0.003 100.000 0.73 92 95
219.0 219.0 0.001 45.948 0.96 32 228
502.0 503.2 0.001 30.810 4.00 11 126
Warning: the peak is very wide and mass shifted!

(Detector = 1560 V)

Tuning of quad 1 in positive mode had the following error(s):
Problem tuning m/z 28.0
Problem tuning m/z 18.0

-----------------------------------------------------------------------------------------------

Tune report for Varian Quadrupole Mass Spec

Time: 12:32:24 Tune file: FC-43 EI (Tuned on 1 Apr 2013) (4)

Ionization mode:EI Scan Optimization: Standard GC (EDR)

Exact Measured Peak Relative Peak Valley Resolution
mass mass height height width
(amu) (amu) (mV) (%) (amu @ 50%) (% of iso) (m/delta-m)
18.0 18.1 0.002 67.243 0.73 57 25
28.0 28.0 0.002 61.757 0.69 95 41
69.0 68.9 0.003 100.000 0.70 85 99
219.0 219.0 0.001 37.811 0.71 37 307
502.0 503.3 0.001 24.405 4.00 19 126
Warning: the peak is very wide and mass shifted!

(Detector = 1560 V)

Tuning of quad 3 in positive mode had the following error(s):
Problem with coarse resolution of m/z 502.0

28 absolute size (mV - EDR on)
- Limit 20.0 - Measured 0.0
- OK!
28/32 Ratio
- Air 3.5:1 - Measured 7.8:1
- OK! - Not indicative of Air
28/18 Ratio
- Limit 1.2:1 - Measured 0.0 :1
- OK!

- No significant leak detected -
- OK -

4. Then the ion source assembly and the hexapole, and the lens 4 have been cleaned, hoping to improve the response of the instrument. However, the results did not improve, but it is even worse. There were almost no peaks for all of the ions.

http://imageshack.us/a/img819/4435/clipimage005k.jpg

Ok, this is well beyond me. You might want to call Bruker and see if anyone there can give you a hand in piecing together what is going on. I know Agilent got this piece of equipment in the Varian sale, but I think Bruker got some of the people who know it best. You're obviously having inconsistencies in obtaining a proper tune, and it has now progressed to the point where you're seeing nothing after maintenance. The only thing I can think of trying is to revert to an earlier tune file (maybe the initial install?) to see if your instrument can re-find the target masses in an autotune. Otherwise, you might be able to manually tune with the cal gas on to try to find the masses yourself. Either that or re-installing your source to make sure everything went back together correctly?

Does anyone have the pinout for the DB37 connector on the back of the 1200? I'm trying to connect an external device and need to know which pins give +5 VDC.