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Ellutia: Specialised detectors, automation and throughput from GC perspective

By Joe Whitworth+

14-Oct-2016

Ellutia 200 Series GC
Ellutia 200 Series GC

Ultra-fast gas chromatography means analysis cycle times are decreasing so the time to prepare the samples to be analysed is becoming the limiting factor, according to an instrument provider.

Ellutia said it is looking at where the bottle neck is in sample preparation and introduction and exploring making it more automated to create more advanced sample prep and handling systems.

The firm added automation improves accessibility but deskills people in the lab which is a problem when it comes to troubleshooting if something goes wrong.

It has been designing and producing gas chromatography instruments for more than five years.

Speed vs resolution

Andrew James, marketing director at Ellutia, said the goal for most chromatographers is to increase speed to get more analysis done or a faster reaction to see things quicker.

“The trade-off for speed is generally either you lose resolution, so you can’t separate your compounds of interest well enough to correctly identify them,” he told FoodQualityNews.

“Or you sacrifice sample capacity, so you have to inject a smaller volume of sample, this means there is less to detect, so compounds are harder to see.

“A big trend is the increase in sample throughput, with more regulations in food safety and environmental testing. The majority of samples generally will have none or very low levels but all will require checking.”

James said there are a lot of similarities with other industries when looking for harmful components, such as environmental screening or materials testing.

“Like the food industry, there are ever increasing regulations with ever decreasing limits of what is an acceptable level for different compounds,” he said.

“Many of the smaller producers probably don’t even think about analytical testing when they are first starting out, but they will often still fall under similar regulations as much larger companies

“They may initially rely on outsourcing this testing or possibly just relying on their supply chain doing the testing that is required. As they grow and become more successful they may very well find it cheaper to bring testing in house.

“They may also want to start their own quality testing, rather than relying on their supply chain so a smaller benchtop GC is cheaper, it is a good starting point for a quick ROI.” 

My first GC and detector choice

Ellutia has the 200 Series GC, originally designed for use in education, but analytical performance means it can compete with larger conventional systems. 

The firm said as it was designed with education in mind it is easy to operate, more compact and has a lower entry price which makes it ideal for labs looking to start out in GC analysis.

James said people not experienced in GC require education on what they should be buying and what the benefits of the different options are.

“They could easily spend £100,000+ on a top end GC-MS system, but a much simpler GC with an FID (Flame Ionisation Detector) that costs less than £6,000 may be suitable for the compounds and levels they need to achieve.

There is apprehension about complex analytical methods, people want to the put the sample in, shut the lid, wait for the result to come out, but on the flip side other people want more information and detail on what levels things are at, applications that involve lower levels such as pesticides and nitrosamines, they appreciate a more complex level of data.”

Quite often people see mass spectrometry as the holy grail solution to everything, said James.

“The detector is capable but it is not always the best choice, a good example is a water company we did work with on nitrosamines. They were looking for one nitrosamine and to get down to the levels of sensitivity required they did mass spectrometry in single ion mode and they found it.

“We ran the sample in question on a TEA detector which is a type of detector that is very selective for that particular type of compound. Meaning we can see all the potential different types of that family of compound even if we are only looking for one in particular. With an MS in single ion monitoring, you can only see the specific compound you are looking for.

“GC needs better range of detectors as the compounds in ultra-fast GC can be eluting quicker than the detectors can handle. More specialised detectors that are tuned to look only at particular compounds of interest, means you potentially don’t have to worry about other compounds eluting close together.”

Helium or hydrogen

Ellutia said it was doing a lot of work on looking at using hydrogen as a carrier gas.

Helium supplies are decreasing and the cost is going through the roof. We have had good results using hydrogen as a carrier gas but there is always concern from lab safety managers as it is an explosive gas and a leak on the column means a build-up of hydrogen in the GC oven,” said James.

“The design of the ovens in our GCs is a flow through oven. So air is constantly flowing in and out of the oven compartment. We use a heat exchanger system to capture the heat from the outgoing air and transfer it to the incoming air, greatly increasing our heating efficiency.

“The benefit of this design is that if there was a small leak on the column the hydrogen would not be able to build up in the oven.”

Column heating challenges

Looking forward, Ellutia said work from the sector on ultra-fast chromatography included heating the least mass possible to heat the column and other techniques to improve column heating.

“The EZ Flash used a metal tube with a fused silica column inside it. The tube is then resistively heated and then heats the fused silica column inside it,” said James.

“With conventional GC and a regular fused silica column, if the front end of your column becomes contaminated you could remove the contaminated section and then carry on using the column. With configurations such as the EZ Flash, because the column is fixed inside a tube it is not possible to remove a contaminated section so they have to be discarded.

“The path we have gone down is using metal columns rather than fused silica. This means they can be directly resistively heated, so the column itself is the heating element.

“Shorter columns are not always a drawback, for example we have found we can achieve the same resolution on 5m column in an ultrafast GC as that of a 30m column in a conventional GC. Column length only really becomes an issue if a conventional application required a very long 60m+ column. Then it becomes much harder to get the same resolution from an ultra-fast system.”

Ellutia will launch the GC 500 series by the end of this year with metal or fused silica columns with an initial focus on the environmental screening market.

“Our 500 Series GC can offer an air blown oven to perform conventional GC analysis with regular fused silica columns.  It can also be used as an ultra-fast GC, if a metal column is used it can be directly heated for ultra-fast analysis. Both modes are included as standard to give users the choice," said James.

“An ultra-fast GC System with a time of flight mass spec will potentially give the best of everything.  Ultra-fast analysis, high levels of sensitivity and positive identification of compounds. However, TOF-MS are currently very expensive.”

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