Sorption and Preconcentration of the Herbicides Atrazine, Simazine, and Ametryne on Montmorillonite

Evaluation of organo-vermiculites as sorbent phases for solid-phase extraction of ibuprofen from water

The study of ibuprofen (IBU) preconcentration was carried out making use of a homemade column for solid-phase extraction (SPE), using vermiculite (VT) or organo-vermiculites (OVTs) as sorbent phases. Aqueous samples (50.0 mL) percolated the column and IBU was sorbed onto the VT or OVT and then desorbed using acetonitrile. Employing this SPE system and OVT, calibration curves were generated for IBU, by spectrophotometric quantification using the α-naphthylamine method. R2 values higher than 0.9950 and LOD between 12 and 18 μg L-1 were observed, for real enrichment factors of 21 and 31, by using OVTs. The analytical protocol was applied to three water samples, which were spiked with IBU solutions to evaluate the precision and accuracy of the method. Recoveries between 77 and 110% at three different IBU concentrations and RSD lower than 18% were observed, even by using the spectrophotometric method. The protocol developed in this study demonstrated that the OVT was appropriate to work as a preconcentration phase for IBU determination in water samples.

New sorbents based on poly(methacrylic acid-TRIM) and poly(vinylimidazole-TRIM) for simultaneous preconcentration of herbicides in water samples with posterior determination by HPLC-DAD

In the present study, poly(methacrylic acid-trimethylolpropane trimethacrylate) (PMA-TRIM) and poly(vinylimidazole-TRIM) (PV-TRIM) have been used for simultaneous extraction of tebuthiuron, hexazinone, diuron, and ametryn with posterior determination by HPLC-DAD.