Chromatographia最新文献

The number of potentially abused substances in horse racing is very large and it is not easy to analyse the full range. To facilitate the analyses of substances of abuse, a method has been developed for 63 substances in horse urine using liquid chromatography–tandem mass spectrometry. The developed method has been validated according to the 2021/808/EC and AORC criteria. The horse urine samples were extracted after enzymatic hydrolysis via a C8-BCX SPE cartridge with an automated SPE and analyzed by LC–MS/MS. According to the validation study results, the within-laboratory reproducibility CV was no more than 13.9% and the average recoveries ranged from 90.71 to 117.94% for repeatability and reproducibility. The decision limits (CCα) for quantitative analysis and detection capabilities (CCβ) for qualitative screening were close to the targeted limit for each substance. The results of the present study showed that the method was able to perform quantitative analyses of 54 substances and screening analyses of 9 substances (total 63) in horse urine and that the results were valid and applicable. The validated method was successfully applied to five proficiency tests and three suspected samples.

The optimization of mobile phase composition in HPLC is crucial for achieving excellent chromatographic performance. Mobile phase additives are very often added to control retention, resolution, peak shape and efficiency. According to the Hofmeister series, additives are classified into chaotropic and kosmotropic agents. When ionizable compounds are analysed by hydrophilic interaction liquid chromatography (HILIC), additives can control the electrostatic interactions and affect the chromatographic parameters. In this study, citicoline, a neurotransmitter, was analysed under HILIC conditions using various additives. Due to the solubility limit in high organic content, the composition of the mobile phase was fixed at a 2/1 (V/V) acetonitrile/water ratio, and the salt concentration set to 25 mM. A total of 21 additives were tested, including short-chain organic acids (formic, acetic, propionic, trifluoroacetic and trichloroacetic acid), cations (lithium, sodium, potassium and ammonium) and anions (acetate, bromide, chloride, dihydrogen citrate, dihydrogen phosphate, nitrate, perchlorate and tetrafluoroborate). With additive-free mobile phases, weak retention of citicoline was observed, which can be explained by the small thickness of the water layer on the surface of the silica stationary phase and electrostatic repulsion between deprotonated silanols and negatively charged citicoline. However, the use of additives improves retention. Short-chain organic acids increased retention, but produce poor peak shape. Cations affected retention in the following order: ({{varvec{L}}{varvec{i}}}^{+}<{{varvec{N}}{varvec{H}}}_{4}^{+}<{{varvec{N}}{varvec{a}}}^{+}<{{varvec{K}}}^{+}), corresponding to the reversed Hofmeister series. The anions trend was: ({{varvec{C}}{varvec{H}}}_{3}{varvec{C}}{{varvec{O}}{varvec{O}}}^{-}<{{varvec{H}}}_{2}{{varvec{P}}{varvec{O}}}_{4}^{-}<{{varvec{B}}{varvec{r}}}^{-}<{{varvec{C}}{varvec{l}}}^{-}<{{varvec{H}}}_{2}{{varvec{C}}{varvec{i}}{varvec{t}}{varvec{r}}{varvec{a}}{varvec{t}}{varvec{e}}}^{-}<{{varvec{N}}{varvec{O}}}_{3}^{-}<{{varvec{C}}{varvec{l}}{varvec{O}}}_{4}^{-}<{{varvec{B}}{varvec{F}}}_{4}^{-}), which corresponds to the direct Hofmeister series, except for acetate and dihydrogen phosphate.

Oflox-TZ, Dto, and Ofnida syrup are well-known antimicrobial combination medications used to treat illnesses caused by parasites and bacteria. Environmentally sustainable model creation for antimicrobial compounds utilizing chemometric application, isosbestic point, and dual wavelength assisted by spectrophotometric and chromatographic analysis using ANOVA comparison with all developed methods. Deconvolution of the spectral overlaps and harmful use of organic solvents in spectrophotometric and chromatographic conditions with these combinations were performed using the partial least squares method, either with or without variable selection methods such as principal component regression. A good agreement was found when comparing the findings of the developed methods statistically to an ANOVA, indicating the efficacy of the suggested methodology. Calibration and validation sets comprising 24 and 12 samples, respectively, were carefully developed using partially factorial designs for the experiments at different dosages. The developed models were validated according to established International Council for Harmonisation (ICH) strategies. For the dual-wavelength approach, Beer’s plot confirmed linearity between 2 and 12 µg/mL for (OFL) and 5 and 30 µg/mL for Tinidazole (TZ) respectively. The mean percent recoveries were found to 101.0% and 102.0% for OFL and TZ. Chemometrics-assisted UV spectrophotometry, employing both partial least squares (PLS) and principal component regression (PCR) analysis models, yielded mean OFL recoveries of 102.3% (PLS) and 102.4% (PCR), and TZ recoveries of 102.6% (PLS) and 102.6% (PCR). Additionally, chromatographic model development using hydrotropic solutions yielded mean percentage recoveries of 100.2% and 100.6% for OFL and TZ, respectively, in commercial drug formulations. The study found that the proposed chemometric-assisted spectrophotometric and chromatographic methods could reliably determine OFL and TZ concentrations in both laboratory-prepared mixtures and pharmaceutical preparations, thereby proving them to be useful analytical instruments for quality control and in-process testing of different pharmaceutical drug preparations. This approach provides a significant outcome over the use of less polluted solvents, making it more precise and economical.

Graphical Abstract

Metal–organic frameworks (MOFs) have a wide range of applications in separation and analytical sciences due to their unique structures. MIL-100(Fe) was immobilized on the inner wall of the capillary column based on the immobilized cysteine (Cys)-triggered in situ growth (ICISG) strategy. By applying this column to capillary electrophoresis, a novel enantioselective separation system based on MIL-100(Fe) nanomaterial was established. By utilizing lactobionic acid (LA) as the chiral selector and optimizing the experimental conditions such as buffer pH, LA concentration and the methanol addition ratio, the CEC system demonstrated a significantly enhanced enantioseparation ability for six basic drugs. The modified capillary column was characterized by scanning electron microscope (SEM), energy-dispersive X-ray spectroscope (EDS) and X-ray diffractometer. The experimental results showed that MIL-100(Fe) was successfully grown on the inner wall of the capillary column. In the present study, the repeatability of the coated column was investigated and the relative standard deviations (RSDs) of the resolution and the migration time for intra-day, inter-day and inter-column were within 8%, proving the good repeatability of the coated column.

The possibility of applying the system: weakly basic Amberlite IRA-68 resin-nitrilotriacetic acid (NTA) solutions for the separation of rare earth elements (REE) by ion exchange chromatography was investigated. Preliminary research results revealed that the affinity of REE towards the ion exchanger is closely correlated with the stability of their negative complexes that they form with NTA. Three separate groups of lanthanides could be distinguished, i.e. light (La, Ce, Pr, Nd), medium (Y, Sm, Eu, Gd, Tb, Dy, Ho, Er) and heavy (Tm, Yb, Lu, Sc). Moreover, it seemed that within the first and third groups it was possible to individually separate elements from each other. Based on the experimentally obtained relationships, the theoretically assumed course of the ion exchange reaction of anionic REE complexes with NTA on the Amberlite IRA-68 resin was confirmed. The influence of the ion exchanger particle size, column size and composition of the mobile phase, i.e. pH, NTA and neutral salt (NaNO₃) concentration, on the chromatographic separation of REE was investigated. It has been shown that the proper selection of these parameters makes it possible not only to divide REE into the three groups mentioned above, but also to individually separate some elements, i.e. La, Ce, Pr, Nd, Tm, Yb, Lu and Sc.

New comb-like polyelectrolytes with triethylammonium (pAUTEA-Br), N-methyl-piperidinium (pAUMP-Br), N-methyl-morpholinium (pAUMM-Br) and pyridinium (pAUPy-Br) cation groups were first used to separate steroid hormones, biogenic amines and amino acids under capillary electrophoresis conditions. The polymers acted as modifiers of electrophoretic systems and were used as dynamic coatings of inner surface of fused-silica capillary and additives to background electrolyte to perform capillary electrochromatography and micellar electrokinetic chromatography regimes, leading to increase in separation selectivity and efficiency, and as reagents for indirect spectrophotometric detection of amino acids. New materials also showed activity during on-line preconcentration of biogenic amines and reduced their limits of detections by 10 times. Thus, new comb-like polyelectrolytes were demonstrated to act as multifunctional materials for capillary electrophoresis. This study discusses the features of the influence of the polyelectrolytes on electrophoretic separation capabilities and their possibilities in separation of model biologically active substances. Modifiers of this type significantly expand the analytical capabilities of the capillary electrophoresis method.

A rapid rise in population has led to the exploitation of natural resources, especially medicinal plants to meet human needs. Repeated harvesting of non-renewable or slow growing plant parts can severely damage plant systems. The whole plant of Cyanthillium cinereum (Sahadevi) is the key ingredient in numerous extract-based commercial herbal formulations beneficial for skin and hair related diseases. Although, the official crude drug Sahadevi covers the whole plant of Cyanthillium cinereum but many reports focus on individual parts as well. This study conducts a systematic comparative chemical investigation using fingerprint and marker based study of different parts (root, stem, leaves and flower) collected from both low land (Indo-gangetic plain) and high altitude regions, comparing then with the whole plant to determine which portion contribute most to the plant’s chemical composition. We employed, multivariate tools including principal component analysis and hierarchical clustering analysis on the fingerprint data for similarity analysis. The results indicate a close chemical similarity between the leaf and flower samples of Cyanthillium cinereum with whole plant based on comparable lupeol content and chemical profile. The high similarity observed in the leaves suggests that they may be used as a substitute for the whole plant, supporting efforts to enhance the plant’s life expectancy. Additionally, this study concluded that samples collected from lowland areas contain a higher concentration of bioactive component than those from high-altitude regions.

Moxidectin (MOX) is a macrocyclic lactone which belongs to milbemycin family of antiparasitic endectocides. MOX is widely used in veterinary medicine for the treatment and control of external and internal parasites, MOX is also used for the treatment of onchocerciasis (river blindness) in humans. In this paper, MOX drug substance was subjected to acidic, alkaline, oxidation, thermal (solid and solution state), and photolytic (solid and solution state) stress degradation. Stress-degraded samples of MOX were analyzed by a reversed phase ultra performance liquid chromatography (RP-UPLC) method using HALO C18 column (100 × 2.1 mm, 2 µm). MOX and all major DPs were adequately separated by a gradient elution using 0.1% formic acid in water as mobile phase-A and acetonitrile as mobile phase-B. Total 12 major DPs, including seven new DPs (2-carboxyl-19-hydroxyl, 2-carboxyl-3,4-epoxy-19-hydroxyl, 14,15-epoxide, 26,27-epoxide, 14-OOH, 15-OOH, and 27-OOH) not previously reported in the literature, were observed. Structural characterization of these DPs was performed using UPLC-high resolution mass spectrometry (HRMS) and by comparison of their fragmentation profile with parent compound. Six major DPs namely 3,4-epoxide, 14,15-epoxide, 26,27-epoxide, 14-OOH, 15-OOH, and 27-OOH were isolated and purified from the stressed samples using semi-preparative HPLC. The chemical structures of these DPs were further confirmed through comprehensive nuclear magnetic resonance (NMR) spectroscopy studies. The study results reported in this paper should be helpful to further understand degradation pathways of MOX under different conditions. These results are also beneficial to facilitate quality monitoring of MOX drug substance as well as identification of unknown degradation products in drug formulations made with MOX drug substance.

Sickle cell disease is a genetic disorder treated with Voxelotor (Vox), the first hemoglobin oxygen-affinity regulator. Although Vox recently received expedited approval in the United States for the sickle cell disease therapy for certain age groups, no monograph is yet available in the official compendia for Vox. Therefore, current study aims to develop a stability-indicating HPLC method for determining five potential impurities in Vox drug substance. The procedure was developed by implementing principles of analytical quality by design (AQbD). A detailed risk evaluation was conducted in accordance with the cause-and-effect relationship. A factorial design was employed to identify the impact of the critical method parameters (CMPs) and their relationship to critical quality attributes (CQAs). The full factorial design was utilized and final method was optimized. The p-values of the model and lack of fit were < 0.0001 and > 0.05, respectively, indicating the best-fit statistical model for the studied responses. The CMPs, such as gradient slope (ratio of mobile phase-B % and gradient time), flow rate of 1.0 mL min⁻¹, and column oven temperature of 40 °C, were optimized from the full factorial design. The best possible separation among all impurities and Vox was achieved with gradient elution using X-Bridge C₁₈, 150 mm × 4.6 mm, 3.5 µm analytical column. The optimized gradient is time (min)/%B: 0.0/15, 3.0/15, 20.0/80, 30/80, 31/15, 35/15. The peak pairs where the separation was highly critical were: impurity-4/impurity-5 and impurity-5/Vox. Method validation, revealed that the mean recovery of the impurities ranged between 100 and 106%, the correlation coefficient (r) > 0.99, across the span for LOQ–150% levels, RSD values (n = 6) ranged between 1.2 and 4.6% for 100% level (i.e., 0.1% of impurities). The peaks from the specificity analysis did not intervene with the known and active analyte (Vox) peak and this study identified impurity-2 as a major degradation product.

DM1, a derivative of maytansine, is the payload of trastuzumab emtansine (T-DM1). In this work, a new gradient reverse-phase ultra-performance chromatographic (RP-UPLC) method was proposed for analysis of five structural analogues (DM1-2, AP-3, DM1-4D, DM1-3D, and DM1-3L) of DM1. The chromatographic separation was accomplished by using a Waters BEH Phenyl column (50 × 2.1 mm, 1.7 μm), at the wavelength of 252 nm. Validation of the method was carried out according the ICH guidelines in terms of specificity, accuracy, precision, linearity and robustness. The developed method was proved to be convenient and reliable for quantitative determination of the DM1 analogue impurities. It can also be used for the related substances determination in DM1 bulk samples.