Analytical Tech & Nanoparticles

• Emission spectrum

  Band of lines observed when an element emits light as electrons move from an excited state to a lower state, seen as colored lines on a black spectrum
• Ground state to excited state transition

  Requires energy to be absorbed
• Ionization energy


  Amount of energy an electron absorbs before being completely removed from its atomic orbitals and becoming an ion
• Absorption spectrum


  Band of lines observed when an element absorbs photons of white light, viewed as a series of black lines on the visible light spectrum corresponding to the energy of photons required for transitions
• Atomic absorption spectroscopy (AAS)


  Used to determine quantity of a metal in an unknown sample, can detect as low as ppb, measures intensity (absorbance) of emitted light relative to original source
• Excited state to ground state transition

  Accompanied by emission of energy
• Flame tests


  Used to identify elements as metals emit characteristic colors when electrons are excited to higher orbital shells
• Electromagnetic spectrum


  Consists of the full range of frequencies of light, photons travel at the speed of light in a vacuum, frequency is the number of waves passing a point each second, wavelength is the distance between two crests or troughs of a wave
• Mass spectrometry

  • Involves the ionisation of substances, separation and detection of resulting ions, spectra can be analysed to determine isotopic composition of elements and interpreted to determine relative atomic mass
• Spectrograph

  Used to distinguish photons of light based on wavelengths
• Mass spectrometry

  1. Ionisation of substances

  2. Separation and detection of resulting ions

  3. Analysis to determine isotopic composition of elements

  4. Interpretation to determine relative atomic mass
• Ground state of atoms

  Refers to the lowest energy, most stable electron shell that an electron can occupy, when an atom absorbs energy, electrons move to higher energy shells, excited state contains more energy than ground state
• Data analysis and interpretation

  1. The sample tested is compared to a set of standards of known concentration of the metal being analysed

  2. A calibration curve of the standards is prepared, and the unknown sample’s concentration is calculated from this
• Determining relative isotopic mass

  1. Mass spec of Si reveals 3 isotopes: 28Si = 92.23%, 29Si = 4.68%, 30Si = 3.09%

  2. Relative atomic mass calculation: (RIM1 x %1) + (RIM2 x %2) + (RIM3 x %3) / 100
• Backtracking calculations

  Given RIM and abundance of one isotope, determine RIM and abundance of the second isotope
• Mass spectrometry shows how many isotopes an element has, the relative mass of each isotope, and the percentage abundance of each isotope
• Mass spectrometry

  1. Analytical technique where chemical elements are ionized and ions are sorted according to their mass to charge ratio

  2. Measured by a Mass spectrometer

  3. Works by bombarding the element with electrons, passing ions through electric and magnetic fields to separate them based on mass to charge ratio
• Standard samples for AAS

  • Standard 1: Concentration (ppm) 0, Absorption 0
  • Standard 2: Concentration 15, Absorption 25
  • Standard 3: Concentration 30, Absorption 50
  • Standard 4: Concentration 45, Absorption 75
  • Standard 5: Concentration 60, Absorption 100
  • Sample: Concentration 80
• The most abundant elements on earth are iron, oxygen, silicon, magnesium, sulfur, nickel, calcium, and aluminum, found in rock-based formations
• Atomic absorption spectroscopy (AAS)


  1. Used to determine the quantity of a metal in an unknown sample

  2. Can detect as low as ppb

  3. The detector measures the intensity (absorbance) of the light emitted relative to the original light source

  4. The greater the intensity (absorbance), the higher the concentration of the metal atoms in the sample
• Living organisms are often referred to as ‘carbon-based’ life forms, but oxygen is the most abundant element in the human body (65%), followed by carbon (18.5%), hydrogen (9.5%), nitrogen (3.2%), and trace elements
• Oxygen has high abundance on earth due to its presence in rock-based compounds, water, and the atmosphere
• Colligative property of a solution depends on the ratio of the number of solute particles to the number of solvent molecules
• Spectroscope is used to determine the chemical composition of a star, where absorption spectra show dark lines referred to as Fraunhofer lines
• As an object approaches the earth from outer space


  Wavelength decreases and frequency increases
• Doppler effect is the change in frequency or wavelength observed as the source of the wave moves past a bystander
• Composition of the human body

  • 65% oxygen
  • 18.5% carbon
  • 9.5% hydrogen
  • 3.2% nitrogen
  • Rest trace elements
• Heterogeneous mixtures consist of two or more substances with distinguishable regions called phases, while homogeneous mixtures have only one visibly distinct phase
• Blue shift


  Occurs when an object's absorption spectrum shifts slightly towards the blue end due to a decrease in wavelength
• Most common elements identified in the sun

  • Hydrogen
  • Helium
  • Calcium
  • Iron
• Red shift

  Occurs when an object moving away emits radiation that spreads further apart, leading to an increase in wavelength and decrease in frequency towards the red spectrum
• Many mixtures are called solutions, where the substance present in the greatest amount is the solvent and all other substances are solutes dissolved in the solvent
• Pure substances have distinct, measurable properties and purity can be established based on physical and chemical properties including melting point, boiling point, density, reactivity, and bond strength
• Granite is a heterogeneous mixture of three solid phases: white quartz mineral made of silica, an orange mineral, and black mica mineral
• Examples of common solutions

  • Air - Gas-gas - Nitrogen - Oxygen, carbon dioxide, argon, water vapor - Clear colorless gas
  • Soft drinks - Liquid-gas - Water - Carbon dioxide gas - Colored liquid
  • Vinegar - Liquid-liquid - Water - Acetic acid - Clear
• Most abundant elements on earth

  • Iron
  • Oxygen
  • Silicon
  • Magnesium
  • Sulfur
  • Nickel
  • Calcium
  • Aluminum
• Star's temperature

  Determined from its color, with hotter stars appearing blue and cooler stars appearing redder
• Adsorption

  Molecule attaches to a surface of a solid or liquid
• Nanomaterials like carbon nanotubes are extremely strong like diamonds, conduct electricity like graphite, are flexible, have high tensile strength, and their conductivity can be engineered to make them insulating, conducting, or semiconducting
• Forming Nanomaterials


  1. Bottom-up method: using specially designed molecules or atoms in chemical reactions to build up new nanoparticles

  2. Top-down method: using larger bulk material as the starting material and breaking it down