Good afternoon folks, welcome back to Advanced Higher Chemistry. This is the first in a series of three videos we're going to do on organic analysis techniques. So if you want to analyse organic molecules then basically these three are your holy grail of figuring out what an earth you're dealing with. Often used in conjunction with each other because they measure slightly different things. The first thing the first video we're going to do is about mass spectroscopy. What is mass spectroscopy? Well, basically mass spectroscopy is you take yourself in organic molecule, you fire really high energy electrons at it and these electrons will knock off electrons off this molecule. Well that's one effect they can have. So you for example you turn it into a large positively charged what's called molecular ion but you don't do anything else to it initially. If you continue to hit it with high energy electrons what you can start to do is you can start to fracture this molecule into little chunks. A bit like me throwing Lego spaceship down the stairs when I was a child and watching them break into pretty little chunks at the bottom. Or was that just me? Anyway, so here's a molecule you could for example you could have the home molecule as one ion you could have a little chunk of a CH3 with a positive charge that would also be a fragment as they're called and then what you do is you collect these fragments in a detector and you end up with a graph that looks something similar to this. So here we have a mass spectrum for compound and the first thing to the two things to get from these mass spectra are first of all seek out the right hand to most line. If you have a look at the bottom here it's M to Z which is the mass over the charge which is what we tend to label the bottom that axis is. Effectively it's the mass so it's like the GFM and up here we have the abundance and you know how many of there is of each particular fragment. That's not used so much but the most useful thing possible you can get from a mass spectrum is the right hand most peak which tells you instantly what the GFM of your molecule is. So that would be the first piece of information and in fact this is a C from continued continuation so we'll have a look at that in a second but that's what I would get first and also I don't ask it very often but you can have a 2 plus charge so in theory you should also get perhaps peaks at 36 which of course is the homolycularine just divided by a charge of 2 here and these are all smaller fragments of this molecule that has broken off. So this was a molecule with multiple C's and H's and I know as well and a couple of O's as well we'll come back to another day so we're looking for a possible ion fragment that has a mass of 27. Well if you're seeing C's and H's and O's and stuff like that you can try juggling about a variety of combinations until you can come up with a certain chunk that would have a GFM of 27. I'm seeing two carbons there 24 you know C2 which leaves you with three H's so basically something like that they probably want you to put the positive charge on it let me just check yes they do in fact so yeah that is a prerequisite they want you to know that the ion fragment has got positive charge on it so a that's pretty much mass spectroscopy let me see if there's any outcomes I didn't cover nope that's it short and sweet for a mass spectroscopy folks