Determination of Pesticide Residues in Red Wine by QuEChERS Extraction, Quick QuEChERS Cleanup and LC–MS-MS Detection

Red wine is a challenging matrix that contains organic acids, sugars, phenols, and pigments such as anthocyanins. This application note describes a simple, fast, novel, and effective method to clean up red wine co-extractives.

Extraction Procedure

a) Add 10 mL red wine to 50 mL tube (RFV0050CT)

b) Add 10 mL acetonitrile, vortex 30 s

c) Add salts from Mylar pouch (ECQUUS2-MP)

d) Shake vigorously for 1 min

e) Centrifuge at 5000 rpm for 5 min

f) Supernatant is ready for cleanup

Table I: Extraction and clean-up materials

Quick QuEChERS Cleanup

a) Load 1 mL supernatant with disposable syringe

b) Push the supernatant slowly through the cartridge (ECPURMPSMC)

c) Collect 0.5 mL extract into 2 mL autosampler vial

d) Add triphenyl phosphate as internal standard

Figure 1: Left: quick QuEChERS cartridges before and after cleanup of 1 mL red wine extract; right: red wine extract before (left) and after (right) Quick QuEChERS cleanup.

LC–MS-MS Instrumentation

LC: Thermo Accela 1250 pump

• Column: SepaxHP-C18, 2.1 ×100 mm, 3 µm, 120 Å

• Guard: Restek C18 2.1 × 2 0 mm, 3 µm

• Column Temperature: Ambient

• Injection: 10 µL at 15 °C

• Mobile Phase: A: 0.1% formic acid in water;

B: 0.1% formic acid in methanol

• Gradient: 0 min: 95% A; 1 min: 95%; 3 min: 50% A;

8 min: 5% A; 14 min: 5% A; 14.2 min: 95% A;

16 min: 95% A

• Flow Rate: 200 µL/min

Table II: SRM transitions

MS/MS: Thermo TSQ Vantage

• Ion source: Heated ESI positive, 350 °C

• Spray voltage: 3000 V

• Sheath gas: N₂ at 40 psi

• Auxiliary gas: N₂ at 10 psi

• Collision gas: Ar at 1.5 mTorr

Recoveries ranging from 81.6% to 112.2% with RSD less than 10.8% were achieved for red wine samples fortified with 10, 50, and 100 ng/mL of pesticides.

UCT, LLC

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Website: www.unitedchem.com