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GC Analysis of Pesticides in Spinach on SLB®-5ms after QuEChERS Extraction then SPE Clean-up using Supel™ Sphere Carbon/NH2

GC Analysis of Pesticides in Spinach on SLB®-5ms after QuEChERS Extraction then SPE Clean-up using Supel™ Sphere Carbon/NH2


sample preparation Solid Phase Extraction (SPE)
sample/matrix spinach extract
extraction process to 10 g homogenized spinach add 10 mL acetonitrile and shake 1 min, add contents of Supel QuE acetate tube (55234-U), shake 1 min and centrifuge, transfer extract to dSPE tube, (add 1 g anhydrous MgSO4, shake 1 min and centrifuge, transfer 5 mL extract to glass tube, evaporate to 1 mL, add 250 µl toluene for a final volume of 1.25 mL QuEChERS extract)
SPE tube/cartridge Supel Sphere Carbon/NH2 SPE Cartridge, 6 mL (54283-U)
condition 10 mL acetonitrile:toluene (75:25), discard
sample addition 1.25 mL QuEChERS extract
elution 20 mL acetonitrile:toluene (75:25) (gravity elution)
eluate post-treatment adjust volume of sample extract to 21.25 mL
column SLB-5ms, 20 m x 0.18 mm I.D., 0.36 µm (28576-U)
oven 50 C (0.5 min), 25 C/min to 125 C (0 min), 10 C/min to 300 C (5 min)
carrier gas helium
sample spinach extract
injection 10 µL, PTV solvent vent, purge flow to split vent 60 ml/min at 2.78 min, vent flow 100 ml/min
liner 4 mm I.D., split/splitless type, wool packed single taper FocusLiner(TM) design
inj. temp. 60 C (0.28 min), 600 C/min to 325 C (5 min)
detector MSD
MSD interface 325 C


Analysis Note Pigments, sterols, sugars, organic acids and fatty acids when extracted from leafy greens such as spinach, pose problems for long term GC performance. An effective clean-up technique is required that will isolate/retain matrix interferences without effecting the pesticide analytes of interest. Solid Phase Extraction is a common and effecient approach to effectivly clean-up extracts for low concentration residue analysis while reducing interferences. A 6 mL Supel Sphere Carbon/ NH2 (54283-U) SPE tube is used for fast, consistant gravity filtration clean-up of spinach extract for GC/MS analysis and produces good recoveries with low background.
Categories Analytical Chromatography, GC Applications, Pesticides
Featured Industry Agriculture
Food and Beverages
Legal Information Supel is a trademark of Sigma-Aldrich Co. LLC, SLB is a registered trademark of Sigma-Aldrich Co. LLC
suitability application for GC, application for SPE


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