UHPLC Determination of Carbofuran in Water with Automatic SPE and Post Column Derivatization

UHPLC with post-column derivatization after enrichment by automatic SPE was applied to the determination of carbofuran (CFR) in water. The water sample (200 mL) was passed through C18 SPE micro-column at a flow rate of 5 mL·min-1. The column was then dried by N2-blowing and eluted with 5 mL of tetrahydrofuran at a flow rate of 1 mL·min-1. The eluate was evaporated to near-dryness by N2-blowing,and the concentrate was dissolved and made up to 1 mL with methanol. Chromatographic separation was made with the sample solution according to the prscribed chromatographic conditions,and the eluate in the mobile phase of CH3OH-H2O (60+40) mixture was led to the post-derivatization unit,where hydrolysis and derivatization were carried out by using 2.0 g·L-1 NaOH solution as hydrolyzing reagent and a solution of o-benzenediformaldehyde in sadium borate solution as derivatizing agent flowing at a same rate of 0.3 mL·min-1,at a hydrolysis temperature of 105 ℃. Intensity of fluorescence of the derivate was measured at λex of 339 nm and λem of 445 nm. Linear relationships between values of peak area and mass concentration of CFR was obtained in the range of 0.010-2.00 mg·L-1,with detection limit (3S/N) of 0.87 μg·L-1. Values of recovery found by standard addition method were in the range of 99.3%-100%. Values of RSD′s (n=6) found were all less than 3.5%.