Use a Bottle-Top Dispenser

A bottle-top dispenser is a hand operated pump that screw on to a reagent bottle. These dispensers are surrounded by a clear plastic sleeve, which protects the glass cylinder from breaking, and eliminates the risk of hazardous spills. The volume is accurate to about 1-2%. The volume to be dispensed is set by adjusting the volume knob on the plunger.



Steps to Use a Bottle-Top Dispenser;

1. Prior to use, check the dispenser to see whether the dispenser volume is set correctly.

2. Make sure that the reagent bottle has enough solution before mounting the bottle-top dispenser on the reagent bottle.

3. Place a graduated cylinder at the outlet.

4. Pull the top of the dispenser up to as far as it will go. Let go of the dispenser and let the plunger fall by gravity. The liquid should be collected in a graduated cylinder.

5. While the liquid is dispensing into the graduated cylinder, observe that there is no air bubble in the liquid. If air bubbles are present, it could be that the container is near empty or the dispenser is malfunctioning. Consult your instructor to refill the solution and check the mounting of the dispenser.

6. Read the graduated cylinder and make sure that the volume collected is within 2% of the preset volume.

7. Place a clean, empty container at the outlet.

8. Repeat steps 3 and 4 to dispense the solution into the container.