5
b.
Simultaneously, depress the syringe plunger and select Collect to begin data
collection. Pull the needle out of the injection port immediately.
7. While the data collection proceeds, repeat Step 4 to thoroughly clean the
syringe and needle. It may take more than three flushes to feel the syringe
plunger move smoothly again, which is your indicator that the syringe and
needle are both suitably clean.
8. Data collection will end after 10 minutes.
9. Analyze your chromatogram.
a.
Choose Peak Integration from the Analyze menu.
b.
To select and integrate the peak, drag across the graph from a little before
the peak to a point far enough to the right so that the entire peak is included.
Choose Add.
Figure 4
Peak integration in
Logger
Pro
c.
Select OK to return to the graph.
10. Using Logger
Pro
or LabQuest App, you can do any of the following.
You can choose to Store a run. (In Logger
Pro
, choose Store Latest Run
from the Experiment menu. In LabQuest App, tap the File Cabinet icon.)
You can choose to save this chromatogram and peak analysis for later use,
with a unique file name, by choosing Save from the File menu.
Print your chromatogram and peak analysis table.
You can rename run names, or peak names.
6
1.0 Product Description and Principles of Operation
Figure 5
Side view of Vernier Mini GC Plus
Figure 5 shows a side view of the Vernier Mini GC Plus. The power input jack,
power switch, USB connection to the computer or LabQuest, and column ventilation
grill are shown in this view.
Principles of Operation
: The Vernier Mini GC Plus is designed to separate mixtures
of gases or volatile liquids and identify components of the mixtures by their specific
retention times. The chromatograph uses ambient air supplied from a pump to carry
a small sample of vapor through a stainless steel column.
The column is a nonpolar, general purpose capillary column made by Restek
(product code: MXT
®
–1). The column is heated using an electric current.
Temperature of the column is monitored by a built-in resistance temperature detector
(RTD) for accurate temperature measurement. The column assembly also has an
independent thermistor to protect against overheating.
At the end of the column is a Seacoast Science chemicapacitor sensor. The sensor is
a micromachined sensor chip coated with a chemoselective polymer. The polymer
absorbs analytes exiting the column. Analyte absorption by the polymer coating is
measured by the detector circuitry.
2.0 Specifications
The Vernier Mini GC Plus is designed for use in an educational laboratory. Ambient
temperature range for safe operation is 5°C to 40°C, and safe range of ambient
relative humidity of 0 to 95%. The Mini GC Plus should not be immersed or sprayed
with liquids. Power for the instrument is supplied by an external power supply. The
Mini GC Plus has a back-lit liquid-crystal display that advises the user of current
status.
