Decagon WP4-T - 6 Sample Preparation; Preparing the Sample

WP
4
PotentiaMeter
Sample Preparation
31
6. Sample Preparation
Your WP4 will continually provide accurate water
potential measurements as long as its internal sen-
sors are not contaminated. Careful preparation and
loading of samples will lengthen time between
cleanings and will help you avoid downtime and
repairs.
Preparing the Sample
To prepare a sample, follow these steps:
1. Place the sample in a disposable sample
cup, completely covering the bottom of the
cup, if possible. WP4 is able to accurately mea-
sure a sample that does not (or cannot) cover
the bottom of the cup. A larger sample surface
area speeds up the reading by shortening the
time needed to reach vapor equilibrium. It also
increases instrument efficiency by providing
more stable infrared sample temperatures.
2. Do not fill the sample cup more than half
full. Overfilled cups may contaminate the
sensors in the chamber (more is not neces-
sarily better!)