I'm going to buy a new GCMS. Which one? Help please...

Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.

9 posts Page 1 of 1
I know there are similar topics in the forum, I have read them all but I could not find the answers to some of my questions.

I'm doing research on natural products, but I would like to be able to analyze other academics' research.

I met with local dealers of Shimadzu, Agilent and Perkin Elmer.

I got the first offer from Shimadzu. They stated that Shimadzu 2020NX is the product that meets my budget. They were going to give it with a 12-vial autosampler.

The second offer came from Perkin Elmer. Clarus SQ 8 + Clarus 690 GC + auto sampler (108) + headspace (40).

The last offer came from Agilent. 5977B. (8890 GC + 5977 with SS and diff pump + Pal3 combipal with headspace unit.)

Shimadzu is working on a better offer for me...
--

But now, I seem to accept agilent's offer. Because they offered a system including combipal.

Also there are disadvantages of Agilent's offer...
They will give diffusion pump and stainless steel ion source. (Not an inert extractor ion source nor Turbo moleculer) All others will give a turbo moleculer pump.

Agilent's dealer said it was better because my samples were not clean and I don't need to buy an inert plus MSD.

Although dealer added, if i need it in the future I can upgrade to inert plus.

---

What do you think I should do?

Is the diffusion pump more suitable for me? Do try to get a turbo molecular pump?

Is the ion source important to someone who works natural products? Or stainless steel is enough?

Do you think which's more important to get Pal3 combi pal or to buy an inert device?

** Customer service is good for shimadzu and agilent here in local.

Thank you in advance for your help.
kerem.canli wrote:
I know there are similar topics in the forum, I have read them all but I could not find the answers to some of my questions.

I'm doing research on natural products, but I would like to be able to analyze other academics' research.

I met with local dealers of Shimadzu, Agilent and Perkin Elmer.

I got the first offer from Shimadzu. They stated that Shimadzu 2020NX is the product that meets my budget. They were going to give it with a 12-vial autosampler.

The second offer came from Perkin Elmer. Clarus SQ 8 + Clarus 690 GC + auto sampler (108) + headspace (40).

The last offer came from Agilent. 5977B. (8890 GC + 5977 with SS and diff pump + Pal3 combipal with headspace unit.)

Shimadzu is working on a better offer for me...
--

But now, I seem to accept agilent's offer. Because they offered a system including combipal.

Also there are disadvantages of Agilent's offer...
They will give diffusion pump and stainless steel ion source. (Not an inert extractor ion source nor Turbo moleculer) All others will give a turbo moleculer pump.

Agilent's dealer said it was better because my samples were not clean and I don't need to buy an inert plus MSD.

Although dealer added, if i need it in the future I can upgrade to inert plus.

---

What do you think I should do?

Is the diffusion pump more suitable for me? Do try to get a turbo molecular pump?

Is the ion source important to someone who works natural products? Or stainless steel is enough?

Do you think which's more important to get Pal3 combi pal or to buy an inert device?

** Customer service is good for shimadzu and agilent here in local.

Thank you in advance for your help.



Hello, My name is Henry

I would tell you that if you can change the diffuser pump for the turbo pump in agilent. Agilent chromatographs are very robust and you will not have to suffer about the person who handles them. On the other hand, the offers of other brands tend to be cheap when you buy the equipment, but then they are expensive in terms of consumables and preventive maintenance. On the contrary, Agilent has expensive equipment prices and consumables are accessible and the service is also much cheaper than other brands. Some earn by starting price but they charge you what they did not charge in the price in consumables.
Henrylozano wrote:
Hello, My name is Henry

I would tell you that if you can change the diffuser pump for the turbo pump in agilent. Agilent chromatographs are very robust and you will not have to suffer about the person who handles them. On the other hand, the offers of other brands tend to be cheap when you buy the equipment, but then they are expensive in terms of consumables and preventive maintenance. On the contrary, Agilent has expensive equipment prices and consumables are accessible and the service is also much cheaper than other brands. Some earn by starting price but they charge you what they did not charge in the price in consumables.



Dear Henry,

Thank you very much for your advices. I can try to change the pump to turbo and also I want to change the ion source but my budget is limited. What do you think about buying MSD with cheaper SS ion source with turbo moleculer pump and upgrading ion source from stainless steel to inert plus in the future.

And one more question. For my applications (dirty samples/scan mode generally) which option is logical, inert plus and turbo moleculer pump with classic autosampler and hs? Or Pal3 combipal with stainless steel ion source?

I like combipal option but I'm not sure as it's worth.

Thanks
Kerem
Hello, dear Kerem

I want to tell you that agilent always sells inert sources, they separate into two, one that is inert alone and the other is a source of extracting ion. The stainless steel inert ion source is fine. As you are starting, buying a source of extractor ion is a lot for you but above all you need to better understand the operation of the equipment. I am not denying your abilities at any time, I just show you that as you have more experience you will see what is best for you in this field of mass spectrometry (Remember that although the mass spectrometer acts as a detector, it does not it is a detector itself). As for the pal, it is the best option you have, since the pal allows you to use three additional basic attachments if you get them (Liquid injection, headspace injection and SPME injection). Agilent is a very good brand and the sensitivity of the equipment is the best. I started working with this brand by injecting trial and error, reading alone and the team was able to resist a rookie like me 10 years ago.

Hello, I am an expert in flavorings, natural essential oils and others. I have enough spectral libraries specialized in terpenes that are excellent but that is a separate story. If you want to continue counting on my collaboration with pleasure you can write to henry_lp04@hotmail.com at no cost.
I have used both the turbo pump and the diffusion pump on the Agilent GC/MS. The only difference will be total pumping capacity and the time it take to reach equilibrium after maintenance.

With Helium, the turbo pump will give better pumping capacity if you plan to have column flows that are very high, but if using normal 0.25mm or smaller columns your flow will be low enough that the diffusion pump will handle it easily. If you use hydrogen and the carrier gas, most people say the diffusion pump will give better performance. The turbo pump is at vacuum within a few minutes, the diffusion pump will take maybe 15-20 minutes to be fully at vacuum, but either way it is best to wait overnight for full temperature and vacuum equilibrium before doing any serious quantitative work with either.

With instrument that are nearly 20 years old, I have replaced only one failed diffusion pump, but at least 3 failed turbo pumps, and if you do not have a service contract the diffusion pump is much less expensive to replace. It is simply a heating element, so it is much more rugged than the high rpm turbo pump, so it will be slower to vent and pump down, but the durability is much better.

For autosampler, if you think you might do SPME, then definitely go with the PAL, as mentioned it can do all three types of injections, SPME, Liquid and Head Space while you normal Agilent autosampler can only do liquid injections.

The standard source is good for most work. If you are looking for ultra trace levels of pesticides or dioxin type samples then the Extractor or HES may be needed, but then you will also need to clean more often since they are more sensitive to any contamination than the normal source will be. With the normal sources I can go sometimes six months without cleaning them, the extractor source is almost as rugged, but I hear the HES definitely needs to be cleaned more often.

If you will do a lot of quantitative work along with unknown spectral searching if going with Agilent the MSDChemstation option for data analysis is also helpful. The MassHunter needs both the quantitative and the qualatative program open to be able to both quantify the sample and to investigate unknown peaks, the MSDChemstation Data Analysis can do both in one program.
The past is there to guide us into the future, not to dwell in.
At least in the US, the only realistic alternative I'd consider to Agilent these days is Thermo, and even then I'm not totally sold on them.

Agilent has a huge amount of market penetration. As mentioned, consumables from them are inexpensive and a lot of service is a straight forward DIY job. For MS consumables you're largely tied to Agilent, but everybody and their mother makes Agilent compatible GC consumables. In fact, Thermo has made a big deal of advertising in the last few years that they use the same septa, liners, and inlet seals as-per my local sales rep-they want to make the transition easier for labs that already have Agilent stuff.

James and I both work the same primary Agilent field service engineer, and she is fantastic. She is always approachable and helpful, and is happy to talk me through fixing an issue up to the point where she advises a service visit-and with someone who knows the instruments decently well she'll walk you decently far into a repair.

AFAIK, Agilent is the only company still fitting diffusion pumps to their GC-MSs. I run two Agilent MSs that have diffusion pumps, and look after a third in the building that I don't actually use. Two of these are 5975s, and one is a 5971. I also look after two other diffusion pump 5971s. The diffusion pumps just silently tick away and do their job, and are happy with an oil change once a decade or so(you may want to do it more often if you run dirty samples). As James said, the heater is the only thing that can really go bad, and in my experience that's a part that rarely failed. One of the 5971s I look after was installed in 1990, and has probably only been opened a handful of times since it was initially brought on line-it just keeps ticking away.

A turbo DOES reach vacuum faster, but realistically you can still get to a reasonable hi-vac range in 45 minutes or so. Even though a turbo can get there in 10 minutes, it still takes an hour or two for everything to come to thermal equilibrium so you're still looking at a few hours of down time after venting even regardless of the pump type. The biggest pain is in venting, where a turbo can be vented pretty much as soon as it spins down while you need to wait for a diffusion to cool to at least where the oil stops boiling(otherwise you can get oil backstreaming and in extreme cases can even end up charring the oil). I'd only REALLY consider the turbo a necessity if doing CI(even that's questionable-Agilent claims you have to have one, but the 5971 and 5972 could do CI with a diffusion pump) or if running large bore and/or very short columns. In general, there are a lot of reasons to run a .25mm or smaller column, and once you get down to .20mm you can still run a fairly short column on a diffusion pump. IIRC, at least one of the mass specs I use(don't remember if it's the 71 or 75) says even a wide bore column(.53mm) is okay with a diffusion pump as long as it's 50m or longer.
Dear James_Ball and dear benhutcherson

Thank you very much for your detailed explanations. Thanks to you, I made my decision clearly.

As far as I understand the diffusion pump is slow, but also reliable. He can do any job that turbo does. And last longer than turbo. In addition, agilent gives a 5 year warranty to the diffusion pump, whereas the warranty for the turbo pump is 2 years. Considering all this, it's pointless to try to get a turbo or to get an inert plus.

The help in this forum is great. Thank you all.
As a small side note, I run a couple of SRI GCs which take a Shimadzu type septum.

As it so happened, in the middle of a class today, one decided to quit giving peaks. A bit of tweaking on the septum nut got it going again, but I have a standing rule that I'm the only one who changes septa on those GCs because of how finicky it is to get right. My predecessor in my position happened to stop by for a visit today, and he agreed with my assessment of never buying a Shimadzu if for no other reason than the septum design.
Diffusion pumps are just fine, but if you have unreliable power you could have a situation where you contaminant the MS with the diffusion pump oil. So be careful with that.

There IS actually a difference between the stainless steel source and the inert source (over the recent history of Agilent GCMS there has been stainless steel, inert, extractor (aka inert plus) and high efficiency (HES.) The stainless steel source is good you just wont see as much of the high mass. For some applications, like older environmental methods, this can actually be preferable.
9 posts Page 1 of 1

Who is online

In total there are 2 users online :: 1 registered, 0 hidden and 1 guest (based on users active over the past 5 minutes)
Most users ever online was 1117 on Mon Jan 31, 2022 2:50 pm

Users browsing this forum: MichaelVW and 1 guest

Latest Blog Posts from Separation Science

Separation Science offers free learning from the experts covering methods, applications, webinars, eSeminars, videos, tutorials for users of liquid chromatography, gas chromatography, mass spectrometry, sample preparation and related analytical techniques.

Subscribe to our eNewsletter with daily, weekly or monthly updates: Food & Beverage, Environmental, (Bio)Pharmaceutical, Bioclinical, Liquid Chromatography, Gas Chromatography and Mass Spectrometry.

Liquid Chromatography

Gas Chromatography

Mass Spectrometry