Detecting ‘invisible’ chemicals

Environmental and Molecular Toxicology

The Gulf Oil SpillDeepwater Horizon

July 15, 2010

The Gulf Oil SpillDeepwater 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

http://learn.genetics.utah.edu/content/begin/cells/scale/

How big are chemicals?

Chemical ConundrumIn 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 SortingColor Size

ShapeCircle 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?

http://www.exploratorium.edu/ronh/weight/

© 2011 Exploratorium        

Can you sort the M&M’s by mass?

How many different types of M&M’s are there?

Regular Peanut Butter

Pretzel Peanut Almond

4.0 – 4.4 g 8.8 – 9.7 g 10.4 – 13.6 12.9 – 15.9 14.7 – 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 MassHow it works: Chemicals are separated

by mass

The mass identifies the chemical Saltwater has a mass of 1.031 g/ml

Chemicals in the Gulf

1.8 g/ml

1.24 g/ml

A mass spec can ‘see’ these

chemicals

Questions?