Protic ionic liquids (PILs) are promising candidates for electrochemical applications due to their wide liquid-state range, tunable physicochemical properties, and the possibility of controlling hydrogen-bond networks via molecular design. In this work, we report the synthesis and characterization of N,N‑diethyl‑octan‑1‑ammonium tetrafluoroborate selectively deuterated at the N–H site, [N228D][BF₄]. The phase behavior and local hydrogen‑bond structure were investigated by combining solid‑state 2H nuclear magnetic resonance (NMR) spectroscopy and differential scanning calorimetry (DSC). DSC revealed the absence of a glass transition in the −120 to +150 °C interval, instead identifying multiple solid–solid transitions and a melting event via intermediate mesophases. Temperature‑dependent 2H NMR spectra demonstrated the coexistence of two distinct hydrogen bonding environments in the solid phases (DQCC = 151–177 kHz and 129–140 kHz) at low and intermediate temperatures, with the transition to an isotropically mobile phase above 283 K. The 2H NMR evidenced the presence of the plastic phase above 283 K and enabled quantitative determination of transition thermodynamics (ΔH° = 59 ± 8 kJ·mol⁻¹; ΔS° = 162 ± 25 J·mol⁻¹·K⁻¹) to the state with mobile cations. The observed intermediate DQCC values reflect hydrogen‑bond strengths in [BF₄]⁻ PILs and evidences multiple hydrogen‑bonding geometries despite anion symmetry. These findings contribute to the understanding of structure–dynamics–phase behavior relationships in asymmetric cation PILs and may inform the design of optimized electrolytes for energy‑related applications.

Miniaturized mass spectrometry has emerged as a powerful analytical technique characterized by its portability, rapid analysis capability, and operational simplicity, making it particularly suitable for on-site detection across various fields. However, the accurate quantitative determination of multiple compounds in complex matrices remains challenging due to factors such as competitive ionization and limited ion storage capacity. In this study, a time-resolved thermal desorption continuous atmospheric pressure interface ion trap mass spectrometer (TRTD-CAPI-ITMS) coupled with an acetone-assisted photoionization source was developed for simultaneous detection of multiple cooling agents for ensuring product safety and quality control. To evaluate the performance of the system, time-resolved thermal desorption curves of cooling agent mixtures with varying boiling points and concentrations were systematically investigated. The prominent signals of all the cooling agents could be observed simultaneously at a thermal desorption time of 2.0 seconds. However, a key challenge was identified during simultaneous quantitation: non-linear concentration-dependent signal responses were observed with increasing cooling agent concentrations. Competitive ionization between the target cooling agents was confirmed as the primary cause of this phenomenon. To address this issue, two critical parameter adjustments were implemented: (1) reducing the sample load to decrease the number of competing analyte components in the ionization region, and (2) elevating the concentration of acetone dimer reagent ions to ensure sufficient reagent ions for effective ionization of the target cooling agents. As a result, competitive ionization was eliminated, and good linear calibration curves were obtained for all four cooling agents, with all linear correlation coefficients (R2) exceeding 0.99. Finally, the TRTD-CAPI-ITMS was applied to the quantitative determination of cooling agents in commercial dentifrice samples, with whole detection time less than 4 minutes, demonstrating the potential of TRTD-CAPI-ITMS as a powerful tool for field detection of cooling agents in complex matrices, with broad applicability in quality control and safety assessment across relevant industries.

Establishment of a LC-MS/MS method for the simultaneous quantitative determination of trimethylamine N-oxide and four precursors in human saliva.

Method development and validation for quantitative determination of urinary biomarkers of food intake for multiple foods.

Fedratinib, a selective Janus kinase 2 (JAK2) inhibitor approved by the FDA for the treatment of myeloproliferative neoplasms, particularly myelofibrosis (MF), has clinical relevance. Despite this, no liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been reported for its quantification in biological matrices. This study aimed to develop and validate an LC-MS/MS method for quantifying fedratinib in mice plasma and assessing its pharmacokinetics. The method employed a Sciex 4500 triple quadrupole mass spectrometer with a Shimadzu LC system in positive ionization mode. Chromatographic separation was achieved using a Phenomenex Kinetex C18 column (2.1 × 50 mm, 5.0 μm) with a gradient mobile phase of 5 mM ammonium formate in 0.1% formic acid and acetonitrile at a flow rate of 0.8 mL/min. Telmisartan was used as the internal standard (IS). The method was validated in accordance with USFDA M10 bioanalytical guidelines. Fedratinib and IS were detected at m/z 525.5 → 468.9 and m/z 515.2 → 276.0, respectively. The assay demonstrated excellent sensitivity (LLOQ: 0.5 ng/mL), linearity (0.5 to 1000.0 ng/mL, r2 = 0.99), and accuracy (95.80-104.52%). Stability studies confirmed the analyte's integrity across multiple freeze-thaw cycles. The developed LC-MS/MS method is selective, sensitive, fully validated, and was successfully applied to pharmacokinetic studies.

Determination of arsenic species in seafood samples using a combination of HPLC and ICP-MS after ultrasonic assisted sample preparation.

A cyclodextrin-deep eutectic solvent-based dispersive liquid-liquid microextraction method for quantitative determination of small molecules in fresh-cut Codonopsis Radix.

Copper-enhanced electrochemical immunosensor based on gold nanoparticles for the quality control of hepatitis A virus vaccines.

A rapid and environmental-friendly method for characterization and determination of the major sesquiterpenoid constituents in the essential oil of Nardostachys jatamansi DC.

The main goal of this study was to develop methods for quality control of naftifine hydrochloride in solution and cream forms, focusing on “Quantitative Determination” and “Related Impurities.” New, precise, accurate, and environmentally friendly high performance liquid chromatography (HPLC) methods were developed for the determination of naftifine hydrochloride and its impurities. “Quantitative determination” was performed using a diode array detector at 254 nm with an isocratic mobile phase (1.154 g of ammonium acetate R dissolved in 300 mL of water R, followed by the addition of 0.2 mL of glacial acetic acid R, mixed well) and methanol (30:70). The chromatographic columns Gemini C18 and Luna C18 were used. “Related impurities” were separated at 270 nm using a gradient mobile phase consisting of 10 M sodium octanesulfonate, 0.4 g/L disodium hydrogen phosphate anhydrous solution (pH 6.5), acetonitrile, and the Synergi Hydro-RP chromatographic column. The developed method, validated according to ICH guidelines, showed run times of 55 min for impurity analysis and 6 min for active ingredient determination. The methods were successfully applied to the quality control of the solution and cream.

Objective: To determine the frequency of different causes of inherited thrombophilia and evaluate clinical presentations in patients presenting with documented venous or arterial thrombosis. Study Design: Cross-sectional study. Place and Duration of Study: Armed Forces Institute of Pathology Rawalpindi, Pakistan from Jan to Jun 2022. Methodology: One hundred and seven patients who fulfilled the selection criteria and gave informed consent in written form were enrolled. Clinical presentations were noted down and patients were assessed for inherited thrombophilia. Polymerase chain reaction was used for the detection of factor V Leiden mutation and prothrombin gene mutation. Pro C global clotting based screening test was used to determine the anticoagulatory capacity of protein C and S. Quantitative determination of the functional activity of antithrombin was performed on CS5100 automated coagulation analyzer. Results: The mean age of the patients was 29.31±14.17 years. Inherited thrombophilia was present in 26(24.3%) patients. Factor V Leiden mutation was present in 14(53.8%), antithrombin deficiency in 6(23.1%), protein C deficiency in 3(11.5%), protein S deficiency in 2(7.7%) and prothrombin gene mutation in 1(3.9%) patient. Commonest clinical presentation was deep venous thrombosis in 10(38.5%) patients followed by pulmonary embolism in 5(19.2%), portal vein thrombosis in 3(11.5%), superficial venous thrombosis in 3(11.5%). Conclusion: The commonest inherited cause of thrombophilia was factor V Leiden mutation and the commonest presenting complaint was deep venous thrombosis.

Pluchea pteropoda (Asteraceae) has been traditionally employed in folk medicine; however, its phytochemical characteristics and biological activities remain insufficiently defined. This study aimed to elucidate the phytochemical composition, antioxidant properties, and acetylcholinesterase (AChE) inhibitory potential of leaf and root extracts prepared using 45% and 70% ethanol. Four extracts of 45% ethanol extract of leaves (L45), 70% ethanol extract of leaves (L70), 45% ethanol extract of roots (R45), and 70% ethanol extract of roots (R70) were obtained and subjected to qualitative phytochemical screening, quantitative determination of total phenolic and flavonoid contents, DPPH radical scavenging and FRAP reducing power assays, as well as AChE inhibition assessment via Ellman’s method. Data were analyzed using regression-based IC50 estimation and reported as the mean of triplicate measurements. Leaf extracts exhibited substantially higher phenolic (up to 52.89 mg GAE/g) and flavonoid contents (20.62 mg QE/g) compared to root extracts. Antioxidant performance varied according to solvent strength: L45 demonstrated the most potent DPPH scavenging activity (IC50 = 194.8 µg/mL), whereas L70 showed superior reducing capability. AChE inhibitory activity followed the order L70 > L45 > R70 > R45, although L70 remained approximately 16 times less potent than galantamine. Collectively, the findings indicate that P. pteropoda possesses noteworthy antioxidant potential and moderate AChE inhibition, suggesting its promise as a natural source for the development of phytotherapies targeting oxidative stress and neurodegenerative disorders.

In this study, we developed a highly sensitive amperometric glucose biosensor based on a nanocomposite of electrochemically synthesized polypyrrole and metal oxide nanoparticles. A platinum electrode was coated by PPy film by cyclic voltammetry, which served as a host matrix for the immobilization of GOD using a chitosan-glutaraldehyde cross-linking system. We conducted a comparative study to evaluate the signal-enhancing effects of incorporating ZnO, TiO₂, and zinc titanate (ZnTiO₃) nanoparticles into the immobilization matrix. A comparative analysis of the current response to varying glucose concentrations was conducted for enzyme electrodes modified with metal oxide nanoparticles (NPs) at concentrations of 0.1, 0.5, and 2.0 mg/mL. The results unequivocally demonstrated that across all three concentrations tested, the electrode modified with ZnO NPs (PPy/ZnO/GOD) yielded a substantially superior amperometric response compared to those incorporating other metal oxides. This pronounced enhancement in current signal underscores the exceptional efficacy of ZnO nanoparticles in facilitating electron transfer within the biosensor matrix. Subsequent to this optimization, the ZnO NP-modified biosensor was deployed for the quantitative determination of glucose in a series of real-world samples, namely apple juice, grape juice, a fizzy beverage, and honey. To rigorously validate the accuracy and reliability of the developed biosensor, its performance was benchmarked against a commercially available spectrophotometric glucose assay kit. The analytical data obtained from both methods exhibited a strong correlation, confirming the high degree of accuracy of the fabricated biosensor. Consequently, it can be confidently asserted that the developed amperometric glucose biosensor exhibits significant potential and robustness for the precise and reliable determination of glucose concentrations in complex real-sample matrices.

The article presents the prospects for creating indicator systems based on ceramic membranes for field use. The aim of this work is to analyse the prospects and current approaches to creating indicator systems based on ceramic membranes modified with organic reagents, with an emphasis on detecting nitrogen-containing compounds and heavy metal ions in aqueous environments. It is noted that in order to create indicator ceramic membranes with high stability, sensitivity and selectivity, their preliminary modification is necessary. An analysis of methods for modifying ceramic materials indicates that covalent bonding is the most promising, but modifying membranes by polymer coating is more promising where high concentrations of analytes are required. Despite its simplicity, the direct adsorption method is not promising for the creation of long-term indicator membranes due to their low stability. It has been found that for the qualitative determination of nitro compounds, it is reasonable to use a simple method involving the use of iron(II) ions, which combines low cost, simplicity, stability and the possibility of effective immobilisation on ceramic materials. For the qualitative and quantitative determination of heavy metal ions, the creation of indicator membranes based on azo dyes, in particular chromazurol S, is promising. In this case, silicon(IV) oxide is the optimal ceramic carrier due to its high specific surface area and reactivity, which, in combination with modification by the polymer layer method, ensures the highest dye content, and by covalent bonding, the best stability. Thus, the article presents great prospects for the creation of indicator systems based on ceramic materials for obtaining indicator systems for field conditions.

Relevance. The article presents a method for the quantitative determination of caffeine-sodium benzoate by infrared Fourier transform spectrometry in the mode of disturbed total internal reflection. The research is aimed at developing an algorithm for the quantitative determination and validation of the method of caffeine-sodium benzoate in solid multicomponent mixtures by Fourier transform IR spectrometry. Aim. Development of an algorithm for the quantitative determination and validation of the method of caffeine-sodium benzoate in solid multicomponent mixtures by Fourier transform IR spectrometry. Materials and Methods. The study was conducted on a model mixture of tablet mass reproducing the composition of Citramon P 500 mg tablets (JSC Pharmstandard-Lexredstva). 30 calibration and 20 control samples were prepared by mixing the substance of caffeine-sodium benzoate with a mixture of auxiliary substances. IR spectra were recorded on a Cary 630 FTIR spectrometer (Agilent, USA) in the range of 4000-650 cm⁻1 (resolution 4 cm⁻1). The data was processed in KNIME 4.5.7 using the Python 3.9.10 package and the scikit-learn 1.3.0 library. Processing stages: normalization, separation of spectrometric data into training/test samples (in a 70:30 ratio according to the Kennard-Stone method), using the optimal configuration of automated preprocessing from a combination of 4 options, using a cascade of models consisting of 6 processing options with automated selection of the best combination of results, obtaining a mathematical (calibration) model, verification of the predictive ability of the model on a test sample, approbation of the model on control samples, validation of the analytical methodology. Results. The coefficient of determination r2 of the mathematical model when analyzing a test sample of spectrometric data was 0.99, which confirms its high predictive ability. When tested on control samples of a mixture similar to the composition of Citramon P tablets, the relative deviation of the calculated concentration from the actual concentration did not exceed ± 0.98%. Conclusions. An algorithm for the quantitative determination of caffeine-sodium benzoate in solid multicomponent mixtures by IR Fourier spectrometry in the mode of disturbed total internal reflection has been developed and tested. The value of the relative deviation ± 0.98% in a wide range of concentrations indicates the applicability of the algorithm. The validation procedure of the analytical methodology has shown that this methodology meets the criteria for the acceptability of validation characteristics in terms of linearity, correctness, and precision. Performing operations according to the methodology described ensures reliable and accurate analysis results.

DETECTION OF HUMAN PD-1 ON T-CELLS USING A FUSION PROTEIN CONSISTING OF AN ANTI-PD-1 SINGLE CHAIN VARIABLE FRAGMENT LINKED TO SUPERFOLDER GFP.

Spectrophotometry is a reliable and widespread physical-chemical method used for the quantitative analysis of pharmaceutical products. However, its use for the analysis of substances is limited due to the lack of government-approved standard samples. Currently, the search for optical reference samples and the development of methods using them are relevant tasks in pharmaceutical analysis. The study focused on the antiretroviral drug darunavir, as it is a preferred choice in antiretroviral therapy regimens. The article discusses the optical properties of darunavir, including the choice of the analytical wavelength of 263 nm, optimal solvent methylcarbaryl solution 95%, the analytical concentration, and the optical reference sample of nicotinic acid. The external optical reference sample was selected based on the analytical wavelength of darunavir, the optimal solvent, and the optimal absorption region of the reference sample. The high degree of purification of the nicotinic acid sample, as well as the stability of the concentration of the resulting solutions based on it, allows us to use nicotinic acid as a standard for the quantitative determination of substances using spectrophotometry. The developed method for the quantitative determination of darunavir in substances and dosage forms using spectrophotometry is a modern tool for assessing the quality of drugs. This method allows for accurate measurement of the concentration of the active substance, as well as the registration and evaluation of the intensity of light absorption by the drug molecules in a specific wavelength range, using reference samples. Based on the validation of the specificity, scope of application, linearity, and convergence of the analysis results, the method can be used for the pharmaceutical analysis of darunavir. The relative error of the spectrophotometric determination of darunavir based on nicotinic acid does not exceed 0.57% in the substance and 1.62% in the tablets. The data obtained confirm that the method is sufficiently accurate and allows for reproducible and reliable results both when analyzing the pure substance of the drug and in the composition of the tablet

The heavy metals (such as Cd, Pb, Zn, Cu etc.) at very low concentration from aqueous solution can be analyzed using AAS, ICP-MS, spectrophotometry and Voltammetry. Each method has its advantages and limitations. Voltammetry is one of the advanced techniques with a very high detection limit. The concentration of metal up to micro-molar or lower than that can be detected using Voltammetric technique. It also can detect more than one metal in the solution provided, if they have noticeable difference in their decomposition potential. The presence of heavy metals, in various ready-to-eat food products (like noodle, pasta, soup etc.) available in local market is investigated in this work. The results indicate that these metals (such as Cd, Pb, Zn, Cu etc.) are detected in nearly all samples; however, their concentrations remain within the acceptable limits. Two different methods were used to prepare the experimental solutions of the said ready to eat food samples in this work, one is digestive juice condition and other is by ashing method. In most of the samples of noodle, pasta and soup, the amount of metals detected by using both methods are in good agreement with each other (which can be considered as validation of results). Overall it indicates that the ready to eat food products are not harmful, with respect to heavy metals, as they are not detected beyond the permissible limit.

ABSTRACT The high market value of certain essential oils (EOs), such as lemon essential oil (LEO), makes them particularly susceptible to adulteration. Such adulteration typically involves the intentional addition of low-value EOs. In this study, we mixed LEO and sweet orange essential oil (SOEO), lime essential oil (LiEO), and grapefruit essential oil (GEO) at varying concentrations. We then used Attenuated Total Reflectance – Fourier Transform Infrared Spectroscopy (ATR-FTIR), and principal component regression (PCR), partial least squares regression (PLS), and artificial neural network (ANN) chemometrics to quantify adulteration in the samples. The ANN models produce the best accuracy, however it is computationally expensive and not practical. We further demonstrate that PLS using the 2000–1000 cm−1, ATR-FTIR spectral region produces good accuracy in predicting % v/v LEO, SOEO, LiEO, and GEO in the samples.

G-quadruplex enhances the peroxidase-like activity of 2D Cu-hemin for sensitive and accurate colorimetric detection of methyl parathion.