New PFTBA, but can not tune

[tung]

I have replaced a new PFTBA standard. After putting the MS back together and run autotune, the instrument can not tune/find all the peaks, 69...it appear to be a bad pftba standard, but unsure.

Does anyone know what is the cause or have a solution to this? Thanks in advance.

[Don_Hilton]

If you filled the vial with PFTBA, it is not a bad standard. The solenoid could be stuck - but if you hear a click when the instrument tries to tune or obtain a profile, that is not the problem.

Have you done something like clean the source or replace the EM? A misplaced or loose wire can cause an instrument to not tune. (I've been down that road...) Take a voltmenter and ohm out the connections. Be sure that connections are made where they should be and that the filaments are intact. And be sure that current does not flow in places where it should not be.

Be sure the instrument is assembled correctly and has good vacuum - if still no tune, go to the instrument default conditions for the mass spec settings. Try again.

[tung]

Thanks for the quick reply, Don.

The tuning can not find the 3 base peaks, 69, 219, 502. At least several peaks along the base peak, like 69, 219, and 502 were found. In the tune window that nornmally displays the peak 69, there are many other peaks that goes along with it that are loudsy. So are the 219 and 502 peaks.

I did a tune few weeks ago, and the EM seems fine (less than 1400). The ion source were cleaned.

I will check to see if the connection were loose when I get back to the lab.

[labstephan]

Hi Tung,

if you are working with a Agilent MSD you have the option to purge the cal gas vial after refilling. This option is somewhre in the tune page. I don`t have access to a MSD at the moment, but wednesday I can look for the menu item.
After refilling the cal gas vial there is a lot of air in the cal gas line. This disturbes the tuning quite a lot.
So I think you should open the cal gas valve without the filaments on for about 10-20 minutes to flush out air. After that tuning should work.

Best regards

Stephan

[tung]

Thanks for the reply.

I purged the pftba and the instrument still cannot tune. First tune came out with an error: "Cannot achieve peak width and the tune was aborted.

Second tune has more than 600 peaks. There are too many peaks near each of the 69, 219, and 502 and they are almost equally in height. I notice I don't hear the "click" sound when I initially perform autotune as I used to when the tune starts.

The system verification printout of abnormal parameters:

Base peak should be 69 or 219 but it is 169.2 Fail
Position of mass 219 is at 219.33 High
Position of isotope mass 220 is at 220.37 High
Position of isotope mass 503 is at 471.66 Low
Ratio of mass 70 to mass 69 = 10.26 High
Ratio of mass 220 to 219 = 34.39 High
Ratio of 219 to 69 = 3.41 Low

Mass 69 Precursor =6.69 High
Mass 219 Precursor =27.19 High

Any help would be appreciated. Thanks in advance.

[Bigbear]

In the Agilent world the tune files can become corrupt. Try a different tune file ( stune, or dfttp ). If they work it's tune file related.
I can't remember all the steps, but there are backup files on the system. Call the 800 number for instructions.

[Steve Reimer]

I've had a similar problem on my Agilent 5975. In that case it turned out to be a broken wire in the ribbon cable.
If the system can't find peaks on a tune try loading an old tune file. Chemstation keeps all your old ones in a directory. I don't know about other software. I keep one in the current tune file directory under a different name just so that in case my bfb.u gets corrupted I have a starting place. It has saved me a couple of times on my 5973.

I would second Don's suggestion that something isn't connected properly.

[Don_Hilton]

If carefully ohming out the source and trying to replace the tune file do not work - you can try to ohm out the ribbon cable. (I've doen this in another instrument - using paperclips to extend the tips of the volt/ohm meter and give narrow enough probes to get into the ribbon connector.) However, sometimes just moving the cable makes it reconnect inside, so you may not find the break. And, it will come apart again at some inoportune time. I would suggest after checking over the source and tune - reseating the connectors on the cable and if the instrument does not come up, call for service.