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GC COLUMNS | APPLICATION-SPECIFIC COLUMNS
Foods, Flavors, & Fragrances
Residual Solvent Analysis for Cannabis Concentrates
Rxi®-624Sil MS Columns (fused silica)
(midpolarity Crossbond® phase)
• Low-bleed, high-thermal stability column—maximum temperatures up to 320 °C.
• Inert—excellent peak shape for a wide range of compounds.
• Selective—G43 phase highly selective for volatile organics and residual solvents,
great choice for USP<467>.
• Manufactured for column-to-column reproducibility—well-suited for validated
methods.
Rxi®-624Sil MS (G43) Structure
x
Si O
(CH 2) 3
CH3 CH3
CH3
Si O R O
CH3
CH3
Si
94% y
CH3
CH3
Si
C N
similar phases
DB-624, VF-624ms, CP-Select 624 CB
20-Meter 30-Meter 60-Meter 75-Meter 105-Meter
ID df temp. limits cat.# price cat.# price cat.# price cat.# price cat.# price
0.18 mm 1.00 µm -20 to 300/320 °C 13865
0.25 mm 1.40 µm -20 to 300/320 °C 13868 13869
0.32 mm 1.80 µm -20 to 300/320 °C 13870 13872
0.53 mm 3.00 µm -20 to 280/300 °C 13871 13873 13874 13875
Similar to: (6%-cyanopropylphenyl)-methylpolysiloxane
1
2
3
4
5 6 7 8
9
10
11
12
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
Time (min)
Residual Solvents in Cannabis Concentrates on Rxi®-624Sil MS by Headspace–Full Evaporation
Technique (HS-FET)
GC_FS0517
Peaks tR(min)
1. Isobutane 0.910
2. Butane 0.996
3. Methanol 1.112
4. Pentane 1.508
5. Ethanol 1.545
6. Acetone 1.795
7. Isopropanol 1.891
8. n-Hexane 2.412
9. Chloroform 2.962
10. Benzene 3.213
11. Heptane 3.363
12. Toluene 4.135
Column Rxi®-624Sil MS, 30 m, 0.25 mm ID, 1.40 µm (cat.# 13868)
Sample Residual solvent mix
Diluent: Dimethyl sulfoxide (DMSO)
Conc.: 500 ppm (For the HS-FET technique, 10 µL of a 1,000 µg/mL
standard was placed into a 20 mL headspace vial to represent a
500 ppm sample concentration, assuming a 20 mg sample.)
Injection headspace-loop split (split ratio 10:1)
Liner: Sky® 1.0 mm ID straight inlet liner (cat.# 23333.1)
Headspace-Loop
Instrument: Tekmar HT3
Inj. Time: 1.0 min
Transfer Line Temp.: 160 °C
Valve Oven Temp.: 160 °C
Needle Temp.: 140 °C
Sample Temp.: 140 °C
Platen temp
equil. time: 1.0 min
Sample Equil. Time: 30.0 min
Vial Pressure: 20 psi
Pressurize Time: 5.0 min
Loop Pressure: 15 psi
Loop Fill Time: 2.0 min
Oven
Oven Temp.: 35 °C (hold 1.5 min) to 300 °C at 30 °C/min (hold 2.0 min)
Carrier Gas He, constant flow
Linear Velocity: 80 cm/sec
Detector FID@ 250 °C
Make-up Gas
Flow Rate: 45 mL/min
Make-up Gas Type: N2
Hydrogen flow: 40 mL/min
Air flow: 450 mL/min
Data Rate: 20 Hz
Instrument Agilent/HP6890 GC
Notes The butane used for standard preparation was a mixture of
butane and isobutane in an unknown ratio. The concentrations of
butane and isobutane should be considered approximate, but do
not exceed 500 ppm for either component.
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