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Resolution limits of size exclusion chromatography columns identified from flow reversal and overcome by recycling liquid chromatography to improve the characterization of manufactured monoclonal antibodies.

The flow reversal (FR) technique consists of reversing the flow direction along a chromatographic column. It is used to reveal the origin (such as poor column packing, active sites, or slow absorption/escape kinetics) for the resolution limit of 4.6 mm × 150 mm long columns packed with 1.7 μm 200 Å Bridge-Ethylene-Hybrid (BEHTM) Particles. These columns are used to separate manufactured monoclonal antibodies (mAb, ∼ 150 kDa) from their close impurities (or IdeS fragments, ∼ 100 kDa) by size exclusion chromatography (SEC). FR unambiguously demonstrates that the resolution limit of these SEC col…

Simultaneously characterization of multiple constituents in Valeriana jatamansi Jones using an online supercritical fluid extraction-high-performance liquid chromatography/supercritical fluid chromatography-mass spectrometry system.

Valeriana jatamansi Jones is a commonly used traditional Chinese medicine, boasting rich effective compositions with versatile chemical structures and wide polarity, including iridoids, chlorogenic acid, and flavonoids. Previous reports indicate that conventional high-performance liquid chromatography (HPLC) analytical methods have proven inefficient performance in comprehensively characterizing components in Valeriana jatamansi. In the present study, a hybrid online analytical platform combining supercritical fluid extraction with both conventional HPLC separation (reverse phase) and supercri…

Use of ammonium formate in QuEChERS for high-throughput analysis of pesticides in food by fast, low-pressure gas chromatography and liquid chromatography tandem mass spectrometry.

The "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) approach to sample preparation is widely applied in pesticide residue analysis, but the use of magnesium sulfate and other nonvolatile compounds for salting out in the method is not ideal for mass spectrometry. In this study, we developed and evaluated three new different versions of the QuEChERS method using more volatile salts (ammonium chloride and ammonium formate and acetate buffers) to induce phase separation and extraction of 43 representative pesticide analytes of different classes. Fast low-pressure gas chromatography ta…

Метод газовой хроматографии для количественного определения остаточных растворителей в наноформуляциях.

Описано разработку и проверку метода газовой хроматографии, который является чувствительным, быстрым и специфичным для оценки 19 распространенных растворителей класса 2 и класса 3, часто используемых в формулировке наномедицины. Проверка метода проводилась с использованием системы газовой хроматографии PerkinElmer с детектированием искровой ионизации и колонки Elite 624 Crossbond 6% цианопропилфенил-94% диметилполисилоксана или DB-Fatwax-Ultra Inert с гелием в качестве носителя. Оценены характеристики валидации, такие как линейность, восстановление при добавлении, точность метода, специфичност

Совпадение в аннотации оригинала
The development and validation of a sensitive, rapid, and specific gas chromatography method for the evaluation of 19 common Class 2 and Class 3 solvents frequently used in nanomedicine formulation is described. Method validation was performed using PerkinElmer's headspace gas chromatograph system with flame ionization detection and an Elite 624 Crossbond 6%…

[Determination of methylcyclohexanol in workplace air by solvent desorption-gas chromatography].

Objective: To establish a gas chromatography method with solvent desorption for the determination of methylcyclohexanol in workplace air. Methods: In February 2024, the workpace air samples were collected through Neutral silicone tubes, desorbed with ethanol, separated by a polyethylene glycol capillary column modified with nitrophenyl terephthalic acid (DB-FFAP), and then determined by a hydrogen flame ionization detector (FID) . Results: 1-methylcyclohexanol, 3-methylcyclohexanol and 4-methylcyclohexanol show good linear relationships when the mass concentrations are between 1.15-1840.00 μg/…

An update on the progress in fundamental understanding of hydrophilic interaction liquid chromatography.

With expanding applications, Hydrophilic Interaction Liquid Chromatography (HILIC) has made significant progress in theoretical and methodological developments in the past decade. Research efforts to elucidate its complex retention mechanisms and kinetic mass transfer characteristics continue to gain more insights. Central to this progress is a refined understanding of the adsorbed water layer on the polar packing surface, which functions as the de facto stationary phase for hydrophilic partitioning. Recent advances, including molecular dynamic simulation and quantitative measurement of phase …

Development of a halofluorocarbon, chromatography-free radiosynthesis of fluorine-18 difluorocarbene.

BACKGROUND: In recent years, the development of the [18F]difluoromethyl radical ([18F]2-((difluoromethyl)sulfonyl)benzo[d]thiazole, [18F]4), … s of [18F]4 and [18F]10 on the GE TRACERlab FXFN module. Additionally, another aim was to develop a chromatography-free, fully-automated synthesis of [18F]10 on the GE FXFN module. RESULTS: Precursors 3 and 8 were synthesised in 21% and 54% yield via decarboxylative bromination, which circumvented the need for ozone-depleting dibromofluoromethane. Difluoromethy …

Introducing Hydrofluoroethers as Modifiers for Enantioseparation in Super/Subcritical Fluid Chromatography.

The addition of modifiers led to a marked expansion of the chemical space that can be analyzed with super/subcritical fluid chromatography. The introduction of new modifiers can help tune selectivity with commercially available stationary phases. This work presents an entirely new class of modifiers, which offers unique selectivity not afforded by conventional solvents. We utilize hydrofluoroethers, commonly designated as Engineered Fluids, as modifier for enantioseparations on polysaccharide-based chiral stationary phases under super/subcritical fluid chromatographic conditions. Engineered fl…

Design and evaluation of semicarbazide-embeddedd stationary phases for liquid chromatography.

Semicarbazide, as a derivative of urea, constitutes a great variety of functional molecules for different needs. Herein, novel stationary phases with an incorporated semicarbazide group were proposed. Using aliphatic (docosanoyl, C22) and aromatic (benzoyl, Bz) hydrazides, the semicarbazide-embedded ligands were synthesized before chemical modification of the silica gel, allowing for an accurate interpretation of the chromatographic properties of the corresponding packings. The new stationary phases were water-wettable, due to the presence of highly polar groups. In particular, Bz-semicarbazid

[Applications of ion chromatography for the analysis of Chinese herbal medicine components].

Ion chromatography (IC) is a novel high performance liquid chromatographic technique that is suitable for the separation and analysis of ionic substances in different matrix samples. Since 1975, it has been widely used in many fields, such as the environment, energy, food, and medicine. IC compensates for the separation limitations of traditional gas chromatography and high performance liquid chromatography and can realize the qualitative analysis and quantitative detection of strongly polar components. This chromatographic technique features not only simple operations but also rapid analysis.…

Quantitation of Bupropion in Urine by Liquid Chromatography-Tandem Mass Spectrometry.

Bupropion is a medication commonly used to treat depression and help people quit smoking. However, it has the potential to be misused or diverted, so it is important to have accurate and sensitive methods to detect it in bodily fluids. We present a fast and dependable quantitative LC-MS/MS method for measuring bupropion levels in urine. This method involves enzymatic hydrolysis and separation using a reversed-phase C18 column, where the effectiveness of the hydrolysis is monitored using morphine-3-b-D-glucuronide. The analysis is conducted using an AB Sciex 3500 mass spectrometer with dual-cha

Development of Centrifugal Partition Chromatography for the Purification of Antibody-Drug Conjugates.

Monoclonal antibody-drug conjugates (ADCs) are an expanding therapeutic class of biomolecules for which relatively few analytical and preparative separation options exist. Purification of ADCs with a specific drug antibody ratio is even more challenging. We report the first application of countercurrent separation (CCS) to this problem. An ADC mimic was successfully chromatographed using an aqueous two-phase system (ATPS) consisting of PEG 1000/sodium citrate pH 7.5/water, 17.75/17.75/64.50 (w/w/w). Notably, different partition coefficients (K) in this ATPS for the ADC mimic (0.09 < K < 0.16)

A convenient separation strategy for fungal anthraquinones by centrifugal partition chromatography.

As recently shown, some fungal pigments exhibit significant photoactivity turning them into promising agents for the photodynamic treatment of microbial infections or malignant diseases. In the present study, a separation strategy for fungal anthraquinones was developed based on centrifugal partition chromatography. A suitable method was explored employing a methanolic extract of the fruiting bodies of Cortinarius sanguineus (Agaricales, Basidiomycota). An excellent fractionation was achieved using a biphasic solvent system comprising chloroform/ethyl acetate/methanol/water/acetic acid (3:1:3:…

Sulfolane as a novel stationary phase for analytical separations by gas chromatography.

Sulfolane is explored as a novel stationary phase for use in analytical separations by capillary column gas chromatography with flame ionization detection (GC-FID). Stainless steel capillaries were found to provide a good substrate for coating and retaining a sulfolane phase, whereas fused silica tubing did not perform well for this. In general, the phase was found to be stable for several hours of use when using elevated carrier gas pressures (90 psi) and a small restriction (25 μm I.D. tubing) at the outlet. This normally provided good performance at temperatures up to about 200 °C with very…

Pseudophase microextraction for in-line sample concentration in micellar electrokinetic chromatography.

Pseudophase microextraction (PPME) as a simple in-line sample concentration technique in micellar electrokinetic chromatography (MEKC) is presented. In contrast to popular electric-field driven stacking techniques in MEKC such as sweeping, PPME is pressure-driven. The technique afforded up to 403-2968x improvements in peak heights for fenoprop, dichlorprop, 1- and 2-naphthol compared to typical injection. Under the same MEKC conditions, the improvements in PPME were up to 23-59x better compared to sweeping. Briefly in PPME, the entire capillary was loaded (up to 20 capillary volumes) with the …