Preconcentration and determination of nicosulfuron, thifensulfuron-methyl and metsulfuron-methyl in water samples using carbon nanotubes packed cartridge in combination with high performance liquid chromatography

A new procedure was described with multiwalled carbon nanotubes as solid phase extraction packing material for the trace analysis of nicosulfuron, thifensulfuron and metsulfuron-methyl in water samples. The possible parameters influencing the enrichment were optimized and the optimal conditions were as followed: eluent, sample pH, flow rate and sample volume were acetonitrile containing 1% acetic acid, pH 3, 8 mL min−1 and 500 mL, respectively. Under the optimal chromatographic separation and SPE conditions, the linear range, detection limit (S/N = 3) and precision (R.S.D., n = 6) were 0.04–40 ng mL−1, 6.8 ng L−1 and 2.5% for nicosulfuron, 0.04–40 ng mL−1, 11.2 ng L−1 and 5.4% for thifensulfuron, 0.02–20 ng mL−1, 5.9 ng L−1, 2.1% for metsulfuron-methyl, respectively. The established method was well employed to determine nicosulfuron, thifensulfuron and metsulfuron-methyl in tap water, seawater, reservoir water and well water samples, and satisfactory results were obtained, the spiked recoveries in the range of 87.2–100.7%, 96.5–105.6% and 83.7–111.1% for them each, respectively.