As promised in my previous blog, in this one I’ll talk about mass spectrometry (or “MS” as scientists call it).
Imagine that you buy one bag with those colorful button-shaped chocolates – M&Ms (no product placement intended). By hand, you separate one by one the chocolates per color. How much time would this procedure take you? I would guess a few minutes to hours, depending on the size of your bag.
Now I give you one chocolate, and I ask you to separate its different molecules. How would you do that? For sure, not by hand. The answer is simple (for the sake of artistic license)… Use a mass spectrometer! It’s (no) dark magic, and the way it works is simple and based on two principles, differences in size and charge .
For the separation of the molecules within a mass spectrometer, the first step is the ionization, meaning that the molecules turn into ions. In this way, the creations of charged particles is achieve. Creating charged molecules, is essential, as in the next step, the molecules enter an electric field. Because of their charge, they accelerate, and the higher the charge, the higher the acceleration. After the acceleration, next step is that of deflection. In this stage, the charged molecules that are concentrated into ion beams enter a magnetic field, and their path changes according to their mass and charge. The lighter and higher in charge they are, the more they are deflected from their original path. The deflection is the main stage, since this is where the separation of the molecules happens, based on their mass and charge. Finally, for us to see the result, detection is necessary. The result is displayed to a so-called “spectrum”. A spectrum is a chart of lines (peaks), demonstrating the separated molecules based on their mass to charge ratio (m/z), and their abundance. The abundance is an indirect indication of the quantity of each molecule in the mixture. “How long will this procedure take?” I hear you ask. If it takes a few minutes to separate a bag of chocolates, it won’t take more than a few milliseconds to get a spectrum of the molecules of one of those chocolates (for the sake of artistic license). Of course, this is not the whole detailed story, but in bulks, as most mass spectrometers employ the same principles, and it’s pointless to explain all details. And because a picture is worth a thousand words (cliché), all the above mentioned story is explained in the sketch below.
Since the first mass spectrometer was designed, the field has had significant development. More and more types of mass spectrometers were constructed, and that’s mostly because of the great applications they offer. Mass spectrometers are used not only for research purposes, to detect molecules, study structures, etc., but also in routine analysis. Pharmaceutical, cosmeceutical, and food industries employ mass spectrometry to reassure the quality of their products. Behind almost every product you use, it’s a mass spectrometer and an analytical scientist, measuring parameters for their quality.
Mass spectrometry is the method I’m employing to detect my substance of interest, through a coupling with a lateral flow immunoassay. This coupling aims to improve food safety testing, by providing food industries a faster and simplified way of testing their products for the absence of specific molecules that risk the safety of food. This work is harder than it seems, and it requires a lot of trial and error, hours of lab work, and even more hours of interpreting the results, and troubleshoot. That’s what I’ve been working on since I joined the FoodSmartphone project. This is what has caused me so much irritation when things don’t work out, but also even greater joy when it works as anticipated!
This will be my last blog for this year. Time flies, memories last (more cliché), make the last days of 2019 worth!
Till next time though,
Peace and Love!