Vernier Go Direct Mini GC Quick Start Manual page 5

The carbon nanotube detector should last for more than 2000 hours of operation.
If performance deteriorates after time, such that the detector must be replaced,
contact Vernier for an RMA number (the sensor cannot be replaced by the user).
You will then send the unit to an RMA address, and be charged a fee for the
replacement.
Storing the Instrument
Proper storage of the Go Direct Mini GC will protect it from damage and
maintain the life of the instrument. The manufacturer recommends flushing the
column with 0.3 μL acetone or n-hexane followed by 15 min purge at 120°C
and 20 kPa. Store the instrument in the protective case provided with
instrument. Store it in a cool, dry environment.
How the Go Direct Mini GC Works
Figure 2 shows a side view of the Go Direct Mini GC. The power input jack,
power switch, USB connection to the Chromebook, or computer, and column
ventilation grill are shown in this view.
Principles of Operation: Go Direct Mini GC 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 –502.2). 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 thermal fuse to protect against overheating.
At the effluent end of the column is a Seacoast Science chemiresistive sensor.
The sensor is a precision-etched sensor chip coated with a chemoselective
polymer-carbon nanotube composite. The composite absorbs analytes exiting the
column. Analyte absorption by the composite coating is measured by the
detector circuitry.
Figure 2
Troubleshooting
Error
Inconsistent flow, not
reaching set pressure
Inconsistent peak areas
Inconsistent retention times
No communication
No power
For additional troubleshooting tips, see
Appendix A
Classes of Compounds That Can Be Used in Go Direct Mini GC
Compound Type Typical
Compounds
Alcohols C
1
Aldehydes C
1
Alkanes C
4
Amides C
3
Aromatics C
6
Carboxylic Acids C
1
Esters C
2
Ethers C
2
Heterocycles C –C
5
Halogenated C
1
hydrocarbons
Ketones C –C
3
Nitriles C –C
2
Nitroalkanes/aromatics C
1
Phosphonates C
3
Sulfides C –C
4
5
Possible Causes
Check and replace septum
Check injection volume, septum, defective
syringe
Check septum, pump
Check cables. Or, make sure you are using
correct software versions.
Check to make sure power plugs are plugged
in properly.
www.vernier.com/til/7281
Range of Acceptable Boiling Points
(°C)
–C 50 –175
6
–C 50 –175
8
–C 30–220
12
–C 150 –250
4
–C 80 –220
11
–C 100–150
4
–C 30 –200
10
–C 30– 110
8
100 –150
8
–C 30–120
8
50 –175
8
50 –120
5
–C 100 –210
6
–C 180 –210
9
90– 150
8