50 May / June 2017
residual solvents. Some manufacturers may use cheap materials in order to produce the products cost-effectively and have a higher profit margin. These cheap materials may have high levels of dangerous solvents. For example, if a product that retains high levels of ethanol is used to treat children, it could cause liver damage. As a result, testing needs to be taken very seriously due to the harmful nature and severe consequences that the solvents can cause.
Experimental Pesticide Analysis
The Chromatogram in Figure 1 shows that a range of common pesticide compounds analysed using a 200 Series Gas Chromatograph. All components normally found when testing the pesticide standard were detected.
Materials
Pesticides in Cannabis were tested by using a readily available standard (Restek Cat.# 32568: GC Multiresidue Pesticide Standard #6 (18 components) Synthetic Pyrethroid Compounds) to show that the compounds can be clearly and easily detected when using a 200 Series Gas Chromatograph. A 1.0 µL sample of the liquid standard mixture was used when testing for pesticides. Some pesticides have large, complex non- volatile molecules. Using liquid samples is the easiest and quickest way to carry out pesticide analysis. A headspace analysis can be used, but requires more time to prepare the samples for injection. The samples were placed in an EL3000A liquid autosampler, and then analysed. All components normally found when testing the pesticide standard were detected, and with low noise levels.
Solvent Residue Analysis
Figure 2 shows a chromatogram of common residual solvents analysed on a 200 series gas chromatograph. All components normally found when testing residual solvents were detected clearly with low noise output.
Materials
Residual solvents in Cannabis were tested by using a readily available standard (a mix of both Supelco Residual Solvents Mix 1 Cat No. 48894 and Mix 2 Cat No. 48895) to show that the compounds can be clearly and easily detected when using a 200 Series
Conditions
GC Conditions Injector Temperature Detector Type
Detector Temperature Carrier Gas Type Constant Pressure Split Flow
Column Type
Temperature Program Initial Temperature Ramp 1
230˚C FID
240˚C
Hydrogen 4.65 psi
70 ml min-1 EL-VOC 60 m x 0.32 mm x 1.8 µm
40˚C (hold 4 mins) 4˚C min-1
to 200˚C (hold 3 mins)
Figure 2 - A 0.5 µL injection of a 25-component residual solvent mix standard
1. Methanol 2. Ethanol
3. 2-Propanol 4. Acetone
5. Methyl Acetate 6. 1-Propanol 7. sec-Butanol 8. 2-Butanone 9. Ethyl Acetate
10. iso-Butanol 11. Tetrahydrofuran
Acetic Acid (breakdown product)
12. Methyl Cellusolve 13. Cyclohexane
14. iso-Propyl Acetate 15. n-Butanol
16. 1-Methoxy-2-Propanol 17. n-Propyl Acetate
Gas Chromatograph. In order for residual solvents to be extracted, the components will need to enter the gas phase, and so headspace sampling was used for this purpose. The samples were placed in a headspace autosampler and the sample
18. 4-Methyl-2-Pentanone 19. 2-Ethoxyethanol 20. iso-Butyl Acetate
21. Toluene 22. Butyl Acetate
23. Methyl Cellusolve Acetate 24. 2-Ethoxyethyl Acetate 25. Cyclohexanone
was heated to encourage the volatile compounds to excite and enter the gas phase. Once this has happened, sampling can take place. The gas sample was injected into the 200 series GC-FID.
A 10 µL volume of the 25 mix standards was
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