Chromatographia最新文献

Calibration is a fundamental step in instrumental quantitative methods that produce an analytical signal proportional to the concentration of the analyte in the sample. Multi-wavelength calibration (MWC), a novel calibration strategy, has been proposed as a simple method for the determination of analytes in samples with complex matrices. It has minimal matrix effects and straightforward sample preparation. The objective of this work was to apply this calibration strategy to the determination of the synthetic dye Sunset Yellow in soft drinks by high-performance liquid chromatography with ultraviolet–visible analysis (HPLC/UV–Vis). Multi-wavelength calibration planning was performed as recommended in the literature. MWC results were statistically compared with conventional external calibration (limit of detection, limit of quantification, linearity, repeatability and recovery). The results obtained with both calibrations showed that the soft drinks complied with Brazilian legislation. The dye contents obtained with both calibration methods did not show significant statistical differences. MWC appears as an alternative or complement to external calibrations and ensures minimal matrix effects and straightforward sample preparation.

Short-chain fatty acids (SCFAs), such as acetic acid, propionic acid, lactic acid, β-hydroxybutyric acid, and crotonic acid, play key biological roles and are also strongly associated with the maintenance of health and the development of age-related diseases. However, an accurate method for SCFAs detection in human serum is lacking. Herein, we developed an UHPLC-QE-Orbitrap MS method based on 3-nitrophenylhydrazine derivatization in negative electrospray ionization through parallel reaction monitoring mode for the simultaneous detection of 11 SCFAs in the serum, and the analysis was performed on an Agilent Proshell 120 EC-C₁₈ column (2.1 mm × 100 mm, 2.7 μm). Three pairs of isomers—isobutyric and butyric acid, isovaleric and valeric acid, and isocaproic and caproic acid—were completely separated in 20 min in a single run. Our method exhibited satisfactory linearity (R > 0.99) for all analytes, and both intra-day and inter-day accuracies (73.74% to 127.9%) and precisions ( < 21%) were acceptable for most targeted compounds. The extraction recoveries ranged from 90.80% to 111.7%, and the internal standard-normalized matrix effects were 74.43%–116.9%. This method was successfully applied to a cohort of 1021 older Chinese individuals. Our results may further the understanding of the metabolic phenotypes associated with SCFAs in other populations.

A novel method for externally adjusting the column length during gas chromatography (GC) operation is introduced. The technique employs the controlled dehydration of a water stationary phase off a stainless-steel capillary column wall, which is then removed by the carrier gas. By halting the dehydration process (i.e. through adding water to the system) at specified times, partial column (i.e. coating) lengths are created as desired. For instance, since the phase is removed in a ‘peeling’ motion from inlet to outlet, then dehydrating 1/2 of the water coating away results in a 1/2 coated column remaining. This, in turn, acts analogous to a 1/2 column length in separations. In this way, direct and effective reduction in analyte retention time results from shortening column length. Adjustable lengths from 3/4 down to 1/10 of a full column are demonstrated. Good stability in maintaining new column lengths is realized, as analyte retention times vary by only about 1% RSD for most lengths and temperatures examined. Through calibration, column length can be predictably adjusted using system dehydration time, with changes being performed in a few minutes. Results indicate that this method could be useful for adjusting column length in-situ to accommodate various samples during GC operation.

A novel capillary electrophoresis method was developed for the determination of new 4-aryl-pyrido[1,2-c]pyrimidine derivatives, potential antidepressant agents, in serum. The derivatives have conformationally restricted tryptamine moiety in pharmacophore portion and exhibit high affinity to molecular targets: 5-HT_1A receptor and serotonin transporter protein. The separation process was conducted using an eCAP fused-silica capillary, detection wavelength 214 nm, 200 mM phosphate buffer adjusted to pH = 8.0, temperature 20 °C, voltage 5 kV. The proposed method was validated by determining its linearity in the concentration range of 200–1000 ng/mL. A satisfactory linearity was obtained for the method, with R² from 0.9978 to 0.9999 for all five derivatives and a limit of quantification level from 287.1 to 310.1 ng/mL. The recoveries for all derivatives were in the range from 94.7 to 100%. The speed of obtaining the result of the analysis was only 3 min. The developed method allows to determine all five derivatives both in water solutions and serum.

Phthalic esters (PEs) are used as plasticizers for plastic products especially for polyvinyl chloride (PVC). Owing to their adverse effects on human health, certain types of PEs are subjected to regulatory measures. Accurate and precision analyses of such regulated PEs are essential for monitoring compliance with regulatory standards; thus, the use of certified reference materials (CRMs) for quality assurance is recommended. To quantify the PE content of PVC products, the National Metrology Institute of Japan has developed a CRM, designated as NMIJ CRM 8156-a. This CRM is designed for validating the analytical methods and screening devices at low concentration levels (ca. 0.01%). Isotope-dilution mass spectrometry, the primary methods of measurement, has been employed for certification in conjunction with optimized gas and liquid chromatography/mass spectrometry techniques. Based on the mean mass fractions of target PEs derived from these two methods, eight certified values were determined for the CRM. The uncertainties associated with these certified values were estimated considering various factors such as characterization, homogeneity, and stability. Furthermore, the NMIJ CRMs were tested in screening devices such as pyrolyzers and thermal desorption mass spectrometers, confirming their suitability for generating calibration curves as well as the semi-quantitative analysis of target PEs. In summary, these CRMs are effective for validating quantitative and screening analytical methods for PEs in PVC and related substances.

The occurrence of coumarin-based photoactive compounds in essential oils has been a concern due to the adverse health effects it has on human health. A fit-for-purpose analytical method for major coumarin-based phototoxins is critical to guarantee the essential oils product safety and compliance with the regulatory requirements. Herein, a liquid chromatography-mass spectrometry (LC–MS) analytical method was developed to identify and quantify 25 coumarin derivatives in essential oils. The sample preparation procedure was optimized to use selective solvent extraction to remove the limonene matrix interference. To achieve the optimal sensitivity and specificity, UHPLC column of biphenyl stationary phase was used for this analysis. An inter-laboratory validation study was conducted to evaluate the method performance. The limit of quantification (LOQ) for all target analytes was validated at 5 µg/g. Satisfactory recoveries were obtained for the majority of analytes in the range of 80–115%. Both the repeatability RSD_r (within-laboratory) and reproducibility RSD_R (between-laboratory) were < 10%. This method was demonstrated as applicable for the quality control testing of coumarin-based phototoxins in essential oils.

Objective

This study sought to evaluate and validate a method for chemical composition analysis and content determination of Goupi plaster components, a conventional prescription preparation of traditional Chinese medicine. This is geared toward providing a basis for quality control research and future development of Goupi plaster.

Methods

UPLC–Q-Exactive-MS was used to qualitatively analyze the chemical components of Goupi plaster from different manufacturers in positive and negative ion modes. UPLC–MS/MS method was used to establish the determination methods for the detection of sinomenine, osthole, and cinnamaldehyde in Goupi plaster from different manufacturers.

Results

A total of 291 chemical components were identified in Goupi plaster from four manufacturers, including 97 chemical components with known source and pharmacological activity. Further, we determined the contents of sinomenine, osthole, and cinnamaldehyde.

Conclusion

In summary, the UPLC–Q-Exactive-MS method was used to analyze the chemical components of Goupi plaster from different manufacturers. We established the UPLC–MS/MS method to determine the contents of sinomenine, osthole, and cinnamaldehyde in Goupi plaster from different manufacturers. The findings indicated that the method was comprehensive, rapid, and accurate, preliminarily revealing the material basis of Goupi plaster and providing a reference for follow-up development of Goupi plaster.

An anticancer drug apalutamide approved by United States Food and Drug Administration in 2018 is one of the most commonly prescribed chemotherapeutic agents used for the treatment of prostate cancer. The present study aims at establishing the chemical structures of all the degradation products of the active pharmaceutical ingredient (API) formed under different forced degradation conditions. Apalutamide degradation was studied under International Council for Harmonisation recommended conditions of hydrolysis (acidic, alkaline, and neutral), oxidation, photolysis, and thermal stress. In total, seven degradation products (DP-1 to DP-7) were observed which were successfully separated on high-performance liquid chromatography and further characterized using liquid chromatography–mass spectrometry quadrupole time-of-flight (LC–MS/MS-QTOF). Degradation pathways for each of the observed DPs have been proposed based on the mass fragmentation pattern of API as well as DPs, identifying the underlying chemical transformations. Prediction of DPs was performed with Zeneth software tool, and the results were compared with the experimental observations. In silico toxicity assessment carried out using Derek suite reveals toxic nature of some of these DPs.

Graphical Abstract