Journal of chromatography open最新文献

An automated identification and quantification system using gas chromatography-mass spectrometry (AIQS-GC) can screening analysis of approximately 1000 chemical substances. It has been adopted as a Japanese Industrial Standards (JIS) and a provisional analytical manual by the Ministry of the Environment. To address potential helium carrier gas shortages, alternative gases like hydrogen and nitrogen are being considered. Hydrogen, in particular, shows minimal spectral changes when using a dedicated ion source. In this study, hydrogen and dedicated ion sources were applied to the AIQS-GC, with measurement conditions set to match helium's performance. The AIQS-GC met performance criteria for 20 out of 21 substances using hydrogen and a dedicated ion source. However, the sensitivity for all 21 substances decreased, suggesting that correction of quantitative values might be necessary if there is a significant difference in sensitivity reduction between the measured substances and internal standards. The AIQS-GC uses target ion and qualifier ion abundance (QT) ratio for substance identification, but low peak intensities caused some QT ratios, like that of captafol, to exceed standard values, requiring manual spectrum checks for accurate identification. Despite these issues, the AIQS-GC with hydrogen carrier gas and a dedicated ion source offers a new screening method for hazardous substances during helium shortages.

The adsorption dynamics of the LL- and DD-enantiomers of Leu-Leu and Gly-Gly on a Chirobiotic V column packed with a CSP bearing glycopeptide antibiotic vancomycin was studied and compared with the adsorption dynamics of the same dipeptides on a Chirobiotic R column packed with a CSP with bonded antibiotic ristocetin A. The column efficiencies were essentially different. The heights equivalent to a theoretical plate (HETP) on Chirobiotic R were 2-4 times larger than on Chirobiotic V, and the shape of van Deemter plots, strongly convex-upwards on the former column, demonstrated minor (Leu-Leu) or lacking (Gly-Gly) convexity on the latter column. This difference is attributed to differences in the binding kinetics of dipeptides to the antibiotics, fast for vancomycin and slow for ristocetin A. Since the kinetic C term of the van Deemter equation cannot explain such a large discrepancy in HETP for the same analyte on two columns, and since the A and B terms for the Chirobiotic R column were essentially larger than for the Chirobiotic V column, it is suggested that binding kinetics influences eddy and longitudinal diffusion processes associated with those terms. It is also hypothesized that unusually high values of van Deemter B coefficients occasionally found in chiral chromatography are not experimental artifacts but the manifestation of coupling the effects of slow adsorption kinetics and longitudinal diffusion.

Pharmacotoxicology is one of the fields that in recent years is growing exponentially, further reaffirming its proven usefulness in the field of forensic sciences. An interesting goal in this field is to identify and quantify the cause of death. This review paper aims to represent a review of the literature in order to evaluate the state of the art regarding the research in the pharmacotoxicology field in cases of Sudden Cardiac Death (SCD), a frequent problem on several occasions, which can be derived from the use of fatal substances or in such concentrations causing sudden death.

In this overview, the most frequently observed biomarkers for SCD were found to be ethanol, illicit drugs, antidepressants, and some common compounds like caffeine and Trenbolone. Concurrently, the most applied instrument configurations is represented by hyphenated liquid (or gas) chromatographic tools coupled with mass spectrometry (LC-MS or GC–MS) in order to reach the high accuracy and confidence levels in the confirmatory analyses, preceded by common sample preparation technique as solid-liquid extraction or liquid-liquid extraction. It was interesting to understand the approaches by which researchers have approached the topic, because on the one hand there are those who have been interested in the comparison between matrices (conventional and not) and on the other hand, who has researched metabolites in order to be able to trace the intake or not of a substance.

In particular, this work want to highlight and evaluate, from a medical-legal point of view, which are the main biomarkers and physiological markers of forensic interest and the methods, and instrumental procedures most frequently used for their evaluation. The paper is organized considering the analytical methods divided by types of drugs/substances.

In recent years, green chemistry has focused on the search for green solvents to replace the toxic organic solvents traditionally used in sample preparation. Ionic liquids (ILs) and deep eutectic solvents (DESs), which belong to neoteric liquids, are environmentally friendly solvents widely used for the extraction and subsequent determination of bioactive molecules and contaminants. ILs are semi-organic molten salts at temperature below 100 °C, composed by organic cations and organic or inorganic anions. DESs are a greener evolution of ionic liquids, consisting of a quaternary ammonium salt that acts as a hydrogen bond acceptor molecule and organic acids, sugars, amines, or polyalcohols that can be used as hydrogen bond donor molecules. DES components, when combined in a specific molar ratio, form an eutectic mixture that is liquid at room temperature. Both DESs and ILs have been widely applied in several extraction procedures, including matrix solid-phase dispersion (MSPD) extraction. MSPD is an extraction technique based on a homogenization phase between a solid sample and a solid dispersing material that has the function of breaking the sample, increasing analytes extraction yield. Three possible uses of neoteric solvents in MSPD extraction were investigated: (i) as extraction solvents to replace traditional organic solvents; (ii) as an adjuvant of MSPD extraction, to be added to the sample and dispersing material during the homogenization step; (iii) as an element to create innovative and highly selective dispersing materials. This review aims to describe and discuss in detail the use of neoteric solvents in the MSPD process in their various applications.

Miniaturized LC, encompassing capillary and nanoLC, presents significant analytical advantages in enhanced chromatographic performance and detectability and delivers considerable environmental and economic benefits. Despite these advantages, its utilization has primarily remained confined to omics sciences, with limited adoption in the routine targeted analysis of small molecules despite the lack of practical limitations. Initially, miniaturized LC encountered challenges related to scale reduction, necessitating the handling of minute sample volumes and lower flow rates. However, these obstacles have largely been overcome, with various instrumental platforms, columns, and consumables now available for efficient separations at the miniaturized scale. Moreover, the miniaturization of instruments facilitated by capillary and nanoLC has given rise to various portable LC platforms for in-situ analysis in recent years. Currently, researchers are exploring their applicability for diverse analytical purposes. However, the transition from conventional HPLC to miniaturized LC has been slow, and the technical factors limiting this shift still need to be clarified. Limited access to technology is among the primary obstacles identified, as transitioning may entail replacing conventional instruments with miniaturized versions.

Additionally, a lack of proper training and background to handle small volumes and flow rates has hindered the widespread adoption of capillary and nano-LC. Notably, expertise in HPLC only sometimes translates to proficiency at the miniaturized scale. Through this review, we aim to facilitate the dissemination of miniaturized LC by providing readers with a comprehensive overview of its current state, showcasing recent advancements, and highlighting remarkable applications beyond omics sciences.

Headspace solid-phase microextraction (HSSPME) of volatile organic compounds (VOCs) from aqueous samples under vacuum conditions (Vac-HSSPME) allows increasing extraction rates and decreasing detection limits compared to HSSPME under atmospheric pressure. The positive effect of the vacuum on HSSPME of an analyte can be quickly estimated using its Henry's law constant (HLC). According to the two-layer model of evaporation, substantial positive effect of the vacuum can be expected for analytes with HLC lower than 1.6·10⁻⁴ atm m³ mol⁻¹ (0.0065 at 25 °C), but the model does not consider possible effects of other important extraction parameters. This research was aimed at the evaluation of the possible effect of vacuum on the equilibration time and extracted amounts of analytes with various HLC and fiber coating-headspace distribution constants (K_fh) using the computational model recently developed in COMSOL Multiphysics® software. It has been proven that HSSPME under vacuum provides faster equilibration of VOCs with all studied K_fh and HLC. The largest vacuum effect on the extracted analyte amount was 3.9–4.0 times at logK_fh = 6 and HLC = 10⁻⁶–10⁻³. The substantial (≥1.5 times) vacuum impact should not be expected for analytes with logK_fh < 5 for 15-min extraction and logK_fh < 5.5 for 30-min extraction. The vacuum impact should be more pronounced when using fiber coatings with a stronger affinity to analytes. The obtained results will be useful for the development of new methods based on Vac-HSSPME and evaluation whether HSSPME is reasonable to conduct under vacuum conditions for faster equilibration and/or lower detection limits.

Chiral organometallic compounds and metal complexes, and more recently metal clusters, have attracted great interest for applications in chemical, biological, medical, and material sciences. In these fields, liquid chromatography has been widely used for fast chiral analysis to determine the enantiomeric purity of metal-containing chiral compounds prepared by asymmetric synthesis, for quality control of commercial chiral metal catalysts, for accessing enantioenriched or pure enantiomers of metal complexes for various applications, and often as test probe analytes for screening the enantioseparation capability of newly developed chiral columns and chromatographic systems. With the aim to show what was done in this field as a useful guide for new applications, in this review the evolution of methods and approaches used to separate the enantiomers of chiral metal-containing compounds is described, showing how this field have been changed over time, from the 1970s until most recent studies. For this purpose, representative applications of enantioselective liquid chromatography for the enantioseparation of chiral organometallic compounds and metal complexes will be presented and discussed, indicating chiral columns, mobile phases, and chromatographic conditions which have been used to obtain successful enantioseparations in this field.

Allantoin represents a compound widely employed in pharmaceutical and cosmetic fields. Its safety has been acknowledged by regulatory bodies such as the US Food and Drug Administration, the European Commission for Cosmetics and Consumer and Health and European Directorate for the Quality of Medicines & HealthCare. This justifies its wide use in dermatological/cosmetic formulations and allows their safe use.

Allantoin possesses an asymmetric carbon atom, resulting in two enantiomers, with the (S)-enantiomer predominating in plants, although racemization may potentially occur during manufacturing processes. Notably, literature currently lacks enantioselective LC methods for allantoin analysis.

In this study, two zwitterionic Cinchona alkaloid-based chiral stationary phases (CSPs), commercially known as CHIRALPAK® ZWIX(+) (CSP¹) and CHIRALPAK® ZWIX(-) (CSP²), were utilized for the enantioseparation of allantoin under polar-ionic conditions. By employing a mobile phase consisting of acetonitrile/methanol/water/acetic acid (96:2:2:0.1, v/v/v/v), nearly complete baseline separation (with α=1.08) of allantoin enantiomers was achieved in less than 15 min with both CSPs. Due to the “pseudo-enantiomeric” nature of the two chiral selectors (quinine-based in CSP¹ and quinidine-based in CSP²), an inversion of the enantiomer elution order was observed with the two CSPs under identical experimental conditions. Remarkably, this represents a rare instance where these CSPs demonstrate the ability to enantioseparate a non-ionic, non-ionizable species.

The application of a molecular dynamics in silico protocol proved useful in elucidating the retention mechanism in depth, casting light on the central role of the H-bond formation and the involvement of the anionic moiety of the CSP 1.

Promethazine (PMZ) is metabolized in the liver giving rise to chiral metabolites, including promethazine sulfoxide (PMZSO) and desmonomethyl promethazine (DMPMZ). Other metabolites, such as dioxopromethazine (DOPMZ), hydroxy promethazine (PMZOH), N-desmethyl-promethazine sulfoxide, and promethazine N-oxide (PMZNO) can also be formed, but information about them is limited. In this work, the enantiomeric metabolic profile of PMZ in ultra-pool human liver microsomes (HLM) was evaluated. For that, a novel enantioselective analytical method, by liquid chromatography coupled with high-resolution mass spectrometry was established and employed to monitor the enantiomers of PMZ and the formation of its main metabolites PMZSO and DMPMZ in two-hours assay with HLM. The enantioseparation optimized conditions were achieved with two immobilized carbamate amylose-based (3‑chloro-5-methylphenylcarbamate) columns: Lux® 3 µm i-Amylose-3 and Chiralpak® IG-U 1.6 µm. The optimized mobile phase for enantioseparation used buffer and ethanol, a green organic solvent, in a low flow rate. The sample preparation was based only in liquid-liquid extraction. (R)-PMZ consistently exhibited higher concentrations than (S)-PMZ, indicating less extension in metabolization. Regarding the metabolites, PMZSO exhibited higher concentrations compared to DMPMZ. A higher concentration for (S)-PMZSO was found when compared to the (R)-PMZSO and (R)-DMPMZ showing higher concentration compared to (S)-DMPMZ, indicating enantioselectivity in the metabolization process. The metabolites, PMZOH or PMZNO and DOPMZ were also identified. The second enantiomer of DOPMZ also showed a higher proportion than the first eluted enantiomer. These results demonstrated enantioselectivity of liver metabolism of PMZ, as well as confirmed PMZOH, PMZNO, and DOPMZ metabolites formation.

Pancreatic hormones are produced in the islets of Langerhans in the pancreas and are secreted to regulate blood sugar levels. Key pancreatic hormones are insulin, glucagon, and somatostatin. The measurement of these peptides/small proteins is essential in the study of the endocrine system, regulating diseases such as diabetes mellitus, but also in doping control and forensics. In this review, we focus on approaches for measuring pancreatic hormones using liquid chromatography-mass spectrometry (LC–MS). A rich variety of LC–MS approaches are used, including variations in LC column dimensions and chemistry, factors that are crucial regarding sensitivity, selectivity, robustness, and speed. In addition, several sample preparation methods are used (protein precipitation, immunopurification, etc.), for the analysis of matrices such as blood, urine, and cell culture medium. There are also several variants for mass spectrometric analysis, both targeted and non-targeted, using both lower and high-resolution instruments. LC–MS allows for sensitive, multi-hormone measurements, confidently distinguishing between hormones and their analogs, metabolites, and degradation products. The speed of analysis can be pushed down to a few minutes, with methods being validated and clinically applied. The review focuses on papers that have been published between 2019 and 2024.