Chromatographia最新文献

{"title":"Analytical Green and White HPLC Method for the Quantification of Nitroso Impurities in Darolutamide with MS/MS Characterization and In silico Toxicity Assessment of Degradation Products","authors":"Katari Ravi Babu,&nbsp;Gowri Sankar Reddipalli","doi":"10.1007/s10337-026-04476-1","DOIUrl":"10.1007/s10337-026-04476-1","url":null,"abstract":"<div><p>The present study describes the development of a green, stability-indicating HPLC method coupled with LC–MS/MS characterization for degradation products (DPs) of darolutamide. The chromatographic separation was achieved on a phenyl-hexyl column (250 × 4.6 mm, 5 µm) using an isocratic mobile phase of ethanol and 5 mM ammonium formate with 0.1% formic acid (55:45, v/v, pH 3.6) at 0.8 mL/min, with UV detection at 238 nm. The method provides sharp, symmetrical peaks with retention times of 5.8 min, 4.2 min, 1.59 min, and 2.96 min for darolutamide, nitroso impurity, and nitroso impurities 1 and 2. The forced degradation studies reveal that darolutamide was most susceptible to acid, base, and oxidative stress. These stress degradation lead to the formation of six novel DPs (DP1-DP6). The structural elucidation by LC–MS/MS confirms that DP1 and DP2 were nitrile hydrolysis products (amide and carboxylic acid derivatives). The DP3 was arising from alcohol oxidation to ketone, whereas DP6 results from acid-catalyzed dehydration to an alkene. The DP4 and DP5 emerge from sequential amide bond cleavage and side-chain loss from the darolutamide. The in silico toxicity prediction classifies all DPs in toxicity classes 4–5 (LD₅₀ = 1000–2200 mg/kg), with low acute toxicity. The method validation confirms the excellent linearity (r² &gt; 0.996), high precision (%RSD &lt; 1.0%), accuracy (recoveries 99.4–101.1%), robustness, and sensitivity (LOD as low as 0.015 µg/mL). The method’s greenness and sustainability were proved with an AGREE score of 0.83, ComplexGAPI, and an RGB whiteness score of 80.1%. This study highlights the compliance of the method with green and white analytical chemistry. This work uniquely addresses the nitroso impurities of regulatory concern with superior environmental and analytical performance. In conclusion, the proposed method was a sustainable, reliable, and regulatory-compliant approach for routine impurity profiling and stability assessment of darolutamide.</p></div>","PeriodicalId":518,"journal":{"name":"Chromatographia","volume":"89 4","pages":"357 - 372"},"PeriodicalIF":1.3,"publicationDate":"2026-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148236594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insight into the Retention Behaviours of Proton Pump Inhibitor Drugs Using Homemade ZIC-HILIC Columns with Greenness, Whiteness, and Blueness Evaluation","authors":"Mustafa J. Mohammed,&nbsp;Ashraf Saad Rasheed,&nbsp;Bashar Qasim","doi":"10.1007/s10337-026-04478-z","DOIUrl":"10.1007/s10337-026-04478-z","url":null,"abstract":"<div><p>In the current investigation, the chromatographic behavior of two homemade ZIC-HILIC stationary phases with different spacer chains between the ionic site groups, the ZIC-1 and ZIC-4, under aqueous mobile phase conditions is presented. As test compounds, two proton pump inhibitors (PPIs) were chosen. The effect of different spacer lengths on the retention behaviors of esomeprazole and lansoprazole was examined. The development process included investigating the impacts of chromatographic parameters, such as the ratio of organic modifier to aqueous buffer, pH values, the ionic strength of the acetate buffer, and experimental evaluation of the principal retention mechanism. The chromatographic separation was conducted using two zwitterionic columns measuring (100 mm × 4.6 mm, 3.5 µm particle size). The mobile phase consisted of a combination of acetonitrile and acetate buffer at a pH of 4.75 and ionic strength of 40 mM, in a ratio of 80:20 (<i>v</i>/<i>v</i>). The elution was performed using a constant flow rate of 0.5 mL min⁻¹. Detection was performed using a UV detector at a wavelength of 285 nm. The findings showed that increasing the spacer chain length causes an increase in the retention time for both analytes. The technique indicates excellent linearity, low detection limits, and high precision, and it was successfully applied to the determination of two analytes in pharmaceutical preparations with recovery values of 98–101%. Five of the most well-known metrics for evaluating the greenness of chemical methods were examined. Amongst these, AES, AGREE, NAMI, BAGI, and GAPI emerged as reliable tools for the assessment of greenness.</p></div>","PeriodicalId":518,"journal":{"name":"Chromatographia","volume":"89 3","pages":"345 - 356"},"PeriodicalIF":1.3,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147621101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Accurate Detection and Quantification of Nineteen Micropollutants by Online SPE-LC–MS/MS Method in Raw and Biologically Treated Wastewater: Assessment of Mobile Phase Composition and Matrix Effect","authors":"Rodrigo B. Carneiro,&nbsp;Elis W. Nogueira,&nbsp;Carolina A. Sabatini,&nbsp;Marcelo Zaiat,&nbsp;Álvaro J. Santos-Neto","doi":"10.1007/s10337-025-04475-8","DOIUrl":"10.1007/s10337-025-04475-8","url":null,"abstract":"<div><p>This study focused on developing an analytical method to quantify nineteen selected micropollutants (MPs), including pharmaceuticals and personal care products, in complex wastewater matrices. An online solid-phase extraction system coupled with LC–MS/MS was used, and different mobile phase compositions were tested in the chromatographic method. The validated method was subsequently applied to real influent and effluent samples from an anaerobic biological reactor in order to assess MP occurrence and removal behavior. The best results were achieved using a mixture of acetonitrile and methanol (50:50 v:v) with 0.1% formic acid, offering high resolution, ionization efficiency, and sensitivity. The method demonstrated good linearity, low detection limits (sewage: 12–143 ng L⁻¹; effluent: 7–45 ng L⁻¹), and RSD &lt; 15%. Matrix effects were observed in both influent and effluent samples, leading to signal suppression. Despite this, the method maintained high selectivity and precision. Sewage presented variable MPs’ concentrations, with paracetamol being the most prevalent (12–20 µg L⁻¹). Removal efficiencies varied among compounds: paracetamol, parabens, and trimethoprim exhibited high biodegradability (&gt; 80%), whereas diclofenac and carbamazepine were poorly removed (&lt; 20%). Application to real wastewater samples revealed highly variable influent concentrations and compound-dependent removal efficiencies, highlighting both the analytical challenges posed by complex matrices and the relevance of the method for evaluating biological treatment performance.</p></div>","PeriodicalId":518,"journal":{"name":"Chromatographia","volume":"89 3","pages":"331 - 343"},"PeriodicalIF":1.3,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10337-025-04475-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147621011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive HPLC and UPLC-MS/MS Analysis for the Multi-component Detection of Hair Growth Compounds in Consumer Health Products","authors":"Kyoung-Moon Han,&nbsp;You Kyung Kim,&nbsp;Chae Gyeong Park,&nbsp;Ha Eun Song,&nbsp;Hyung Soo Kim,&nbsp;Hyun-Kyung Kim","doi":"10.1007/s10337-026-04479-y","DOIUrl":"10.1007/s10337-026-04479-y","url":null,"abstract":"<div><p>Hair loss is a disorder that occurs regardless of sex and affects both the patient’s appearance and quality of life. Rather than visiting a doctor for treatment, many patients prefer to use consumer health products, such as cosmetics (hair loss tonic or ampoules) or dietary supplements. To date, medicines such as minoxidil, finasteride, and flutamide have been successfully employed as treatments for hair loss, while prostaglandin F_2α analogs have been proposed as alternative treatments for hair loss. Nevertheless, these compounds can cause various adverse reactions, and the illegal adulteration of the corresponding products has also been reported. Consequently, significant caution is required when employing such treatments. In this study, high-performance liquid chromatography and ultra-performance liquid chromatography combined with tandem mass spectrometry were used to simultaneously analyze 17 hair growth compounds (bimatoprost free acid, bimatoprost isopropyl ester, bimatoprost serinol amide, cyclopropylmethylbimatoprost, cyproterone acetate, dechloro ethylcloprostenolamide, dutasteride, estradiol, finasteride, flutamide, 15-ketobimatoprost, latanoprost, methyltestosterone, minoxidil, spironolactone, testosterone propionate, and triaminodil). The developed method was validated in accordance with the International Conference on Harmonization guidelines to evaluate its specificity, limits of detection and quantification, linearity, recovery, precision, and accuracy. Finally, the developed method was applied in the analysis of specific products. The established method therefore enables the reliable detection of illicit hair growth compounds, supporting both regulatory compliance and consumer safety.</p></div>","PeriodicalId":518,"journal":{"name":"Chromatographia","volume":"89 4","pages":"373 - 385"},"PeriodicalIF":1.3,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148236511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of a New UPLC–MS/MS Method for the Analysis of Salicylic Acid and Its Metabolites, Gentisic Acid and Salicyluric Acid, in Rat Serum and Urine","authors":"Marta Karaźniewicz-Łada,&nbsp;Joanna Suliburska","doi":"10.1007/s10337-026-04480-5","DOIUrl":"10.1007/s10337-026-04480-5","url":null,"abstract":"<div><p>Salicylates have analgesic, antipyretic, anti-inflammatory, and antiplatelet effects and play a preventive role in the development of preeclampsia. The pharmacological effects of salicylates are closely related to their concentrations, which depend mainly on salicylate intake. A new UPLC–MS/MS method was developed for the determination of salicylates, including salicylic acid (SA) and its metabolites: gentisic acid (GA) and salicyluric acid (SCA), in rat serum and urine. The analytes were separated using a Luna Phenyl-Hexyl analytical column and a mobile phase consisting of 0.1% formic acid in water and acetonitrile. MS detection was performed using a triple quadrupole mass spectrometer with electrospray ionization in negative mode for SA and GA, and in positive mode for SCA. The lower limit of quantification was 0.005 µg mL⁻¹ for SA and 0.02 µg mL⁻¹ for GA and SCA in serum, and 0.02 µg mL⁻¹ for SA and 0.2 µg mL⁻¹ for GA and SCA in urine. The inter- and intra-day precision of the method, expressed as relative standard deviation, ranged from 2.77 to 17.1% in serum and from 1.37 to 16.5% in urine. The accuracy of the method was 91.2–118.0% in serum and 80.4–115.0% in urine. The extraction recoveries were between 58.3 and 79.6%. The validated method was successfully applied to the analysis of these compounds in the serum and urine of twelve preeclamptic rats fed a standard diet, half of which also received acetylsalicylic acid (ASA) (10 mg kg⁻¹ of diet). It was observed that the urinary excretion profile of salicylates was ASA dose-dependent.</p></div>","PeriodicalId":518,"journal":{"name":"Chromatographia","volume":"89 3","pages":"319 - 330"},"PeriodicalIF":1.3,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147621032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fabrication of Mechanical Pencil Copper Electrodes for Capillary Electrophoretic Measurement of Sugars in Lycium Barbarum","authors":"Lingxiao Peng,&nbsp;Xinyang Zhang,&nbsp;Gang Chen","doi":"10.1007/s10337-026-04477-0","DOIUrl":"10.1007/s10337-026-04477-0","url":null,"abstract":"<div><p>A novel capillary electrophoresis with electrochemical detection (CE-ECD) method based on a mechanical pencil copper electrode was developed and applied for the analysis of four free sugars in <i>Lycium barbarum</i>. A commercial polyester enameled copper wire with a core diameter of 550 µm was integrated into a mechanical pencil, and its tip was polished into a disk shape to fabricate a novel mechanical pencil copper disk electrode. Utilizing this electrode, CE-ECD was employed for the determination of four free sugars in <i>Lycium barbarum</i>. Key parameters, including the concentration of NaOH in the background electrolyte, separation voltage, and injection time, were optimized to establish the best detection conditions. Under the optimized conditions—75 mM NaOH solution, a separation voltage of 12 kV, and a 45 cm long fused silica capillary—the four free sugars were effectively separated within 11 min. The current responses exhibited linearity over a concentration range of 1 to 2000 µM, with detection limits (S/N = 3) ranging from 0.35 to 0.89 µM. This method was successfully applied to quantify the four free sugars in <i>Lycium barbarum</i>, producing highly satisfactory results.</p></div>","PeriodicalId":518,"journal":{"name":"Chromatographia","volume":"89 3","pages":"311 - 318"},"PeriodicalIF":1.3,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147621031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantification of Menthol by Chromatography Applying Analytical Quality by Design","authors":"Santiago Puentes,&nbsp;Julian Puentes,&nbsp;Ronald Andrés Jiménez,&nbsp;Emerson León Ávila","doi":"10.1007/s10337-025-04460-1","DOIUrl":"10.1007/s10337-025-04460-1","url":null,"abstract":"<div><p>The concept of analytical quality by design (AQbD) has recently gained prominence and offers multiple advantages for the pharmaceutical industry. AQbD is an approach that uses risk management to develop robust analytical methods that comply with regulatory requirements. Menthol is a standard raw material used in formulating various pharmaceutical products, including creams, ointments, and salves. We implemented an analytical quality by design (AQbD) approach to establish optimal parameters for the identification and quantification of menthol. This methodology utilizes gas chromatography coupled with an internal standard to create a reliable, reproducible, and cost-effective analytical method. In developing the method through AQbD, we first defined the analytical target profile (ATP). We employed risk management tools to identify critical analytical attributes (CAAs), such as resolution, retention time, theoretical plates, capacity factors, and choking factors. We also determined critical process parameters (CPPs), including oven temperature and flow rate. The influence of CPPs on CAAs was assessed using a factorial experimental design. Subsequently, we established the method operable region (MODR) to pinpoint the optimal conditions and specified parameters for each CAA, as indicated by response surface diagrams. The optimized method was validated in accordance with international regulatory guidelines to ensure system suitability. This validation process included evaluations of linearity, accuracy, and precision, as well as the determination of limits of detection and quantification. The results confirmed that the conditions were appropriate for analyzing menthol using gas chromatography with an internal standard.</p></div>","PeriodicalId":518,"journal":{"name":"Chromatographia","volume":"89 3","pages":"299 - 310"},"PeriodicalIF":1.3,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10337-025-04460-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147621100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on Antioxidant Activity of Phenolic Compounds from Bistorta Vivipara L. Achenes Based on Solid-Phase Extraction Coupled with On-Line Ferric Ion Reducing Antioxidant Potential–High-Performance Liquid Chromatography (FRAP–HPLC)","authors":"Weiqi Yang,&nbsp;Xiaofei Li,&nbsp;Wenhao Wang,&nbsp;Qi Huang,&nbsp;Hui Fan,&nbsp;Zhengming Qian","doi":"10.1007/s10337-025-04474-9","DOIUrl":"10.1007/s10337-025-04474-9","url":null,"abstract":"<div><p><i>Bistorta vivipara</i> L. achenes (<i>B. vivipara</i> achenes), rich in phenolic acids and flavonoids, are a valuable food and medicinal resource. However, a detailed analysis of its individual components and their mechanisms remains unexplored. This study introduces solid-phase extraction (SPE) for selectively isolating and purifying total phenolic acids and flavonoids from <i>B. vivipara</i> achenes. The antioxidant potential of the extracts was evaluated using ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), DPPH (2,2-diphenyl-1-picrylhydrazyl), and FRAP (ferric ion reducing antioxidant potential) assays. Results showed significant antioxidant activity in the total phenolic acid extract (125.1 ± 0.7 mg GAE/g dry weight [DW]) and total flavonoid extract (1491.1 ± 19.9 mg RE/g DW). Using online FRAP–high-performance liquid chromatography (FRAP–HPLC), seven antioxidant components were identified in the phenolic acid fraction and thirteen in the flavonoid fraction. Notably, protocatechuic acid, cryptochlorogenic acid, isochlorogenic acid A, isochlorogenic acid B, isochlorogenic acid C, shaftoside, isoshaftoside, isoorientin, taxifolin, and vitexin are reported for the first time as antioxidant constituents in <i>B. vivipara</i> achenes. These findings highlight <i>B. vivipara</i> achenes as a promising source of natural antioxidants and functional food ingredients. The SPE–FRAP–HPLC method enables comprehensive analysis by selectively enriching active compounds and enhancing sensitivity and accuracy compared with crude extracts. Furthermore, the application of online FRAP–HPLC facilitates real-time monitoring of the antioxidant activity of individual compounds during chromatographic separation, providing a detailed antioxidant activity profile of phenolic compounds in <i>B. vivipara</i> achenes.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":518,"journal":{"name":"Chromatographia","volume":"89 3","pages":"285 - 297"},"PeriodicalIF":1.3,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147381664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lab-in-Syringe Solid-Phase Microextraction Using Nanoparticles as Sorbents","authors":"Isam Eldin Hussein Elgailani","doi":"10.1007/s10337-025-04469-6","DOIUrl":"10.1007/s10337-025-04469-6","url":null,"abstract":"<div><p>Sample preparation is a crucial phase in the analytical procedure. Recently, nanoparticles and lab-in-syringe (LIS) solid-phase microextraction (SPME) have garnered significant interest from researchers aiming to develop microextraction techniques for sample preparation. Lab-in-syringe (LIS) represents a novel methodology in analytical chemistry that consolidates sample handling, extraction, and occasionally detection into a singular syringe-based apparatus. The LIS approach, when integrated with SPME, presents numerous critical advantages, enhancing its relevance in sample preparation and analysis. The closed environment of the syringe facilitates enhanced regulation of extraction parameters (e.g., mixing, temperature, and timing), hence augmenting the efficiency and sensitivity of SPME. This review elucidates the function of syringes in SPME methods, emphasizing the utilization of nanoparticles as effective sorbents owing to their significantly elevated surface area to volume ratio relative to traditional materials, which provides increased binding sites and enhances extraction efficiency and analyte capacity. A complete description of the many forms of SPME, sorbents, syringes, the functions of syringes, multiple techniques of LIS, and types of nanoparticles that provide variable extraction mechanisms for lab-in-syringe solid-phase microextraction (LIS-SPME). LIS-SPME presents a promising avenue for novel research and assists in the selection of effective and economically viable methodologies, contingent upon the analyte. The benefits of LIS-SPME render it especially simplicity without the necessity for specialized equipment, affordability, less solvent usage and waste production.</p></div>","PeriodicalId":518,"journal":{"name":"Chromatographia","volume":"89 2","pages":"135 - 151"},"PeriodicalIF":1.3,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147342874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermodynamic Parameters for Predicting Retention of Metronidazole, Efavirenz, and Nevirapine on a GC Capillary Column: Comparison of van’t Hoff–Glew and Clark with Density Functional Theory Calculated Results","authors":"Kwenga Sichilongo,&nbsp;Taye B. Demissie,&nbsp;Wangu Masenga,&nbsp;Zibo Keolopile","doi":"10.1007/s10337-025-04470-z","DOIUrl":"10.1007/s10337-025-04470-z","url":null,"abstract":"<div><p>Thermodynamic properties, the change in enthalpy and entropy, for analyte distribution between the mobile and stationary phase during gas chromatography separation of efavirenz, nevirapine, and metronidazole were experimentally determined. Calculations were based on data obtained by isothermal separation of the three compounds over a temperature range of 433.15–463.15 K on a GC column stationary phase. Two thermodynamic models, i.e., the Clarke and Glew theory based on the integrated van’t Hoff equation and the Castells model were used to calculate the changes in enthalpy and entropy. The values obtained from the two models were compared with those obtained by density functional theory calculations. Using the van’t Hoff model, the change in entropy for efavirenz was − 79.3 ± 3.4 JK⁻¹ mol⁻¹ and − 71.5 ± 2.1 JK⁻¹ mol⁻¹ using the Castells model, while it was − 65.7 ± 11.6 JK⁻¹ mol⁻¹ using DFT calculations. This trend was observed for nevirapine and metronidazole across the temperature range studied. Error analysis revealed that the temperature range used in making van’t Hoff model estimates violated the requirement espoused by Clarke and Glew, i.e., that application of the integrated van’t Hoff equation was only applicable over a narrow temperature range of 10 K. The Castells model values compared well with DFT values and were upheld for retention time predictions. The James–Martin compressibility factor was independent of temperature due to no change in the viscosity of the helium carrier gas over the range studied. It changed with inlet to outlet pressure ratio, which was dependent on the helium carrier gas flow rate.</p></div>","PeriodicalId":518,"journal":{"name":"Chromatographia","volume":"89 3","pages":"273 - 283"},"PeriodicalIF":1.3,"publicationDate":"2025-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147621034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}