Identify the function of labware pieces used in the clinical laboratory: Understanding the specific roles labware plays in laboratory environments assists in accurate experimentation and analysis.
Explain TD (To Deliver) and TC (To Contain): Grasping the distinctions between To Deliver and To Contain measurements is crucial for precise laboratory practices and interpreting results correctly.
Describe glassware cleaning according to specification: Proper cleaning methods are vital for maintaining the integrity of glassware, ensuring safety, preventing contamination, and producing reliable results in experiments.
Labware: Articles or containers specifically designed for laboratory use, often constructed from materials that can withstand various laboratory conditions.
Uses:
Testing Procedures: Essential for accurately conducting laboratory tests and experiments.
Preparing Reagents: Involves mixing chemicals or solutions necessary for tests.
Storing Reagents: Labware provides safe and effective storage for reagents, which are often critical for laboratory analyses and experiments.
Top Safety Rules:
Label Labware Before Adding Contents: Clear labeling prevents mix-ups and ensures that hazardous materials are identified quickly.
Always Use Personal Protective Equipment (PPE): Standard safeguards like gloves, goggles, and lab coats reduce the risk of contamination and exposure to harmful substances.
Store Unused Labware at the Back of the Bench: This minimizes the risk of accidental spills and breakage, creating a safer work environment.
Carry Test Tubes in a Rack: Using a test tube rack prevents tip-overs and accidents while moving multiple tubes.
Ensure Correct Preparation of Reagents: Accurate preparation of solutions is vital for obtaining reliable patient testing results and ensuring the validity of experimental outcomes.
Plasticware
Advantages:
Cost-Effective: Generally less expensive than glassware, making it accessible.
Durable (Unbreakable): Ideal for environments where breakage could lead to safety hazards or loss of materials.
Flexible Applications: Particularly effective in situations requiring chemical resistance, such as storing alkaline substances.
Disadvantages:
Less Stability: Risks such as leaching, permeability, or evaporation may occur.
Generally Less Clarity Compared to Glass: Not suitable for applications requiring clear visibility of the contents.
Common Plastic Types
Polyethylene:
Used for various containers; has limitations regarding heat resistance which may limit its applications.
Polypropylene:
Known for its rigidity, heat resistance, and capability of withstanding autoclaving for sterilization purposes.
Polystyrene:
Commonly utilized in Petri dishes and microtiter plates; however, it lacks heat resistance, limiting its use with hot substances.
PVC/Tygon:
Typically used in tubing applications; known for its flexibility and clarity, making it suitable for fluid transfer.
Glassware
Types of Glass:
Borosilicate Glass: Offers high thermal resistance, often exemplified by Pyrex, suitable for heating and contamination-sensitive procedures.
Alumina-Silicate Glass: Provides enhanced optical properties, often used for applications demanding clarity, although it is pricier.
Low-Actinic Glass: Protects light-sensitive materials from degradation due to exposure to light.
Soda Lime Glass: The least expensive option; typically not recommended for storing substances long-term due to its reactive nature.
Non-Critical Measurements: Involves estimated volumes using less precise devices (e.g., beakers), sufficient for general applications where accuracy is not paramount.
Critical Measurements: Requires precise measurements essential for accuracy, typically using calibrated glassware to ensure reliable results.
Importance: Validating method accuracy using known standards is necessary for confirming results in scientific experimentation.
Class A Glassware: This type meets stricter calibration standards to assure users of accuracy in measurements.[Volumetric Flask]
To Contain (TC)
Specifically designed to hold a specified volume of liquid; however, it typically delivers less due to liquid adhering to the walls of the container, which is crucial for users to understand to avoid measurement errors.
Labeling: Written on the side of all lab glassware.
Design Purpose: Designed to contain a certain amount of volume. When transferred to another container, it will deliver less than the indicated volume due to liquid clinging to the side (remaining in the primary container).
Transfer Loss: Approximately 0.5-1% of the liquid being transferred sticks to the side walls of the measuring container.
To Deliver (TD)
Designed to deliver an exact indicated volume; in practice, it often involves delivering a slight excess of liquid to ensure complete transfer of contents, making it suitable for precise applications in laboratory settings.
Containers: Includes test tubes, beakers, and flasks (including Erlenmeyer and Florence), essential for holding and mixing samples.
Volumetric Ware: Comprised of volumetric flasks, cylinders, and pipettes designed for accurate measurement of liquids.
Calibration of Lab Glassware
Calibration Temperature: Most glassware for routine lab use is calibrated at 20°C.
Definition of Calibration: Validating a method by using a known standard.
Temperature Consideration: Liquid and glassware must all be at room temperature for measurement to be accurate.
Physical Properties: Remember that liquids expand when hot and contract when cooled.
Test Tubes: Available in various sizes for handling biological samples and assays effectively.
Reagent Bottles: Should be chosen based on compatibility with their contents; it’s essential to avoid using low-quality glass for long-term storage of volatile chemicals.
Beakers: Best for mixing solutions and estimations rather than for performing precise measurements due to their design.
Volumetric Flasks: Specifically designed to hold precise volumes and are used in preparing critical standard solutions, ensuring accuracy in concentration.
Definition: The curvature of a liquid’s surface due to surface tension, which is an important aspect of liquid measurement in labware.
Measuring: Always ensure that the meniscus is at eye level when reading volume for accurate measurement, as parallax error can lead to miscalculation.
Definition: The permissible deviation from a specified volume, as noted on the measurement markings of glassware; understanding this is critical for achieving consistent and reliable experimental outcomes.
Example: A 10 mL flask may have a tolerance of ± 0.025 mL, which indicates the precision expected during measurement routines.
to contain [TD]
Material: Can be made from plastic or glass.
Sizes and Shapes: Available in different sizes and shapes, ordered according to length and diameter (e.g., 10 mm x 75 mm holds about 3 mL).
Contents: May hold blood, urine, plasma, serum.
Graduation: May be graduated but not calibrated to be accurate.
Heating: If tubes need to be heated, choose those made of heat-resistant borosilicate glass (e.g., Pyrex or Kimax).
Material Considerations: Plastic bottles should be used only for reagents that don’t interact with plastic. Low-quality glass containers slowly release ions into the reagents, so they should not be used for long-term storage.
Sizing: Bottles should be only slightly larger than the volume of reagent within.
Light Protection: Opaque plastic or brown glass bottles should be used for light-sensitive reagents.
Size Range: Available in a wide range of sizes (i.e., 25 mL, 50 mL, 400 mL, etc.).
Design: Wide-mouthed, straight-sided, and with a pouring spout.
Uses: Used for stirring, mixing, or heating liquid; ideal for estimating volumes (not for precise measurements).
Calibration: Not calibrated but labeled to indicate approximate capacity in mL and estimated accuracy (e.g., 250 mL ± 5%).
Shape: Flat bottom with sloping sides that gradually narrow.
Opening: Bottle-like opening, which can be plain or threaded.
Volume Range: Available in various volumes (10 mL to 4000 mL).
Uses: Ideal for mixing solutions without the risk of spilling.
Design: Rounded sides and a long neck.
Uses: Used for holding and heating solutions and reagents.
Volume Range: Can be found in various volumes from 5 to 1000 mL.
Manufacturing Standards: Manufactured to strict standards - To Contain (TC).
Accuracy: Guaranteed to contain a specific volume at a certain temperature.
Graduation Line: Etched graduation line indicates the correct fill.
Critical Measurements: Used for the preparation of standard solutions.
Design Purpose: Designed to deliver a precise volume by holding slightly more than the indicated volume on the glassware, ensuring that the accurate volume is delivered.
Usage: Often involves delivering a slight excess of liquid to ensure complete transfer of contents, making it suitable for precise applications in laboratory settings.
Design: Upright, straight-sided, flared base.
Calibration: Features calibrated markings for measuring.
Accuracy: More accurate than beakers and some flasks, but not used for precise measurements – To Deliver.
Example of Use: Measuring the volume of 24-hour urines.
Volume Capacities: Range from 5 to 2000 mL.
Definition: Curvature in the top surface of a liquid.
Cause: Surface tension draws up the edges of the liquid.
Measurement: The lowest part of the meniscus should be on the calibration marks.
Reading Position: The calibration mark must be at eye level for accurate measurement.