Method development for routine food testing presents many challenges – whether you are looking to increase the speed of your screening or simplify your method there can be different solutions suited to the task at hand. During RAFA 2015 in Prague, Steve Lock, Market Development Manager for SCIEX Separations in EMEA outlines how CESI-MS may be best suited for polar pesticide analysis.
Video Transcription (view video below)
Hello and welcome to RAFA, I’m Steve Locke and I would like to present some work I’ve done using CESI-MS for the analysis of polar pesticides.
I’d first like to start with an introduction to CESI-MS – Basically, it is the combination of capillary electrophoresis (CE) with mass spectrometry, running the CE flow directly into your mass spec.
We believe this technique is complementary to liquid chromatography (LC) as the separation is based on charge and size rather than interactions of the compound with a stationary phase of an LC column, so it can provide some unique separation possibilities which LC doesn’t give you.
Why use CESI-MS for Polar Pesticide Analysis?
This example shows glyphosate analysis and the detection of polar compounds such as Fosetyl Alumina and Phosphonic Acid. These are really difficult to analyze by LC, because they are so polar they fly off the column and they can be really impacted the matrix effects. Now as CE runs at a really low flow rate (down to 10 nanolitres per minute) matrix effects are essentially really reduced, so it gives you benefits of removing matrix effects.
Also, it gives you this complementary nature of separation which is different to LC, so rather than detecting many contaminants in the solvent front (of a reverse phase separation) you actually separate these individual compounds.
So here (above) you have examples such as phosphonic acid and foestyl alumina, and here you have glyphosate with some of its metabolites.
The potential of CESI-MS
So let’s just envision the future where you have CE coupled to mass spec. Everything can be done on one column, meaning you can flip the polarity and look at positive polar contaminants as well as negative compounds so rather than using multiple columns you just have 2-3 capillaries to do your method development.
I believe that CESI-MS has a real future, especially as a way to speed up method development and look at complicated analysis’ which are difficult by LC, specifically around the nature of polar compounds – in this case, glyphosate.
To explore this topic further you can download the full Polar Pesticide Analysis by CESI-MS poster or browse our complete pesticide resource kit