Surrogate optimization with multivariate adaptive regression splines for supercritical fluid extraction-supercritical fluid chromatography hyphenated to tandem mass spectrometry.

Development of an ultra-fast polarity-switching ion mobility spectrometer ready for coupling with supercritical fluid chromatography.

In the contemporary landscape, polysaccharide-based chiral stationary phases have garnered significant popularity for several reasons: (i) their broad application range, (ii) the availability of diverse chemistry options in both coated and immobilized forms, and (iii) their substantial loading capacity, advantageous for preparative-scale operations. Undoubtedly, chiral separations continue to be a focal point, especially within the pharmaceutical sector, where supercritical fluid chromatography is swiftly gaining traction. However, its utilization presents greater complexity compared to high-performance liquid chromatography. The provided examples serve to elucidate the development of analytical-scale chiral separation methods and the impact of each operational parameter, such as flow rate, outlet pressure, and temperature variations, on chiral separation.

Integration of automated synthesis and fragment descriptor-based machine learning enables accurate prediction of SFC retention times and accelerates column characterization.

Ultra high-performance supercritical fluid chromatography-mass spectrometry emerging as a complementary approach for targeted steroid analysis.

Combined chiral-achiral supercritical fluid chromatography method for the impurity analysis of dapoxetine reveals insights in entropy-driven retention and acid-modulated selectivity.

Lansoprazole is an effective proton pump inhibitor utilized for managing various acid-related disorders, such as ulcers and gastroesophageal reflux disease (GERD), by significantly reducing stomach acid production. It has demonstrated a general tolerance among users, with common side effects including headaches, nausea, and diarrhea, while serious side effects are comparatively rare. Importantly, lansoprazole may provide superior healing results for conditions like ulcers and esophagitis compared to alternative medications such as ranitidine. Furthermore, it plays a key role in eradicating Helicobacter pylori bacteria when used in combination with antibiotics. Domperidone is a dopamine antagonist primarily used to treat nausea, vomiting, and gastrointestinal motility disorders. It functions both as an antiemetic, alleviating symptoms of nausea and vomiting, and as a prokinetic agent, enhancing gastric emptying. Notably, it is regarded as safer compared to metoclopramide due to its limited ability to cross the blood-brain barrier, thus minimizing central nervous system side effects. However, its safety profile is under scrutiny, particularly concerning potential cardiac effects and its impact on mental health during lactation. The future scope for the simultaneous estimation of Lansoprazole (LAN) and Domperidone (DOM) emphasizes the development of efficient, sustainable, and high-throughput analytical methods. Key areas of focus include minimizing hazardous solvent use through green chemistry principles, potentially utilizing supercritical fluid chromatography (SFC) or aqueous- based mobile phases in reverse-phase high-performance liquid chromatography (RP-HPLC). Research is anticipated to concentrate on ultrahigh performance liquid chromatography (UHPLC) and chip-based microfluidic systems, offering faster analysis and reduced solvent consumption compared to traditional HPLC. There is a trend towards integrating analytical methods to enhance specificity and sensitivity, such as liquid chromatography-mass spectrometry (LC-MS/MS) for trace analysis, pharmacokinetic studies, and impurity profiling essential for regulations. The development of automated sample preparation and analysis systems aims to boost efficiency in quality control during manufacturing. Additionally, the use of chemometrics and multivariate calibration methods, including Partial Least Squares (PLS) and Principal Component Regression (PCR), alongside UVspectrophotometry is expanding to improve accuracy and reduce analysis times, particularly in complex samples. Emphasis is also placed on creating robust methods that can accurately differentiate and quantify active pharmaceuticals from degradation products under various stress conditions, including acidic, basic, thermal, oxidative, and photolytic environments. Future methods will require thorough validation according to the International Conference on Harmonization (ICH) guidelines regarding accuracy, precision, linearity, specificity, limits of detection (LOD), limit of quantification (LOQ), and robustness, ensuring compliance with major regulatory bodies like the

This study investigated the synthesis and chiral separation of a series of bio-based amide derivatives. Moreover, the greenness of both separation techniques, that is, high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC), was compared. The synthesis employed a two-step, solvent-free, one-pot procedure at 60°C, yielding esters quantitatively and amides with yields of 31%-70%. Chiral separations were performed on polysaccharide stationary phases under the most optimal green conditions. Using a 70/30 heptane/ethanol mobile phase in HPLC, racemate 13 exhibited the highest resolution (Rs=11.8) and retention time (72.5min); however, using a 40% ethanol phase reduced both resolution and retention times. SFC, using a 50/50 CO2/ethanol mobile phase, provided baseline resolution (Rs=1.51-9.13) for all analytes and significantly reduced analysis times (maximum retention time of 12.6min for the second eluting enantiomer of racemate 13). Greenness evaluation was carried out using the AGREE and Analytical Method Greenness Score (AMGS) tools. The AGREE score averaged at 0.55 for HPLC and 0.64 for SFC, indicating a slight preference for SFC due to reduced solvent hazards and waste. The AMGS scores confirmed this trend: HPLC showed an average of 40.9 (up to 128 for racemate 13), whereas SFC averaged 14.9 (maximum 31.1). Instrument energy consumption was the dominant contributor to the AMGS score for both techniques, accounting for over 95% of the score for HPLC and over 93% for SFC. For racemate 13, this proportion increased to 99% and 96%, respectively.

Development, validation and application of an SFC-ESI-QqQ-MS/MS method for simultaneous analysis of malondialdehyde and typical α,β-unsaturated aldehydes in edible oils and oil-containing foods.

Following the valsartan scandal in 2018, the testing of drug substances and drug products for N-nitrosamines has become a critical and mandatory quality control measure. The European Pharmacopoeia chapter 2.5.42 currently describes three analytical methods for this purpose: HPLC-MS/MS, GC-MS, and GC-MS/MS. The US Pharmacopeia monograph 〈1469〉 adds four other methods, LC-high-resolution mass spectrometry (HRMS), headspace GC-MS, LC-MS/MS, and GC-MS/MS. In addition, our group has developed a universal method on the basis of supercritical fluid chromatography (SFC), capable of separating 16 different N-nitrosamines within just 4min. These eight methods differ significantly in terms of sustainability, with particular emphasis on the reagents used, the separation techniques employed, and their performance characteristics. When assessing the sustainability of such analytical methods, it is essential to consider not only ecological but also economic factors.

Four new methionine sulfoxide-containing diketopiperazines, (+)-dysidmetsulfoxide A [(+)-1], (+)-dysidmetsulfoxide B [(+)-2], (+)-dysidmetsulfoxide C [(+)-3] and (−)-dysidmetsulfoxide C [(−)-3], were isolated from the South China Sea sponge Dysidea sp. These compounds represented the first example of diketopiperazines possessing the unit of methionine sulfoxide (MetO) isolated from marine sponges. As it was difficult to determine the configuration of chiral sulfur atom in the thionyl group, the structures with absolute configurations of these compounds were elucidated by spectroscopic analyses and total synthesis. It was noteworthy that the purchased synthetic precursors, Fmoc-L- and Fmoc-D-MetO, were mixtures of epimers, respectively, due to the stereogenic sulfur atom in MetO, which were separated to prepare the optically pure isomers via the method of supercritical fluid chromatography (SFC). In addition, the other four optical isomers [(−)-1, (−)-2, (+)-4 and (−)-4] were also synthesized. Furthermore, (+)-1, (−)-1, (+)-3, (+)-4 and (−)-4 showed potential anti-Parkinson’s disease activities in an in vivo zebrafish model.

As interest in human enhancement continues to rise in Europe, kratom (Mitragyna speciosa) products have raised significant public health concerns. Kratom, which is used for its dose-dependent stimulant and sedative effects, has grown in popularity to enhance mood and self-manage pain or opioid withdrawal symptoms. This study aimed to assess the East-Central European online kratom market, evaluate product quality, and analyze potential toxicological risks to inform evidence-based harm reduction strategies. A comprehensive approach was employed, including online market surveillance, detailed content analysis of vendor websites, test purchase of products, followed by chemical analysis. Google search engine results were used to identify vendors shipping to Hungary. A total of 59 web shops were identified, and 25 distributors were selected for further analysis. Eight online sellers were included in test purchases. Mitragynine content was analyzed using supercritical fluid chromatography coupled with tandem mass spectrometry (SFC-MS/MS) and high-performance liquid chromatography with diode-array detection (HPLC-DAD). Toxicovigilance data were extracted from the United States Food and Drug Administration Adverse Event Reporting System (FAERS) and the Center for Food Safety and Applied Nutrition Adverse Event Reporting System (CAERS). The online kratom market in East-Central Europe is extensive and accessible, with many sellers identified in Hungary, the Czech Republic, Slovakia, and the Netherlands. While 68% (n/N = 17/25) of the evaluated web shops promoted enhancement effects, only 32% (n/N = 8/25) presented any information on potential adverse effects. Analysis of the products revealed highly variable mitragynine content, with mean concentrations ranging between 14.16 and 18.41mg/g in powder form, and 42.60-210.20µg/mL in prepared teas. Vigilance databases revealed 1090 cases in FAERS and 630 in CAERS associated with kratom use, with high rates of serious outcomes, including 592 deaths reported in FAERS. The online kratom market in East-Central Europe poses a significant public health threat, particularly to individuals seeking its enhancement effects. The significant variability in the mitragynine content, combined with the lack of safety information creates a high-risk environment. Toxicological data revealed a high incidence of serious adverse reactions, particularly in cases of polysubstance use. These findings highlight the urgent need for regulatory oversight and harm reduction strategies.

Green analytical chemistry (GAC) aims to achieve faster, safer, accurate, and sustainable analysis by minimizing the hazardous impact of organic solvents on the environment. Here, the focus will be on impurity profiling of pharmaceuticals. This can be done by employing green chromatographic techniques using eco-friendly solvents, advanced spectroscopic approaches, microextraction, and miniaturization techniques. Pharmaceutical analysis's greenness can be evaluated using various assessment tools and the advanced analytical greenness metric (AGREE). This review comparatively discusses all these tools by highlighting their eco-friendly nature, methodology, adherence to the 12 major principles of green chemistry, and validation of their results. Furthermore, state-of-the-art case studies utilizing green chemistry principles for impurity profiling of pharmaceuticals have also been discussed, along with their employed techniques and observations, thus offering insights into successful implementation. Still, cost, affordability, scalability, and reproducibility vary across techniques, with, for example, supercritical fluid chromatography (SFC) showing more substantial potential than nuclear magnetic resonance (NMR). Greenness metrics also lack global harmonization, limiting comparability. Challenges like stringent regulatory frameworks and a lack of standardized global policies should be overcome by integrating artificial intelligence (AI) and machine learning (ML), as well as more interdisciplinary collaboration among associated professionals, for the widespread adoption of efficient, sustainable, and eco-friendlier pharmaceutical analysis techniques. For AI/ML, trustworthiness will require validation and regulatory alignment to ensure they complement rather than replace existing protocols.

Pesticides are chemical substances widely used to control, prevent, or eliminate pests in agriculture, gardening, and other sectors. However, their use poses risks to human health, and recent regulatory efforts have focused on minimizing exposure and monitoring residue levels. In this study, the separation of seven pesticides was investigated using supercritical fluid chromatography coupled to diode-array detection (SFC-DAD). The influence of six different stationary phases and various organic modifiers, as well as additional parameters such as temperature, pressure, and the presence of additives, was systematically evaluated to optimize the chromatographic conditions. The best separation performance was achieved using a LiChrospher® 100 DIOL column with methanol as the organic modifier under a gradient program. Analyses were carried out at a flow rate of 3 mL/min, a column temperature of 35 °C, and a system back pressure of 150 bar, resulting in a total analysis time of approximately 4 min. The optimized method allowed for a faster separation of the selected agricultural pesticides by SFC-DAD compared to conventional chromatographic techniques.

A wet oxidation method was developed to remove the bonded phase from silica-based packing materials in spent chromatographic columns, thereby regenerating sub-3µm monodisperse superficially porous particles (SPPs). The (2-hydroxyethyl)-β-cyclodextrin was grafted onto the surface of the regenerated particles, creating a chiral stationary phase (CSP). For comparison, CSPs were also prepared based on commercially available fully porous particles (3 µm, FPPs) and commercially available SPPs (2.7 µm). The chiral separation performance of these CSPs was evaluated using nine racemic compounds in reversed-phase liquid chromatography (RPLC) and supercritical fluid chromatography (SFC). The results showed that the regeneration method effectively removed the bonded phase from the spent column packing materials while maintaining the structural integrity of the SPP. Under the same chromatographic conditions, the SPP-CSP achieved a comparable enantioselectivity relative to the FPP-CSP while demonstrating superior column efficiency. The SPP-CSP displayed higher enantioselectivity when chromatographic conditions were altered to yield equivalent analysis times. SFC and RPLC demonstrated complementary chiral recognition ranges. SFC achieved higher enantioselectivity and better chromatographic performance within their jointly effective separation ranges. Compared to commercially available (2-hydroxypropyl)-β-cyclodextrin column of identical structure and specifications, the (2-hydroxyethyl)-β-cyclodextrin SPP-CSP exhibits different enantioselectivity. CSPs prepared from regenerated SPPs exhibit no significant differences in chiral separation performance compared to commercially available SPPs of the same brand, structure, and specifications. The (2-hydroxyethyl)-β-cyclodextrin SPP-CSP, synthesized via a straightforward and uncomplicated method, demonstrates favorable stability and chiral resolution capabilities.

Back to basic: Using ammonium hydroxide to improve peptide epimer/isomer liquid chromatography separations.

Determination of the diastereomeric excesses of chiral flavonoids in organs of Citrus aurantium with two-dimensional supercritical fluid chromatography.

Highly sensitive separation and characterization of multiple mycotoxins by supercritical fluid chromatography combined with ion mobility quadrupole time-of-flight mass spectrometry

Reversed-phase liquid chromatography coupled to high-resolution mass spectrometry (RP-LC-HRMS) is the standard for nontarget screening (NTS) of environmental samples but lacks retention of highly polar contaminants. We compared 12 chromatographic methods across four platforms, RP-LC, anion chromatography (IC), supercritical fluid chromatography (SFC), and hydrophilic interaction chromatography (HILIC), using 127 environmentally relevant compounds (logDpH7.4 -5.6 to 6.6). Compounds were analyzed in solvent and for a polar subset, in groundwater enriched by vacuum evaporation. Data were collected across four laboratories using 5 RP-LC-, 3 HILIC-, 2 SFC-, and 2 IC-HRMS setups. Feature detection with standard tools yielded more false negatives for SFC and IC. To enable a fair and method-agnostic comparison, an extracted ion chromatogram (EIC)-based workflow was used. Of the 127 compounds, 125 were detected by at least one platform. For logDpH7.4 > 0, RP-LC covered ∼90%, followed by SFC (∼70%), while IC and HILIC each covered <30%. For very polar compounds (logDpH7.4 < 0), coverage dropped across all platforms. SFC and HILIC detected up to 60% of polar analytes; IC performed better in negative ionization mode, consistent with anion-exchange separation. Detection frequency declined with polarity, reflecting analytical limitations. Combining RP-LC with either SFC or HILIC increased coverage to 94%. In spiked groundwater, coverage was lower (73%) due to matrix effects and losses during vacuum enrichment. Peak widths were narrowest for SFC (∼2.5 s) and RP-LC (∼4 s) and broadest for HILIC (∼7 s) and IC (∼17 s). Retention times showed limited cross-platform correlation while ionization efficiency was consistent, except for SFC. As no single method provided full coverage, combining RP-LC with one complementary platform (SFC, HILIC, or IC) is required to extend chemical space in environmental NTS.

Acidic methine-containing compounds are prone to racemization driven by keto-enol tautomerization, which can lead to products with distinct pharmacological and toxicological properties. Glutarimide, a core structural component of cereblon binders, and thiazolidinediones, a class of antidiabetic agents, are particularly susceptible to this instability. In this study, we developed an H/D exchange method to investigate the racemization or epimerization kinetics of 28 compounds, including 3 thiazolidinediones, as well as 13 molecular glues and 12 proteolysis targeting chimeras (PROTACs), both containing the glutarimide scaffold. In phosphate buffer (0.1 M, D2O, pD 7.8) at 37 °C, the racemization half-lives of glutarimide-based molecular glues ranged from 3.0 to 7.3 h, while thiazolidinediones exhibited substantially faster racemization with half-lives of 0.8 to 1.0 h. The correlation of H/D exchange and racemization rates were confirmed using chiral supercritical fluid chromatography. Reverse (D/H) exchange demonstrated a 3.6- to 8.5-fold improvement in chiral stability for methine-deuterated compounds, attributed to a primary kinetic isotope effect. Moreover, several PROTACs demonstrated substantially greater chiral stability than molecular glues, highlighting their distinct chiral behavior. Human serum albumin was found to influence chiral stability, accelerating racemization in some compounds while stabilizing others. Finally, conformational analysis revealed that PROTACs can adopt three distinct conformations; however, a clear correlation between enhanced chiral stability and specific conformers has yet to be established. These findings highlight the utility of the H/D exchange method as a robust and streamlined technique for assessing racemization and epimerization kinetics in various biologically relevant media. This approach enables rapid evaluation of chiral stability and highlights the potential of deuteration as a strategy to enhance chiral stability and optimize therapeutic agents within these compound classes.