Diversity of plant pollen sources, microbial communities, and phenolic compounds present in bee pollen and bee bread.

The pollination of several crops, as well as wild plants, depends on honeybees. To get the nutrients required for growth and survival, honeybee colonies are dependent on pollen supply. Bee pollen (BP) is partially packed in honeycomb cells and processed into beebread (BB) by microbial metabolism. The composition of pollen is highly variable and is mainly dependent on ecological habitat, geographical origin, honey plants, climatic conditions, and seasonal variations. Although there are important differences between the BP and the BB, little comparative chemical and microbiological data on this topic exists in the literature, particularly for samples with the same origin. In this study, BP and BB pollen samples were collected from two apiaries located in the Campania and Molise regions of Southern Italy. Phenolic profiles were detected via HPLC, while antioxidant activity was determined by ABTS·+ and DPPH· assay. The next-generation sequencing (NGS) based on RNA analysis of 16S (rRNA) and internal transcribed spacer (ITS2) regions were used to investigate the microbial community (bacteria and fungi) and botanical origin of the BP and BB. Chemical analysis showed a higher content of flavonols in BP (rutin, myricetin, quercetin, and kaempferol), while in BB there was a higher content of phenolic acids. The NGS analysis revealed that the microbial communities and pollen sources are dependent on the geographical location of apiaries. In addition, diversity was highlighted between the microbial communities present in the BP and BB samples collected from each apiary.

Design, Synthesis and Biological Evaluation of Aromatase Inhibitors Based on Sulfonates and Sulfonamides of Resveratrol.

A library of sulfonate and sulfonamide derivatives of Resveratrol was synthesized and tested for its aromatase inhibitory potential. Interestingly, sulfonate derivatives were found to be more active than sulfonamide bioisosteres with IC50 values in the low micromolar range. The sulfonate analogues 1b-c and 1j exhibited good in vitro antiproliferative activity on the MCF7 cell line, evidenced by MTT and LDH release assays. Structure-activity relationships suggested that electronic and lipophilic properties could have a different role in promoting the biological response for sulfonates and sulfonamides, respectively. Docking studies disclosed the main interactions at a molecular level of detail behind the observed inhibition of the more active compounds whose chemical stability has been evaluated with nano-liquid chromatography. Finally, 1b-c and 1j were highlighted as sulfonates to be further developed as novel and original aromatase inhibitors.

A Rapid Nano-Liquid Chromatographic Method for the Analysis of Cannabinoids in Cannabis sativa L. Extracts.

Cannabis sativa L. is an herbaceous plant belonging to the family of Cannabaceae. It is classified into three different chemotypes based on the different cannabinoids profile. In particular, fiber-type cannabis (hemp) is rich in cannabidiol (CBD) content. In the present work, a rapid nano liquid chromatographic method (nano-LC) was proposed for the determination of the main cannabinoids in Cannabis sativa L. (hemp) inflorescences belonging to different varieties. The nano-LC experiments were carried out in a 100 µm internal diameter capillary column packed with a C18 stationary phase for 15 cm with a mobile phase composed of ACN/H2O/formic acid, 80/19/1% (v/v/v). The reverse-phase nano-LC method allowed the complete separation of four standard cannabinoids in less than 12 min under isocratic elution mode. The nano-LC method coupled to ultraviolet (UV) detection was validated and applied to the quantification of the target analytes in cannabis extracts. The nano-LC system was also coupled to an electrospray ionization-mass spectrometry (ESI-MS) detector to confirm the identity of the cannabinoids present in hemp samples. For the extraction of the cannabinoids, three different approaches, including dynamic maceration (DM), ultrasound-assisted extraction (UAE), and an extraction procedure adapted from the French Pharmacopeia's protocol on medicinal plants, were carried out, and the results achieved were compared.

Stereoisomer separation of flavanones and flavanone-7-O-glycosides by means of nanoliquid chromatography employing derivatized ß-cyclodextrins as mobile-phase additive.

A nanoliquid chromatographic method for the stereoisomer separation of some flavanone aglycones and 7-O-glycosides has been proposed employing a C18 capillary column and a chiral mobile-phase additive such as cyclodextrin. The chiral separation of eriodictyol, naringenin, and hesperitin was obtained by addition of carboxymethyl-ß-cyclodextrin to the mobile phase, whereas eriocitrin, naringin, narirutin, and hesperidin diastereoisomers were resolved by using sulfobutyl ether-ß-cyclodextrin. The influence of the composition of the mobile phase, the length of the capillary column, and the flow rate on the chiral recognition were investigated. At optimum conditions, baseline separation for the selected aglycones and glycosylated forms were achieved with a mobile phase consisting of 50 mM sodium acetate buffer pH 3 and 30% methanol containing 20 mM of carboxymethyl-ß-cyclodextrin and 10 mM of sulfobutyl ether-ß-cyclodextrin, respectively. Precision, linearity, and sensitivity of the method were tested. Limits of detection and quantification for the studied flavanone glycosides were in the range 1.3-2.5 and 7.5-12.5 µg/mL, respectively. The method was used for the determination of the diastereomeric composition of the flavanone-7-O-glycosides in Citrus juices after solid-phase extraction procedure.

Synthesis, biological evaluation, and docking study of indole aryl sulfonamides as aromatase inhibitors.

In order to identify new aromatase enzyme inhibitors, thirty aryl sulfonamide derivatives containing an indole nucleus have been synthesized. The enzyme inhibition assay showed that four compounds inhibit aromatase in the sub-micromolar range. Loading concentrations of these four compounds were afterwards tested for cell viability and cytotoxicity on MCF7 human breast cancer cells, revealing a time- and dose-dependent decrease of active metabolizing cells over the time of the culture (0-72 h), starting from a concentration of 100 µM. Likewise LDH released raised up to 40% at early time of exposures (24 h). Finally, the docking study showed that the best active compounds efficiently bound in the active site of the aromatase; high values of HBD and low levels of HBA are the principal requirement evidenced by the QSAR model.

Ordered mesoporous silica functionalized with ß-cyclodextrin derivative for stereoisomer separation of flavanones and flavanone glycosides by nano-liquid chromatography and capillary electrochromatography.

In this paper a chiral stationary phase (CSP) was prepared by the immobilization of a ß-CD derivative (3,5-dimethylphenylcarbamoylated ß-CD) onto the surface of amino-functionalized spherical ordered mesoporous silica (denoted as SM) via a urea linkage using the Staudinger reaction. The CSP was packed into fused silica capillaries 100µm I.D. and evaluated by means of nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) using model compounds for the enantio- and the diastereomeric separation. The compounds flavanone, 2'-hydroxyflavanone, 4'-hydroxyflavanone, 6-hydroxyflavanone, 4'-methoxyflavanone, 7-methoxyflavanone, hesperetin, hesperidin, naringenin, and naringin were studied using reversed and polar organic elution modes. Baseline stereoisomer resolution and good results in terms of peak efficiency and short analysis time of all studied flavonoids and flavanones glycosides were achieved in reversed phase mode, using as mobile phase a mixture of MeOH/H2O, 10mM ammonium acetate pH 4.5 at different ratios. For the polar organic mode using 100% of MeOH as mobile phase, the CSP showed better performances and the baseline chiral separation of several studied compounds occurred in an analysis time of less than 10min. Good results were also achieved by CEC employing two different mobile phases. The use of MeOH/H2O, 5mM ammonium acetate buffer pH 6.0 (90/10, v/v) was very effective for the chiral resolution of flavanone and its methoxy and hydroxy derivatives.

Online sample concentration and analysis of drugs of abuse in human urine by micelle to solvent stacking in capillary zone electrophoresis.

A sensitive and rapid CZE-UV method was developed to determine drugs and their metabolites' presence in human urine. Ten drugs of abuse were analyzed including four amphetamines, cocaine, cocaethylene, heroin, morphine, 6-monoacetylmorphine, and 4-methylmethcathinone. An MSS (micelle to solvent stacking) approach was evaluated to enhance method sensitivity. This method considers composition of the micellar sample solution matrix and the injection time. Several analytical conditions influencing the resolution of the drugs mixture as pH and buffer concentration, organic solvent content, were also investigated. The base-line separation of all studied analytes in the same run was achieved within 18 min in an uncoated fused silica capillary (50 µm id × 60 cm) using a background solution containing 50 mM phosphate buffer pH 2.5 and 30% ACN v/v. Other experimental parameters such as applied voltage and capillary temperature were set up at 20 kV and 20°C, respectively. LOD values ranging between 15 and 75 ng/mL for all studied compounds were obtained. From a comparison with conventional CZE, the proposed method provides an increase of sensitivity (39- to 55-fold enhancement factor). Under optimal MSS-CZE conditions, good linearity was achieved (R2 ≤ 0.9998). The method was finally applied to the analysis of urine samples spiked with a standard mixture after a sample pretreatment, reaching satisfactory recovery values.

Rapid determination of nucleotides in infant formula by means of nano-liquid chromatography.

A rapid method for the quantification of five ribonucleotides 5'- monophophates (adenosine, cytidine, guanosine, inosine, uridine, 5'-monophosphate), in infant formula, has been proposed using nano-LC. To separate the studied compounds, capillary columns packed with different C18-based stationary phases were investigated. All the columns tested were laboratory prepared. The experiments were performed in ion-pairing RP chromatographic mode using tetrabutylammonium hydroxide as ion-pairing reagent. The method was developed using a core-shell XB-C18 capillary column with a mobile phase consisting of 5% v/v methanol and 95% v/v 100 mM ammonium formate, pH 8, containing 20 mM tetrabutylammonium hydroxide. All compounds were baseline resolved in less than 5 min with a flow rate of 500 nL/min in isocratic elution mode. Nucleotides were detected at 260 nm. Analytical validation parameters were evaluated. The RSD values for intraday and interday repeatability for retention time and peak area were <2.4 and 4.2%, respectively. The method linearity was good (R(2) < 0.9995) for the studied compounds. LOD and limit of quantitation were 0.25 and 0.50 µg/mL, respectively. The method was applied to the determination of nucleotides in infant formula, subjected to a centrifugal ultrafiltration process, prior their analysis. The amounts found were in agreement to the labeled contents.

Comparison of nano and conventional liquid chromatographic methods for the separation of (+)-catechin-ethyl-malvidin-3-glucoside diastereoisomers.

Nano-liquid chromatography and conventional HPLC were used for the separation of diastereomers of (+)-catechin-ethyl-malvidin-3-glucoside. Those bridged anthocyanin dyes were obtained by reaction of (+)-catechin with malvidin-3-glucoside in the presence of acetaldehyde. Both diastereomers were isolated with semipreparative chromatography and their structures were confirmed by nuclear magnetic resonance and mass spectrometry. In-laboratory prepared capillary columns packed with fully porous particles Chromosphere C18, dp=3µm, core-shell particles Kinetex C18, dp=2.6µm (100µm i.d.) and monolithic column Chromolith CapRod (100µm i.d.) were used for the separation of (+)-catechin, malvidin-3-glucoside and both diastereomers. Chromosphere C18 stationary phase provided the best chromatographic performance. Mobile phase containing water:acetonitrile (80:20) acidified with trifluoroacetic acid (0.1%, v/v/v) was used in an isocratic elution mode with a flow rate of 360nLmin(-1). Separation of studied compounds was achieved in less than 7min under optimized conditions. The nano-liquid chromatographic method and a conventional HPLC one using the same fully porous particles (Chromosphere C18, 3µm, 100mm×4.6mm) were compared providing higher separation efficiency with the first analytical method and similar selectivity. A better peak symmetry and higher resolution of the studied diastereomers was achieved by conventional chromatography. Nevertheless, nano-liquid chromatography appeared to be useful for the separation of complex anthocyanin dyes and can be utilized for their analysis in plant and food micro-samples. The developed method was used for analysis of red wine grape pomace.

Determination of key flavonoid aglycones by means of nano-LC for the analysis of dietary supplements and food matrices.

A method for the analysis of flavonoids (myricetin, quercetin, naringenin, hesperitin, and kaempferol), with interesting bioactivity, has been developed and validated utilizing nano-LC technique. In order to find optimal conditions, capillary columns (75 µm id × 10 cm) packed with different types of stationary phases, Kinetex® C18 core-shell (2.6 µm particle size), Hydride-based RP-C18 (sub-2 µm particle size), and LiChrospher® 100 RP-18 endcapped (5 µm particle size) were evaluated. The method was validated using Hydride-based RP-C18 stationary phase, with sub-2 µm particle size. A good chromatographic performance, expressed in terms of repeatability (RSD, in the range 1.63-4.68% for peak area), column-to-column reproducibility (RSD not higher than 8.01% for peak area), good linearity and sensitivity was obtained. In particular limit of detection values between 0.07 and 0.31 µg/mL were achieved with on column focusing technique. The method was applied to the determination of studied flavonoids in dietary supplements as well as in food matrices. The amount of quercetin found in the first analyzed dietary supplement, was in agreement to the labeled content. In the other samples, where the content of flavonoids was not labeled, most of the studied flavonoids were determined in amounts somewhere comparable to those reported in literature.

Enantiomeric separation of new cathinone derivatives designer drugs by capillary electrochromatography using a chiral stationary phase, based on amylose tris(5-chloro-2-methylphenylcarbamate).

In this study, a chiral CEC method for the enantiomeric separation of ten cathinone derivatives, by means of a polysaccharide-based chiral stationary phase, has been developed. Capillary columns of 100 µm id packed with amylose tris(5-chloro-2-methylphenylcarbamate) coated on silica, also called Sepapak 3 or Lux Amylose-2, were used to achieve the enantioseparation of the studied designer drugs. Enantioresolution, chromatographic retention, and separation efficiency were evaluated in dependence of mobile-phase composition in terms of the content of the organic modifier, nature, and pH buffer. To obtain a sensitivity improvement, a field-amplified sample injection was evaluated optimizing the sample solvent composition and injection time. The LODs and LOQs values were in the range 25-100 and 50-150 ng/mL, respectively, for all the racemic compounds. Good results in terms of resolution (Rs ), separation efficiency (N/m), and short analysis times were obtained using a mixture of ACN/methanol/sodium acetate pH 9 (89/10/1, v/v/v). Applying a voltage of 10 kV and a temperature of 20°C, the analyzed cathinone derivatives were separated in their enantiomers in less than 10 min. A study, concerning the method precision, in terms of intra- and interday repeatability and column-to-column reproducibility was carried out in accordance with the analytical procedures for method validation. Intra- and interday repeatability provided RSD values in the ranges 1.1-1.7, 1.3-2.3% for retention time and 1.3-2.6, 2.1-3.4% for peak area, respectively.

Current applications of miniaturized chromatographic and electrophoretic techniques in drug analysis.

In the last decade, miniaturized separation techniques have become greatly popular in pharmaceutical analysis. Miniaturized separation methods are increasingly utilized in all processes of drug discovery as well as quality control of pharmaceutical preparation. The great advantages presented by the analytical miniaturized techniques, including high separation efficiency and resolution, rapid analysis and minimal consumption of reagents and samples, make them an attractive alternative to the conventional chromatographic methods for drug analysis. The purpose of this review is to give a general overview of the applicability of capillary electrophoresis (CE), capillary electrochromatography (CEC) and micro/capillary/nano-liquid chromatography (micro-LC/CLC/nano-LC) for the analysis of pharmaceutical formulations, active pharmaceutical ingredients (API), drug impurity testing, chiral drug separation, determination of drugs and metabolites in biological fluids. The results concerning the use of CEC, micro-LC, CLC, and nano-LC in the period 2009-2013, while for CE, those from 2012 up to the review draft are here summarized and some specific examples are discussed.

Enantiomeric separation of amlodipine and its two chiral impurities by nano-liquid chromatography and capillary electrochromatography using a chiral stationary phase based on cellulose tris(4-chloro-3-methylphenylcarbamate).

In this work, a novel polysaccharide-based chiral stationary phase, cellulose tris(4-chloro-3-methylphenylcarbamate), also called Sepapak 4 has been evaluated for the chiral separation of amlodipine (AML) and its two impurities. AML is a powerful vasodilatator drug used for the treatment of hypertension. Capillary columns of 100 µm id packed with the chiral stationary phase were used for both nano-LC and CEC experiments. The optimization of the mobile phase composed of ACN/water, (90:10, v/v) containing 15 mM ammonium borate pH 10.0 in nano-LC allowed the chiral separation of AML and the two impurities, but not in a single run. With the purpose to obtain the separation of the three pairs of enantiomers simultaneously, CEC analyses were performed in the same conditions achieving better enantioresolution and higher separation efficiencies for each compound. To fully resolve the mixture of six enantiomers, parameters such as buffer pH and concentration sample injection have been then investigated. A mixture of ACN/water (90:10, v/v) containing 5 mM ammonium borate buffer pH 9.0 enabled the complete separation of the three couples of enantiomers in less than 30 min. The optimized CEC method was therefore validated and applied to the analysis of pharmaceutical formulation declared to contain only AML racemate.

Analysis of synthetic cannabinoids in herbal blends by means of nano-liquid chromatography.

In this study, a rapid and simultaneous separation of 12 synthetic cannabinoids and Δ(9)-tetrahydrocannabinol (Δ(9)-THC) in herbal blends was obtained by means of nano-liquid chromatography (nano-LC). The nano-LC experiments were performed in a 100µm i.d. capillary column packed with Cogent(®) bidentate C(18) silica particles for 25.0cm. All compounds were resolved using an isocratic elution mode in less than 30min. A mobile phase containing ACN/MeOH/H(2)O/formic acid 69/5/25/1 (v/v/v/v) was employed for the chromatographic separation. The developed analytical method was validated in terms of precision, linearity, sensitivity and accuracy. Under optimal nano-LC-UV conditions, the resulting RSD percentages for intra-day and inter-day repeatability, related to retention time and peak area, were below 2.98 and 6.40%, respectively. Limits of detection and quantification were 0.2 and 0.5µg/mL, respectively, for all the studied compounds. Linearity was assessed in the concentration range of interest for all analytes with determination coefficients r(2)≥0.9975. The method was then applied to the determination of synthetic cannabinoids in herbal blends. Quantitative analyses of the cannabimimetic compounds in six products showed that there was a wide difference in the concentration of the studied compounds among different products. Further, the nano-LC system was coupled with a mass spectrometer measuring the MS and MS-MS spectra to unequivocally identify the cannabinoids present in smoking mixtures.

Evaluation of novel amylose and cellulose-based chiral stationary phases for the stereoisomer separation of flavanones by means of nano-liquid chromatography.

Three polysaccharide-based chiral stationary phases, Sepapak(®) 1, Sepapak(®) 2 and Sepapak(®) 3 have been evaluated in the present work for the stereoisomer separation of a group of 12 flavonoids including flavanones (flavanone, 4'-methoxyflavanone, 6-methoxyflavanone, 7-methoxyflavanone, 2'-hydroxyflavanone, 4'-hydroxyflavanone, 6-hydroxyflavanone, 7-hydroxyflavanone, hesperetin, naringenin) and flavanone glycosides (hesperidin, naringin) by nano-liquid chromatography (nano-LC). The behaviour of these chiral stationary phases (CSPs) towards the selected compounds was studied in capillary columns (100µm internal diameter (i.d.)) packed with the above mentioned CSPs using polar organic, reversed and normal elution modes. The influence of nature and composition of the mobile phase in terms of concentration and type of organic modifier, buffer type and water content (reversed phase elution mode) on the enantioresolution (R(s)), retention factor (k) and enantioselectivity (α) was evaluated. Sepapak(®) 3 showed the best chromatographic results in terms of enantioresolution, enantioselectivity and short analysis time, employing a polar organic phase mode. A mixture of methanol/isopropanol (20/80, v/v) as mobile phase enabled the chiral separation of eight flavanones with enantioresolution factor (R(s)) in the range 1.15-4.18. The same analytes were also resolved employing reversed and normal phase modes with mixtures of methanol/water and hexane/ethanol at different ratios as mobile phases, respectively. Loss in resolution for some compounds, broaden peaks and longer analysis times were observed with these last two chromatographic elution modes. Afterwards, a comparison with the other two CSPs was performed. A lower discrimination ability of Sepapak(®) 1 and Sepapak(®) 2 towards all the studied flavanoids was observed. However, Sepapak(®) 1 allowed the separation of naringenin enantiomers and naringin stereoisomers in polar organic phase which were not resolved with the other two CSPs. The nature of the chiral selector was found to be of utmost importance for the resolution of the selected compounds. Indeed, significant differences in enantioresolution among the three tested CSPs were observed. With regard to the only few data reported in the literature for the resolution of this class of compounds using polysaccharide-based CSPs by high performance liquid chromatography (HPLC), the results obtained in this study by means of nano-LC showed higher (R(s)) values and shorter analysis time.

Analysis of drugs of forensic interest with capillary zone electrophoresis/time-of-flight mass spectrometry based on the use of non-volatile buffers.

The present work is aimed at investigating the influence of the background electrolyte composition and concentration on the separation efficiency and resolution and mass spectrometric detection of illicit drugs in a capillary zone electrophoresis-electrospray ionization-time of flight mass spectrometry (CZE-ESI-TOF MS) system. The effect of phosphate, borate and Tris buffers on the separation and mass spectrometry response of a mixture of 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, methadone, cocaine, morphine, codeine and 6-monoacetylmorphine was studied, in comparison with a reference ammonium formate separation buffer. Inorganic non-volatile borate and Tris buffers proved hardly suitable for capillary electrophoresis-mass spectrometry (CE-MS) analysis, but quite unexpectedly ammonium phosphate buffers showed good separation and ionization performances for all the analytes tested. Applications of this method to real samples of hair from drug addicts are also provided.

Simultaneous analysis of cocaine and its metabolites in urine by capillary electrophoresis-electrospray mass spectrometry using a pressurized liquid junction nanoflow interface.

A new method for the simultaneous separation of cocaine and four metabolites in urine by CE-ESI-MS via a pressurized nanoliquid junction interface was developed. The resolution of cocaine, cocaethylene, benzoylecgonine, norcocaine, and ecgonine methyl ester was achieved in a polyvinyl-alcohol-coated capillary with 75 µm id × 50 cm total length, using a 15 mM ammonium formate electrolyte solution (pH 9.5) in less than 15 min. In addition, to enhance sensitivity, a field-amplified sample injection (FASI) was evaluated in terms of injection time and sample solvent composition. The limits of detection achieved with the FASI method ranged from 1.5 to 10 ng/mL for all the compounds. The detection of the studied compounds was performed using an ion-trap mass spectrometer in a positive ionization mode. A mixture of methanol:water (80:20 v/v) containing 0.1% v/v of formic acid was employed as spray liquid and delivered at ~200 nL/min. Under optimal CE-MS conditions, linearity was assessed in the concentration range of interest for all analytes with correlation coefficients r² ≥ 0.9913. Intra- and inter-day precision provided a relative standard deviation lower than 1.54% for migration times and lower than 12.15% for peak areas. Finally, urine samples, spiked with the standard mixture, were extracted using a solid-phase extraction procedure and injected under FASI conditions, providing recoveries from 80% to 94% for all analytes.

Analysis of polyphenols and methylxantines in tea samples by means of nano-liquid chromatography utilizing capillary columns packed with core-shell particles.

In this study, a rapid separation of eleven polyphenols and three methylxanthines was obtained by means of nano-liquid chromatography (nano-LC), employing a 100 µm I.D. capillary column packed with C18 core-shell particles (2.7 µm) for 10 cm. All compounds were baseline resolved with a step gradient elution in less than 15 min. The developed analytical method was validated and the resulting RSD% for intra-day and inter-day repeatability, related to retention time, retention factor and peak area, were below 5.1 and 5.7%. LOD and LOQ values corresponded to 0.300 and 0.625 µg/mL, while linearity range assessed gave R² no lower than 0.990. Then, the method was used to determine studied compounds in tea extracts. Further, the nano-LC system was coupled with a mass spectrometer to confirm the components present in real samples. Finally the results were compared with those obtained using a capillary column (100 µm I.D. × 10 cm) packed with C18 sub-2 µm particles, applying the same nano-LC experimental conditions.

Advances in the enantioseparation of ß-blocker drugs by capillary electromigration techniques.

ß-Blocker drugs or ß-adrenergic blocking agents are an important class of drugs, prescribed with great frequency. They are used for various diseases, particularly for the treatment of cardiac arrhythmias, cardioprotection after myocardial infarction (heart attack), and hypertension. Almost all ß-blocker drugs possess one or more stereogenic centers; however; only some of them are administered as single enantiomers. Since both enantiomers can differ in their pharmacological and toxicological properties, enantioselective analytical methods are required not only for pharmacodynamic and pharmacokinetic studies but also for quality control of pharmaceutical preparations with the determination of enantiomeric purity. In addition to the chromatographic tools, in recent years, capillary electromigration techniques (CE, CEC, and MEKC) have been widely used for enantioselective purposes employing a variety of chiral selectors, e.g. CDs, polysaccharides, macrocyclic antibiotics, proteins, chiral ion-paring agents, etc. The high separation efficiency, rapid analysi,s and low consumption of reagents of electromigration methods make them a very attractive alternative to the conventional chromatographic methods. In this review, the development and applications of electrodriven methods for the enantioseparation of ß-blocker drugs are reported. The papers concerning this topic, published from January 2000 until December 2010, are summarised here. Particular attention is given to the coupling of chiral CE and CEC methods to MS, as this detector provides high sensitivity and selectivity.

Investigation of polar stationary phases for the separation of sympathomimetic drugs with nano-liquid chromatography in hydrophilic interaction liquid chromatography mode.

In this study, the retention and selectivity of a mixture of basic polar drugs were investigated in hydrophilic interaction chromatographic conditions (HILIC) using nano-liquid chromatography (nano-LC). Six sympathomimetic drugs including ephedrine, norephedrine, synephrine, epinephrine, norepinephrine and norphenylephrine were separated by changing experimental parameters such as stationary phase, acetonitrile (ACN) content, buffer pH and concentration, column temperature. Four polar stationary phases (i.e. cyano-, diol-, aminopropyl-silica and Luna HILIC, a cross-linked diol phase) were selected and packed into fused silica capillary columns of 100 µm internal diameter (i.d.). Among the four stationary phases investigated a complete separation of the all studied compounds was achieved with aminopropyl silica and Luna HILIC stationary phases only. Best chromatographic results were obtained employing a mobile phase composed by ACN/water (92/8, v/v) containing 10mM ammonium formate buffer pH 3. The influence of the capillary temperature on the resolution of the polar basic drugs was investigated in the range between 10 and 50°C. Linear correlation of lnk vs. 1/T was observed for all the columns; ΔH° values were negative with Luna HILIC and positive with aminopropyl- and diol-silica stationary phases, demonstrating that different mechanisms were involved in the separation. To compare the chromatographic performance of the different columns, Van Deemter curves were also investigated.