Search Results (276)

The competitive retention of pollutants in water tables determines their environmental fate and guides routes for their removal. To distinguish the fine differences in competitive binding at zeolite adsorption centers, a group of neonicotinoid pesticides is compared, relying on theoretical (energy of adsorption, orientation, charge distribution) and experimental (spectroscopic and thermogravimetric) analyses for quick, inexpensive, and reliable screening. The MOPAC/QuantumEspresso platform was used for theoretical calculation, indicating close adsorption energy values for acetamiprid and imidacloprid (−2.2 eV), with thiamethoxam having a lower binding energy of −1.7 eV. FTIR analysis confirmed hydrogen bonding, among different dipole-dipole interactions, as the dominant adsorption mechanism. Due to their comparable binding energies, when the mixture of all three pesticides is examined, comparative adsorption capacities are evident at low concentrations, owing to the excellent adsorption performance of the FAU zeotype. At higher concentrations, competition for adsorption centers occurs, with the expected thiamethoxam binding being diminished due to the lower bonding energy. The catalytic impact of zeolite on the thermal degradation of pesticides is evidenced through TG analysis, confirming the adsorption capacities found by UV/VIS and HPLC/UV measurements. Detailed analysis of spectroscopic results in conjunction with theoretical calculation, thermal profiles, and UV detection offers a comprehensive understanding of neonicotinoids’ adsorption and can help with the design of future adsorbents. Full article

The impact of exogenous melatonin treatment on the postharvest quality and storability of blue honeysuckle fruit was investigated. Fruits were immersed in melatonin solutions at concentrations of 0 (control), 0.01, 0.05, and 0.25 mM for 5 min and subsequently stored at –1 °C for 63 d. Among all treatments, the combination of two-week storage without fruit puncturing and 0.05 mM melatonin application significantly delayed fruit softening and decay even at the initial stage of storage, while also increasing the concentration of phenolic compounds and enhancing antioxidant activity. During the later storage period (28–63 d), melatonin-treated fruits maintained higher levels of maltose, fructose, and sucrose, contributing to improved flavor retention. In contrast, both lower (0.01 mM) and higher (0.25 mM) concentrations were less effective or even detrimental to fruit quality. HPLC-ESI-QTOF-MS² analysis revealed that 0.05 mM melatonin effectively preserved several functional phenolics, including p-coumaroylquinic acid, caffeoyl glucose, 5-O-caffeoylquinic acid, 3-O-caffeoylquinic acid, luteolin-7-O-glucoside, and hydroxytyrosol. Thus, 0.05 mM melatonin is effective in delaying senescence and maintaining the postharvest quality of blue honeysuckle fruit. Full article

The separation of three proton pump inhibitors (omeprazole, lansoprazole, and rabeprazole) as exemplified molecules containing chiral sulfoxide groups was investigated in polar organic liquid chromatographic mode on seven different polysaccharide stationary phases (Chiralcel OD and OJ; Chiralpak AD, AS, and IA; Lux Cellulose-2 and -4). Different alcohols, such as methanol, ethanol, 1-propanol, 2-propanol, and their combinations, were used as eluents. After method optimization, semi-preparative enantioseparation was successfully applied for the three proton pump inhibitors to collect the individual enantiomers. A detailed investigation was conducted into elution order reversal, thermodynamic parameters, the effect of eluent mixtures, and the hysteresis of retention time and selectivity. Using Chiralpak AS, containing the amylose tris[(S)-α-methylbenzylcarbamate] chiral selector, the separation of the investigated enantiomers was achieved in all four neat eluents, with methanol providing the best results. In many cases, a reversal of the enantiomer elution order was observed. In addition to chiral-selector-dependent reversal, eluent-dependent reversal was also observed. Notably, even replacing methanol with ethanol altered the enantiomer elution order. Both enthalpy- and entropy-controlled enantioseparation were also observed in several cases; however, temperature-dependent elution order reversal was not. The hysteresis of retention and selectivity was further investigated on amylose-type columns in methanol–2-propanol and methanol–ethanol eluent mixtures. The phenomenon was observed on all amylose columns regardless of the eluent mixtures employed. Hystereticity ratios were calculated and used to compare the hysteresis behaviors of different systems. Multivariate statistical analysis revealed that Chiralpak AS exhibited the most distinct enantioselective behavior among the tested columns, likely due to the absence of a direct connection between the carbamate moiety and the aromatic substituent. The present study aided in understanding the mechanisms leading to enantiomer recognition, which is crucial for developing new chiral stationary phases and chiral HPLC method development in general. Full article

The agri-food sector faces the challenge of valorizing by-products and reducing waste. The frozen pumpkin industry generates substantial amounts of by-products rich in nutritional value, especially β-carotene. This study evaluates the nutritional and physical impact of incorporating pumpkin pulp flour (dehydrated and freeze-dried) obtained from by-products into cracker formulation. Crackers were prepared by replacing 10% and 20% of wheat flour with pumpkin flour, assessing the effects based on drying method. Physical parameters (expansion, color, and texture parameters) were measured, in the dough and in the baked products. Furthermore, β-carotene content was analyzed by HPLC-DAD, antioxidant capacity was measured with DPPH, ABTS, and ORAC, and total phenolic content was evaluated with the Folin–Ciocalteu method. Proximate composition and mineral content were also analyzed. Additionally, a preliminary sensory evaluation was conducted with 50 untrained consumer judges to assess acceptability of external appearance, texture, and taste. The inclusion of pumpkin flour significantly increased β-carotene content (up to 2.36 mg/100 g), total phenolics, and antioxidant activity of the baked crackers. Proximate analysis showed a marked improvement in fiber content and a slight reduction in energy value compared to wheat flour. Mineral analysis revealed that pumpkin flours exhibited significantly higher levels of K, Ca, Mg, and P, with improved but not always statistically significant retention in the final crackers. Freeze-dried flour retained more bioactive compounds and enhanced color. However, it also increased cracker hardness, particularly with dehydrated flour. Only the 10% freeze-dried formulation showed mechanical properties similar to those of the control. Sensory analysis indicated that all formulations were positively accepted, with the 10% freeze-dried sample showing the best balance in consumer preference across all evaluated attributes. Frozen pumpkin by-products can be effectively valorized through their incorporation into bakery products such as crackers, enhancing their nutritional and functional profile. Freeze-drying better preserves antioxidants and β-carotene, while a 10% substitution offers a balance between nutritional enrichment and technological performance and sensory acceptability. Full article

Background/Objectives: This study aims to present a strategic approach to enhancing the photostability and antioxidative resilience of curcumin and capsaicin by integrating selected natural stabilizers within a nanoemulsion-based delivery system. Methods: Coffee extract (Coffea arabica Linn.), along with its active components and vitamin E-containing natural oils, was assessed in terms of improving the photostabilizing and antioxidative retention abilities of curcumin and capsaicin. An optimized ratio of the active mixture was then loaded into a nanoformulation. Results: The analysis of active contents with validated high-performance liquid chromatography (HPLC), ferric reducing antioxidant power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays confirmed the stabilization enhancement after irradiation with UV and white light for 72,000–84,000 lux hours. The optimized combination of coffee extract with turmeric and chili mixtures loaded into the optimized nanoemulsion enhanced the half-lives (T_1/2) of curcumin and capsaicin by 416% and 390%, respectively. The interactions of curcumin and capsaicin with caffeine and chlorogenic acid were elucidated using computational calculations. Interaction energies (E_int), HOMO-LUMO energy gap (HLG) analysis, and global reactivity descriptors revealed hydrogen bonding interactions be-tween capsaicin and chlorogenic acid, as well as between curcumin and caffeine. Conclusions: By leveraging the synergistic antioxidative properties of coffee extract and vitamin E within a nanoemulsion matrix, this study overcomes the intrinsic stability limitations of curcumin and capsaicin, offering a robust platform for future pharmaceutical and nutraceutical applications. Full article

The application of high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) in the analysis of peptide therapeutics demonstrates its capacity to achieve high sensitivity and selectivity, which are essential qualities for the expanding peptide therapeutic industry. Given the challenges posed by hydrophilic peptides in reversed-phase chromatography, we investigated the necessity of a derivatization procedure to improve chromatographic separation and quasimolecular ion fragmentation during MS/MS detection. We investigated how eight different derivatizing agents react with a hydrophilic lysine- and arginine-containing human ezrin peptide-1 (HEP-1) to identify the most suitable one. The results showed that the reaction of HEP-1 with propionic anhydride proceeds most rapidly and completely, providing a high and reproducible yield of the product, which has sufficient retention on the RP column. The 4-propionylated derivative of HEP-1, compared to the other derivatives considered, demonstrates the most pronounced MS/MS fragmentation. The retention time of 2.42 min allows the separation of the substance from the interfering components of the blood plasma matrix and provides a limit of quantification of 5.00 ng/mL, which allows the use of this derivatizing agent for subsequent applications in pharmacokinetic studies, and this approach can improve the analytical parameters of similar peptides in other HPLC-MS/MS studies. Full article

Natural polymer-based nanoparticles have emerged as promising stabilizers for Pickering emulsions, offering biocompatibility, environmental sustainability, and improved protection of active compounds. This study developed chitosan/gum arabic (CH/GA) nanoparticles as solid stabilizers for quercetin-loaded Pickering emulsions to enhance the stability and antioxidant bioactivity of quercetin (QE), a plant-derived flavonoid known for its potent radical-scavenging activity but limited by oxidative degradation. A systematic formulation strategy was employed to evaluate the effects of CH/GA concentration (0.5–2.0% w/v), oil type (olive, soybean, sunflower, and coconut), and oil volume fraction (ϕ = 0.5–0.7) on emulsion stability. The formulation containing 1.5% CH/GA and olive oil at ϕ = 0.6 exhibited optimal physical and interfacial stability. Quercetin (0.1% w/w) was incorporated into the optimized emulsions and characterized for long-term stability, particle size, droplet morphology, rheology, antioxidant activity (DPPH), cytocompatibility, and intracellular reactive oxygen species (ROS) protection using HaCaT keratinocytes. The olive oil-based formulation (D1-QE) exhibited greater viscosity retention and antioxidant stability than its soybean-based counterpart (E2-QE) under both room temperature (RT) and accelerated heating–cooling (H/C) storage conditions. Confocal microscopy confirmed the accumulation of CH/GA nanoparticles at the oil–water interface, forming a dense interfacial barrier and enhancing emulsion stability. HPLC analysis showed that D1-QE retained 92.8 ± 0.5% of QE at RT and 82.8 ± 1.5% under H/C conditions after 30 days. Antioxidant activity was largely preserved, with only 4.7 ± 1.7% and 14.9 ± 4.8% loss of DPPH radical scavenging activity at RT and H/C, respectively. Cytotoxicity testing in HaCaT keratinocytes confirmed that the emulsions were non-toxic at 1 mg/mL QE and effectively reduced H₂O₂-induced oxidative stress, decreasing intracellular ROS levels by 75.16%. These results highlight the potential of CH/GA-stabilized Pickering emulsions as a polymer-based delivery system for maintaining the stability and functional antioxidant activity of QE in bioactive formulations. Full article

Background/Objectives: The treatment of atopic dermatitis frequently involves using a topical corticosteroid and a moisturizer. While the sequential application of these products is a common dermatological practice, their influence on drug penetration remains poorly understood. There is no clear evidence on how hydration, application sequence, and massage affect cutaneous drug delivery. Hence, this study aimed to evaluate the effects of formulation type, moisturizer composition, application sequence, and mechanical stimulation on betamethasone dipropionate (BET) cutaneous penetration. Methods: Two commercial formulations (cream and ointment) of BET were evaluated in different experimental conditions, including drug application combined with moisturizers (Cetaphil^®, as an emollient; Nivea^®, as an occlusive) pre- or post-application, with or without a 30 s massage. In vitro skin penetration assays were conducted for 12 h using porcine skin mounted in modified Franz diffusion cells. BET levels were extracted from the skin layers and quantified by HPLC. Results: The cutaneous BET penetration was strongly influenced by the application sequence, type of moisturizer, and mechanical stimuli. Pre-application of an occlusive or emollient moisturizer, followed by 30 s physical stimuli, significantly enhanced drug retention in the stratum corneum. For the cream, pre-application of moisturizers followed by massage notably increased BET levels in both the stratum corneum and viable skin. Conversely, post-application of moisturizers hindered BET absorption. The ointment showed limited penetration across all conditions, with no drug detected in the viable skin. Conclusions: The results showed pre-hydrating the skin, combined with a 30 s massage, was the best strategy for BET diffusion into the skin following cream administration. The formulation type and the order of application directly influence the effectiveness of drug therapy and the topical absorption of BET. Full article

Berries are highly perishable due to their high water content, making them prone to rapid deterioration and spoilage. This study investigates the effects of osmotic dehydration and edible coatings, with and without bioactive compounds, on various quality attributes of blueberries, raspberries, and strawberries during storage. The berries were pretreated using osmotic dehydration with apple juice, followed by the application of edible coatings from Chlorella vulgaris protein, with or without the addition of aqueous rosemary extract as a source of bioactive compounds. The results indicated that the combination of the two methods significantly reduced weight loss in all berry types, with the incorporation of bioactive compounds further enhancing moisture retention up to approximately 3% for blueberries and raspberries and 5% for strawberries. Total phenolic content and antioxidant activity exhibited significantly increased stability in coated samples, with bioactive coatings contributing to improved antioxidant properties. The HPLC analysis proved that the bioactive profile was preserved after the treatments. Microbial analysis demonstrated that edible coatings, particularly those enriched with bioactive compounds, effectively inhibited microbial growth (TC approximately 4.5 log(CFU/g) with limit = 5 log(CFU/g) and YM approximately 3.5 log(CFU/g) with limit 4 log(CFU/g)), thereby extending the shelf life of the berries. These findings suggest that the synergistic application of osmotic dehydration and edible coatings, especially those containing bioactive compounds, significantly enhances the quality, shelf life, and potential health benefits of fresh berries during storage. Full article

The use of photoselective nets has gained interest in highbush blueberry production systems in recent years. Although some work has been conducted on their effects on the growth and development of the fruit, the performance of fruit grown under those nets after harvest has not been addressed yet. Here we focus on the performance of fruit grown under photoselective nets (exclusion, red, yellow, black) during long cold storage for the first time. The experiment was performed in two different years, monitoring morphological parameters, as well as primary and secondary metabolites using HPLC-MS and GC-MS. Minimal differences between treatments were noticed in fruit color, firmness and total soluble solids contents (TSS). In terms of fruit metabolism, two different periods were described during storage, with an inflection point at 14 days; in the first period, an increase in sugar content and a decrease in volatile content was observed, while after that, we found the opposite behavior. Overall, fruit grown under red nets showed the highest retention of secondary metabolites and the highest sugar/organic ratio, probably associated with a higher antioxidant capacity promoted by an increased red light proportion during the growth season. On the other hand, yellow nets showed the least favorable storage performance, as the light quality did not significantly improve the metabolism. Full article

Background/Objectives: Cyclophosphamide is one of the most commonly used cytotoxic drugs in chemotherapy protocols. Its preparation in the hospital setting involves handling concentrated solutions, which pose occupational exposure risks and potential variations in the final dose administered. The aim of this study was to evaluate the effect of aspiration devices on the concentration of cyclophosphamide in reconstituted solutions. Methods: An analytical method was validated using high-performance liquid chromatography coupled to a diode-array detector (HPLC-DAD) for quality control. Cyclophosphamide solutions were prepared and aspirated using either a conventional needle or spike device with or without a filtration system. Results: The validated method demonstrated linearity (R² = 0.9999), high precision (0.22–4.59%) and accuracy (88.9–99.4%), with a limit of quantification of 4.03 µg/mL. Significant differences (p < 0.001) were observed between samples aspirated with a needle and those aspirated with a spike fitted with a 5 µm filter, with the latter showing lower cyclophosphamide concentrations, suggesting partial retention of the drug. No significant differences were found between the needle and filterless spike preparations. Conclusions: These results suggest that the choice of aspiration device influences the final drug concentration, potentially affecting therapeutic efficacy. Standardisation of preparation techniques and an awareness of device limitations are essential to ensure accurate chemotherapy dosing and patient safety. Full article

Hydroxychloroquine (HCQ), a cornerstone therapeutic agent for autoimmune diseases, requires precise serum concentration monitoring due to its narrow therapeutic window. Current HCQ monitoring methods such as HPLC and LC-MS/MS are sensitive but costly and complex. While electrochemical sensors offer rapid, cost-effective detection, their large chambers and high sample consumption hinder point-of-care use. To address these challenges, we developed a microfluidic electrochemical sensing platform based on a screen-printed carbon electrode (SPCE) modified with a hierarchical nanocomposite of gold nanoparticles (AuNPs), copper-based metal–organic frameworks (Cu-MOFs), and multi-walled carbon nanotubes (MWCNTs). The Cu-MOF provided high porosity and analyte enrichment, MWCNTs established a 3D conductive network to enhance electron transfer, and AuNPs further optimized catalytic activity through localized plasmonic effects. Structural characterization (SEM, XRD, FT-IR) confirmed the successful integration of these components via π-π stacking and metal–carboxylate coordination. Electrochemical analyses (CV, EIS, DPV) revealed exceptional performance, with a wide linear range (0.05–50 μM), a low detection limit (19 nM, S/N = 3), and a rapid response time (<5 min). The sensor exhibited outstanding selectivity against common interferents, high reproducibility (RSD = 3.15%), and long-term stability (98% signal retention after 15 days). By integrating the nanocomposite-modified SPCE into a microfluidic chip, we achieved accurate HCQ detection in 50 μL of serum, with recovery rates of 95.0–103.0%, meeting FDA validation criteria. This portable platform combines the synergistic advantages of nanomaterials with microfluidic miniaturization, offering a robust and practical tool for real-time therapeutic drug monitoring in clinical settings. Full article

The evaluation of the time spent by a solute exclusively in the mobile phase (dead time) is of fundamental interest for the interpretation of the retention data and obtainment of thermodynamic parameters for the HPLC process. This parameter depends on the volume occupied by the mobile phase and on the volume of the effective stationary phase from the HPLC column, and the measurement of these volumes poses a real challenge. This review discusses the evaluation of volumes of various phases involved in the retention process of solutes, which are related to the dead time, and the phase ratio for the separation. This paper attempts to cover as many points of view as possible regarding this topic in liquid chromatography, which is of importance for almost all separation mechanisms. Full article

Dronedarone (DRO) is an antiarrhythmic drug that should be used under close supervision, and therapeutic drug monitoring (TDM) may be one of the tools supporting pharmacotherapy. The aim of our study was to develop an economical HPLC method for determining DRO and its active metabolite debutyldronedarone (DBD) in human plasma. An HPLC isocratic system with a manual injector was applied. The separation was performed on a Supelcosil LC-CN column (150 × 4.6 mm, 5 µm) at an ambient temperature. The mobile phase was a mixture of CH₃OH:CH₃CN:H₂O:0.5 M KH₂PO₄ (170:85:237.2:7.8 (v/v)) + 0.1 mL 85% H₃PO₄ pumped at a flow rate of 1.8 mL/min. The UV detection was set at λ = 290 nm. A methyl tert-butyl ether was used for the extraction from a 0.4 mL alkalized plasma sample. The analytes were eluted at retention times of 4.0 min, 5.2 min and 6.0 min for DBD, internal standard bepridil and DRO, respectively. The method was calibrated in the range of 10–1000 ng/mL for both DRO and DBD. The adequate specificity, accuracy and precision were demonstrated in accordance with EMA guidelines, i.e., ≤15% (≤20% for the LLOQ), which ensures the reliability of the measurements. This method can be recommended for laboratories with basic HPLC equipment for TDM, adherence assessments and even in PK studies during chronic DRO therapy. Full article

When high-performance liquid chromatography (HPLC) is used for the analysis of polycyclic aromatic hydrocarbons (PAHs) in complex samples, further examination of HPLC fractions is recommended to confirm PAH assignments solely based on retention times. Gas chromatography–mass spectrometry (GC-MS) has been particularly relevant in the unambiguous determination of PAHs with remarkably similar retention times. The combination of HPLC and GC requires lengthy analysis times to ensure proper assignments. This article presents an approach for the analysis of co-eluted PAHs with no need for further chromatographic separation. Benzo[a]pyrene (BaP) and dibenzo[a,l]pyrene (DBalP) were directly determined in a co-eluted HPLC fraction via room-temperature fluorescence excitation–emission matrices (RTF-EEMs). RTF-EEMs can be recorded in a matter of seconds with a spectrofluorometer equipped with a multichannel detection system. The spectral overlapping of BaP and DBalP was resolved using parallel factor analysis (PARAFAC). The analytical advantages of this approach were demonstrated with the trace analysis (ng/mL) of these two PAHs in pre-concentrated tobacco extracts. Full article