The nano‐LC technique is increasingly used for both fast studies on enantiomeric analysis and tes... more The nano‐LC technique is increasingly used for both fast studies on enantiomeric analysis and test beds of novel stationary phases due to the small volumes involved and the short conditioning and analysis times. In this study, the enantioseparation of 10 drugs from different families was carried out by nano‐LC, utilizing silica with immobilized amylose tris(3‐chloro‐5‐methylphenylcarbamate) column. The effect on chiral separation caused by the addition of different salts to the mobile phase was evaluated. To simultaneously separate as many enantiomers as possible, the effect of buffer concentration in the mobile phase was studied, and, to increase the sensitivity, a liquid–liquid microextraction based on the use of isoamyl acetate as sustainable extraction solvent was applied to pre‐concentrate four chiral drugs from tap and environmental waters, achieving satisfactory recoveries (>70%).
Analytical and Bioanalytical Chemistry, Apr 2, 2011
In this work, the simultaneous separation of a group of 12 pesticides (carbaryl, fensulfothion, m... more In this work, the simultaneous separation of a group of 12 pesticides (carbaryl, fensulfothion, mecoprop, fenamiphos, haloxyfop, diclofop, fipronil, profenofos, fonofos, disulfoton, nitrofen, and terbufos) by nano-liquid chromatography with UV detection is described. For the analyses, a 100 μm internal diameter capillary column packed with silica modified with phenyl groups was used. Experimental parameters, including the use of a trapping column for increasing the sensitivity, were optimized and validated. A preliminary study of the applicability of a rapid and practical dispersive solid-phase extraction (DSPE) procedure was developed for the extraction of some of these pesticides (carbaryl, fensulfothion, fenamiphos, fipronil, profenofos, fonofos, disulfoton, nitrofen, and terbufos) from Milli-Q water samples using multi-walled carbon nanotubes (MWCNTs). The method was validated through a recovery study at three different levels of concentration, obtaining limits of detection in the range 0.016-0.067 μg/L (below European Union maximum residue limits) for the majority of the pesticides. In this work, MWCNTs were reused up to five times, representing an important reduction of the waste of stationary phase. Furthermore, DSPE permitted a clear diminution of the total sample treatment time with respect to conventional SPE.
Capillary electrophoresis has been used for the separation of venlafaxine and two of its impuriti... more Capillary electrophoresis has been used for the separation of venlafaxine and two of its impurities deriving from the synthesis process. The electrophoretic experiments were performed using background electrolytes at different pHs in the 2.5-9.2 range in order to study the effective mobilities and resolution of the three examined compounds. The optimum experimental conditions for the baseline resolution of the three analytes was found at pH 6.5. Very good repeatability for both migration time and corrected peak areas was achieved. The calibration curve was studied for venlafaxine (concentration range 26-224 micrograms/mL), and the plot of the peak area ratio (sample/internal standard [IS]) versus venlafaxine concentration was linear with a correlation coefficient of 0.9991. The effect of different cyclodextrins (CDs), namely, gamma-cyclodextrin (gamma-CD), hydroxypropyl-beta-CD (HP-beta-CD), and alpha-cyclodextrin (alpha-CD), on effective mobility and enantiomeric resolution (R) of venlafaxine (Wy45030) and its impurities (imp1 and imp2) was studied at different pHs, and the best results were obtained at pH 9.2. Venlafaxine was baseline resolved in its enantiomers using gamma-CD or HP-beta-CD, while imp1 (Wy45494) was baseline resolved using alpha-CD.
The nano‐LC technique is increasingly used for both fast studies on enantiomeric analysis and tes... more The nano‐LC technique is increasingly used for both fast studies on enantiomeric analysis and test beds of novel stationary phases due to the small volumes involved and the short conditioning and analysis times. In this study, the enantioseparation of 10 drugs from different families was carried out by nano‐LC, utilizing silica with immobilized amylose tris(3‐chloro‐5‐methylphenylcarbamate) column. The effect on chiral separation caused by the addition of different salts to the mobile phase was evaluated. To simultaneously separate as many enantiomers as possible, the effect of buffer concentration in the mobile phase was studied, and, to increase the sensitivity, a liquid–liquid microextraction based on the use of isoamyl acetate as sustainable extraction solvent was applied to pre‐concentrate four chiral drugs from tap and environmental waters, achieving satisfactory recoveries (>70%).
Analytical and Bioanalytical Chemistry, Apr 2, 2011
In this work, the simultaneous separation of a group of 12 pesticides (carbaryl, fensulfothion, m... more In this work, the simultaneous separation of a group of 12 pesticides (carbaryl, fensulfothion, mecoprop, fenamiphos, haloxyfop, diclofop, fipronil, profenofos, fonofos, disulfoton, nitrofen, and terbufos) by nano-liquid chromatography with UV detection is described. For the analyses, a 100 μm internal diameter capillary column packed with silica modified with phenyl groups was used. Experimental parameters, including the use of a trapping column for increasing the sensitivity, were optimized and validated. A preliminary study of the applicability of a rapid and practical dispersive solid-phase extraction (DSPE) procedure was developed for the extraction of some of these pesticides (carbaryl, fensulfothion, fenamiphos, fipronil, profenofos, fonofos, disulfoton, nitrofen, and terbufos) from Milli-Q water samples using multi-walled carbon nanotubes (MWCNTs). The method was validated through a recovery study at three different levels of concentration, obtaining limits of detection in the range 0.016-0.067 μg/L (below European Union maximum residue limits) for the majority of the pesticides. In this work, MWCNTs were reused up to five times, representing an important reduction of the waste of stationary phase. Furthermore, DSPE permitted a clear diminution of the total sample treatment time with respect to conventional SPE.
Capillary electrophoresis has been used for the separation of venlafaxine and two of its impuriti... more Capillary electrophoresis has been used for the separation of venlafaxine and two of its impurities deriving from the synthesis process. The electrophoretic experiments were performed using background electrolytes at different pHs in the 2.5-9.2 range in order to study the effective mobilities and resolution of the three examined compounds. The optimum experimental conditions for the baseline resolution of the three analytes was found at pH 6.5. Very good repeatability for both migration time and corrected peak areas was achieved. The calibration curve was studied for venlafaxine (concentration range 26-224 micrograms/mL), and the plot of the peak area ratio (sample/internal standard [IS]) versus venlafaxine concentration was linear with a correlation coefficient of 0.9991. The effect of different cyclodextrins (CDs), namely, gamma-cyclodextrin (gamma-CD), hydroxypropyl-beta-CD (HP-beta-CD), and alpha-cyclodextrin (alpha-CD), on effective mobility and enantiomeric resolution (R) of venlafaxine (Wy45030) and its impurities (imp1 and imp2) was studied at different pHs, and the best results were obtained at pH 9.2. Venlafaxine was baseline resolved in its enantiomers using gamma-CD or HP-beta-CD, while imp1 (Wy45494) was baseline resolved using alpha-CD.
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Papers by Salvatore Fanali