Recent developments in electromigration techniques related to pharmaceutical and biomedical analysis - A review.

The analysis of pharmaceutical compounds is an important research topic as the use of different drugs affects people's daily life for the treatment of diseases. In addition to the widespread use of the internet, counterfeit drugs have appeared in the market. The development of modern analytical techniques, reliable, precise, sensitive, and rapid methods, has provided powerful means of analysis used in various fields such as drug production, quality control, determination of impurities and/or metabolites, biochemistry, pharmacokinetics, etc.

An enantioselective high-performance liquid chromatography-mass spectrometry method to study the fate of quizalofop-P-ethyl in soil and selected agricultural products.

In this study, the attention was focused on quizalofop-ethyl, a chiral herbicide whose formulation has recently been marketed as quizalofop-P-ethyl, i.e. the (+)-enantiomer exhibiting herbicidal activity.

Enantiomeric analysis of drugs in water samples by using liquid-liquid microextraction and nano-liquid chromatography.

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.

Carbon nanomaterial-based membranes in solid-phase extraction.

Carbon nanomaterials (CNMs) have some excellent properties that make them ideal candidates as sorbents for solid-phase extraction (SPE). However, practical difficulties related to their handling (dispersion in the atmosphere, bundling phenomena, reduced adsorption capability, sorbent loss in cartridge/column format, etc.) have hindered their direct use for conventional SPE modes.

Enantioselective high-performance liquid chromatographic separations to study occurrence and fate of chiral pesticides in soil, water, and agricultural products.

As many as 40% of all plant protection products currently used contain chiral active ingredients. Enantiomers of the same pesticide have identical physicochemical properties in an isotropic medium, but they may display different activity and toxicity because of their interaction with enzymes or other naturally occurring asymmetric molecules. This difference may also lead to variations in biotic degradation rates, making one enantiomer more persistent than the other in natural and agricultural environments.

Enantioseparation of selected chiral agrochemicals by using nano-liquid chromatography and capillary electrochromatography with amylose tris(3‑chloro-5-methylphenylcarbamate) covalently immobilized onto silica.

In this paper enantiomers of selected chiral agrochemicals representing various structural classes were separated by using nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) employing a capillary column packed with silica particles containing immobilized amylose tris(3‑chloro-5-methylphenylcarbamate) (i-ADMPC) as a chiral selector (CS). Special attention was paid to peak dispersion in nano-LC and CEC instruments used in order to make comparison between these two techniques more reliable. Enantioseparations were studied utilizing methanol (MeOH) or acetonitrile-water (ACNHO), both containing 5 mM of ammonium acetate as the mobile phases (MPs).

Dispersive liquid-liquid microextraction, an effective tool for the determination of synthetic cannabinoids in oral fluid by liquid chromatography-tandem mass spectrometry.

In the present work, dispersive liquid-liquid microextraction (DLLME) was used to extract six synthetic cannabinoids (JWH-018, JWH-019, JWH-073, JWH-200, or WIN 55,225, JWH-250, and AM-694) from oral fluids. A rapid baseline separation of the analytes was achieved on a bidentate octadecyl silica hydride phase (Cogent Bidentate C; 4.6 mm × 250 mm, 4 μm) maintained at 37 °C, by eluting in isocratic conditions (water:acetonitrile (25:75, )).

Potentiality of miniaturized techniques for the analysis of drugs of abuse.

Capillary electromigration (CE) and liquid chromatographic techniques (CLC/nano-LC) are miniaturized techniques offering distinct advantages over conventional ones in the field of separation science. Among these, high efficiency, high chromatographic resolution, and use of minute volumes of both mobile phase and sample volumes are the most important. CE and CLC/nano-LC have been applied to the analysis of many compounds including peptides, proteins, drugs, enantiomers, ions, etc.

History, advancement, bottlenecks, and future of chiral capillary electrochromatography.

Capillary electrochromatography (CEC) represents a technique with less than 30 years of intense development and in this period this technique has seen huge promise, fast development, stagnation, and significant decline of innovative activity. The major goal of the present overview is not to present an extensive review of the literature on chiral CEC but to analyze the reasons for this dramatic development and attempting to answer questions such as: 1) Was the potential of CEC reasonably evaluated in 1990s before starting the explosive development in this field? 2) Did the development of this technique take the right track? 3) What other developments and competitive trends led to stagnation in the advancement of CEC? 4) Why is the activity in this field currently decreasing? 5) What are the current challenges and promises and what is the future of chiral CEC?

Implant primary stability with an osteocondensation drilling protocol in different density polyurethane blocks.

The implant primary stability is a fundamental condition for avoiding implant micro-motions that might result in fibrous encapsulation; its achievement is facilitated by macro- and micro-geometry of the implant, and by the bone density and architecture at the intended implant site. The aim was to evaluate an osteocondensing drilling protocol for dental implant positioning compared to standard protocol on polyurethane block. A total of 40 implants, 20 for each osteocondensing group (Test) and 20 for standard drilling group (Control), were positioned.

Further study on enantiomer resolving ability of amylose tris(3-chloro-5-methylphenylcarbamate) covalently immobilized onto silica in nano-liquid chromatography and capillary electrochromatography.

In the present study separation of enantiomers of some chiral neutral, basic and weakly acidic analytes was investigated on the chiral stationary phase (CSP) made by covalent immobilization of amylose tris(3-chloro-5-methylphenylcarbamate) onto aminopropylsilanized (APS) silica in nano-liquid chromatography (nano-LC) in aqueous methanol or acetonitrile mixtures. It has been shown that similar to high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) this chiral selector is useful for separation of enantiomers of neutral, basic and acidic analytes also in nano-LC. In comparison to our previous research, in which the chiral selector (CS) was bonded on native silica, in this study, the CS was immobilized on APS silica in order to improve chromatographic performance towards basic analytes.

Multi-residue determination of organic micro-pollutants in river sediment by stir-disc solid phase extraction based on oxidized buckypaper.

This paper describes a procedure for the isolation of 20 organic micro-pollutants among pesticides, drugs, recreational drugs, flame retardants from river sediments. After a solid-liquid extraction with a methanol:water (50:50, v/v) solution, the supernatant was diluted with water and cleaned up by stir-disc solid-phase extraction (SPE). The disc was made of buckypaper, a self-supporting entangled assembly of carbon nanotubes, which was used as a highly porous, two-sided, sorbent membrane.

Preparation and application of teicoplanin functionalized polymeric monolith for enantioseparation of chiral drugs.

A novel chiral stationary phase (CSP), based on a monolithic organic polymer chemically modified with teicoplanin, was fabricated within a 100 μm I.D. fused silica capillary.

Comparative study on enantiomer resolving ability of amylose tris(3-chloro-5-methylphenylcarbamate) covalently immobilized onto silica in nano-liquid chromatography and capillary electrochromatography.

In the present study separation of enantiomers of some chiral neutral and weakly acidic analytes was investigated on the chiral stationary phase (CSP) made by covalent immobilization of amylose tris(3-chloro-5-methylphenylcarbamate) onto silica in nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) in acetonitrile and aqueous acetonitrile. Few comparisons were made also between the enantioseparations in nano-LC and high-performance liquid chromatography (HPLC) with the chiral column of 4.6 × 250 mm dimension.

Nano-liquid chromatography for enantiomers separation of baclofen by using vancomycin silica stationary phase.

The chiral separation of baclofen (Bac) was obtained by nano-liquid chromatography tandem mass spectrometry (nano-LC-MS/MS) using a 100 μm I.D. fused silica capillary column packed with silica particles chemically modified with vancomycin.

Some thoughts about enantioseparations in capillary electrophoresis.

In this overview the goal of the authors was to analyze from the historical perspective the reasons of success and failure of chiral capillary electrophoresis. In addition, the current trends are analyzed, unique advantages of capillary electrophoresis are highlighted and some future directions are discussed.

Application of Sub-2 Micron Particle Silica Hydride Derivatized with Vancomycin for Chiral Separations by Nano-Liquid Chromatography.

1.8 μm Silica hydride particles have been derivatized with vancomycin and applied to the enantioseparation of some racemic herbicides and nonsteroidal anti-inflammatory drugs (NSAIDs) by nano-liquid chromatography. The chiral stationary phase (CSP) was packed for only 11 cm and the enantiomers were separated utilizing a laboratory-assembled instrumentation.

Analysis of Enantiomers in Products of Food Interest.

The separation of enantiomers has been started in the past and continues to be a topic of great interest in various fields of research, mainly because these compounds could be involved in biological processes such as, for example, those related to human health. Great attention has been devoted to studies for the analysis of enantiomers present in food products in order to assess authenticity and safety. The separation of these compounds can be carried out utilizing analytical techniques such as gas chromatography, high-performance liquid chromatography, supercritical fluid chromatography, and other methods.

Enantioseparation of tryptophan and its unnatural derivatives by nano-LC on CSP-teicoplanin silica based.

This work deals with the potentiality of nano liquid chromatography (Nano-LC) for the chiral separation of racemic mixture of tryptophan and some selected derivatives by using 100 µm i.d. fused silica capillary packed with teicoplanin bonded to 5 µm diol silica stationary phase.

Rotating-disc micro-solid phase extraction of F2-isoprostanes from maternal and cord plasma by using oxidized buckypaper as sorbent membrane.

This paper describes the development of an original micro-solid phase extraction device and its evaluation for the isolation of F2-isoprostanes (F2-IsoPs) from cord and maternal plasma samples. The unit is very simple and consists in a rotating disc (1.8 cm diameter) of oxidized buckypaper (BP), enwrapped in a polypropylene mesh pouch.