Isopropylammonium formate (IPAF), a new alkylammonium formate (AAF) room temperature ionic liquid, has been synthesized from isopropylamine and formic acid and characterized as an organic solvent mobile phase replacement for reversed-phase liquid chromatography (LC). Characterization of IPAF solvent properties in water such as pH, conductivity, and viscosity, as well as its synthesis, is descri...

A major disadvantage of gradient elution in terms of speed results from the need to adequately re-equilibrate the column. This work distinguishes two states of re-equilibration: (1) run-to-run repeatability and (2) full equilibration. We find that excellent repeatability (+/-0.002 min in retention time) is achieved with at most 2 column volumes of re-equilibration whereas full equilibration can...

The zein proteins of eight opaque maize mutants were examined by reversed-phase high-performance liquid chromatography (RP-HPLC) and the microstructure of their endosperms by scanning electron microscopy (SEM). The opaque (0) mutants included 01, 05, 09) 010) 011) hI, Oh43JlI and V\ 64AJll. In these opaque mutant maize kernels, the proportion (%) of ex-zein, the major component of the alcohol-e...

A simple method for the simultaneous determination of hippuric acid and benzoic acid in urine using reversed-phase high performance liquid chromatography was described. Chromatography was performed on a Nova-Pak C18 (3.9 x 150 mm) column with a mobile phase of mixed solution methanol: water: acetic acid (20:80:0.2) and UV detection at 254 nm. The calibration curve was linear within concentratio...

Titania microspheres were synthesized using hydrothermal methods to exploit a new liquid chromatography stationary phase. The prepared titania microspheres were approximately 7 μm in diameter, and the particle size distribution was relatively narrow and uniform. Furthermore, the average specific surface area was 276.0 m2·g−1, the average pore volume was approximately 0.25 mL·g−1, and the pore d...

an air–assisted liquid–liquid microextraction method for the extraction and preconcentration of trace amounts of some synthetic phenolic antioxidants in biological fluids followed by their determination by gas chromatography–flame ionization detection has been reported. in this method the target analytes are extracted into a few microliters of carbon tetrachloride (extraction solvent) from an a...

background: a new microextraction method named dispersive liquid-liquid microextraction (dllme) for determination of chloroform in pool water and blood of swimmers after swimming is described. methods: this method was performed based on coupling dispersive liquid-liquid microextraction (dllme) with gas chromatog­raphy-mass spectrometry (gc-ms). methanol and trichloroethylenes were used as the d...

Chromatographic procedures were developed and successfully employed for the separation of a high number of organic and inorganic compounds present at trace level in complicated accompanying matrices. The capacity of chromatographic separation technologies can be increased by the modification of both the stationary and the mobile phase of the system. Because of their specific adsorption characte...

A solid-phase extraction (SPE) method for sample clean-up and preconcentration followed by reversed-phase high-performance liquid chromatography (RP-HPLC) with uv detection is reported for determination of polycyclic aromatic hydrocarbons (PAHs) in the caspian seawater. A good resolution was obtained using acetonitrile:water (40:60) as mobile-phase for separation of these compounds. The eff...

terials, operated in a pressure-driven mode, plotted as a function of inverse temperature. This Rgure is intended to give some appreciation of the Suxes that are attainable; however, they are not normalized to a given partial pressure gradient or thickness of membrane, and thus the Suxes are not directly comparable. Taking a value of between 10 and 100 L m 2 min 1 as the level of oxygen Sux nee...