Micromeritics ASAP 2460 - t-Plot

Appendix C ASAP 2460 Operator’s Manual
C-12 246-42800-01 - Aug 2013
t-Plot
A least-squares analysis fit is performed on the (t
i
, N
ads,
i
) data pairs where t
i
is the independent variable
and N
ads,i
is the dependent variable. Only the values of t
i
between t
min
and t
max
, the minimum and max-
imum thickness, are used. The following are calculated:
a.) Slope (S cm
3
/g-Å STP)
b.) Y-intercept (Y
int
cm
3
/g STP)
c.) Error of the slope (S
err
cm
3
/g-Å STP)
d.) Error of the Y-intercept (YI
err
cm
3
/g STP)
e.) Correlation coefficient
Using the results of the above calculations, the following can be calculated:
External Surface Area (m
2
/g):
where
10
4
= unit conversions
F = surface area correction factor, user-entered on the t-Plot Report Options
window
V
mol
= liquid molar volume, from the fluid property information
Micropore Surface Area (m
2
/g):
where SA
total
is the BET surface area if the user enabled the BET report exclusively, or Langmuir sur-
face area if the user enabled the Langmuir report exclusively. If neither report has been selected, SA
total
is the BET surface area value calculated using a set of default parameters.
Micropore Volume (cm
3
liquid/g):
SV
mol
F 22414cm
3
STP
---------------------------------------------
10
4

SA
p
SA
total
SA
ext
+=
Y
int
V
mol
22414cm
3
STP
------------------------------------