GC/MS/MS Analysis of Pesticides in Chamomile on SLB®-5ms after QuEChERS Cleanup using SupelClean™ Ultra
Materials
analytical column
accessory
Certified Vial Kit, Low Adsorption (LA) QsertVial™
volume 0.3 mL, QsertVial, amber glass vial, natural PTFE/silicone septa, thread for 9 mmCONDITIONS
sample/matrix
chamomile
extraction tube
Supel™ Que non-buffered extraction tube (4 mg NaSO4, 1 g NaCl in 12 mL tube) (55294-U)
extraction process
Add 10 mL acetonitrile/IS Extraction Solvent and allow to sit 15 minutes, then shake or vortex 30 sec. Add contents of Supel Que non-buffered extraction tube (55294-U). (Shake by hand immediately to prevent clumping. Shake on shaker for 30 minutes at 2250 rpm, centrifuge for 5 minutes at 4500 rpm. Draw off supernatant for cleanup.)
clean-up tube
Supelclean Ultra 2400, 3 mL (54281-U)
clean-up process
See description text
column
SLB-5ms, 30 m x 0.25 mm I.D. x 0.25 μm (28471-U)
oven
105°C (3 min), 10 °C/min to 130 °C, 4°C/min to 200°C, 8°C/min. to 300°C (10 min)
inj. temp.
programmed: 100 °C (.05 min), to 280 °C at 720°C/min, hold 45 min
detector
MS/MS
MSD interface
300 °C
scan range
MRM
carrier gas
helium, 1.4 mL/min constant flow
injection
2 μL splitless
liner
2 mm ID
sample
QuEChERS extract of chamomile
Description
Analysis Note
QuEChERS is a common method used for extraction of pesticide residues from dry botanicals. The resulting extracts are often very high in background, requiring a rigorous cleanup prior to analysis. The standard SPE cleanup approach uses a dual layer cartridge containing graphitized carbon (GCB) and PSA. In this application, Supelclean™ Ultra 2400 was used for SPE cleanup of chamomile extracts. Supelclean Ultra offers several advantages over the standard cartridge: (1) smaller size and thus less solvent usage, (2) does not require the use of toluene for elution, and (3) better recovery of pesticides with planar structures.
Other Notes
Clean-up process:
Cartridge: Top 3 mL Supelclean Ultra 2400 SPE cartridge (54281-U) with ~0.10 g anhydrous sodium sulfate
Condition: 3 mL of acetonitrile
Load: 750 μL of QuEChERS extract
Elute: using 8 mL of acetonitrile containing 0.5% formic acid, apply slight vacuum at end if needed.
Collect eluent in glass or plastic centrifuge tubes (glass preferred)
Concentrate: all eluent extracts in water bath at 45-50°C w/3 psi nitrogen purge to ~50-100 μL.
Legal Information
SLB is a registered trademark of Merck KGaA, Darmstadt, Germany
Supel is a trademark of Sigma-Aldrich Co. LLC
Supelclean is a trademark of Sigma-Aldrich Co. LLC