Multiresidue pesticides in spinach

sample preparation

SPE (Solid Phase Extraction)

sample/matrix

10 g of fresh spinach spiked at 0.2 ppm each pesticide

SPE tube/cartridge

Supelclean ENVI-Carb-II/PSA, 500mg/300mg/6mL (55119-U)

condition

5 mL acetonitrile:toluene (3:1, v/v)

sample addition

1 mL concentrated sample extract

elution

20 mL acetonitrile:toluene (3:1, v/v)

eluate post-treatment

Evaporate eluate to dryness with nitrogen at 40 °C. Reconstitute in 1 mL acetone:hexane (1:1, v/v).

column

Equity-1, 30 m x 0.25 mm I.D., 0.25 μm (28046-U)

oven

50 °C (5 min), 25 °C/min to 125 °C, 10 °C/min to 30 °C (8 min)

inj. temp.

200 °C, aux: 325 °C (8 min)

detector

MSD, scan range 45-450 amu

carrier gas

helium, 0.9 mL/min., constant flow mode

injection

1 μL, splitless (splitter open at 1 min)

liner

4 mm I.D., single taper