A simple and cost-effective hybrid stationary phase for the separation of peptides, proteins and benzene derivatives through liquid chromatography.

A very simple and cost-effective silica-based hybrid stationary phase was synthesized for the separation of five synthetic peptides, five proteins, and benzene derivatives. Silica monolith was synthesized sol-gel process. Particles obtained through the grinding of silica monolith were suspended in methanol and sedimented under gravity to obtain sub-2 μm particles.

Synthesis of monolith silica anchored graphene oxide composite with enhanced adsorption capacities for carbofuran and imidacloprid.

Highly efficient adsorbent was prepared for the removal of carbofuran and imidacloprid pesticides from wastewater. The silica monolith anchored graphene oxide composite was synthesized by the modified Fischer esterification protocol. The composite showed improved adsorption capacity for the removal of pesticides from wastewater.

Synthesis, column packing and liquid chromatography of molecularly imprinted polymers for the acid black 1, acid black 210, and acid Brown 703 dyes.

Molecularly imprinted polymers have been synthesized for the acid black 1, acid black 210, and acid brown 703 dyes using methacrylic acid, ethylene glycol, and azobisisobutyronitrile as the monomer, cross-linker, and initiator, respectively, in the ratio of 1 : 10 : 44 (template:monomer:cross-linker). The MIPs were used for the selective removal of their corresponding dyes. The selective nature of the MIPs towards their respective dyes was confirmed by a homemade liquid chromatography system.

Particle packed mixed-mode chromatographic stationary phase for the separation of peptide in liquid chromatography.

A particle-based stationary phase has been prepared for the separation of five synthetic peptides and a mixture containing tryptic digest of cytochrome C in liquid chromatography. Particles originating from silica monolith were differentially sedimented to obtain 1-2 μm particles. A stationary phase was achieved by the coating of poly(styrene-methacrylic acid-N-phenylacrylamide) copolymer onto the particles via reversible addition-fragmentation chain transfer polymerization reaction.

An optimized mixed-mode stationary phase based on silica monolith particles for the separation of peptides and proteins in high-performance liquid chromatography.

A phase with both hydrophobic and hydrophilic functionalities has been synthesized by modification of ground silica monolith particles with C18 and 1-[3-(trimethoxysilyl)propyl] urea ligands. A series of phases was prepared by changing the ratio of the two ligands to determine the optimal ratio in view of separation efficiency. The resultant optimized stationary phase was packed in narrow-bore glass-lined stainless-steel columns (1 × 300 mm and 2.

Styrene-N-phenylacrylamide co-polymer modified silica monolith particles with an optimized mixing ratio of monomers as a new stationary phase for the separation of peptides in high performance liquid chromatography.

A stationary phase was prepared by chemical derivatization of the support particles with a layer of copolymer composed of styrene and N-phenyl acrylamide. Silica monolith particles of ca. 2.

Polystyrene bound silica monolith particles of reduced size as stationary phase of excellent separation efficiency in high performance liquid chromatograhy.

Ground silica monolith particles of quite smaller average size (2 μm) have been prepared by sol-gel process followed by soft grinding and calcination. Next a highly efficient chromatographic stationary phase has been prepared by reaction of those particles with (3-chloropropyl) trimethoxysilane followed by initiator attachment and modification of polystyrene by reversible addition-fragmentation chain transfer polymerization. The resultant phase of ca 3 μm particle size was packed in micro-columns (1.

Sedimentation assisted preparation of ground particles of silica monolith and their C18 modification resulting in a chromatographic phase of improved separation efficiency.

The sedimentation procedure has been adopted in production of ground silica monolith particles to improve chromatographic separation efficiency of the resultant phase. First, silica monolith particles have been successfully prepared in a large scale by a sol-gel process followed by grinding. The particles after calcination were separated by sedimentation into three zones using an Imhoff sedimentation cone.

Open tubular capillary column of 50 μm internal diameter with a very high separation efficiency for the separation of peptides in CEC and LC.

A specially designed long open tubular capillary column (50 μm internal diameter and 112 cm effective length) was prepared by fabrication of a thin three-component co-polymer layer on the inner surface of silica capillary. A pretreated silica capillary was reacted with 4-(chloromethyl)phenyl isocyanate in the presence of dibutyltin dichloride as catalyst followed by sodium diethyl dithiocarbamate. Then a thin polymer layer was made on the inner surface of capillary by reversible addition-fragmentation transfer polymerization of styrene, N-phenylacrylamide, and methacrylic acid.

Polyether ether ketone encased monolith frits made of polyether ether ketone tubing with a 0.25 mm opening resulting in an improved separation performance in liquid chromatography.

Tiny polyether ether ketone encased monolith frits have been prepared by modified catalytic sulfonation of the inner surface of polyether ether tubing (1.6 mm od, 0.25 mm id) followed by modified formation of organic monolith and cutting of the tubing into slices.

Open tubular capillary column for the separation of cytochrome C tryptic digest in capillary electrochromatography.

A silica capillary of 50 μm internal diameter and 500 mm length (416 mm effective length) was chemically modified with 4-(trifluoromethoxy) phenyl isocyanate in the presence of dibutyl tin dichloride as catalyst. Sodium diethyl dithiocarbamate was reacted with the terminal halogen of the bound ligand to incorporate the initiator moiety, and in situ polymerization was performed using a monomer mixture of styrene, N-phenylacrylamide, and methacrylic acid. The resultant open tubular capillary column immobilized with the copolymer layer was used for the separation of tryptic digest of cytochrome C in capillary electrochromatography.

Organic monolith frits encased in polyether ether ketone tubing with improved durability for liquid chromatography.

This study introduces a preparation method for polymer-encased monolith frits with improved durability for liquid chromatography columns. The inner surface of the polyether ether ketone tubing is pretreated with sulfuric acid in the presence of catalysts (vanadium oxide and sodium sulfate). The tubing was rinsed with water and acetone, flushed with nitrogen, and treated with glycidyl methacrylate.

Open tubular capillary electrochromatography with an N-phenylacrylamide-styrene copolymer-based stationary phase for the separation of anomers of glucose and structural isomers of maltotriose.

A ligand with a terminal halogen (4-chloromethylphenyl isocyanate) was chemically bound on the inner surface of pretreated silica capillary with 50 μm internal diameter and 58 cm total and 50 cm effective length in the presence of dibutyl tin dichloride as a catalyst through isocyanate-hydroxyl reaction. Attachment of initiator (sodium diethyl dithiocarbamate) to the bound ligand was carried out and followed by in situ polymerization. Reversible addition-fragmentation chain transfer polymerization was used for the immobilization of N-phenylacrylamide-styrene copolymer on the inner surface of capillary column.

C₁₈-bound porous silica monolith particles as a low-cost high-performance liquid chromatography stationary phase with an excellent chromatographic performance.

Ground porous silica monolith particles with an average particle size of 2.34 μm and large pores (363 Å) exhibiting excellent chromatographic performance have been synthesized on a relatively large scale by a sophisticated sol-gel procedure. The particle size distribution was rather broad, and the d(0.

Fritting techniques in chromatography.

It is surprising that there has been no devoted review article for frits and relevant studies so far despite the long history of packed columns and the use of frits in them. This review was activated for such a reason. Both separate frits and in situ permanent frits have been covered since the appearance of primitive frits.

Catalyst assisted synthesis of initiator attached silica monolith particles via isocyanate-hydroxyl reaction for production of polystyrene bound chromatographic stationary phase of excellent separation efficiency.

Dibutyltin dichloride (DBTDC) was used as a catalyst to chemically bind 4-chloromehtylphenylisocynate (4-CPI) to porous monolithic silica particles via isocyanate-hydroxyl reaction, and the reaction product was reacted with sodium diethyldithiocarbamate (SDDC) to yield initiator attached silica monolith particles. Reversible addition-fragmentation transfer (RAFT) polymerization was taken place on them to result in polystyrene attached silica particles that showed excellent separation efficiency when packed in a chromatographic column (1.0 mm × 300 mm).

Comprehensive overview of recent preparation and application trends of various open tubular capillary columns in separation science.

Open tubular (OT) capillary columns have been increasingly used in a variety of fields of separation science such as CEC, LC, and SPE. Especially their application in CEC has attracted a lot of attention for their outstanding separation performance. Various forms of OT stationary phase materials have been employed such as in-situ prepared polymers, molecular imprinted polymers (MIPs), brush ligands, host ligands, block copolymers, aptamers, carbon nanotubes, polysaccharides, proteins, tentacles, nanoparticles, monoliths, and polyelectrolyte multi-layers.

Polystyrene bound stationary phase of excellent separation efficiency based on partially sub-2μm silica monolith particles.

Partially sub-2μm porous silica monolith particles have been synthesized by a renovated procedure and modified to polystyrene coated silica particles with excellent separation efficiency when used as chromatographic media. In the procedure of preparing silica monolith particles in this study, subtle control of formulation of the reaction mixture and multi-step heating followed by calcination, without any washing and sieving process, enabled formation of silica particles characterized by proper particle and pore size distribution for high separation efficiency. 3-Chloropropyl trimethoxysilane was used as the halogen terminal spacer to combine the initiator to silica particles.

Recent applications of molecular imprinted polymers for enantio-selective recognition.

Molecular imprinted polymer (MIP) techniques have been increasingly used in a variety of fields including chromatography, sample pretreatment, purification, sensors, drug delivery, and catalysts, etc. MIP is a specific artificial receptor that shows favored affinity to the template molecule. The cavities of the template are produced by carrying out polymerization of a reaction mixture followed by eliminating the template molecules by washing.

Open tubular molecular imprinted phases in chiral capillary electrochromatography.

A generalized preparation protocol for open tubular (OT) molecular imprinted polymer (MIP) silica capillary columns for chiral separations in capillary electrochromatography (CEC) is described. For -different chiral molecules the same general composition of the MIP reaction mixture can be used except for the choice of the specific template. This protocol is valid for a variety of templates including acidic, basic, and neutral molecules, enabling formation of rugged and porous thin MIP layers on the inner surface of the capillary resulting in columns with high chiral separation efficiencies if the template has a good chiral recognition susceptibility.

Molecular imprinted polymers for separation science: a review of reviews.

Molecular imprinted polymer is an artificial receptor made by imprinting molecules of a template in a polymer matrix followed by removing the template molecules via thorough washing to give the permanent template grooves. They show favored affinity to the template molecule compared to other molecules, and this property is the basic driving force for such diverse application of this techniques. Such techniques have been increasingly employed in a wide scope of applications such as chromatography, sample pretreatment, purification, catalysts, sensors, and drug delivery, etc.

Analysis of phospholipids using an open-tubular capillary column with a monolithic layer of molecularly imprinted polymer in capillary electrochromatography-electrospray ionization-tandem mass spectrometry.

In this study, an open-tubular capillary electrochromatography (OT-CEC) column with a monolithic layer of molecularly imprinted polymer (MIP) based on methacrylic acid, ethylene glycol dimethacrylate, and 4-styrenesulfonic acid was utilized for the simultaneous separation and characterization of phospholipid (PL) molecular structures by interfacing with electrospray ionization-tandem mass spectrometry (ESI-MS-MS). Introducing an MIP-based monolith along with charged species at the OT column made it possible to separate PL molecules based on differences in head groups and acyl chain lengths in CEC. For the interface of OT-CEC with ESI-MS-MS, a simple nanospray interface utilizing a sheath flow was developed and the resulting OT-CEC-ESI-MS-MS was able to separate PL standards (phosphatidylserines, phosphatidylethanolamines, phosphatidylglycerols, phosphatidic acid, and lysophosphatidylglycerols).

Open tubular capillary columns with basic templates made by the generalized preparation protocol in capillary electrochromatography chiral separation and template structural effects on chiral separation capability.

Some open tubular (OT) molecule imprinted polymer (MIP) silica capillary columns have been prepared using atenolol, sulpiride, methyl benzylamine (MBA) and (1-naphthyl)-ethylamine (NEA) as templates by the pre-established generalized preparation protocol. The four MIP thin layers of different templates showed quite different morphologies. The racemic selectivity of each MIP column for the template enantiomers was optimized by changing eluent composition and pH.