Specifications; Care And Maintenance - Vernier Go Direct Mini GC Quick Start Manual

10. When you are done with data collection, make sure to turn the power switch
to the Off position and disconnect the Mini GC from AC power. The Mini
GC should be turned off with the power switch when not in use. We
recommend unplugging and disconnecting the power supply and
disconnecting the USB cable while the instrument is not in use. The
chromatograph has a built-in timer to turn off heating of the column and
pressure from the pump after 2 hours with no communication via Bluetooth
wireless technology or USB.

Specifications

Column Restek MXT-502.2 Column - Siltek-treated stainless
steel with proprietary diphenyl/dimethyl polysiloxane
phase
Column operating 30°C to 160°C with a maximum heating ramp of
temperature 10°C/min
Detector Seacoast Science carbon-nanotube chemiresistive
detector
Dimensions and 108 mm height, 191 mm length, 133 mm width; 1.3 kg
weight
Power requirements 24 VDC, 2.5 A from an external power supply
Utility External power supply rated for 100–240 VAC, 1.5 A
50–60 Hz
Carrier gas Ambient air
Environmental Temperature: 5°C to 40°C Humidity: 95% or less, (non-
conditions condensing environment)
Liquid injection 0.01 to 0.6 µL
volume
Operating pressure 1 to 21 kPa
(above ambient
pressure)

Care and Maintenance

To extend the life and ensure the proper functioning of the Go Direct Mini GC,
there are some routine cleanings and replacements that should be followed.
DO NOT inject more than 0.6 μL liquid analyte; injecting excess liquid may
l
damage the sensor. Note: Much larger head-space gas volumes can safely be
injected, up to 1 mL.
DO NOT inject the following liquids/substances into Go Direct Mini GC:
l
Water, or compounds with significant amounts of water impurity
l
Amines (or any other alkaline substances)
l
Liquids containing compounds with large molecular weights, larger than
l
the molecular-weight ranges shown in Appendix A. These types of
compounds can become deposited in the column and degrade its
performance.
Column maintenance and/or Replacement
®
The Restek MXT – 502.2 column is a general-purpose column that performs
very well for our recommended families of reagents and laboratory exercises. It
is a stainless-steel capillary column, 11 meters in length, and coated with
®
Siltek to make the stainless steel unreactive. MXT- 502.2 is coated with a
proprietary diphenyl/dimethyl polysiloxane phase having selectivity for volatile
organic pollutants, light weight hydrocarbons, aromatics, and a wide range of
compounds. If separation efficiency deteriorates, conditioning the column with
0.3 μL of acetone or n-hexane, or running the chromatograph for 1–2 hours at
120°C and 20 kPa with air or an inert carrier gas may help to restore proper
function.
If you use our recommended procedures and substances with your Go Direct
Mini GC, you should get many years of use from the high-quality Restek
column. But, if performance deteriorates after time, such that the column must be
replaced, contact Vernier for an Return Material Authorization (RMA) number
(the column cannot be replaced by the user). You will then send the unit to an
RMA address, and be charged a fee for the replacement.
Cleaning the Exterior of the Case
Before cleaning the case, disconnect power. For routine cleaning of the exterior
of the case, use mild detergent and a damp cloth. Do not allow water to leak
inside of the case as this may result in electrical shock or shorts. Abrasive
cleansers should not be used to clean the instrument.
Replacing the Septum
The septum should be replaced after approximately 150 injections. The septum
may be replaced by unscrewing (counterclockwise) the septum retainer nut
using a coin or a large screwdriver. Note: Two additional septa were shipped
with your new Go Direct Mini GC (in a small Ziploc bag). With the retainer nut
removed, spear the defective septum with a syringe needle and lift it out. Place a
new septum flat in the cavity. Screw the retainer nut to snug tightness.
Overtightening the retainer nut will not give a better seal of the septum but will
damage the instrument. After you have used your original septum, and the two
replacements, you can order additional septa.
Vernier Order Information: Septa Replacement, pkg of 4, order code GC-SEP
Replacing the Chemiresistive Detector
The Seacoast Science carbon nanotube chemiresistive detector is a precision-
etched 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.
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