HPLC Determination of Carbofuran in Water with Pre-enrichment by SPE

Two hundred mL of water sample were taken and passed through C18 SPE column to enrich trace amount of carbofuran on the column. Five mL of tetrahydrofuran were used to elute carbofuran from the column, and the eluate was evaporated to dryness by Ar-blowing at 35 ℃. The residue was taken up with 1.0 mL of methanol which was used for HPLC analysis. The Eclipse XDB C18 chromatographic column and the mobile phase of mixture of methanol and water (1+1) were used for separation. Fluorescence detection at λex of 285 nm and λem of 320 nm was adopted in the determination. Linear relationship between values of peak area and mass concentration of carbofuran was obtained in the range of 5×10-4-5.0 mg·L-1, with detection limit (3S/N) of 0.02 μg·L-1. Recovery and precision were tested on water samples by standard addition method at 3 concentration levels of 1.0, 50.0, 200.0 μg·L-1, giving results of recovery in the range of 94.0%-99.6% and RSD′s (n=7) in the range of 1.2%-4.2%.