HPLC Analysis of Nonvolatile Pesticides in Water on SUPELCOSIL^™ LC-18-DB after SPE using Supelclean^™ ENVI-Carb^™

sample preparation

SPE (Solid Phase Extraction)

sample/matrix

water spiked with pesticides at 10-50 μg/L

SPE tube/cartridge

Supelclean ENVI-Carb, 250 mg/3 mL (57088)

condition

5 mL methylene chloride:methanol (80:20); 1 mL methanol; 10 mL 2% acetic acid in water (keep bed moist until sample addition)

sample addition

100 mL sample at 5 mL/min

drying

1 minute with vacuum

elution

0.8 mL methanol; 2 x 35 mL methylene chloride:methanol (80:20)

eluate post-treatment

dry eluate to 500 μL under gentle nitrogen stream, reconstitute to 1 mL with methanol

column

SUPELCOSIL LC-18-DB, 25 cm × 4.6 mm I.D., 5 μm particles (58355-U)

mobile phase

[A] water:acetonitrile (90:10), [B] acetonitrile; gradient 80% A for 5 min then to 30% A over 30 min

flow rate

1.5 mL/min

detector

UV, 220 nm

injection

20 μL