N is for Nitrogen #AtoZChallenge

N is for Nitrogen

Nitrogen is the most abundant gas in the Earth’s atmosphere. It is also an important component of the amino acids that make up proteins in the bodies of living organisms.

Isotopes of nitrogen fractionate according to trophic level, that is, where the organism lies on the food chain (more properly, the food web). This is the origin of the common saying in isotope geochemistry, “You are what you eat, plus a few permil.” For nitrogen, on average a consumer’s δ15N is 3‰ more positive than the organism that is being eaten (whether it be a plant or another animal).

This relationship of nitrogen isotopes in proteins can be used to determine predator-prey relationships between extinct animals, presuming that proteins are preserved.

M is for Magnet #AtoZChallenge

M is for Magnet

A common feature of mass spectrometers is a magnet. A strong magnetic field is necessary to separate the molecules of slightly different mass for measurement.

Not all mass spectrometers work in the exact same way, but all use powerful magnets to select atoms and molecules of specific masses so that it’s possible to measure the amount of the different isotopes of specific elements. The configuration of these magnets differs depending on the isotopes being measured.

Mass spectrometers such as the DeltaPlus XP here at SIREAL have a single magnet that splits a beam of ionized gas into two or three beams of different masses that are measured simultaneously. This makes it possible to calculate the ratios necessary for the delta values (see D is for delta).

SIREAL is blogging from A to Z

The Blogging from A to Z challenge is an event each April in which bloggers worldwide prepare 26 posts – one for each letter of the English alphabet – and present them over the course of the month.

SIREAL (Stable Isotopes Ratios in the Environment, Analytical Laboratory) is joining the fun through their manager, Penny, who has participated in the Blogging from A to Z challenge many years in the past. Our posts will be mirrored on her blog over at paleopix.com. Scroll to the end to see her A to Z themes.

The A to Z posts by SIREAL will all relate to terms, methods, and scientific results from the analysis of light stable isotopes from natural materials.

Since “Isotope” isn’t a term that will turn up right away, we will quickly define it here: Continue reading “SIREAL is blogging from A to Z”