Journal of separation science最新文献

Adduction on protein nucleophile sites by mustard agents can be monitored to assess detection of retrospective exposure to these agents. Cysteine 34 (Cys34) on human serum albumin was selected as the target of choice. This work targets di- and tripeptides adducted on Cys34 by sulfur mustard, sesquimustard, and nitrogen mustards separated in hydrophilic liquid chromatography (HILIC) and Reversed–Phase (RP) mode. The effect of several mobile phase additives on the mass spectrometry (MS) and MS/MS signal and on LC retention profile was studied. A mix of ammonium acetate and acetic acid offered satisfactory results in terms of MS sensitivity. Screening of HILIC columns was performed, and ZIC-HILIC stationary phase was selected for HILIC mode, and C₁₈ stationary phase was used for RP analysis. Negative ionization mode leads to a higher S/N ratio compared to positive ionization mode. Adducted tripeptides were selected for the monitoring of mustard agents’ exposure, allowing better sensitivity than their dipeptide homologues. The two developed chromatographic methods have similar sensitivities with LOQs ranging from 1.9 to 20.5 ng/mL for the reversed-phase liquid chromatography (RPLC)–ESI–(−)–MS/MS method and from 1.7 to 43.3 ng/mL for the HILIC–ESI–(−)–MS/MS method. The monitoring method should be selected based on the targeted mustard agent, and the remaining method can be a confirmation tool.

Chiral macrocycles have emerged as attractive media for chromatographic enantioseparation due to their excellent host-guest recognition properties. In this study, a new chiral stationary phase (CSP) based on 1,1'-binaphthyl chiral polyimine macrocycle (CPM) was reported. The CPM was synthesized by one-step aldehyde-amine condensation of (S)-2,2'-dihydroxy-[1,1'-binaphthalene]-3,3'-dicarboxaldehyde with 1,2-phenylenediamine and bonded on thiolated silica via the thiol-ene click reaction to afford the CSP. The enantioseparation performance of the CSP was evaluated by separating different types of racemates including alcohols, esters, ketones, amides, organic acids, and ethers in both normal-phase (NP) and reversed-phase (RP) elution modes. As a result, enantioseparations of 10 and 15 racemates were achieved in the two elution modes, respectively. Meanwhile, the effects of chromatographic conditions on separation, such as mobile phase composition and injection mass, were studied in detail. Moreover, a comparison of the proposed CSP for the separation of the tested racemates with commercial Chiralcel OD-H and Chiralpak AD-H columns was also conducted, and results revealed that the proposed CSP can achieve some enantioseparations that cannot be achieved by the two commercial columns. This study indicates that the chiral macrocycle is a promising chiral selector for high-performance liquid chromatography.

Micellar liquid chromatography (MLC) has proven beneficial efficiency and ecological impact for routine quality control activities. In the proposed study, cyrene was investigated for the first time, together with other green additives, as a novel safe organic solvent in reversed-phase MLC. Quality-by-design (QbD) approach screened their effect on the separation performance. Six antidiabetic drugs from different classes, namely, metformin (MTF), empagliflozin (EMP), ertugliflozin (ERT), linagliptin (LNT), sitagliptin (SIT), and gliclazide (GCZ) were utilized to assess some newly approved antidiabetic drugs and combinations. An organic solvent-free mobile phase consisting of (0.01 M Brij-35, 0.09 M sodium dodecyl sulfate, and 0.01 M ammonium acetate, pH 5.0) separated the studied drugs using an RP-C18 core–shell column. The flow rate was set at 1.2 mL/min, and analytes were detected using a photodiode array detector at 245, 270, and 225 nm. System suitability parameters demonstrated MLC capability to eliminate organic solvents without compromising separation efficiency. The method was validated across a concentration range of 2.0–30.0 µg/mL for EMP, ERT, and LNT, 20.0–120.0 µg/mL for GCZ and SIT, and 100.0–600.0 µg/mL for MTF. The method successfully determined analytes in different single and multicomponent tablets. Greenness assessment was performed using MoGAPI and AGREE metrics.

Silica-based monoliths offer higher separation efficiency per unit pressure drop compared to particle-packed columns. Their application is limited by the commercial availability of different column chemistries. Pentafluorophenyl ligands enable hydrogen bonding, dipole–dipole, π–π, and hydrophobic interactions, facilitating the separation of various compounds. This study employs an in situ modification procedure, namely, the silylation reaction to bond these specific ligands to silica-based monoliths. Three chromolith silica monoliths were modified with three different PFP-moieties. The silica monolith was successfully modified in situ with 3-(pentafluorophenyl)propylmethyldichlorosilane and the separation behavior was compared to a particle-packed pentafluorophenyl column and a C18 monolith for the separation of tocochromanols (Vitamin E-related compounds). The C18 monolith failed to resolve all the tocochromanols, while the PFP particle-packed column and monolith were comparable under their optimized conditions. The PFP monoliths conditions are as follows: isocratic water-methanol (22:78, v/v) mobile phase, with a flow rate of 1.45 mL/min, at 15°C. Further chromatographic comparisons between the PFP particle-packed column to the PFP monolith included selectivity studies under isocratic conditions via the linear solvent strength model, which also showed comparable selectivity behavior. Differences in selectivity was demonstrated for a gradient separation of eight compounds to represent a relatively more complex separation. In addition, backpressure and Van Deemter comparisons were performed, and it was demonstrated that the main PFP monolith advantages were obtained near the pressure maximum of the PFP particle-packed column at 3.5 mL/min, comparable efficiencies were obtained, and the PFP monolith decreased the backpressure by one-third.

This study introduces a green approach to sample preparation by applying natural deep eutectic solvents (NADES) to determine phthalates in carbonated soft drinks using high-performance liquid chromatography with diode array detector (HPLC-DAD). The method employs hollow fiber-microporous membrane liquid-liquid microextraction combined with a 96-well plate system, utilizing fatty-acid-based DES in the pores of the membranes. This methodology substantially reduces the use of organic solvents, and its efficiency is comparable to or better than conventional methods. Fatty acids with chain lengths ranging from 6 to 12 carbons were investigated for the determination of dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), and benzyl butyl phthalate (BBP). The optimized approach used a NADES of decanoic and nonanoic acids (2:3 molar ratio), with 60 min of extraction and 30 min of desorption in acetonitrile:methanol (1:1 ratio). Limits of detection were reported as 8.2 µg/L for DMP, 7.6 µg/L for DEP and DBP, and 3.0 µg/L for BBP. Intraday precision ranged from 2.2% to 18.6% and inter-day precision from 8.8% to 18.8%. Relative recovery across 3 levels ranged from 83.1% to 113.5%. The methodology was evaluated by two tools with green metrics to indicate sustainability. Analytes are extracted, quantified, and confirmed as phthalates in two brands of carbonated soft drinks.

Disinfection by-products (DBPs) have received considerable focus due to potential teratogenic, carcinogenic, and mutagenic effects; however, there is an evident gap in the availability of analytical methodologies for the simultaneous determination of DBPs in fish, especially iodinated DBPs. This paper developed an innovative analytical method for the simultaneous determination of 12 DBPs, including four trihalomethanes (THMs), three haloacetonitriles, and five iodinated THMs (I-THMs), in fish muscle, utilizing solvent extraction followed by gas chromatography with electron capture detection. The method incorporates tert-butyl methyl ether as an extraction solvent, performing efficient vortex mixing, extraction, and centrifugation under reduced temperature conditions to facilitate the processing of physically disrupted fish tissues. It demonstrates sensitivity with detection limits from 0.21 to 4.02 ng/g, with recoveries from 58.7% to 129.7%. Applied to real fish samples, including bass (n = 7) and carp (n = 7), all contained detectable DBPs, with concentrations between 8.2 and 275.25 ng/g. Significantly, bass from aquaculture facility exhibited the highest contamination, particularly with chlorodiiodomethane at 194.57 ng/g. I-THMs present in all fish samples. Notably, this is the first paper about the analytical protocol of I-THMs in biological matrices. This developed method will facilitate further research on human exposure assessment of DBPs through consumption of fish.

Natural products play a vital role in human health because people find that they can reduce the incidence of many diseases, such as cancer and cardiovascular diseases. Therefore, researchers have developed many effective techniques for screening and separating active compounds from natural products. High-speed countercurrent chromatography is a unique unsupported liquid–liquid chromatography technology that has been widely used in the separation of natural products. In this paper, the research progress of screening and separating active components from natural products by combining high-speed countercurrent chromatography technology with other technologies is reviewed from two aspects: pre-column activity assay and post-column activity assay. The purpose of this paper is to provide some theoretical support for the screening and separation of natural active compounds by high-speed countercurrent chromatography. I hope that the contents summarized in this paper can provide more basis for the development of screening and separation of natural active compounds to realize large-scale preparation.

To achieve specific adsorption-based sample preparation for the poorly soluble veterinary drug oxibendazole, this study employed 4-vinylpyridine as the functional monomer and conducted radical polymerization on the surface of functionalized silica nanoparticles to synthesize a surface molecularly imprinted polymer (OBZMIP). This OBZMIP exhibited good adsorption capacity for oxibendazole within 30 min, with its adsorption behavior conforming to the pseudo–second-order kinetic and Langmuir models, predicting a maximum adsorption capacity of 4.93 mg/g. After five adsorption–desorption cycles, the adsorption capacity remained unchanged, demonstrating excellent reusability. In a mixed system containing eight similar compounds, the selectivity coefficients ranged from 1.3 to 16.9, indicating outstanding specific recognition ability. Utilized as an adsorbent packing material for solid-phase extraction, the prepared OBZMIP demonstrated significantly high recovery rates in the extraction of oxibendazole from four distinct meat samples. Therefore, OBZMIP holds promising applications in the selective extraction of veterinary drug oxibendazole residues during the pretreatment of meat samples.