Oxidized carbon nanotubes as sorbent for miniaturized solid-phase extraction of progestins from environmental water samples prior to their determination by HPLC-UV.

A solid-phase extraction method is presented for micro-extraction of three progestins (levonorgestrel, 19-norethisterone acetate and medroxyprogesterone acetate) from water samples. A mini-column was packed with 60 mg of oxidized multiwalled carbon nanotubes and coupled to a flow injection assembly. The extraction parameters, such as washing solution, eluent type, eluent volume, flow rate and sample volume, were optimized.

Ionic liquid mediated extraction, assisted by ultrasound energy, of available/mobilizable metals from sediment samples.

A new extraction method for metals from sediment samples was developed. In this procedure, the chelating agent EDTA was combined with a minimal amount of the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (Bmim[BF]), assisted by ultrasound energy. The available analytes -Cd, Cr, Cu, Ni, Pb and Zn- were extracted under optimal conditions for a 12.

Second order advantage in the determination of amaranth, sunset yellow FCF and tartrazine by UV-vis and multivariate curve resolution-alternating least squares.

A direct spectrophotometric method for the determination of three artificial colors--amaranth, sunset yellow FCF and tartrazine--in beverages samples is proposed. The spectra were recorded between 359 and 600 nm. The spectra of the samples (just filtrated), pure dyes (concentrations ranged between 0.

Fast chromatographic method for the determination of dyes in beverages by using high performance liquid chromatography--diode array detection data and second order algorithms.

A fast chromatographic methodology is presented for the analysis of three synthetic dyes in non-alcoholic beverages: amaranth (E123), sunset yellow FCF (E110) and tartrazine (E102). Seven soft drinks (purchased from a local supermarket) were homogenized, filtered and injected into the chromatographic system. Second order data were obtained by a rapid LC separation and DAD detection.