Dear Andriy,

The compounds are separated by the column to be detected by the detector, whether it is a MSD or a FID or a TCD.  The MS will provide a better method of identifying the compounds based on their fragmentation ion pattern.  Ethylene mass is 28 while acetylene is 26.  Ethylene's fragmentation ions includes a 26 m/z ion.  Either column should work as long as they separate your compounds.

I assume that you are using helium for the carrier gas, as this will allow you to scan down to say 20 m/z so you can detect these compounds.  You might also see nitrogen (28), oxygen (32), argon (40) peaks with the MS, but these should elute well before your compounds.

When testing for methane, ethene, ethane and propane in ground water for the recent hydraulic fracturing issues we used a different column with a FID detector, so we were not concerned with a particle trap.  We did try the particulate U-Bond column on an Ion Trap MS without a filter and destroyed the MS.  The Agilent Essentials catalog from 2011/2012 states that a trap is not necessary when going into a MS, but I would play it safe and use one in our lab, in my humble opinion.

Best regards,

Roger Bardsley

Applications Chemist

Teledyne Tekmar

Dear Roger,

Thank you for answer!

I realize that FID is ideal combined with PLOT column for my application, but I don’t have it. :-)

Main question in protection of MSD from damage by particles dislodged from PLOT column. In case of BOND column Agilent use instruction say …BOND column carry an in-situ generated solid layer (no particles). GC-GASPRO column also described as no particle column …ideal for GC/MS. But there is no much information in scientific literature about using PLOT columns with MSD detector. Is it safety for MSD to use PLOT columns? GC-GASPRO column described as no particle column. Does it mean that it could be used without particle traps? Agilent propose PLOT columns with integrated particle traps https://www.chromatographytoday.com/articles/gc-mdgc-gc-ms/32/daron_decker/improved_gc_columnsfor_the_petroleum_industry/1579/. Restek recommend use particle traps in any case to protect MSD.

Technically I could ad particle trap for PoraBOND Q but according to your experience using U-Bond column with Ion Trap MS such protection are questionable.

Will be waiting information from Agilent.

Could you please tell me what exactly crashed in your Ion Trap after using it with U-Bond column (ion source, mass-filter, pump or etc)?.

When using PLOT columns in MS system,it is advisable to use a trap which will retain any particle that may get dislodged because of the vacuum effect.   This way PLOT columns can be used effectively with MS.  In case of FID, this problem does not take place. 

The columns you mentioned do not need particle traps and are perfectly fit for GC/MS instruments. I routinely use both of them, particularly the GasPro for greenhouse gases atmospheric measurements.

Dear Salvatore,

Thanks for answer!

Do you use particle traps with this columns?

Thanks!

If you like to stay on the safe side, use the GasPro column which has an excellent resolving power for light hydrocarbons, no need for particle traps, very stable and reproducible. Moreover you have a 0.32 i.d. one that is better tha a 0.25 for gas injections

I would advise buy and install and FID detector and split or turn the flow to it to detect ethylene and acetylene. This detector is much cheaper, very robust, reliable, low cost maintenance and its limits of detection for hydrocarbons are comparable to those of MSD.

Hi Ademario,

Thanks for your advice. This problem arises for me because our old GC system with FID which I used for ethylene/acetylene analysis is down. There is no possibility to equip GC/MS with FID now.   

Hi Andriy,

Just to support the answer provided by by Salvatore. These columns actually do not need any trap. I had used a Q-PLOT column to analyse TFA which was derivitised. This went on successfully. The only thiogn we did was to play around with the carrier gas pressure. 

Hi Abdullahi!

Thanks for answer. Could you please specify?

Did you use a column trap with Q-PLOT?

Which type of detector did you use?

What was the reason that you was forced to optimize carrier gas pressure?

Hi Andriy,

We did not use a column trap. It was on an MSD (using a Schimadzu QP2010 SE). One of the reasons why we played around with the pressure was, we had drop in pressure when we used the normal settings for other columns. Perhaps, might not experience such. I advise you try with your normal column swap procedure, but if you experience pressure loss/drop then you can adjust accordingly.

Hope this helps.

Abdullahi

Abdullahi,

Thank you for answer!

Hi Andriy,

For safety reasons, we always use a column trap at the end of PLOT column, as in the event of some loose particles you run into problems.

By the way, for analysing ethylen and acetylene we are using a PLOT column with Al2O3 / Na2SO4. With this colum, the more polar unsaturated compounds are eluted after the saturated hydrocarbons.

So we analysed ethylen and acetylen in hydrocarbons for seveal years with excellent separation - far better than using Porabond Q columns.

Best regards, Peter

Hi Peter!

Thanks for your answer and additional information.

Could you please answer on one more question?

Does the particle trap full effective in MSD protection in your application? Do you observe any damages in detector internal parts or any “spikes or ghost” peaks on chromatograms caused by particles from column? What type of high vacuum pump installed on system works with PLOT column? Is it necessary to change traps time to time (like guard columns in hplc)?

Best regards,

Andriy   

Hi Andriy,

as I already mentioned we always have a trap mounted at the end of our Poraplot Q, P and Al2O3 Column.

As a direct consequence, we did not observe spikes in the MS caused by PLOT particles.

As we are using these columns also with TC detectors, particle traps play an important role for preventing serious damages of TCDs.

We use the PLOT colums together with some 5972 and 5973 MSDs from Agilent with high vacuum diffusion pumps and with a turbo molecular pump as well.

Changing traps with PLOT columns is not an issue.

The Al2O3/Na2SO4 Plot colums has bee in use for about 2 years nearly continuouly without replacing the first mounted trap.

Within some applications we used our PLOT colums together with MS detectors as well as wit FIDs and / or TCS - fully stisfied.

So my advice: Mount traps at the column outlets within some minutes and be happy.

Best regards, Peter

Thanks Peter!

I appreciate for such detailed response.

Best regards,

Andriy.