LC-MS/MS growing as food testing tool – AB SCIEX
Previously, testing was done with PCR or ELISA with pitfalls including cross reactivities, one kit for each test and problems with some foods.
AB SCIEX said its Q-TRAP LC-MS/MS System is next-generation technology for metabolite identification, detection and confirmation of low-level pesticides, and protein/peptide quantitation for biomarker verification and validation.
LC-MS/MS in its simplest way as a triple quad is the most universal tool to detect contaminants in any food matrix.
Detecting contaminants
Harald Möller-Santner, business development manager, applied markets Central Europe, said selectivity is becoming more and more of a trend in food analysis.
“It is very sensitive and it is very selective but the challenges are often the matrix and the MRL‘s that are tending to get lower and lower. The lower you get with your concentrations that you have to detect the more problems you get with chemical background and signal to noise issues,” he told FoodQualityNews.com.
Another selectivity method is using ion mobility as a tool to separate the precursor ion from the chemical background.
“The best selectivity you get if you use high resolution MS or MS-MS techniques," he said.
"Because if you combine the selectivity of MS-MS with high resolution and even ion mobility which can be combined in one instrument like the 50-600 Triple TOF system then you get the utmost selectivity and the best signal to noise.”
Driving factors
Möller-Santner said regulations often follow demands from consumers and NGOs but it differs from country to country.
“Also if you look at the evolution of the LC-MS/MS system over the last 15-20 years you will see that the sensitivity has been increased by not less than six orders of magnitude, which is huge,” he said.
“I think that there is not too much space for further improvement and probably also not so much need because now we are able to detect parts per trillion (PPT) or in some cases parts per quadrillion (PPQ) levels.
“That is not relevant for human health anymore, it could be in environmental matrixes in water for endocrine disruptors. They have effects on animals at incredibly low concentrations but usually you are at the level of sensitivity which you need. Now you need more selectivity and specificity and that is what the latest generation of instruments and accessories usually add.”
Increasing number of analytes
Speed was neglected in the past but with increasing number of analytes to cover with the growing panels you can add more only by squeezing more in one chromatographic run so experiments to detect them need to be shorter and shorter.
The latest instruments are using modern electronics to speed up the process.
Triple-TOF allows the user to detect all the compounds as you get the full spectra unlike the Triple Quad or Q-TRAP technology where you need to decide before which analtyes you want to look for, said Moller-Santer.
For customers starting with the technology the firm developed a user interface called Cliquid.
“It is a user interface with enables the operator to get to the result with four clicks which obviously needs some method development before,” said Möller-Santner.
“We also developed methods called IMethods which is exactly what the Cliquid user needs to start right after the installation of the instrument. It includes the method parameters, all the chromatographic settings to be downloaded and it includes full documentation of the sample preparation for a number of matrixes, source information for the re-agents for what you need.”
