Detecting ‘invisible’ chemicals Environmental and Molecular Toxicology

The Gulf Oil Spill Deepwater Horizon July 15, 2010

The Gulf Oil Spill Deepwater Horizon 2 years later… Is the oil still present?

Oil – a mixture Mixture – several things all mixed together – Examples of mixtures Salt water (Salt + water) Salsa (Tomatoes + onion) Chemical mixtures (Pesticides) What are chemicals? – Examples of common chemicals Water Carbon Household cleaning products

How big are chemicals?

Chemical Conundrum In the Gulf Oil Spill, there were a lot of chemicals released into the ocean. Scientists needed to identify those chemicals to determine if they were dangerous. First, scientists took samples of the contaminated water. From that sample, they sorted out the different types of chemicals

Chemical Conundrum We are using M&Ms to represent the different sorts of chemicals that were found in the Gulf Divide into groups of two Take a sample, using a Dixie cup, of the M&M mixture Discuss different ways to sort the M&Ms

M&M Sorting Color Size Shape Circle Oblong Mass?

Mass vs Weight

Definitions Mass – a measure of how much ‘stuff’ is in something – In every day use, we say how much something weighs Our mass on Earth is the same as our weight Weight – the gravitational force acting on an object or a person Would our mass be the same on Mars? Would our weight be the same on Mars?

© 2011 Exploratorium Exploratorium

Can you sort the M&M’s by mass? How many different types of M&M’s are there?

RegularPeanut Butter PretzelPeanutAlmond 4.0 – 4.4 g8.8 – 9.7 g10.4 – – – 15.7 Take 5 of any group of M&M and weigh it. Can you identify the type of M&M? Which M&M’s are hardest to distinguish? Which M&M group is the most variable? Has the biggest range of weights?

How Scientists use Mass How it works: Chemicals are separated by mass The mass identifies the chemical Saltwater has a mass of g/ml Chemicals in the Gulf 1.8 g/ml 1.24 g/ml A mass spec can ‘see’ these chemicals

Questions?