What information does mass spectrometry provide about isotopes?

Mass spectrometry provides information about the relative abundance and the mass of different isotopes of an element.

Mass spectrometry is a powerful analytical technique that can identify the isotopes of an element and measure their relative abundance. It works by ionising a sample of the element, which means it knocks off electrons to create positive ions. These ions are then accelerated through an electric field. The speed at which they travel depends on their mass: lighter ions travel faster than heavier ones.

When the ions reach a detector, they create a signal that can be measured. The strength of the signal is proportional to the number of ions hitting the detector, which gives us information about the relative abundance of each isotope. The time it takes for the ions to reach the detector gives us information about their mass.

For example, if we were analysing a sample of chlorine, we would find two signals. One would be from chlorine-35 ions and the other from chlorine-37 ions. The relative heights of these signals would tell us the relative abundance of these two isotopes in the sample. The time it took for the ions to reach the detector would tell us their masses: the chlorine-35 ions would arrive first, followed by the chlorine-37 ions.

So, mass spectrometry provides us with two key pieces of information about isotopes. Firstly, it tells us what isotopes are present in a sample. Secondly, it tells us the relative abundance of these isotopes. This information is crucial for understanding the properties of elements and their behaviour in chemical reactions.