Bottle-Top Dispenser And How Does It Work?

A bottle-top dispenser is a commonly used laboratory instrument that allows precise and controlled dispensing of liquid reagents from bottles. It is particularly useful when working with solutions that need to be dispensed in specific volumes with high accuracy and reproducibility. Bottle-top dispensers are widely utilized in various scientific fields, including molecular biology, biochemistry, pharmaceuticals, and clinical diagnostics. Understanding the working principle of bottle-top dispensers is essential for their proper use in laboratory applications.

Working Principle of Bottle-Top Dispensers:

Bottle-top dispensers operate based on the principle of positive displacement. They consist of several key components that work together to facilitate accurate liquid dispensing:

1. Dispensing Cylinder: The dispensing cylinder is the central component of the bottle-top dispenser. It is attached to the bottle by screwing it onto the bottle neck. The cylinder has an adjustable volume setting, allowing the user to select the desired volume for dispensing.

2. Piston and Seals: Inside the dispensing cylinder, there is a piston that moves up and down. The piston is equipped with seals that provide a tight seal against the cylinder walls, preventing leakage during dispensing.

3. Adjustment Knob: The adjustment knob is located on the top of the bottle-top dispenser and is used to set the desired volume. It is connected to the piston and adjusts its position within the cylinder to control the dispensed volume.

4. Inlet Valve: The inlet valve is located at the top of the dispenser and is connected to the liquid source. It allows the liquid to enter the dispensing cylinder when the dispenser is in the aspirating mode.

5. Outlet Valve: The outlet valve is located at the bottom of the dispenser and is connected to the dispensing tip. It controls the flow of liquid from the dispensing cylinder to the tip during the dispensing process.

Working Steps of Bottle-Top Dispensers:

1. Priming: Before using the bottle-top dispenser, it needs to be primed to eliminate any air bubbles and ensure accurate dispensing. The dispenser is attached to the liquid source, and the adjustment knob is set to the maximum volume. The dispenser is then operated in the aspirating mode, drawing the liquid into the dispensing cylinder until it overflows from the tip. This step removes air and ensures that the liquid completely fills the cylinder.

2. Volume Adjustment: Once primed, the adjustment knob is set to the desired dispensing volume. The volume scale on the adjustment knob allows precise selection of the desired volume.

3. Dispensing: The dispenser is positioned over the receiving vessel, and the outlet valve is opened by depressing the dispenser plunger or operating the dispensing lever. As the piston moves up, the liquid is forced out of the dispensing tip in the desired volume. The dispensing process is controlled and stopped by releasing the pressure on the plunger or lever, closing the outlet valve.

4. Calibration and Cleaning: Bottle-top dispensers need regular calibration to ensure accurate volume delivery. Calibration can be performed using a calibration kit or by gravimetric methods. Additionally, regular cleaning of the dispenser is essential to prevent cross-contamination between different reagents and maintain accurate dispensing.

Applications of Bottle-Top Dispensers:

Bottle-top dispensers are versatile instruments used in a wide range of laboratory applications:

1. Reagent Preparation: Bottle-top dispensers are commonly used for the accurate preparation of reagents, buffers, and solutions with specific volumes required for experiments.

2. Media Dispensing: In cell culture applications, bottle-top dispensers are used for dispensing cell culture media, serum, and other additives into culture vessels with precise volumes, ensuring consistent growth conditions.

3. Chemical Dispensing: Bottle-top dispensers are utilized for dispensing chemicals and reagents during chemical synthesis.