Liquid Chromatographic Method Research Articles

Integrated approach to predicting habitat suitability and evaluating quality variations of Notopterygium franchetii under climate change.

The impact of climate change on medicinal plants has significantly altered their suitable environments, thereby affecting the quality of herbal medicines. Notopterygium franchetii (N. franchetii), a medicinal plant intricately linked to its natural habitat, exhibits substantial quality variations influenced by the ecological conditions of its native region. In this study, comprehensive field surveys were conducted to gather occurrence records and samples of N. franchetii. The Maxent model and ArcGIS software were employed to predict the suitable habitats of N. franchetii during different time periods. A high-performance liquid chromatography (HPLC) method was developed to establish the chemical fingerprints of 21 sample batches. Fourteen common peaks were subjected to cluster analysis, principal component analysis, and orthogonal partial least squares-discriminant analysis. The findings revealed quality variations correlated with their geographic origins, identifying peaks 10, 1, 14, 3, and 4 as crucial for quality differentiation. The study indicates that precipitation, temperature, and altitude significantly influence the distribution of N. franchetii. Under current climate conditions, the suitable habitat area for N. franchetii is estimated to be approximately 94,637.33 km2. However, projections under three future climate scenarios suggest a declining trend in suitable habitat areas. A quality zoning map of N. franchetii was developed, integrating a correlation model between chemical composition and environmental variables with the spatial analysis and visualization capabilities of ArcGIS. The high-quality regions for N. franchetii are predominantly located in the Gannan, Linxia, Dingxi, Longnan, and Wuwei districts. These research outcomes offer a valuable reference for identifying suitable cultivation areas and assessing the quality of N. franchetii in Gansu Province.

Method development and validation of an analytical quality by design ultrafast liquid chromatographic method for the determination of bedaquiline from pharmaceutical bulk and nanoemulsions.

Bedaquiline (BDQ) is a drug used to treat multidrug-resistant tuberculosis (MDR-TB). It exhibits exposure-dependent efficacy in eliminating Mycobacterium tuberculosis (Mtb). An easy, efficient and precise reverse-phase ultrafast liquid chromatography (RP-UFLC) method was developed to validate the free base of the antitubercular medication BDQ. BDQ was separated using a 10:90 v/v mobile phase of ammonium acetate buffer solution (pH = 5.4) and high-performance liquid chromatography-grade methanol, with a flow rate of 1.5mL/min and a UV detection wavelength of 226 nm. By using the Box-Behnken design (BBD) and response surface methodology (RSM), the method was optimised by varying critical analytical attributes (CAA) and critical performance attributes (CPAs) namely ammonium acetate fraction (%), flow rate (ml/min), buffer system molarity (M) and pH. BDQ was eluted at 7.5min utilising isocratic elution. The method was linear in the concentration range of 0.5-300 μg/mL with limit of detection values of 0.039 μg/mL and limit of quantification of 0.12 μg/mL. The results indicate that this validated method can be used as an alternative method for assay of BDQ.

From historical drugs to present perils: UHPLC-QqQ-MS/MS determination of methaqualone and its designer analogs (NPS) with comprehensive fragmentation pathways study (QTOF)

Methaqualone, introduced in the 1960s as a sedative-hypnotic alternative to barbiturates, was withdrawn from the market due to its side effects and growing recreational use. Despite this, interest in methaqualone and its analogs remains high, raising concerns about potential abuse in the future. An ultra-high-performance liquid chromatography method coupled with triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) was developed to determine nine methaqualone-related compounds simultaneously. Biological samples were prepared using liquid-liquid extraction with ethyl acetate at pH 9, quantification was performed in blood using multiple reaction monitoring (MRM) mode. Methaqualone-d7 served as an internal standard. The limit of quantification (LOQ) ranged from 0.1 to 0.2 ng/mL, with precision and accuracy within 20%. Recovery ranged from 84.2% to 113.7%. The developed method allowed chromatographic separation of all compounds tested, including two structural isomers: methtylmethaqualone and etaqualone. The mass spectra aquired from quadrupole time-of-flight mass spectrometer allowed for the elucidation of comprehensive fragmentation study of methaqualone derivatives. The described situation poses a significant problem from the analytical point of view, as well as interpretation and forensic toxicological expertise. The developed method will contribute to increased analytical capabilities and enhanced detection of compounds from the methaqualone group that may appear on the illicit market.

Dairy Chain Safety in the Context of Antibiotic Residues—Current Status of Confirmatory Liquid Chromatography Methods: A Review

With ever-developing analytical capabilities, the protection of the dairy chain from contamination by residues of veterinary drugs is improving. Legislative requirements are an inherent part of this process. Of antibiotics in dairy farming, representatives of the beta-lactams, tetracyclines, sulfonamides, (fluoro)quinolones, aminoglycosides, or polypeptide antibiotics are the most widely used. Due to the typically low levels of antibiotic residues in milk, mass spectrometry is the most commonly used detection technique. However, the interference of the sample matrix is one of its main limiting factors, and therefore, it needs to be eliminated. In the first step, the lipid fraction is removed and proteins are precipitated, followed by solid-phase or liquid–liquid extraction. The current trends include the reduction in the consumption of organic solvents (to reduce occupational hazards and burden to the environment) and automation, eliminating the influence of human error and optimizing the workflow. These trends lead to the development of new microextraction and automated techniques as well as the use of new sorbents and/or (green) solvents of natural origin. To capture the latest developments in the field and the relatively recent aforementioned trends, this review focuses on papers investigating antimicrobial residues in milk that were published between 2015 and 2024, providing an overview of emerging techniques applicable to antibiotic residue detection in milk samples.

Study of the Acidic, Basic, and Thermal Degradation Kinetics of Three Antihypertensive Drugs—Individually and in Combination

Background/Objectives: The importance of fixed-dose combinations (FDCs) for the treatment of hypertension is well established. However, from a stability perspective, FDCs present a challenge since the degradation of one active pharmaceutical ingredient (API) can be affected by the presence of another API. The aim of this study was to compare the degradation behaviors and evaluate the degradation kinetics of three antihypertensive drugs, perindopril tert-butylamine (PER), amlodipine besylate (AML), and indapamide (IND). Methods: The degradation processes were studied using the previously developed reverse phase high-performance liquid chromatographic (RP-HPLC) method after exposing each drug individually, as well as the combinations of two/three drugs, to different stress factors, such as light, oxidation, acidic, basic, or neutral pH values at different temperatures. Results: The results show that PER is most unstable under basic conditions and that AML displays a negative, while IND displays a positive effect, on PER stability when combined. AML is most affected by basic conditions and oxidation, and its stability is affected by both drugs positively; IND undergoes extreme photolysis, which is positively affected by AML but negatively by PER. Conclusions: Great care must be taken when formulating FDCs with these three drugs, as well as solutions or oral suspensions adjusted for geriatric or pediatric populations, since the stability of all three drugs is greatly affected by pH conditions, as well as light or oxidation factors and their interactions.

Development of a liquid chromatography method for the analysis of oil extract of artemisia cina

Introduction. The problem of development and implementation of own drugs in Kazakhstan today is acute and urgent. The solution to this problem is possible through the use of own resources – domestic medicinal plant raw materials. A promising medicinal raw material is Artemisia cina – an endemic medicinal plant of the of the Turkestan region of Kazakhstan.Aim. Designing a liquid chromatography methodology to analyze the oil extract obtained from Artemisia cina.Materials and methods. Standard sample (SS) of santonin, Artemisia cina’s oil extract. The substance was identified and quantitatively determined using an Agilent Technologies 1200 liquid chromatograph (USA) equipped with ChemStation software.Results and discussion. The main active substance of the oil extract was analyzed using high-performance liquid chromatography (HPLC) method. Choosing the separation conditions for the column involves determining the best composition of the mobile phase and the rate of elution. There were used a reversed-phase system with sorbent C18 and a mobile phase consisting of acetonitrile and a phosphate buffer with a pH of 6.8. Chromatographic studies of the substance were carried out in a gradient mode at an analytical wavelength of 237 nm. The retention time of the standard sample (SS) of santonin matched the retention time (tR) of santonin isolated from the oil extract of Artemisia cina and amounted to 14.3 minutes.Conclusion. A liquid chromatography method has been established for the identification and quantitative determination of the oil extract, focusing on the main active substance, santonin.

Single Method for Determination of Biocides Benzalkonium Chloride, Chloroxylenol and Chlorhexidine Gluconate in Cosmetics, Hygiene and Health Care Products by Using High Performance Liquid Chromatography.

Benzalkonium chloride (BKC), chloroxylenol (PCMX) and chlorhexidine gluconate (CHG) are widely recognized biocidal compounds that require precise control and monitoring in various applications, including cosmetics, hygiene, health and ophthalmic products. In this study, we present a straightforward and highly sensitive high-performance liquid chromatographic (HPLC) method for the detection of these substances. The HPLC method we developed allows for the detection of BKC at concentrations as low as 1.0ppm, PCMX at 1.0ppm and CHG at 2.0ppm, all with a signal-to-noise (S/N) ratio exceeding 3.0. Additionally, the method enables quantification up to 2.0ppm for BKC, 2.0ppm for PCMX and 5ppm for CHG, with an S/N ratio surpassing 10.0. This validated method serves as a versatile tool for the accurate quantification of BKC, PCMX and CHG in cosmetics, hygiene products, health products and ophthalmic products. Its applicability extends across a wide range of industries, ensuring the reliable assessment of these critical biocides.

Dual-Template Molecularly Imprinted Polymers for Dispersive Solid-Phase Extraction Combined with High Performance Liquid Chromatography for the Determination of Sulfonamide Antibiotics in Environmental Water Samples

In this study, we designed a molecularly imprinted polymers-dispersive solid-phase extraction-high-performance liquid chromatography (MIPs-DSPE-HPLC) method, as a simple and efficient platform for the sensitive detection of two sulfonamide antibiotics (SAs) of sulfamethoxine (SMM) and sulfamethoxazole (SMZ) in environmental water samples. Using SMM and SMZ as templates, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the crosslinking agent, and azodiisobutyronitrile as the catalyst, the dual-template molecularly imprinted polymers (dt-MIPs) were successfully synthesized via surface imprinting technology and multi-template imprinting strategy. The adsorption properties of the prepared MIPs were characterized, and the adsorption capacities of MIPs towards SMZ and SMM were 27.35 mg/g and 30.92 mg/g, respectively. The detection limits of the method in three environmental water samples were in the range of 0.23–1.74 μg/L, and the recoveries were between 82.7 and 110.3%, with relative standard deviations less than 5.93%. The construction process of this MIPs-DSPE-HPLC method is straightforward, exhibits high sensitivity and selectivity, and thus provides a versatile method for the quantification of SAs in complex matrices.

Stability Indicating High‐performance Liquid Chromatography Method for Quantification of Amoxapine and Characterization of Forced Degradation Products Employing Quadrupole‐Time of Flight Mass Spectrometry

ABSTRACTAmoxapine, a tricyclic antidepressant, has been widely used for long‐term treatment of depression along with other psychiatric disorders involving neurosis, agitation, and anxiety. The drug may undergo degradation during manufacturing, transportation, and storage. To ensure drug safety, both identification and characterization of the degradation products (DPs) should be considered. Accordingly, a sensitive and selective stability‐indicating assay method was developed for amoxapine using high‐performance liquid chromatography (HPLC). The amoxapine drug was subjected to acidic hydrolysis, basic hydrolysis, and oxidation separately. The degradation susceptibility of the amoxapine was found to be in the order of Acid hydrolysis > Oxidation > Base hydrolysis. The developed method was validated as per the International Council for Harmonization Q2(R2) guideline. Further, LC‐electrospray ionization‐quadrupole‐time of flight‐tandem mass spectrometry was employed for the identification and characterization of the DPs formed under stress conditions. The study revealed that under accelerated stress conditions, three hydrolytic DPs and one oxidative DP were formed. Three of the four DPs were found to be novel and never reported before. In addition, a plausible mechanism representing the formation of all DPs has also been established.

Assessing Drug Product Shelf Life Using the Accelerated Stability Assessment Program: A Case Study of a GLPG4399 Capsule Formulation

Objective: To evaluate and project the shelf life of GLPG4399, an early-phase clinical drug formulation by applying the Accelerated Stability Assessment Program (ASAP) approach. Methods: Forced degradation conditions were implemented to identify the stability-limiting degradation product. The drug and its degradation products were separated using a validated liquid chromatography method. Then, the selected clinical capsule formulation was placed in a glass vial and exposed to accelerated short-term conditions of combinations of high- and low-level heat and humidity in an open state for 5 weeks. The liquid chromatography results were evaluated using the ASAP, which is based on the moisture-modified Arrhenius principle. The resulting data were fitted using a suitable diffusion kinetics method. Results: The developed model was applied to predict the shelf life of the drug product when using clinically appropriate primary packaging (high-density polyethylene container). The derived stability parameters of the moisture-modified Arrhenius equation were the Arrhenius collision frequency, activation energy, and humidity sensitivity constant. The goodness of fit parameters R2 (>0.95) and goodness of prediction Q2 (>0.80) parameters for the selected model were acceptable. The results of the accelerated, short-term stability study were verified against real-time, long-term 12-month data. Conclusions: We demonstrated the application of the ASAP approach to evaluate the shelf life of a GLPG4399 solid capsule formulation. The studied ASAP approach can be extended to evaluate the stability and shelf-life estimations of other early-phase clinical formulations.

Quality by Design Approach Driven Development and Validation of Reverse Phase‐High‐Performance Liquid Chromatography Methodology for Dual Quantification of Aspirin and Rivaroxaban

ABSTRACTClinical trials have shown that combining a modest dose of Rivaroxaban (RIV) with Aspirin (ASP) is more effective than ASP alone in reducing cardiovascular mortality, myocardial infarction, and stroke. A high‐performance liquid chromatography method developed using Quality by Design (QbD) effectively estimates ASP and RIV for routine pharmaceutical analysis. The Plackett‐Burman design assessed key factors including organic phase volume, mobile phase pH, flow rate, temperature, and injection volume using an Ishikawa fish‐bone diagram for risk assessment. These parameters were then optimized via Box‐Behnken design in 15 trials. The method meets the International Council For Harmonization standards with a mobile phase ratio of 45:55 (v/v) acetonitrile: buffer (pH 3, adjusted with orthophosphoric acid), a flow rate of 1 mL/min, a column temperature of 30°C, and an injection volume of 20 µL. A Phenomenex Luna C18 column (250 × 4.6 mm, 5 µm particle size) with detection at 251 nm ultra‐violet wavelength. The retention times of 4.54 min for ASP and 5.81 min for RIV were obtained. Validation confirmed linear ranges: 40–200 µg/mL for ASP and 2–10 µg/mL for RIV, with excellent recovery rates (ASP: 99.30%–101.9%; RIV: 98.52%–101.84%). Developed using QbD principles, the method proved specific, accurate, precise, sensitive, and robust for routine quality control of both compounds in pharmaceutical formulations.

Determination and Quantification of Related Impurity Substances in Elvitegravir Drug Substance by Full Factorial Design Evaluated Liquid Chromatography Method

ABSTRACTHerein, our work deals with developing a rapid, accurate, and reliable high‐performance liquid chromatographic technique with the application of quality by design (QbD) experimental tool to quantify Elvitegravir drug (Integrase inhibitors of antiretroviral drug) and its novel related impurities at low levels. Further, this unique method has been validated to prove its consistency. Separation of N‐methyl Elvitegravir (Impurity‐I), 2‐fluoro Elvitegravir (Impurity‐II), and Elvitegravir isopropyl ester (Impurity‐III) in Elvitegravir drug substance was executed by using Kinetex C18 column (150 mm × 2.1 mm × 1.7 µm) with water, acetonitrile, formic acid, and triethylamine (690:300:6:2, v/v/v/v/), mobile phase (MB‐A) and acetonitrile, formic acid and triethylamine (990:6:2, v/v/v), MB‐B. This developed analytical technique gave a well‐separated peak at the retention times of 9.126 min (Elvitegravir), 7.713 min (Impurity‐I), 7.972 min (Impurity‐II), and 8.548 min (Impurity‐III) adequate with the peak properties as per the United States Pharmacopeia guideline. The method's sensitivity and linearity are established by its detection and quantification limits at low levels with a correlation coefficient of 0.998. The method's repeatability, specificity, and accuracy suggest that this developed technique is a reliable determination strategy for Elvitegravir drug substance and its related impurities (Impurity‐I, Impurity‐II, and Impurity‐III) in a simple, feasible, and affordable way.

A Pharmacokinetic Study of the Interaction Between Regorafenib and Paracetamol in Male Rats

Background: In clinical practice, the prevalent problem of polypharmacy could result in increased risks of drug–drug interactions. Regorafenib (REG) is commonly co-administered with paracetamol (PA) as a treatment protocol in cancer patients with pain therapy. Purpose: This study aimed to demonstrate the effect of paracetamol on the pharmacokinetic parameters of regorafenib and its metabolites following a single administration of both substances in rats. Additionally, the influence of REG and its metabolites on the pharmacokinetics of paracetamol was also determined. Methods: Twenty-four rats were divided randomly into three groups: REG group (IIREG, regorafenib 20 mg/kg, n = 8), PA group (IIIPA, paracetamol 100 mg/kg, n = 8), and REG+PA co-administration group (IREG+PA, REG 20 mg/kg and PA 100 mg/kg, n = 8). The concentrations of regorafenib, regorafenib-N-oxide (M-2), and N-desmethyl-regorafenib-N-oxide (M-5) were determined using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS). The plasma concentrations of PA and its glucuronide (GPA) and sulfate (SPA) metabolites were measured using the validated high-performance liquid chromatography method with ultraviolet detection (HPLC–UV). The pharmacokinetic parameters were calculated using a non-compartmental model. The statistical evaluation was performed in the SAS program. Results: After the administration of PA, the Cmax and AUC0–∞ of REG increased by 890% and 1140%, respectively; for M-2, they increased by 220% and 170%, and for M-5, by 2130% and 1730% (Cmax and AUC0–∞, respectively). A difference in the ratio of M-2/REG for AUC0–∞ and Cmax between the groups was observed, but not for M-5/REG. The AUC0–∞ for PA and GPA decreased by 20.7% and 51.1%, respectively, when PA was co-administered with REG. But the AUC0–∞ for SPA increased by 91.35% in the IREG+PA group. A difference in the ratio of GPA/PA for Cmax and for SPA/PA for AUC0–t and AUC0–∞ between the groups was observed. Conclusions: Paracetamol increased the plasma exposure of regorafenib, M-2, and M-5, which may exacerbate the drug’s side effects. In contrast, REG reduced paracetamol exposure and contributed to its faster elimination, which may reduce the analgesic and antipyretic effects of paracetamol. These findings suggest clinical relevance for oncology patients requiring analgesic treatment.

Evaluation of MENAQUINONE‐7 and fat‐soluble vitamin production by starter cultures during fermentation in dairy products using RPLC method

AbstractVitamin K2, also known as menaquinone, has become a significant research focus, particularly in fermented products. This study aims to investigate the content of menaquinone‐7 (MK‐7), an essential form of vitamin K, and other fat‐soluble vitamins (A, D, E) during the fermentation of various fermented milk products. The vitamin contents of six fermented milk products were analyzed: two yogurt samples (produced with commercial starter and probiotic starter), two kefir samples (produced with commercial starter and kefir grain), and milk fermented with Lactobacillus acidophilus or Bifidobacterium bifidum. Throughout the fermentation process, continuous pH monitoring was conducted, and fermentation was terminated based on pH levels. Fat‐soluble vitamins and vitamins K1, K2 were extracted from samples taken at specific fermentation periods and quantitatively determined using the reverse phase liquid chromatography (RPLC) method. The developed method was validated according to ICH guidelines. Simultaneously, the microbial content of the samples was analyzed. Among the fermented dairy products analyzed, the highest MK‐7 content (4.82 μg/100 g) was found in the kefir sample produced with kefir grain (KG). The diverse microorganisms in kefir grains necessitated detailed research to explain their role in this complex mechanism. In yogurt samples, the presence of L. acidophilus in the YB sample suggests that this bacterium may be responsible for the observed differences. This is supported by the LA sample, where production with L. acidophilus strain showed an increase from 0.97 to 1.70 at the 20th hour of fermentation. It was noted that the concentration of menaquinone‐7 increased throughout the fermentation period. Given the critical health effects of essential fat‐soluble vitamins and MKs, determining their content in commonly consumed fermented dairy products and understanding the influence of starter cultures, which are potential probiotics, on vitamin production underscores the importance of this research. It is important to highlight the potential of fermented products in nutritional recommendations.

Fabrication of a molecularly imprinted poly(methyl methacrylate) decorated graphite electrode for detection of aloe emodin in Aloe vera

In this work, the authors represent a comprehensive approach for the development and validation of a novel graphite-supported molecularly imprinted poly(methyl methacrylate) electrode for the selective and sensitive detection of aloe emodin (AE) in aloe-based cosmetic products. The electrocatalytic activity of the electrode was evaluated using cyclic voltammetry and differential pulse voltammetry techniques in phosphate buffer saline. Surface morphology, structural characteristics, and imprinting endorsement were investigated using field emission scanning electron microscopy, Fourier-transform infrared spectroscopy, and UV-Vis spectroscopy. Under the optimal conditions, the electrode showed an oxidative differential pulse voltammetry peak at -0.2931±0.011 V (vs. Ag/AgCl, saturated KCl). The current was increased linearly with increasing concentrations of AE from 0.0005 to 350 µM, with a low detection limit of 0.0003 µM. The voltammetric analysis has been validated by reverse-phase high-performance liquid chromatography (RP-HPLC) methods. A partial least square regression model was developed to correlate the results obtained from the proposed system with the reference values obtained by RP-HPLC. The model showed a high prediction accuracy of 95.95 % for the detection of AE in cosmetic samples. The developed electrode provides a low-cost, rapid, easy, and convenient method for the detection of AE in cosmetic products, offering potential benefits for quality control and safety assessment in the cosmetic industry.

Assessment of miligram(Mg) content of some notable analgesics used by residents of Maiduguri Metropolis: evidence from high performance liquid chromatographic technique

Diclofenac sodium and paracetamol are Over the counter (OTC) medications used as analgesic and antipyretic agents to relieve pains, fever and headaches. The aim of this work was determine the mg content of paracetamol and diclofenac sodium in selected samples across the Maiduguri metropolis using High Performance liquid chromatography (HPLC) method. For paracetamol samples an intersil ODS-3V column (150 mm × 4.6 mm; 5 μm pore size) was used at the temperature of 35oC the mobile phase was methanol: water (20:80) using isocratic elution at the flow rate of 2 mL/min, injection volume of 10 μL and a diode array detector. For diclofenac sodium samples, the chromatographic conditions were the same except the mobile phase which was methanol: water (63:37), flow rate of 0.8 mL min, injection volume of 20 μL and column temperature was set at 30 oC. A total of 45 samples were analysed; which comprised of paracetamol tablet, paracetamol syrup and diclofenac sodium tablet which were randomly selected from three different sources; hospital pharmacy, community pharmacy and drug patent stores. The percentage mg content for paracetamol tablets ranged from 48 to 83 % while that of the paracetamol syrups ranged from 72 to 120 % and finally diclofenac sodium tablets ranged from 73 to 174 %. Adopting the United State Pharmacopoeia (USP) as reference for assessment tool, it was observed that all the paracetamol tablet samples failed, 4 out of 15 paracetamol syrup samples failed, and 11 out of 15 diclofenac sodium tablet samples failed. There was statistical significance (p< 0.05) between class of drug and percentage mg content but there was no significance (p< 0.05) between source of drug and percentage constituent. HPLC technique was used successfully for quantitative determination of paracetamol and diclofenac sodium dosage forms.

Determination of 3-hydroxyanthranilic acid in the sweat of healthy older adults

3-Hydroxyanthranillic acid (3HAA) is one of the key metabolites from the tryptophan (TRP) metabolism pathway and is associated with aging, age-associated diseases, and healthy lifespan extension. This study aims to detect 3HAA in the sweat of healthy older adults using simple, high-performance liquid chromatography (HPLC) method. Chromatographic separation using 20 mmol/L sodium acetate, 3 mmol/L zinc acetate, and 7% (v/v) acetonitrile as mobile phase is possible to simultaneous detect 3HAA, KYN, and TRP with UV and fluorescence detection, respectively, under 6 min. This method demonstrated excellent linearity with coefficient of determination (r2) greater than 0.998 for all analytes. The linear range were 0.05–6 µg/mL for TRP, 0.1–6 µg/mL for KYN and 0.2–6 µg/mL for 3HAA. Percentage recoveries from spiked in human sweat ranged from 90 ± 7–101 ± 3 for TRP, 86 ± 1–92 ± 3 for KYN, and 96 ± 1–103 ± 4 for 3HAA. The precision (%RSD) of repeatability and reproducibility is less than 3% and 6%, respectively. This method was used in a cross-sectional study with 81 participants aged 50–79 years, selected randomly from a local primary healthcare hospital’s sampling frame. A detectable amount of 3HAA was observed in all sweat samples, marking the first report of 3HAA presence in human sweat. Additionally, the results revealed that the 3HAA sweat levels increased with age analyzed in three different age groups ranging from 50–59, 60–69, and 70–79. These findings enhance our understanding of sweat profiles and their correlation with aging, potentially further improving early diagnosis, disease monitoring, and development of customized treatment programs for older adults.

Does Fungal Chitosan Leave Noticeable Traces in Treated Wines?

Background (1): The use of fungal chitosan as an antiseptic in wine appears as a promising alternative to sulfur dioxide for the elimination of Brettanomyces bruxellensis sensitive strains. Nevertheless, its utilization raises the question, “how are the treated wines different from the untreated ones?” Methods (2): Chitosan treatment residues were sought in the oligosaccharide and polysaccharide fractions and among 224 low MW ions (<1800 g·mol−1) in several wines by using liquid chromatography (size exclusion HPLC or LC-MS) and GC-MS. Standard oenological parameters were also examined as well as possible sensory modifications by a panel of tasters composed of experts and non-experts. Results (3): None of these methods enabled the reproducible and reliable identification of a treated wine without comparing it to its untreated control. The fingerprints of treatment are not reliably detectable by the analytical methods used in this study. However, the treated wines seem permanently protected against the development of chitosan-sensitive strains of B. bruxellensis. Conclusions (4): If chitosan treatment modifies the wine, the associated changes were not identified by the liquid chromatography method mentioned above and they were not perceived by most people in our taster panel. However, the expected antimicrobial action of chitosan was observed on B. bruxellensis sensitive strains and persisted at least one year. Tolerant strains were less affected by these persistent effects.

Bioconversion of mango peels into itaconic acid through submerged fermentation and statistical optimization of parameters through response surface methodology.

Itaconic acid is an industrially crucial organic acid due to its broad range of applications. The main hurdle in itaconic acid production is the high cost of the substrate, i.e., pure glucose, required for the fermentation process. Pakistan annually produces about 1.7 to 1.8 million metric tonnes of mango fruit. Keeping this in view, the potential of a sugar-rich fruit by-product, i.e., mango peels, was analyzed to be used as a substrate for the biosynthesis of itaconic acid using Aspergillus niger by submerged fermentation. Different physicochemical parameters (incubation period, temperature, agitation rate, inoculum size, and pH) were optimized using the central composite design (CCD) design of response surface methodology (RSM). The maximum production of itaconic acid, i.e., 4.6 g/L, was analyzed using 10% mango peels w/v (water hydrolysate), 3 mL inoculum volume after 5 days of fermentation period at pH 3, and a temperature of 32 °C when the media was kept at a 200-rpm agitation speed. The itaconic acid extraction from mango peels was done using the solvent extraction method using n-butanol. The identification and quantification of itaconic acid produced in the study were done using the Fourier Transform Infrared Spectroscopy (FTIR) spectrum and the High-Performance Liquid Chromatography (HPLC) method. According to HPLC analysis, 98.74% purity of itaconic acid was obtained in the research. Hence, it is concluded from the results that sugar-rich mango peels can act as a promising substrate for the biosynthesis of itaconic acid. Further conditions can be optimized at the bioreactor level to meet industrial requirements.

Quality control analyses of selected honey samples from Serbia based on their mineral and flavonoid profiles, and the invertase activity

Abstract Nowadays, climate changes induce deviations in the composition of honey varieties characteristic of a specific geographic region. Therefore, according to Codex Alimentarius for honey, the slight variations in values of determined parameters cannot be strictly regarded as a sign of its adulteration. Here, modified methods are presented for preparing honey samples for inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis and the high-performance liquid chromatography (HPLC) method to use them as fast and reliable methods in the food industry. ICP-OES analysis suggested that all analysed honey samples are natural, and HPLC-DAD (diode-arrray detection) analysis on the flavonoids showed that one sample is probably not natural. Invertase activity showed an overlap with this HPLC-DAD finding but suggested more samples as possibly adulterated, which can be neglected due to possible thermal treatment of those natural samples, causing a decrease in invertase activity. Therefore, results obtained from the analyses of investigated honey samples based on the mineral content, number, and quantity of flavonoids, together with the invertase activity, indicated that the combination of analyses could be a reliable tool for determining the quality of honey samples.