Scientific Analytical Calorimeter Solutions
 

How To Measure Volatile Samples

Introduction

Volatile samples are alcohols and acetone. Some fuels have a volatile component as well.

If the sample evaporates between the weight-in and the ignition then the evaporation must be stopped otherwise the result will be low.


How to do it

The procedure is the standard procedure for spiking. The crucible cover disc (CAL2K-FLDS) is the spike. The CV of the cover disc must be measured if not done already.

Measure the CV of the cover disc (traditional and EASY) once

Fold the cover-disc and weight it in to a crucible and prepare the vessel.
Set the ‘MISFIRE LIMIT’ =0 (to allow small CV’s)
Run a determination
Enter the obtained CV via the keyboard in ‘SPIKE VALUE’
If EASY spike used: Read ‘READ LAST N_RISE’. Enter value in ‘CAPSULE RISE’
Set the ‘MISFIRE LIMIT’=0.44

Measure the CV of the volatile sample (with traditional spiking method)

Make sure that the ‘SPIKE VALUE’ was entered. Step ‘d’ above.
Tare the empty crucible
Stick the cover disc on to the crucible rim
Weigh the crucible and the cover disc.
This is the Spike mass. It must be entered manually with: ‘SPIKE MASS’. This enables spiking!
Tare the balance
Fill a syringe with the volatile liquid. Pierce a hole in the cover disc and inject a small amount of the liquid until the target weight is reached.
Enter this weight as the sample mass
Prepare the vessel normally. Put the cotton thread on top of the cover disc
Run the sample

The CAL3K will ignite the sample and measure the CV value. The energy (Spike mass x Spike Value) of the cover-disc is deducted automatically.

Measure the CV of the volatile sample (with EASY spiking method)

Make sure that the ‘CAPSULE RISE’ was entered. Step ‘e’ above.
Enable EASY spiking ‘SET CAPSULE EN’=YES
Stick the cover disc on to the crucible rim
Tare the balance
Fill a syringe with the volatile liquid. Pierce a hole in the cover disc and inject a small amount of the liquid until the target weight is reached.
Enter this weight as the sample mass
Prepare the vessel normally. Put the cotton thread on top of the cover disc
Run the sample

The CAL3K will ignite the sample and measure the CV value. The temperature rise of the cover-disc is deducted automatically.

Summary

The volatile sample will not evaporate through the pierced hole. But the oxygen will enter the crucible and the sample and the cover disc will burn completely. The cover-discs are reasonable consistent so that the EASY spiking method can be used.

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