Speciation analysis of mercury in sediments using vortex-assisted liquid-liquid microextraction coupled to high-performance liquid chromatography-cold vapor atomic fluorescence spectrometry.

A simple and fast solvent microextraction method termed vortex-assisted liquid-liquid microextraction (VALLME) coupled with high-performance liquid chromatography-vapor generation atomic fluorescence spectrometry (HPLC-CVAFS) has been developed for the trace analysis of methylmercury (MeHg(+)), ethylmercury (EtHg(+)) and inorganic mercury (Hg(2+)) in sediment samples. Carbon tetrachloride was used as collecting solvent for the extraction of mercury species from sediment by a vortex-assisted extraction. In VALLME, 100 μL 1% (m/v) l-Cysteine were used as extraction solvent and were injected into 4 mL carbon tetrachloride.

Vortex-assisted extraction combined with dispersive liquid-liquid microextraction for the determination of polycyclic aromatic hydrocarbons in sediment by high performance liquid chromatography.

A simple, rapid, and efficient method, vortex-assisted extraction followed by dispersive liquid-liquid microextraction (DLLME) has been developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) in sediment samples prior to analysis by high performance liquid chromatography fluorescence detection. Acetonitrile was used as collecting solvent for the extraction of PAHs from sediment by vortex-assisted extraction. In DLLME, PAHs were rapidly transferred from acetonitrile to dichloromethane.

[Determination of trace amounts of mercury in sediments by sequential injection cold vapor atomic fluorescence spectrometry coupled with microwave-assisted digestion].

A novel method for the determination of trace amounts of mercury in sediments by sequential injection cold vapor atomic fluorescence spectrometry coupled with microwave assisted digestion was developed in this paper. Satisfactory results were found when the digestion was carried out at 140 degrees C for 5 min by using 10% HCl-50% HNO3- 40% H2O or 30% HCl-20% HNO3- 50% H2O media. The linear range was 0.

Determination of chemical oxygen demand in fresh waters using flow injection with on-line UV-photocatalytic oxidation and spectrophotometric detection.

A flow injection manifold incorporating UV-photocatalytic oxidation for the determination of chemical oxygen demand (COD) in freshwater is reported. The method utilises the UV-photocatalytic oxidation of organic compounds instead of conventional heating (used in the standard method), with acidified potassium permanganate as the oxidant. Sodium oxalate, d-glucose and potassium hydrogen phthalate were used as COD standards.