Untargeted approach for the evaluation of anthropic impact on the sheltered marine area of Portofino (Italy).

Seawater passive sampling with Polar Organic Chemical Integrative Samplers (POCIS) combined with Gaschromatography-Mass Spectrometry analysis were employed as a tool for screening unknown contaminants in a complex Ligurian marine coastal area. The untargeted approach allowed recognizing different classes of compounds, mainly hydrocarbons from C20 to C30. Besides, two chemicals, deriving from anthropic activities, N-butylbenzenesulfonamide (NBBS) and diphenyl sulfone (DPS), were identified and quantified in all samples. Both analytes showed decreasing concentrations from the more confined site to the outer one. The oceanographic characterization of the area performed with multiparametric probes provided useful information, in agreement with chemical analyses. The presence of NBBS and DPS in the site presenting lower continental inputs demonstrated the usefulness of the integrative sampling approach for temporal and spatial monitoring, especially for low level and/or short-term pollution events that traditional monitoring can fail to detect.

Liquid chromatography-tandem mass spectrometry and passive sampling: powerful tools for the determination of emerging pollutants in water for human consumption.

Among the wide range of emerging pollutants, perfluorinated compounds and various pharmaceuticals, such as nonsteroidal anti-inflammatory drugs, are showing growing concern. These contaminants can be found in freshwater ecosystems because of their incomplete removal during wastewater treatments so, their water solubility and poor degradability result in their continuous discharge and pseudo-persistent contamination. Usually, expected levels of these analytes are particularly low; therefore, sensitive and selective analytical techniques are required for their determination. Moreover, sampling and preconcentration are fundamental steps to reach the low detection limits required. The polar organic chemical integrative sampler (POCIS) represents a modern sampling approach that allows the in-situ preconcentration of ultra-trace pollutants. In this work, a fast liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method was developed for the determination of diclofenac, ketoprofen, mefenamic acid, naproxen, ibuprofen, perfluorooctanoic acid, perfluorooctanesulfonate and caffeine in water for human consumption. The chromatographic separation of analytes was achieved in less than 6 min. Quantitative analysis was performed in multiple reaction monitoring mode using ketoprofen-d3 as internal standard. Two different sites of Northern Italy were studied deploying POCIS for four weeks in both inlet and outlet of two drinking water treatment plants. The evaluation of time-weighted average concentration of contaminants was accomplished after the calibration of POCIS; to this aim, the sampling rate values for each compound were obtained by means of a simple calibration system developed in our laboratory. Ketoprofen, perfluorooctane sulfonate, perfluorooctanoate and caffeine were measured in both sites at the ng l(-1) level. Copyright © 2016 John Wiley & Sons, Ltd.

Green Synthesis of Novel Polyaniline Nanofibers: Application in pH Sensing.

An optically active polyaniline nanomaterial (PANI-Nap), doped with (S)-naproxen, was developed and evaluated as a potent pH sensor. We synthesized the material in one pot by the addition of the dopant, (S)-naproxen, prior to polymerization, followed by the addition of the oxidizing agent (ammonium persulfate) that causes polymerization of the aniline. This green chemistry approach allowed us to take only 1 h to produce a water-soluble and stable nanomaterial. UV-visible spectroscopy, fluorescence spectroscopy, FT-IR spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the designed nanomaterial. This nanomaterial exhibited excellent pH sensing properties and showed long term stability (up to one month) without loss of sensor performance.

Innovative sampling and extraction methods for the determination of nonsteroidal anti-inflammatory drugs in water.

Two different innovative approaches were used for the determination of nonsteroidal anti-inflammatory drugs (NSAIDs) in water: stir bar sorptive extraction (SBSE) and passive sampling, followed by electrospray ionization liquid chromatography-tandem mass spectrometry. SBSE was developed by comparing EG-Silicone and PDMS stir bars and optimizing main parameters to attain high preconcentration. Quantitative analysis was carried out by mass spectrometry in negative ionization mode and multiple reaction monitoring. The SBSE-LC-MS/MS method provided satisfactory figures of merit with LOD (7.5-71 ng L(-1)) and LOQ (22.5-213 ng L(-1)). The developed method was successfully applied to real samples collected from river water and wastewater effluents. The obtained results showed the presence of all analytes at trace levels, in a wide range of concentrations. The passive sampling approach was carried out by using Polar Organic Chemical Integrative Sampler (POCIS); samplers were deployed for 15 days in river and tap water, allowing to detect analytes at ultra-trace levels. Time-Weighted Average concentration of NSAIDs in river water was estimated in the range 0.33-0.46 ng L(-1), using the sampling rates previously obtained by means of a simple calibration system.

'Extreme mass spectrometry': the role of mass spectrometry in the study of the Antarctic environment.

A focus on the studies of the Antarctic environment that have been performed by mass spectrometry is presented herein; our aim is to give evidence of the essential role of this instrumental technique in the framework of the scientific research in Antarctica, with a comprehensive review on the main literature of the last two decades. Due to the wideness of the topic, the present review is limited to the determination of organic pollutants, natural molecules and biomarkers in Antarctica, thus excluding elemental analysis and studies on inorganic species. The work has been divided into five sections, on the basis of the considered environmental compartment: air; ice and snow; seawater, pack ice and lakes; soil and sediments; and organisms and biomarkers.

Green synthesis and characterization of novel gold nanocomposites for electrochemical sensing applications.

Synthesis, characterization and application of Au-PANI-Calix and Au-PANI-Nap nanocomposites, is reported herein. An easy template free green synthesis is proposed and discussed for easy expediency. A variety of analytical techniques were used to characterize the nanocomposites: UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Dynamic light scattering (DLS), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) were used to characterize the nanocomposites. Surface morphology was studied by transmission electron microscopy (TEM). The nanocomposites were immobilized on screen-printed electrode and showed electroactivity in neutral pH, making them promising candidates for various analytical applications. A sensitive and selective detection of Cu(2+) was perceived on the Au-PANI-Calix modified electrode with no interference from ions K(+), Ni(2+), Co(2+), Pb(2+), Cr(3+) with a detection limit of 10nM. The copper detection is facilitated for accessible ligation with 4-sulfocalix[4]arene, so as the Cu(II)-Calix complex formed. The electrode modified with Au-PANI-Nap showed sensing application towards H2O2 with a detection limit of 1 µM. The modified electrodes were reproducible and stable for 2 months.

Study of Convolvulus pluricaulis for antioxidant and anticonvulsant activity.

Convolvulus pluricaulis Choisy is a perennial wild herb commonly found on sandy & rocky areas under xerophytic conditions in northern India. It is a reputed drug of ayurveda and reported to posses antioxidant, brain tonic, nervine tonic, laxative and has been used in anxiety, neurosis, epilepsy, insomnia, burning sensation, oedema and urinary disorders. In the present study, methanolic extract of whole plant of Convolvulus pluricaulis Choisy was evaluated for antioxidant activity by using 1, 1-diphenyl-2-picryl- hydrazyl (DPPH) free radical scavenging model and anticonvulsant activity by using maximal electroshock seizure model. In antioxidant activity, ascorbic acid was used as standard agent while results of anticonvulsant studies were compared with phenytoin. Results of antioxidant activity have demonstrated significant free radical scavenging effect for methanolic extract of Convolvulus pluricaulis Choisy. IC50 value of methanolic extract was observed as 41.00µg/ml as compared to 2.03µg/ml of ascorbic acid. Methanolic extract of C. pluricaulis was evaluated for anticonvulsant activity at 250, 500 and 1000mg/kg. Experimental results have shown that at the dose of 500 and 1000mg/kg, C. pluricaulis didn't abolish the hind limb extension, but reduced the mean recovery time from convulsion.

Indirect enantioresolution of (R,S)-mexiletine by reversed-phase high-performance liquid chromatography via diastereomerization with [(S,S)-O,O'-di-p-toluoyl tartaric acid anhydride], (S)-naproxen and nine chiral reagents synthesized as variants of Marfey's reagent.

Eleven chiral derivatizing reagents (CDRs) were used for preparation of diastereomers of (R,S)-mexiletine containing a primary amino group in close proximity to the stereogenic center. One anhydride, namely [(S,S)-O,O'-di-p-toluoyl tartaric acid anhydride] was synthesized and (S)-naproxen was used as such as the chiral derivatizing reagent. The other nine CDRs were synthesized by substituting one of the fluorine atoms in 1,5-difluoro-2,4-dinitrobenzene with six amino acid amides and three amino acids. The diastereomers were separated by reversed-phase high-performance liquid chromatography. The method was validated for linearity, accuracy, limit of detection and limit of quantification. The limit of detection was found in the range of 10-30 pmol.

Different approaches of impregnation for resolution of enantiomers of atenolol, propranolol and salbutamol using Cu(II)-L-amino acid complexes for ligand exchange on commercial thin layer chromatographic plates.

Atenolol and propranolol (the beta-blocking agents) and salbutamol (broncho- and vasodilator) were resolved into their enantiomers by adopting different modes of loading/impregnating the Cu(II) complexes of L-proline (L-Pro), L-phenylalanine (L-Phe), L-histidine (L-His), N,N-dimethyl-L-phenylalanine (N,N-Me(2)-L-Phe), and L-tryptophan (L-Trp) on commercial precoated normal phase plates. The three different approaches were (A) using the Cu(II)-L-amino acid complex as chiral mobile phase additive, (B) ascending development of plain commercial plates in the solutions of Cu complex, and (C) using a solution of Cu(II) acetate as mobile phase additive for the commercial TLC plates impregnated with ascending development of plates in the solutions of amino acid. Spots were located using iodine vapour. The results obtained for the three methods have been compared for their efficiency and the issue of involvement of the Cu(II) cation for the best performance of the three methods has been discussed with respect to the same mobile phase. The detection limit is 0.18 microg for each enantiomer.

Synthesis of dinitrophenyl-L-Pro-N-hydroxysuccinimide ester and four new variants of Sanger's reagent having chiral amines and their application for enantioresolution of mexiletine using reversed-phase high-performance liquid chromatography.

Four chiral derivatizing reagents (CDRs) having enantiomerically pure amines and two CDRs namely, [N-succinimidyl-(S)-2-(6-methoxynaphth-2-yl)propionate], and [dinitrophenyl-L-Pro-N-hydroxysuccinimide ester, DNP-L-Pro-SU] were synthesized and were used to prepare diastereomers of (R,S)-mexiletine (MEX); these were separated by reversed-phase high-performance liquid chromatography (RP-HPLC). The method was validated for linearity, accuracy, limit of detection (LOD) and limit of quantification (LOQ).

Reversed-phase high-performance liquid chromatographic enantioresolution of six beta-blockers using dinitrophenyl-L-Pro-N-hydroxysuccinimide ester, N-succinimidyl-(S)-2-(6-methoxynaphth-2-yl) propionate and twelve variants of Sanger's reagent as chiral derivatizing reagents.

Twelve chiral derivatizing reagents (CDRs) were synthesized by substituting one of the fluorine atoms in 1,5-difluoro-2,4-dinitrobenzene (DFDNB) with three optically pure amines [(R)-(-)-1-cyclohexylethylamine, (+)-dehydroabietylamine and (S)-(-)-alpha,4-dimethylbenzylamine], six amino acid amides [L-Ala-NH(2), L-Phe-NH(2), L-Val-NH(2), L-Leu-NH(2), L-Met-NH(2) and D-Phg-NH(2)] and three amino acids [L-Ala, L-Val and L-Leu]. In addition, dinitrophenyl-L-Pro-N-hydroxysuccinimide ester and N-succinimidyl-(S)-2-(6-methoxynaphth-2-yl) propionate were also synthesized and used as CDR. Keeping in view the presence of an amino group, diastereomers of six beta-blockers (atenolol, propranolol, bisoprolol, metoprolol, salbutamol, and carvedilol) were synthesized by reaction with these 14 CDRs. The diastereomers were separated by RP-HPLC. The method was validated for linearity, accuracy, limit of detection and limit of quantification.

Reversed-phase liquid chromatographic determination of enantiomers of atenolol in rat plasma using derivatization with Marfey's reagent.

An HPLC method was established for enantioseparation of (R,S)-atenolol (ATE) and determination of enantiomers in rat plasma. Marfey's reagent (1-fluoro-2,4-dinitrophenyl-5-L-alanine amide, FDNP-L-Ala-NH(2), MR) was used as chiral derivatizing reagent with detection of diastereomers at 340 nm. It was shown that the R-isomer eluted before the S-isomer. The method was validated for linearity, repeatability, limits of detection and limit of quantification (LOQ). Recovery of ATE at LOQ was 92.8% for (R)-ATE and 92.6% for (S)-ATE.

Chromatographic separation of enantiomers of non-protein alpha-amino acids after derivatization with Marfey's reagent and its four variants.

Some non-protein alpha-amino acids were derivatized with 1-fluoro-2,4-dinitrophenyl-5-L-alaninamide (Marfey's reagent, MR, FDNP-L-Ala-NH(2),) and four of its structural variants FDNP-L-Phe-NH(2), FDNP-L-Val-NH(2), FDNP-L-Leu-NH(2) and FDNP-L-Pro-NH(2). The resultant diastereomers were separated by normal and reversed phase thin layer chromatography (TLC) and reversed phase HPLC. In normal phase TLC, best resolution was obtained with solvent combination of phenol-water (3:1) while in reversed phase TLC mixtures of acetonitrile with triethylammonium phosphate buffer were found successful for resolution of diastereomers. The separation behavior of diastereomers prepared with different reagents was compared. The diastereomers of most of the amino acids prepared with FDNP-L-Leu-NH(2) were best separated while those prepared with FDNP-L-Pro-NH(2) failed to separate in most of the cases. The diastereomers were also separated on a reversed phase C(8) column with gradient elution using mixture of aqueous-trifluoroacetic acid (TFA) and acetonitrile and with detection at 340 nm. The effects of TFA concentration, flow rate and run time on HPLC separation were studied.

Synthesis of succinimidyl-(S)-naproxen ester and its application for indirect enantioresolution of penicillamine by reversed-phase high-performance liquid chromatography.

Synthesis of N-succinimidyl-(S)-2-(6-methoxynaphth-2-yl) propionate was carried out by the reaction of (S)-naproxen with N-hydroxysuccinimide in the presence of dicyclohexyl carbodiimide. It was characterized and was used as a chiral derivatizing reagent, under mild conditions, to form diastereomers of dl-penicillamine which were resolved by reversed-phase high-performance liquid chromatography using triethyl ammonium phosphate buffer (pH 4.0, 5mM)-acetonitrile (linear gradient (30min) of acetonitrile from 30 to 70%). Excellent separation was achieved with gradient mobile phase. The detection limit was at pmol level.

Direct TLC resolution of atenolol and propranolol into their enantiomers using three different chiral selectors as impregnating reagents.

Direct resolution of racemic atenolol and propranolol into their enantiomers was achieved by normal phase TLC on silica gel plates impregnated with optically pure L-tartaric acid, (R)-mandelic acid and (-)-erythromycin as chiral selectors. Different solvent systems were worked out to resolve the enantiomers. Spots were detected using iodine vapour. The TLC method was validated for linearity, limit of detection and limit of quantification. The influence of pH, temperature and concentration of chiral selector was studied.