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Laboratory Operations

Basic Lab Equipment

I know in this era of total lab automation, it can be easy to overlook the fundamentals. But I want you to think of the modern laboratory like a high-tech kitchen run by a master chef. That chef may have a fancy molecular gastronomy kit and a blast chiller, but I guarantee they still have a deep respect for a perfectly sharpened knife, a sturdy mixing bowl, and an accurate oven

Our basic laboratory equipment items are the “knives and bowls” of our profession. Mastering their use isn’t just a box to check off; it’s the foundation upon which all the complex, automated results are built. A mistake made with a simple pipette or a poorly balanced centrifuge can invalidate the result from a million-dollar analyzer. So let’s review these foundational tools with the respect they deserve

Volumetric Glassware & Plasticware: The Art of Measurement

At its heart, so much of what we do involves precisely measuring and transferring liquids. Whether it’s patient serum, a reagent, or a quality control product, getting the volume exactly right is non-negotiable. This is where volumetric ware shines. The first principle you must burn into your brain is the difference between TC and TD

  • TD (To Deliver): This is the most common type of glassware we use for transferring liquids. It is calibrated to deliver the exact volume specified. Think of a measuring cup for baking—it’s designed to deliver one cup of flour out of the cup. Pipettes are classic TD instruments
  • TC (To Contain): This glassware is calibrated to contain the exact volume specified. If you were to pour the liquid out, a small amount would remain clinging to the walls, and you would not have delivered the full volume. These are primarily used for preparing solutions with a specific final volume. Volumetric flasks are the prime example

Types of Pipettes

Pipettes are the workhorses for liquid transfer. They are not all created equal

  • Volumetric Pipettes: These are the specialists. You’ll recognize them by the single calibration line and the bulge in the middle. They are designed to deliver one, single, fixed volume with extremely high accuracy (e.g., a 10.0 mL volumetric pipette). You use these for preparing calibrators, standards, or critical reagents where precision is paramount. You let them drain by gravity and never blow out the last drop
  • Serological and Mohr Pipettes: These are the generalists. They are straight tubes with graduation marks along the side, allowing you to deliver variable volumes. Serological pipettes have markings all the way to the tip, while Mohr pipettes stop before the tip. They are less accurate than volumetric pipettes and are used for tasks where high precision is not as critical, like adding reagents to tubes. Pay attention to whether it’s a “blow-out” pipette (indicated by an etched ring or two at the top), which means you must expel the last drop
  • Micropipettes: These are the modern, essential tools for handling very small volumes (typically 1 µL to 1000 µL). They use a plunger and disposable plastic tip to create a vacuum (air displacement) to draw up liquid. Mastery involves selecting the correct size pipette for the job, ensuring the tip is seated correctly, and using a smooth, consistent plunger motion to ensure accuracy and precision

Centrifuge: The Great Separator

Think of a centrifuge as the lab’s merry-go-round with a serious purpose. Its entire job is to use high-speed spinning (centrifugal force) to separate substances of different densities within a liquid. We use it constantly to spin down blood tubes to separate serum or plasma from cells, to concentrate urine sediment for microscopic examination, or to separate precipitated proteins

The single most important rule of centrifugation is BALANCE. You must always place tubes of equal size, shape, and volume directly opposite each other in the rotor. An imbalanced centrifuge will shake violently and can literally walk itself off the bench, causing catastrophic damage to the instrument and posing a serious safety hazard to everyone in the room. Always balance your tubes before you spin!

Temperature Control Equipment

Many biological and chemical reactions are highly dependent on temperature. Our ability to control this variable is critical

  • Refrigerators and Freezers: These aren’t just for staff lunches. They are precisely monitored units for storing patient specimens, reagents, and controls to maintain their stability. Lab refrigerators are typically kept at 2-8°C, while freezers are at -20°C or even ultra-low at -70°C. Daily temperature monitoring and logging is a key part of our quality management program
  • Incubators and Water Baths: These provide a stable, warm environment, most often 37°C (body temperature). Incubators are used for growing bacterial cultures in microbiology, while both can be used to warm reaction blocks or tubes to allow an enzymatic reaction to occur at its optimal temperature. Water baths require regular cleaning to prevent microbial growth

Balances and pH Meters

  • Balances (Scales): Used for the precise measurement of mass. We use them primarily for preparing powdered reagents or standards where an exact weight is required to create an exact concentration. High-precision analytical balances are so sensitive they must be enclosed in glass to prevent drafts from affecting the reading
  • pH Meters: These measure the acidity or alkalinity of a solution. They require careful calibration with standard buffer solutions (e.g., pH 4, 7, and 10) to ensure they are reading accurately before use

Safety Equipment

  • Biological Safety Cabinets (BSCs): These are not the same as a chemical fume hood. A BSC is an enclosed, ventilated workspace that uses HEPA filters to protect you, the environment, and your specimen from contamination when working with infectious biological material
  • Chemical Fume Hoods: These are designed to pull noxious or hazardous chemical fumes away from the user and vent them outside. They offer user protection but do not offer the sterile environment needed for microbiology or molecular work

Key Terms

  • Pipette: A laboratory tool used to transport a measured volume of liquid. Can be designed for fixed (volumetric) or variable (serological) volumes
  • Centrifuge: A machine that uses centrifugal force to separate components of a fluid. Its primary rule of operation is that it must be properly balanced
  • Meniscus: The curved upper surface of a liquid in a tube. For accurate measurement, volumetric readings must be taken from the bottom of the meniscus at eye level
  • TC (To Contain): A designation on laboratory glassware indicating it is calibrated to contain a specific volume of fluid. Volumetric flasks are a primary example
  • TD (To Deliver): A designation on laboratory glassware indicating it is calibrated to deliver a specific volume of fluid when drained. Most pipettes are TD
  • Biological Safety Cabinet (BSC): An enclosed, ventilated hood that uses HEPA filters to provide personnel, environmental, and product protection when working with biohazards
  • Calibration: The process of configuring an instrument or glassware to ensure its accuracy. For glassware, this is done by the manufacturer; for instruments like pH meters or balances, it is a routine user task