INFICON RQCM - Quartz Crystal Microbalance Research System - Manual (Page 59)

RQCM – RESEARCH QUARTZ CRYSTAL MICROBALANCE
THEORY OF OPERATION 5-7
illustrated by Figure 14 and Figure 15, respectively. Note that some of the discrepancy in the
resistance curve could arise from an error in estimating the active electrode area.
The RQCM utilizes the PLO technology which allows the sensor crystal to operate under heavy
viscous loading. INFICON Crystal Holders support operation in gas and liquid environments and
provide single-electrode exposure to liquids as required for compatibility with electrochemical
QCM measurements. The RQCM will maintain oscillation up to a series resonance resistance of
about 5 kΩ. It will support crystal operation in highly viscous solutions up to 88% weight
percentage of glycerol 28 . The RQCM computer software provides a friendly interface for setting
up the RQCM to log and graph data collected from the sensor crystal such as frequency change,
resistance change, mass, etc.
Frequency Change vs. Wt % Glycerol
-10000
-9000
-8000
-7000
-6000
-5000
-4000
-3000
-2000
-1000
0
0 10 20 30 40 50 60 70 80 90 100
Wt % Glycerol
D
e
lt
a Frequency (
H
ert
z
)
Theory
RQCM
Figure 14 Frequency Change vs. Wt % Glycerol