Laboratory Techniques and Solution Analysis

Laboratory Techniques

• Measuring and Weighing:
  • Graduated cylinders measure liquids precisely.
  • Balances weigh substances, requiring calibration.
  • Pipettes, manual or automated (micropipettes), measure small liquid volumes accurately.

Solution Analysis Techniques

• Titration: Determines the concentration of an unknown solution by reacting it with a solution of known concentration (titrant) until an endpoint. Endpoint often determined by color change.

• Filtration: Separates solids from liquids or gases using techniques like gravity, vacuum, or membrane filtration.

• Distillation: Separates liquids based on differing boiling points. Simple distillation for significantly different boiling points; fractional distillation for similar boiling points.

• Centrifugation: Separates components in a mixture based on their density using centrifugal force.

• Chromatography: Separates mixtures into components. Includes paper chromatography (using a solvent), TLC (thin-layer chromatography using a silica gel plate), GC (gas chromatography), and HPLC (high-performance liquid chromatography).

Spectroscopy and Other Instrumental Methods

• Spectroscopy: Measures absorption, emission, or scattering of light (or other electromagnetic radiation) by substances. Includes:
  • UV-Vis spectroscopy for identifying and quantifying UV/visible light-absorbing substances.
  • Infrared (IR) spectroscopy for identifying functional groups in organic compounds.
  • Nuclear Magnetic Resonance (NMR) spectroscopy for detailed molecular structure analysis.
  • Mass spectrometry (MS) for identifying compounds based on their molecular mass.

Electrophoresis and Sample Preparation

• Electrophoresis: Separates charged molecules (proteins, nucleic acids) in a gel under an electric field.

• Incubation and Growth: Used in biological and microbiological labs to promote growth of microorganisms or cells under specified conditions (e.g., temperature, media).

• Microtomy: Creates thin sections of specimens (tissues) for microscopic examination using a microtome.

• Electrochemical Analysis: Techniques (e.g., potentiometry, coulometry) analyze ions or electrode reactions in solutions.

• pH Measurement: pH meters or indicators measure the acidity or alkalinity of solutions.

• Microscopy:

  • Light microscopy observes small organisms or thin sections.
  • Electron microscopy provides high magnification for ultrastructural details.

Heating, Cooling, and Mixing

• Heating and Cooling: Techniques using Bunsen burners, hot plates, ice baths, or cryogenic conditions to control experimental conditions.

• Buret and Pipette Technique: Precise liquid handling for transferring specific amounts of liquids.

• Lysis and Extraction: Techniques for releasing cellular contents (cell lysis), or extracting compounds using solvents (solvent extraction).

• Serial Dilutions: Creates a series of solutions of progressively lower concentrations, often used in microbiology or chemistry.

• Bacterial Staining (Microbiology): Techniques (e.g., Gram staining) identify bacterial species or structures based on their cell wall properties.

• Vortexing: Rapidly mixes or agitates liquids in containers.

• Vacuum Evaporation: Removes solvents under reduced pressure to concentrate solutions, purify compounds.

• Gel Electrophoresis: Separates macromolecules (e.g., DNA, RNA, proteins) based on size and charge.

• Solid-Phase Synthesis: Step-by-step synthesis of biomolecules, using a solid support and adding reagents.