SPE (Solid Phase Extraction)
10 g homogenized food sample (green onions, apples, Napa cabbage, button mushrooms)
Supelclean ENVI-Carb II/PSA SPE Tube (54067-U)
5 mL acetone:toluene (65:35)
1 mL sample extract
10 mL of acetone:toluene (65:35)
Evaporate fraction to 0.5 mL then adjust volume to 1 mL with ethyl acetate for GC-NPD analysis
SLB-5ms, 30 m x 0.25 mm I.D., 0.25 μm (28471-U)
110 °C (2 min), 2.5 °C/min to 205 °C, 10 °C/min to 310 °C (10 min)
250 °C
NPD, 310 °C
helium, 0.9 mL/min constant flow
2 μL, splitless
4 mm I.D. dual tapered
Sample pretreatment: To a 10 g sample of homogenized food (green onions, apples, Napa cabbage, button mushrooms) was added 10 mL acetonitrile and 4 g magnesium sulfate (that had been heated at 550 °C) and 1 g sodium chloride. After centrifugation, the supernatant was removed and mixed with 1 g magnesium sulfate and centrifuged. 5 mL of the supernatant was removed and evaporated to 1 mL for SPE loading.
Organophosphorous pesticide use in agriculture is widespread due to the fact that they are more amenable to environmental degradation in comparison to organochlorine or organonitrogen compounds. There are a large number of pesticides in the organophosphorous group, and because of their potential health effects, they are of particular concern on produce imported from areas in which they are commonly used. This chromatogram illustrates the separation of 63 of these pesticides by GC on the SLB-5ms using nitrogen phosphorus detection (NPD).
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Supelclean is a trademark of Sigma-Aldrich Co. LLC