Choice of analytical method depends on question - Vogon Labs
Ralph Hindle, owner of Vogon Laboratory Services, based in Canada, said the analysis of trace organics is a big circle.
“Whether it is in food or environmental where a discovery is made…this opens up a whole new area where you are looking for broad screening and so when you are looking at things like that and fuller requirements due to regulations on the food side you need more sensitivity,” he told FoodQualityNews.
“As you develop more sensitivity more compounds can be discovered and as they get discovered and epidemiological studies or risk assessments are taking place there may be more need to monitor these compounds at lower levels to see what the chronic problems might be.
“The biggest thing I see besides the sensitivity, seems to be the availability of ToF (Time of Flight) and QToF, the accurate mass instruments, compared to five or ten years ago. A lot of labs are going that way because they see the benefit of having that accurate mass.”
Getting the most out of what you know
Hindle was a speaker at Agilent’s Environmental and Food MS meeting in Bristol, UK, in January.
“It is developing our expertise and our networks, it is really important to be able to share the information,” he said of the event.
“There are too many benefits from networking to ignore that aspect. It is very easy to sit here, I’ve got some very sophisticated instrumentation upstairs and I’ve got a lot of experience behind me, but until I can see what other people are doing, until I can share what I’ve done with other people it’s a little bit limited in how I am going to use that to get the most out of it.”
Vogon Labs is one of more than 30 partner labs that Agilent has and it provides specialized analytical testing using high-end mass spectrometry in industries including food.
Hindle does contract work for Agilent and is an official buying partner, so does system evaluations on their behalf for customers looking to buy equipment and prepares application notes for areas of expertise and training on equipment.
“I would give up my triple quad (QqQ) before I gave up my Q-ToF simply because it is more sensitive,” he said.
“Triple quad is generally looked at as the gold standard for analysis because of the sensitivity and specificity. But in non-targeted analysis or when you want to go back and review data then ToF and Q-ToF are excellent tools for that because of the quality of scan data all the time.
“They’re not really suffering from the detection limit limitation anymore and in the accurate mass there is just too much information to give up there, it is great for confirming chemical formulas as well as chemical structures with the MS/MS.”
High throughput and sensitivity
Hindle said high production tends to be the way that most labs are going.
“With triple quads you have the frame of mind how many samples per day can I analyse, if you are looking at ToF and QToF it is how many days per sample is it going to take me to get through the data analysis,” he said.
“QToF allows you to approach more open ended questions like: What is in my food? That is not a very useful way to go into an analysis as there is no end to that question because of all the things you can see.
“So you need to really define your question before you start using ToF and QToF, whereas with triple quad that question is already there, how many pesticides are above my maximum residue limit for the regulations that I am trying to enforce?”
The additional sensitivity from current instrumentation is ‘really key’ to the entire analysis, said Hindle.
“If you’ve got an instrument that is ten times more sensitive then what you had today, you bring that in tomorrow, it doesn’t necessarily mean you are going to look for residues 10 times less concentrated in the sample – it can affect your entire sample preparation,” he said.
“As long as you have a representative sample at the beginning you could take smaller subsets of sample, smaller solvent volumes for extraction, reduced clean-up – all these things are going to increase the speed at which you can get the sample onto the instrument and also reduce the cost for all the consumables required to get it there.”
Look to the future
Hindle said the equipment is not cheap so when buying he tries to get as much equipment for the money available while looking downstream.
“So if you look at a Q-ToF instead of a triple quad you may not get the throughput but you may start to discover some other components that are there, some other metabolites or degradation products and these are going to feedback into your target analysis and you’d probably never get that opportunity with a triple quad.”
Hindle said there are definitely occasions when you don’t know what you’ve found.
“Agilent has its own library and database products, so for example in forensic toxicology they have a database and library with over 9,000 compounds and one for pesticides with over 1,500 compounds so they are definitely available and they are producing more all the time,” he said.
“These are really key, if I can pay a few thousand dollars for a library that has this information in there, then I’m way ahead of the game when it comes to analysing my samples and searching against it rather than having to have all of those compounds in the freezer.”
He said Agilent is working hard at improving and adding workflows depending on what the user is trying to do but there is still a need to have an expert.
“This does allow a less experienced user to walk up to the system and use it, they actually have walk up software, were the methods cannot be edited but it will submit samples using methods developed and put in place by quite experienced users,” he said.
“So yes it is going that way but there’s always going to be a need for a specialist, number one to develop those methods in the first place and number two, the more experience you have the better, you are able to troubleshoot and interpret results when you get into some kind of grey area, whether it is based on detection limits or spectral interpretation.
“The better you are at getting experience with these tools the better the quality of the data.”
