Refer to <SN / T 1923-2007 determination of glyphosate and its metabolites in food>
Glyphosate, also known as Roundup, is a broad-spectrum herbicide, widely used in tea garden, orchard, corn field and other agricultural production. With the wide use of glyphosate, the detection of Glyphosate Residues in tea, fruit, corn and other plant-derived foods has attracted more and more attention at home and abroad. Glyphosate (GLY) and its metabolite aminomethylphosphonic acid (AMPA) are small molecular compounds with strong polarity, easily soluble in water and difficult to dissolve in various organic solvents, which brings great difficulties and challenges to conventional detection. Biocomma use Copure® glyphosate column (Cat. No: COGLY3000) to treat glyphosate and its metabolites in tea. Determinated by UPLC-MS / MS method, when the spiked concentration of glyphosate and its metabolites was 80 μ g / kg, the recovery rate was 70-100% and RSD was within 5%, which met the determination standard.
1. Sample extraction
Accurately weigh 1.0g(accurate to 0.001g) of crushed tea sample into a 50ml centrifuge tube, add 100μL of 1,2-c13n15glyphosate isotope internal standard solution with concentration of 10 mg/L, add 10ml of water, vortex mixing for 20 min, ultrasonic oscillation for 10 min and centrifugation at 4000 R / min for 8 min.
Transfer 5 ml supernatant to 15 ml centrifuge tube, add 5 ml dichloromethane, vortex for 5 min and centrifugation at 4000 R / min for 4 min. Take 2.5 ml supernatant and pass through the Copure® glyphosate column (Activate with 3 ml methanol and 3 ml water in turn before using the Copure® glyphosate column), discard several drops of filter liquid at the front end and collect the filtrate.
Take 1ml of the above filtrate for derivatization, add 1.0 ml of 50 g / L sodium borate solution and 0.5 ml of 10 g / L FMOC-Cl in turn, vortex mixing for 2 min, 40 ℃ water bath derivatization for 1 h, vortex for 1 min and centrifugation at 8000 R / min for 3 min. The supernatant was filtered through 0.22 μm filter membrane for detection.
4.Instrument conditions (Thermo Fisher TQS Endura)
4.1 Liquid phase part:
Chromatographic column: Copure®CS211003C18 (2.1 mm × 100 mm, 3 μ m)
Mobile phase: A: acetonitrile (0.1% formic acid) B: 5 mmol / L ammonium acetate
Flow rate: 0.4 ml / min Column temperature: 30 ℃ Injection volume: 5μL
4.2 Mass spectrum conditions
Ion source: HESI Electrospray voltage: 3500 V Sheath gas pressure: 30arb
Auxiliary gas pressure: 5 arb Ion transfer tube: 250 ℃ Auxiliary gas temperature: 350 ℃
Table 2 list of component names, retention time and characteristic ions (* is quantitative ion)
Table 3 recovery results of glyphosate and its metabolites in tea