Absorption Spectroscopy with Vernier Logger Pro 3.8.3
–
4
Calibration for Absorption Measurements
(
M
ust be performed with
all
absorption experiments
)
1)
Launch
Logger Pro
.
2)
From the
Experiments
menu select:
Calibrate
>
Spectrometer
:1
.
3)
Th
e
Calibrate Spectrometer
d
ialog
ue
box will . Wait 9
0
seconds for
lamp
warm
–
up
.
4)
Place blank cuvette (cuvette with
solvent
or
reagent
only
) in holder and click
on
Finish Calibration
.
5)
Click
OK
.
Absorption vs.
Wavelength
(Abs vs. ?)
1)
Fill cuvette ˜ 2/3 full
with sample
.
NEVER EXCEED
2/3
full
, as this leads to
spills, which damage the
$2000+
spectrometer
!
2)
Wipe exterior of cuvette with a Kimwipe
TM
(to remove drips, fingerprints, etc.)
3)
Place sample in cuvette holder
.
4)
Click
C
ollect
(Green rectangle with
?
)
.
5)
Click
Stop
(Red rectangle with
¦
) to end data collection
.
6)
If the tallest
peak
(
s
)
return absorptions > 1.5
, dilution of the sample is
necessary.
Avoid

maxed
–
out

peaks
.
7)
Run the next dilution by clicking
Collect
again.
Whe
n the save dialogue box
s,
chose
Store Latest Run
to store
the
previous spectrum data.
8)
Repeat for the remaining dilutions. Note that each dilution should be
represented by a separate curve
(different colors)
in the Abs vs.
? graph and
spreadsheet data
to the left.
9)
To highlight a given wavelength, click the
Examine
icon (curve with an X) in
the tool bar.
Use
this to label the
wavelength of maximal absorption (?
max
).
10)
Additionally, you can expand (zoom
–
in) by changing the x
–
axis limits: double
click o
n the left
–
most wavelength and type in the desired lower limit, then do
likewise for the right
–
most wavelength to set the upper wavelength limit.
11)
From the spreadsheet, the absorbance of each
dilution can be read for
constructing an Abs vs. C plot.