Attention:

Certain features of Sigma-Aldrich.com will be down for maintenance the evening of Friday August 18th starting at 8:00 pm CDT until Saturday August 19th at 12:01 pm CDT.   Please note that you still have telephone and email access to our local offices. We apologize for any inconvenience.

GC Analysis of Pesticides in Spinach on SLB®-5ms after QuEChERS Extraction then SPE Clean-up using Supelclean™ ENVI-Carb/NH2 Dual Layer

GC Analysis of Pesticides in Spinach on SLB®-5ms after QuEChERS Extraction then SPE Clean-up using Supelclean™ ENVI-Carb/NH2 Dual Layer

Conditions

sample preparation Solid Phase Extraction (SPE)
sample/matrix Spinach extract by QuEChERS, as described in the pretreatment step
extraction process to 10 g homogenized spinach, add 10 mL acetonitrile, shake 1 min, add contents of Supel QuE acetate tube (55234-U), shake 1 min, 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 Supelclean ENVI-Carb/NH2 SPE Cartridge, 6 mL (54035-U)
condition 10 mL acetonitrile:toluene (75:25), discard
sample addition 1.25 mL spinach 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
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 design (2877505-U)
inj. temp. 60 C (0.28 min), 600 C/min to 325 C (5 min)
detector MSD
MSD interface 325 C
scan range SIM

Description

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 efficient approach to effectively clean up extracts and reduce interferences for low concentration residue analysis. A 6 mL Supelclean ENVI-Carb/ NH2 (54035-U) SPE tube is used for clean-up of spinach extract for GC/MS analysis and produces good recoveries with very low background.

Sample pretreatment: 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
Categories Analytical Chromatography, GC Applications, Pesticides
Featured Industry Agriculture
Food and Beverages
Legal Information Supelclean 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

Materials

     
Related Links