Chemical Detection Methods

Part Per Million (ppm)

Concentration unit for something with extremely low concentration

Part of Billion (ppb)

Concentration unit for something with even lower concentration than ppm

Density of water at room temperature

Approximately 1 g/mL

Water (H2O)

Can exist in solid, liquid, aqueous, and gas states

1 ppm of H20(g)

Equivalent to 1 mg/L

1 ppb

Equivalent to 1 μg/L

Mass percent

Concentration expressed as the mass of solute divided by the mass of solution, multiplied by 100%

Volume percent

Concentration expressed as the volume of solute divided by the volume of solution, multiplied by 100%

Mass/Volume percent

Concentration expressed as the mass of solute divided by the volume of solution, which measures the mass or weight of a solute in grams, multiplied by 100%

Acute Toxicity

Lethal Dose (LD50) or Lethal Concentration (LC50) that causes 50% death in a given species of animals

PFAS

Class of man-made chemicals that persist in the environment for a long time

LC50

Chemical concentration in air or water that causes 50% death in a given species of animals

PFOA

One of the PFAS chemicals

PFOS

One of the PFAS chemicals

Dangers of mixing chemicals

Potential hazards that can occur when certain chemicals are combined

Analytical methods

Techniques used to analyze and study chemical substances

Chromatography

Process of separating a chemical mixture into components based on differential distribution of solutes

Gas Chromatography

Separation technique for volatile mixtures using a gas as the mobile phase

Liquid Chromatography

Separation technique for dissolving substances in a solvent before injecting them into a column

HPLC

High-performance liquid chromatography, a very effective separation technique

Gas Chromatography - Mass Spectrometry (GS-MS)

Technique used to identify unknown compounds, quantify known compounds, and determine structure and chemical properties of molecules

High resolution MS

Mass spectrometry technique that provides more accurate results

Atomic structures

The arrangement of electrons in an atom

Electrons

Particles that orbit the nucleus of an atom

Chemical Bondings

Three types of bonding: metallic, ionic, and covalent

Metallic bond

Bonding between metal atoms in pure metals

Ionic bond

Bonding between metal cations and non-metal anions via electrostatic force

Covalent bond

Bonding between non-metal atoms

Plastics

Polymers linked together by covalent bonds

OLED

Organic electroluminescent diode

Allotropes

Different forms of the same element with different properties

Diamond

Very hard allotrope of carbon, used to cut glass

Graphite

Soft and slippery allotrope of carbon, used as an absorbent and lubricant

Electromagnetic Spectrum

Range of frequencies of electromagnetic radiation

X-ray

Form of electromagnetic radiation used for diagnostic imaging and non-destructive testing

Ion Mobility Spectrometry

Technique used to separate and identify ions based on their size, shape, and charge in the gas phase

Chemical Mixtures

Samples that contain multiple chemicals

Collected samples

Samples that are mixtures of various gases

Gas Chromatography

Used to separate low-boiling mixtures

High Performance Liquid Chromatography

Used to separate high-boiling mixtures

Mass Spectrometry

Technique used to determine the atomic mass of elements and the molecular mass of compounds

Atomic mass

The mass of an atom or molecule

Glucose

Molecular mass of C6H12O6 is 180 g/mol for low-resolution mass spectrometry and 180.15588 g/mol for high-resolution mass spectrometry

High-Resolution mass spectrometry

Provides more accurate results than low-resolution mass spectrometry

Spectroscopy

Study of the interaction between matter and electromagnetic radiation

Electromagnetic radiation

Radiation that consists of oscillating electric and magnetic fields

X-rays

Used for diagnostic imaging and non-destructive testing

Infrared

Used for spectroscopy to study the vibrational modes of molecules

Ultraviolet/Visible

Used for spectroscopy to study electronic transitions in molecules

Raman

Used for spectroscopy to study molecular vibrations and rotations

Energy

Required for the production of cement, steel, plastics, and ammonia

Cement Production

Involves the reaction of water with calcium carbonate to produce calcium oxide and carbon dioxide

Smelting Steel

Involves heating metal ores with a reducing agent to convert them to their pure forms

Ammonia Production

Uses natural gas as the source of hydrogen and energy for the chemical process

Hydrogen

Potential alternative to natural gas for the synthesis of ammonia and smelting of steel

Green hydrogens

Hydrogen produced from renewable energy sources

Blue hydrogens

Hydrogen produced from natural gas with carbon capture and storage

Gray hydrogens

Hydrogen produced from natural gas without carbon capture and storage

Pink hydrogens

Hydrogen produced from nuclear energy