PASCO PS-2117 Drop Counter - Manual (Page 2)

D r o p C o u n t e r
2
Introduction
The Drop Counter measures the number of drops of fluid
that fall through the rectangular opening of the sensor. It is
typically used in conjunction with a pH sensor and other
equipment to perform a titration. Data from the Drop
Counter and other sensors are recorded and displayed in soft-
ware such as SPARKvue, PASCO Capstone, or on a datalog-
ging interface such as the SPARK SLS or Xplorer GLX.
The Drop Counter can be mounted on a support rod and the
support rod can be clamped to a rod stand. The counter is
equipped with three integrated probe holders. The included
Micro Stir Bar fits onto the end of a pH probe or probe of the
same diameter.
Assembling the Drop Dispenser
1. Remove the plunger from the syringe.
2. Connect the two stopcocks together and set the valves at
right angles. Connect the stopcocks to the end of the
syringe.
3. Connect the drop tip to the bottom of the stopcocks.
Acid-Base Titration (Calibration Method)
Calibration
1. Attach the Drop Dispenser (syringe, stopcocks and drop
tip) to a support rod.
2. Fill the syringe with titant and adjust the valves on the
stopcocks so that the drops fall at a rate of about 1 drop
per second. Close the bottom valve after the rate is
achieved.
3. Connect the Drop Counter to a PASPORT-compatible
interface.
4. Align the drop tip with the opening in the Drop Counter.
Put a 10 ml graduated cylinder under the Drop Counter
opening.
5. Open the bottom stopcock valve and monitor the num-
ber of drops per 10 mL of titrant.
6. Open the calibration screen in the data acquisition soft-
ware and input the number of drops and the volume.
Procedure
1. Setup the equipment and consumables as shown.
2. Connect the Drop Counter and pH Sensor to the
PASPORT-compatible interface.
3. Start the data acquisition software.
4. Use the software to create a graph of pH vs. Fluid Vol-
ume.
5. Start the stir plate.
6. Touch, press, or click to begin recording data.
7. Open the valve on the bottom stopcock so the titrant
drops fall at about 1 drop per second.
60 mL syringe
with 50 mL of
0.1 M NaOH
150 mL
beaker with
100 mL of
0.005 M HCl
Three-finger
Clamp
Multi
Clamp
Stopcock
Stopcock
Drop Tip
pH Probe
Micro Stir
Bar
Stir Plate