Organic Modifier Research Articles

Mixed-mode column allows simple direct coupling with immobilized enzymatic reactor for on-line protein digestion

Liquid chromatography coupled with mass spectrometry is widely used in the field of proteomic analysis after off-line protein digestion. On-line digestion with chromatographic column connected in a series with immobilized enzymatic reactor is not often used approach. In this work we investigated the impact of chromatographic conditions on the protein digestion efficiency. The investigation of trypsin reactor activity was performed by on-line digestion of N-α-benzoyl-L-arginine 4-nitroanilide hydrochloride (BAPNA), followed by separation of the digests on the mixed-mode column. Two trypsin column reactors with the different trypsin coverage on the bridged ethylene hybrid particles were evaluated.To ensure optimal trypsin activity, the separation temperature was set at 37.0 °C and the pH of the mobile phase buffer was maintained at 8.5. The on-line digestion itself ongoing during the initial state of gradient was carried out at a low flow rate using a mobile phase that was free of organic modifiers. Proteins such as cytochrome C, enolase, and myoglobin were successfully digested on-line without prior reduction or alkylation, and the resulting peptides were separated using a mixed-mode column. Additionally, proteins that contain multiple cysteines, such as α-lactalbumin, albumin, β-lactoglobulin A, and conalbumin, were also successfully digested on-line (after reduction and alkylation). Moreover, trypsin immobilized enzymatic reactors were utilized for over 300 injections without any noticeable loss of digestion activity.

Organically modified mesoporous silica as a performance additive in tubular quenched polypropylene films

Mesoporous silica nanoparticles were synthesized by base-catalyzed hydrolysis of tetraethyl orthosilicate in the water-acetone medium. For surface modification of mesoporous silica, commercially available silane, 3-(trimethoxysilyl)propyl methacrylate was reacted with mono-thioglycerol via 2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl (TEMPO) aided thiol-ene reaction, and the obtained silane was incorporated on the surface of neat mesoporous silica to graft extended alkyl chains terminating in hydroxyl groups. The prepared MSNs were characterized by thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), nitrogen adsorption-desorption analysis, scanning electron microscopy, and dynamic light scattering. These MSNs were compared to conventionally used commercial silica as an additive in tubular quenched polypropylene films (TQPP) for their anti-blocking, thermal, mechanical, optical, and barrier properties. Organic modification of MSNs decreased the blocking force in TQPP films. The mechanical properties including % elongation and tensile strength increased for TQPP films with mesoporous silica, while it decreased for films containing commercial silica. Both modified and unmodified MSNs decreased haze and enhanced gloss in TQPP films, showing improved optical properties as compared to commercial silica particles. In TQPP film with modified MSNs, a reduced value of the water contact angle was obtained, indicating better wettability of the surface of the TQPP film.

Lipophilic Studies and In Silico ADME Profiling of Biologically Active 2-Aminothiazol-4(5H)-one Derivatives.

Pseudothiohydantoin derivatives have a wide range of biological activities and are widely used in the development of new pharmaceuticals. Lipophilicity is a basic, but very important parameter in the design of potential drugs, as it determines solubility in lipids, nonpolar solvents, and makes it possible to predict the ADME profile. The aim of this study was to evaluate the lipophilicity of 28 pseudothiohydantoin derivatives showing the inhibition of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) using chromatographic methods. Experimentally, lipophilicity was determined by reverse phase thin layer chromatography (RP-TLC) and reverse phase high-performance liquid chromatography (RP-HPLC). In both methods, methanol was used as the organic modifier of the mobile phase. For each 2-aminothiazol-4(5H)-one derivative, a relationship was observed between the structure of the compound and the values of the lipophilicity parameters (log kw, RM0). Experimental lipophilicity values were compared with computer calculated partition coefficient (logP) values. A total of 27 of the 28 tested compounds had a lipophilicity value < 5, which therefore met the condition of Lipinski's rule. In addition, the in silico ADME assay showed favorable absorption, distribution, metabolism, and excretion parameters for most of the pseudothiohydantoin derivatives tested. The study of lipophilicity and the ADME analysis indicate that the tested compounds are good potential drug candidates.

Prepared eggshell-derived hydroxyapatite for biomedical applications

In this Research are interesting used eggshells to create a product with added value, such as nanoscale hydroxyapatite (HA). HA must have the appropriate nanoscale characteristics, such as crystallinity, particle size, shape, surface area, porous nature, and so on, because they contain calcium carbonate and biologically required trace elements such as Mg, Si, and others for many biological applications. The same effect can be obtained by adjusting the reaction parameters, selecting the appropriate synthesis mode, and employing organic modifiers. Eggshell bio-waste was used as the calcium source in this study to create hydroxyapatite powder. We investigated its characteristics for application in manufacturing a functionally graded material (NiTi/HA) utilized in bone culture. The powder was tested using XRD, FTIR, SEM, and a particle analyses. Whereas XRD revealed the structure of the resulting powder, which is comparable to the conventional form of HAP powder, FTIR revealed the presence of the primary compound Hydroxyapatite in producing powder, such as (P?4 3-, C?22- and bending OH-). As a result of this research, we can conclude that the synthetic eggshell produced HA has good particle size, bioactivity, and porous nature.

Integrating micellar HPLC and green analytical chemistry tools in greenness assessment of five commonly Co-formulated antidiabetic drugs

The ecological impact of routine quality control activities in the pharmaceutical industry is crucial, producing large amounts of dangerous organic waste. For that, the use of mixed-micellar LC was found beneficial. When sodium dodecyl sulfate (SDS) is mixed with Brij-35 as surfactants in the mobile phase, no organic modifier was needed for enhancing the analytes' elution time or resolution. In the proposed study, five antidiabetic drugs belonging to different antidiabetic classes; namely metformin (MTF), glibenclamide (GBC), gliclazide (GCZ), linagliptin (LNT) and dapagliflozin (DPF), have been studied using organic-solvent free Micellar RP-HPLC technique. The combination of double or even triple antidiabetic therapies from different classes is common and was proved efficient for the control of type-2 diabetes. The optimal mobile phase was composed of 0.12 M SDS, 0.008 M Brij-35 and 0.15 M triethylamine in water, adjusted to pH 4.5. The flow rate was set at 1.5 mL min−1 on RP-monolithic column (100 × 4.6 mm). Photodiode array detection was set at wavelength 245 nm for MTF and 225 nm the other analytes. Linearity ranges were 50–600 μg mL−1 for MTF, and 5–60, 2.5–30, 7.5–60, and 2.5–30 μg mL−1 for DPF, LNT, GCZ and GBC, respectively (R2 ≥ 0.997). Trueness and precision have been established across the specified ranges with recovery percentages range 98–105% and relative standard deviation of the results less than 2.5%. The obtained results of resolution, peaks’ symmetry and theoretical plates for the drugs under study proved the analytical capability of using mixed-micellar mobile phases for elimination of the organic-solvents without affecting the separation efficiency.

Organic Bromide Salts Interface Modification for High‐Efficiency Perovskite Solar Cells with Printed Carbon Electrode

Perovskite solar cells (PSCs) using carbon as the counter electrode fabricated through a low‐temperature full solution‐process method can significantly simplify the preparation process and reduce production cost. Herein, a high‐performance PSC is presented with printed carbon electrode and dopant‐free poly(3‐hexylthiophene) (P3HT) is employed as hole transport materials. Different organic bromide salts are employed to modify the perovskite/P3HT interface to further enhance the performance. As a result, methylammonium bromide (MABr) modification significantly enhances the device open‐voltage (Voc) and fill factor (FF) by reducing interface defects and facilitates charge transport. A champion power conversion efficiency (PCE) of 19.22% (Voc of 1.118 V, FF of 0.765, and short‐circuit current of 22.48 mA cm−2) is achieved with MABr modification. The unencapsulated devices maintain 96% of the initial efficiency after storage for 3600 h and 88% after thermal treatment at 70 °C for 1200 h. Additionally, perovskite solar modules are also prepared based on printing and interface passivation route with PCE reaches 13.20%. These results represent an important progress in the enhancement of device PCE and up‐scaling of PSCs with cost‐effective, stable, and printed carbon electrode.

Application of Principal Component Analysis and DoE-Driven Green Analytical Chemistry Concept to Liquid Chromatographic Method for Estimation of Co-formulated Anti-Hypertensive Drugs.

The fixed-dose combination (FDC) of metoprolol succinate (MTS), cilnidipine (CDN), and telmisartan (TST) is used for the management of hypertension. Numerous reversed phase (RP)-HPLC methods have been reported in the literature for chromatographic analysis of MTS, CDN, and TST. According to the concept of green analytical chemistry (GAC), toxic organic solvents should be avoided or minimized during chromatographic method development for the safety of analysts and the protection of the environment. The reported RP-HPLC methods have been developed using acetonitrile (ACN) or methanol as an organic component of the mobile phase and diluent for sample preparation. These organic solvents are considered toxic solvents as per the International Council for Harmonization (ICH) Q3C (R6) guideline and Pfizer medicinal chemistry solvent selection (PMCSS) guide. We aimed to develop an environment-friendly and economical RP-HPLC-photo-diode array (PDA) method for the analysis of MTS, CDN, and TST using less toxic organic solvents to support the concept of GAC. The method development was carried out by the implementation of chemometrics and design of experiments (DoE) to avoid wastage of organic solvent. Principal component analysis (PCA) was applied as a chemometric tool for the identification of critical method risk variables (MRVs) and method performance attributes (MPAs). The identified critical MRVs and MPAs were further studied by DoE-based response surface modelling for optimization of the method. The chromatographic analysis of MTS, CDN, and TST was carried out using a Shim-pack ODS column as a stationary phase and ethanol as an organic modifier in the mobile phase. The developed method was applied to the assay of FDCs and results were found to be in compliance with the label claim. The greenness profiles of reported and present RP-HPLC methods were evaluated by national environmental method index (NEMI) and analytical greenness (AGREE) methods. The developed method was found to be green, robust, and economical as compared to published methods for the analysis. Development and validation of an RP-HPLC method for simultaneous estimation of MTS, CDN, and TST using safe organic solvents. Implementation of a analytical quality by design (AQbD) approach in method development using PCA and DoE. Application of the method for assay of FDCs of MTS, CDN, and TST.

Principles of Self-Repairing Ability of Tripodal Ligand-Stabilized Hybrid Cobalt Hydroxide Nanosheets for Alkaline Water Electrolysis.

Self-repairing catalysts are promising new materials for achieving long lifetime of alkaline water electrolyzers powered by renewable energy. Catalytic nanoparticles dispersed in an electrolyte were deposited on the anode to repair a catalyst layer by electrolysis. A hybrid cobalt hydroxide nanosheet modified with tris(hydroxymethyl)aminomethane on the surface (Co-ns) was used as a catalyst. Assuming a pseudo-first-order process, the rate constant of an electrochemical deposition was linearly correlated with the electrode potential during electrolysis. Thus, it is expected that the repair of the catalyst is automatically controlled by changes in the OER overpotential. The essential step of the electrochemical deposition was the anodic oxidation of Co2+ to Co3+. Surface modification of Co-ns protects Co2+ against the autooxidation of Co2+ caused by the dissolved oxygen. The redox properties and organic modification of Co-ns make them well-suited for the self-repair of anode catalysts.

Estimating the hydrophobicity extent of molecular fragments using reversed-phase liquid chromatography.

A fast HPLC method was developed to study the hydrophobicity extent of pharmaceutically relevant molecular fragments. By this strategy, the reduced amount of sample available for physico-chemical evaluations in early-phase drug discovery programs does not represent a limiting factor. The sixteen acid fragments investigated were previously synthesized also determining potentiometrically their experimental log D values. For four fragments it was not possible to determine such property since their values were outside of the instrumental working range (2<pKa <12). An RP-HPLC method was therefore optimized. For each scrutinized method, some derived chromatographic indices were calculated, and Pearson's correlation coefficient (r) allowed to select the so-called "φ0 index" as the best correlating with the log D. The was fixed at 3.5 and a modification of some variables [organic modifier (methanol vs. ACN), stationary phase (octyl vs. octadecyl), presence/absence of the additives n-octanol, n-butylamine, and n-octylamine], allowed to select the best correlation conditions, producing a r=0.94 (p<0.001). Importantly, the φ0 index enabled the estimation of log D values for four fragments which were unattainable by potentiometric titration. Moreover, a series of molecular descriptors were calculated to identify the chemical characteristics of the fragments explaining the obtained φ0 . The number of hydrogen bond donors and the index of cohesive interaction correlated with the experimental data.

Current Knowledge on Friction, Lubrication, and Wear of Ethanol-Fuelled Engines—A Review

The urgent need for drastic reduction in emissions due to global warming demands a radical energy transition in transportation. The role of biofuels is fundamental to bridging the current situation towards a clean and sustainable future. In passenger cars, the use of ethanol fuel reduces gas emissions (CO2 and other harmful gases), but can bring tribological challenges to the engine. This review addresses the current state-of-the-art on the effects of ethanol fuel on friction, lubrication, and wear in car engines, and identifies knowledge gaps and trends in lubricants for ethanol-fuelled engines. This review shows that ethanol affects friction and wear in many ways, for example, by reducing lubricant viscosity, which on the one hand can reduce shear losses under full film lubrication, but on the other can increase asperity contact under mixed lubrication. Therefore, ethanol can either reduce or increase engine friction depending on the driving conditions, engine temperature, amount of diluted ethanol in the lubricant, lubricant type, etc. Ethanol increases corrosion and affects tribocorrosion, with significant effects on engine wear. Moreover, ethanol strongly interacts with the lubricant’s additives, affecting friction and wear under boundary lubrication conditions. Regarding the anti-wear additive ZDDP, ethanol leads to thinner tribofilms with modified chemical structure, in particular shorter phosphates and increased amount of iron sulphides and oxides, thereby reducing their anti-wear protection. Tribofilms formed from Mo-DTC friction modifier are affected as well, compromising the formation of low-friction MoS2 tribofilms; however, ethanol is beneficial for the tribological behaviour of organic friction modifiers. Although the oil industry has implemented small changes in oil formulation to ensure the proper operation of ethanol-fuelled engines, there is a lack of research aiming to optimize lubricant formulation to maximize ethanol-fuelled engine performance. The findings of this review should shed light towards improved oil formulation as well as on the selection of materials and surface engineering techniques to mitigate the most pressing problems.

Corrosion protection of folic acid and lauric acid modified films prepared by anodic oxidation on WE43 magnesium alloys

The corrosion protection of folic acid (FA) and lauric acid (LA) modified films prepared by anodic oxidation on WE43 magnesium alloys was particularly evaluated by scanning electron microscopy (SEM), electron probe microanalysis (EPMA), static contact angle (CA) and electrochemical tests. The combined results of SEM and EPMA showed that both FA and LA penetrated into the cavities and cracks to repair the defects of the anodic films. The polarization resistance of the FA-modified films increased by 1.56 × 105 Ω cm2 and the LA-fmodified films showed the largest value (6.36 × 106 Ω cm2). They improved by two and three orders of magnitude compared with the substrate, which objectively revealed the excellent corrosion resistance capacity of the modified films on measurement results level. The CA results indicated that the obtained anodic films modified by LA were hydrophobic. Furthermore, the process of the organic modification sealing and the corrosion protection mechanism of the anodic films modified by FA and LA were discussed.

Tailoring of 3D printed polyethylenimine functionalized MCM-41 based monoliths and scrutiny on CO2 adsorption characteristics

Amine functionalized mesoporous silica materials have emerged as promising adsorbents in terms of CO2 capture. Despite the noteworthy advancement in the development of novel adsorbents, commercial implementation of solid-gas contactors in real-time application is challenging. This is because, the conventional packed bed systems exhibit high-pressure drop, poor mass as well as heat transfer characteristics, attrition, and dusting issue. Therefore, it is pre-requisite to develop definite structured configurations in view of industrial applications. In the current work, 3D printing technique is used to fabricate PEI functionalized MCM-41 based structured configuration and their CO2 adsorption performance is investigated. In this study, MCM-41 is subjected to organic modification using PEI entities with different molecular weights (MW ∼ 600, 1200, 1800) and formulated into 3D printable ceramic ink using appropriate binders and plasticizers. The ceramic ink showed shear thinning behavior when the plasticizer is minimal in the formulation. The ceramic ink is then processed into three-dimensional configurations using pneumatic extrusion technique and their physicochemical characteristics are analyzed in addition to their powder counterparts. The current work aims to envisage the influence of molecular weight of organic moiety used for the functionalization of MCM-41 on the CO2 uptake capacity of 3D printed monoliths at different temperature conditions (30, 45, 60, 75, 90, 105 ℃). Through this study, we aim to tailor the design of 3D printed polyethylenimine functionalized MCM-41 based monoliths and assess their CO2 adsorption properties, selectivity, and stability across multiple cycles. By addressing these aspects, our research contributes to the field by advancing the understanding of tailored adsorbent materials for CO2 capture and highlighting the potential of 3D printing technology in fabricating structured adsorbents for industrial applications.

Characterization of Coating Films of Thixotropic Solvent Gel Containing Organo‐modified Nanodiamonds

AbstractA gelation solvent containing a diamide‐based thixotropic additive with two hydrocarbons and organo‐modified nanodiamonds was prepared and evaluated herein as a coating film. Nanodiamonds were introduced into a solvent containing diamide‐based thixotropic additive molecules with 12‐hydroxystearyl chains which were uniformly dispersed due to organic chain modification on the outermost layer surface. In addition to common solvents including toluene, ethyl cetyl hexanoate, a cosmetic emollient, forms nanodiamond‐containing gels. The helical nanofibers formed by the diamide‐based thixotropic additive molecule with two hydrocarbons in the gel showed affinity for the organo‐modified nanodiamonds, and the contact morphology between the nanofibers and nanodiamond particles was confirmed. Nanodiamonds exhibited a denaturation effect on biomolecules adsorbed on their surfaces. Overall, nanodiamond‐containing emollient gels are expected to exhibit antibacterial properties against viruses and malodorous bacteria on skin as part of thixotropic immobilization films for cosmetic powders.

Guest-Stimulated Nonplanar Porphyrins in Flexible Metal-Organic Frameworks.

Nonplanar porphyrins with out-of-plane distortions play crucial roles in many biological functions and chemical applications. The artificial construction of nonplanar porphyrins usually involves organic synthesis and modification, which is a highly comprehensive approach. However, incorporating porphyrins into guest-stimulated flexible systems allows to manipulate the porphyrin distortion through simple ad/desorption of guest molecules. Here, a series of porphyrinic zirconium metal-organic frameworks (MOFs) is reported that exhibit guest-stimulated breathing behavior. X-Ray diffraction analysis and skeleton deviation plots confirm that the material suffers from porphyrin distortion to form a ruffled geometry under the desorption of guest molecules. Further investigation reveals that not only the degree of nonplanarity can be precisely manipulated but also the partial distortion of porphyrin in a single crystal grain can be readily achieved. As Lewis acidic catalyst, the MOF with nonplanar Co-porphyrin exhibits active properties in catalyzing CO2 /propylene oxide coupling reactions. This porphyrin distortion system provides a powerful tool for manipulating nonplanar porphyrins in MOFs with individual distortion profiles for various advanced applications.

A State-of-the-Art Review of Organic Polymer Modifiers for Slope Eco-Engineering.

In slope ecological restoration projects, reinforcing soil and promoting vegetation growth are essential measures. Guest soil spraying technology can be used to backfill modified soil and vegetation seeds onto the slope surface, resulting in successful ecological restoration. The use of organic polymer modifiers to reinforce soil has several benefits, such as high strength, effective results, and low pollution levels. Organic polymer soil modifiers can be divided into two categories: synthetic polymer modifiers and biopolymer modifiers. This paper provides a thorough review of the properties and interaction mechanisms of two types of polymer modifiers in soil consolidation. The properties of organic polymer modifiers make them applicable in soil and vegetation engineering on slopes. These modifiers can enhance soil mechanics, infiltration, and erosion resistance and promote vegetation growth. Therefore, the suitability of organic polymer modifiers for soil and vegetation engineering on slopes is demonstrated by their properties and potential for improvement in key areas. Furthermore, challenges and future prospects for slope protection technology using organic polymer modifiers are suggested.

Mobile phase and column chemistry selection for high sensitivity non-targeted LC/ESI/HRMS screening of water

Systematic selection of mobile phase and column chemistry type can be critical for achieving optimal chromatographic separation, high sensitivity, and low detection limits in liquid chromatography electrospray high resolution mass spectrometry (LC/MS). However, the selection process is challenging for non-targeted screening where the compounds of interest are not preselected nor available for method optimization. To provide general guidance, twenty different mobile phase compositions and four columns were compared for the analysis of 78 compounds with a wide range of physicochemical properties (logP range from −1.46 to 5.48), and analyte sensitivity was compared between methods. The pH, additive type, column, and organic modifier had significant effects on the analyte response factors, and acidic mobile phases (e.g. 0.1% formic acid) yielded highest sensitivity. In some cases, the effect was attributable to the difference in organic modifier content at the time of elution, depending on the mobile phase and column chemistry. Based on these findings, 0.1% formic acid, 0.1% ammonia and 5.0 mM ammonium fluoride were further evaluated for their performance in non-targeted LC/ESI/HRMS analysis of wastewater treatment plan influent and effluent, using a data dependent MS2 acquisition and two different data processing workflows (MS-DIAL, patRoon 2.1) to compare number of detected features and sensitivity. Both data-processing workflows indicated that 0.1% formic acid yielded the highest number of features in full scan spectrum (MS1), as well as the highest number of features that triggered fragmentation spectra (MS2) when dynamic exclusion was used.

A comprehensive study to reveal the potential of a more sustainable ultra-high performance enantioselective reversed-phase chromatography on Pirkle-type stationary phase, with Whelk-O1 as a case study

In this study, we aimed to make enantioselective chromatography more sustainable, more sensitive, and compatible with aqueous formulations analysis and ESI-MS. To achieve this, we examined the effects of transitioning from normal-phase chromatography (which uses hydrocarbon-based solvents) to reversed-phase chromatography (using mobile phases based on water) using broad-spectrum Whelk-O1 columns as a critical study. For the first time, we holistically compared the thermodynamics and kinetics of the two elution modes in order to answer the question of whether same-column chemistry can effectively separate the compounds even in reversed-phase mode and found, unexpectedly, that reversed-phase chromatography using acetonitrile as the organic modifier was competitive from a kinetic standpoint. We also evaluated the effectiveness of three organic modifiers simultaneously on a sample of 11 molecules already resolved in NP conditions with different resolutions and achieved a resolution value of 1.5 for 91% and a resolution value of 2 for 82% of cases. Finally, we separated three racemates (within a k factor of 9) using only 480 µL of solvent per chromatographic run on a millibore column of 1 mm I.D., demonstrating that our approach allows for greener chromatographic separations.

Synthesis and Characterization of Inorganic-Organic Derivatives of Layered Perovskite-like Niobate HSr2Nb3O10 with n-Amines and n-Alcohols.

A protonated and hydrated Dion-Jacobson-phase HSr2Nb3O10∙yH2O was used to prepare two series of inorganic-organic derivatives containing non-covalently intercalated n-alkylamines and covalently grafted n-alkoxy groups of different lengths, as they are promising hybrid materials for photocatalytic applications. Preparation of the derivatives was carried out both under the conditions of standard laboratory synthesis and by solvothermal methods. For all the hybrid compounds synthesized structure, quantitative composition, a type of bonding between inorganic and organic parts as well as light absorption range were discussed using powder XRD, Raman, IR and NMR spectroscopy, TG, elemental CHN analysis, and DRS. It was shown that the inorganic-organic samples obtained contain approximately one interlayer organic molecule or group per proton of the initial niobate, as well as some amount of intercalated water. In addition, the thermal stability of the hybrid compounds strongly depends on the nature of the organic component anchoring to the niobate matrix. Although non-covalent amine derivatives are stable only at low temperatures, covalent alkoxy ones can withstand heat up to 250 °C without perceptible decomposition. The fundamental absorption edge of both the initial niobate and the products of its organic modification lies in the near-ultraviolet region (370-385 nm).

Owens–Wendt Characterization of Femtosecond-Laser-Textured Hydrophobic Aluminum Surfaces

The eligibility of applying the Owens–Wendt approach to determining the free surface energy of liquid-repellent aluminum surfaces, with micro- and nanotextures formed by a femtosecond laser, was considered. This approach has been shown to be applicable using two essential parameters that can be derived from the graphs. The first is related to the fraction of the contact area between the liquid and the solid surface in the Cassie state. The second is related to the degree of intrinsic polarity of the surface material or the applied organic modifier. The presented interpretation was used to compare the liquid repellency of the obtained textures. A microtexture with a period of 60 μm and a groove width of 45 μm has been shown to be the most liquid repellent. Among the modifiers, 1H,1H,2H,2H-perfluoroctyltriethoxysilane was the most effective, and stearic acid was only slightly inferior, but promising in terms of cost and environmental friendliness. It was shown that spontaneous hydrophobization provided a contact angle with water up to 159°, but the stability of such textures was inferior to the considered modifiers.

Understanding the Transition from High-Selective to High-Efficient Chiral Separations by Changing the Organic Modifier with Zwitterionic-Teicoplanin Chiral Stationary Phase.

The retention behavior of small molecules and N-protected amino acids on a zwitterionic teicoplanin chiral stationary phase (CSP), prepared on superficially porous particles (SPPs) of 2.0 μm particle diameter, has shown that efficiency and enantioselectivity, and so enantioresolution, dramatically change depending on the employed organic modifier. In particular, it was found that while methanol permits the boost of enantioselectivity and resolution of the amino acids, at the cost of efficiency, acetonitrile allows for the ability to reach extraordinary efficiency even at high flow rates (with reduced plate height <2 and up to 300,000 plates/m at the optimum flow rate). To understand these features, an approach based on the investigation of mass transfer through the CSP, the estimation of the binding constants of amino acids on the CSP, and the assessment of compositional properties of the interfacial region between bulk mobile phase and solid surface has been adopted.