Question

Using a sterile transfer pipette, rinse the depression slide with alcohol. Tap the excess alcohol off on the paper towel. Then, holding the slide with a forceps pass it through the flame and let the alcohol burn off. Do NOT perform this step over the paper towel or the alcohol because a drop of flaming alcohol can start a fire. After it cools, place it on the paper towel with the depression upwards.

Short answer

Rinse the slide with alcohol, tap off excess, hold with forceps, flame it away from flammable items, cool it, then place depression side up.

Step-by-step solution

Rinse the Slide

Using a sterile transfer pipette, carefully rinse the depression slide with alcohol to sterilize it.

Remove Excess Alcohol

Tap the excess alcohol off onto a paper towel to ensure the slide is not dripping.

Hold Slide with Forceps

Using forceps, securely hold the slide to avoid direct contact with your hands.

Pass Through Flame

Quickly pass the slide through a flame to burn off the remaining alcohol. Make sure this is done away from the paper towel and any additional alcohol to avoid fire hazards.

Let Slide Cool and Place

Allow the slide to cool down after passing through the flame. Once cool, place it on the paper towel with the depression side facing upwards.

Key concepts

Depression Slide

In microbiology and laboratory work, a depression slide is an essential tool used for observing liquid specimens under a microscope. It has a concave dip in the center, which holds drops of liquid more securely compared to flat slides. The concavity helps in focusing on samples without the liquid running off during observation. When using a depression slide, it is important to ensure it is thoroughly clean and sterile before use to prevent contamination. Proper handling is also crucial to avoid smudges or fingerprints that could obstruct the view under the microscope.

Flame Sterilization

Flame sterilization is a quick and effective technique used to sterilize laboratory tools and equipment. By exposing the object to a flame, usually from a Bunsen burner, any microorganisms present are incinerated due to the high temperatures. When performing flame sterilization, it’s vital to handle the objects with forceps to avoid burns and to ensure safety. Holding the object in the flame for a few seconds should be sufficient. However, one should always be cautious about potential fire hazards, especially when dealing with flammable substances like alcohol.

Laboratory Safety

Ensuring safety in the laboratory is paramount. Here are some crucial tips to follow:

• Always wear appropriate personal protective equipment (PPE) such as gloves, lab coats, and safety goggles.
• Know the location and proper usage of safety equipment like fire extinguishers, eye wash stations, and first-aid kits.
• Avoid eating, drinking, or applying cosmetics in the lab to prevent contamination.
• Be mindful of your surroundings and keep your workspace neat and clutter-free.
• Dispose of laboratory waste, such as broken glass or chemical residues, according to established safety protocols.

Another key aspect is following proper procedures for handling hazardous materials to minimize risks of spills and accidents.

Sterile Transfer Pipette

A sterile transfer pipette is a disposable tool used to transfer small amounts of liquid in the laboratory, while maintaining sterility. These pipettes are individually packaged and pre-sterilized, ensuring that they are free from contaminants when first used. When handling a sterile transfer pipette:

• Only touch the exterior of the pipette and avoid contact with the tip or the interior.
• Use a new pipette for each sample to prevent cross-contamination.
• Make sure to dispose of used pipettes properly according to laboratory waste disposal guidelines.

Proper use of sterile transfer pipettes helps maintain the integrity of samples and ensures accurate experimental results.