Hasil untuk "Analytical chemistry"

Uxue Uribe-Martinez, Leire Mijangos, Juan F. Ayala-Cabrera et al.

The occurrence and spatial distribution of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), fragrances, UV filters and photoinitiators were investigated in surface sediments of Nerbioi-Ibaizabal estuary between 2005 and 2013, in 2020. Samples were extracted by focused ultrasound solid–liquid extraction technique and analyzed by gas chromatography coupled with mass spectrometry. Total PAHs, PCBs, OCPs, musks, UV filters and photoinitiators concentrations ranged between not detected (n.d.) and 43000 ng g⁻¹, n.d. and 2500 ng g⁻¹, n.d. and 820 ng g⁻¹, n.d. and 880 ng g⁻¹, n.d. and 91 ng g⁻¹ and from nd to 120 ng g⁻¹, respectively. Hexachlorocyclohexanes (HCHs) were ubiquitous in the estuary, suggesting that these compounds, although banned, leach from landfills. The PCB concentrations showed a decreasing trend. Ecological risk assessments based on sediment quality guidelines (SQGs) and risk quotient (RQ) suggested semi-volatile organic compounds could represent a potential ecological risk in the Nerbioi-Ibaizabal estuary.

Alexandros Makis, Eleftheria Hatzimichael, Theodoros Palianopoulos et al.

<b>Background/Objectives</b>: Oxidative stress and iron overload remodel erythrocyte membranes in β-thalassemia, but their systemic metabolic correlates are not well defined. We applied untargeted metabolomics to identify serum biomarkers reflecting these pathophysiological processes. <b>Methods</b>: Thirty-one adults with β-thalassemia [18 transfusion-dependent (TDT), 13 non-transfusion-dependent (NTD)] and 8 age/sex-matched healthy controls were studied. Fasting serum was profiled using untargeted UHPLC–Orbitrap MS. Multivariate modeling (SIMCA-P) and FDR-controlled univariate statistics identified discriminant features, followed by pathway enrichment analysis. Associations with clinical variables (chelation regimen, ferritin, cardiac MRI T2*, and liver iron concentration) were examined. <b>Results</b>: A total of 183 metabolites were detected; versus controls, 124 were decreased, 54 increased, and 5 remained unchanged in patients. Key discriminants included lysophosphatidylcholines (LysoPC 18:1, 18:3), polyunsaturated fatty acid (PUFA)-bearing phosphatidylcholines (PC 20:4/18:0, PC 18:0/20:4), conjugated bile acids (glycocholic acid, glycochenodeoxycholic acid, and glycoursodeoxycholic acid), and bilirubin. Pathway analysis revealed significant enrichment (FDR-corrected) in linoleic acid metabolism (q = 0.024, impact = 1.000) and arachidonic acid metabolism (q = 0.022, impact = 0.433), with supportive nominal signals from glycerophospholipid (impact = 0.401) and porphyrin/heme (impact = 0.242) pathways. No significant metabolic differences were observed between TD and NTD patients. <b>Conclusions</b>: β-thalassemia serum metabolomics reflects oxidative membrane lipid remodeling with a prominent PLA₂/LysoPC–arachidonic axis and evidence of heme turnover and altered bile-acid signaling. These data propose a practical biomarker panel-LysoPCs, arachidonic acid-enriched PCs, and conjugated bile acids-warranting targeted validation alongside conventional clinical parameters for disease monitoring and therapeutic assessment.

Serik D. Fazylov, Oralgazy A. Nurkenov, Zhangeldy S. Nurmaganbetov et al.

In this study, the synthesis and properties of β-cyclodextrin-functionalized silver nanoparticles and their loading with a drug component are considered. β-Cyclodextrin was used as a reducing agent and stabilizer in the preparation of silver nanoparticles. The use of β-CD-AgNPs in loading molecules of the alkaloid cytisine (Cz) and its O,O-dimethyl-N-cytisinilphosphate (CzP) derivative, which have pronounced antiviral properties, was studied. The formation of β-CD-Cz-AgNPs and β-CD-CzP-AgNPs was confirmed by UV spectroscopy and X-ray diffraction spectroscopy. Scanning electron microscopy and transmission electron microscopy showed that the obtained β-CD-Cz-AgNP and β-CD-CzP-AgNP nanocomposites were well dispersed with particle sizes in the range of 3–20 nm. ¹H-, ¹³C-NMR and COSY, HMQC, HMBC and Fourier transform infrared spectroscopy revealed the reduction and encapsulation of AgNPs by β-Cz, and the TEM imaging results showed an increase in the size of nanoparticles after the introduction of cytisine and its phosphorus derivative. The kinetic parameters of the thermal degradation process of β-CD, Cz, CzP and their inclusion complexes Cz(CzP)-β-CD-AgNPs under isothermal conditions, which ensure the preservation of the kinetic triplet, were determined. The differences in the mechanism of thermal decomposition of the studied materials are described by the parameters of the Šesták–Berggren model (m and n), which demonstrated differences for different compounds: for β-CD, the values of the parameters m and n are 0.47 and 0.53, respectively, while for CzP-β-CD-AgNPs they reach values of 0.66 and 1.34. These results indicate differences in the mechanism of thermal decomposition of the studied materials.

Princee Tyagi, Akash More, Namarata Anjankar et al.

Infertility is considered a global concern, significantly contributing to females with PCOS. This case study describes the journey of a 33-year-old woman with PCOS and her 35-year-old male partner, who had been trying to conceive for over four years. They also had a history of failed intrauterine insemination (IUI) and intracytoplasmic sperm injection (ICSI) cycles despite normal semen parameters of the male partner, the female investigations revealed abnormalities in hormonal luteinizing hormone (LH) and follicle-stimulating hormone (FSH) that were the identified contributing factors. Further, the couple underwent significant counseling emphasizing lifestyle changes to manage infertility caused by polycystic ovarian syndrome (PCOS). Following ovarian stimulations for oocyte retrieval, 17 oocytes were retrieved, and eight were of Metaphase II. Six zygotes formed after performing an ICSI. They expanded into blastocysts, and further blastocysts underwent cryopreservation. Later, with progesterone support, the frozen embryo transfer was performed, resulting in a successful pregnancy. After embryo transfer, the female patients underwent regular follow-ups to monitor the possible complications of pregnancy. This case report demonstrates the potential challenges and success of ART employing PCOS patients, despite previously unsuccessful IUI and ICSI attempts and the presence of hormonal imbalances. The utilization of controlled ovarian stimulation, ICSI, FET, and lifestyle modifications worked effectively to achieve positive outcomes in pregnancy. The case study highlights the significance of individualized treatments and guidance in managing infertility caused by PCOS. The significance of routine follow-ups in ensuring the health of both the mother and the fetus, that shows PCOS patients, can have successful reproductive outcomes.

Ru Wu, Yue Cao, Zixuan Chen et al.

Graphene quantum dots (GQDs), as an emerging class of nascent carbon-based materials, demonstrate remarkable promise in fluorescence sensing applications. Those potentials stem from several factors, including their favorable photoluminescence (PL) characteristics, feasibility of surface functionalization, excellent biocompatibility, and low cytotoxicity. This review concentrates on the fundamental optical properties of GQDs, with specific reference to the manipulation of intrinsic characteristics both by heteroatom doping and surface/edge functionalization. These modifications permit the alteration of optical properties, thereby rendering GQDs more versatile for an array of applications. Subsequently, we then delve into the recent applications of GQDs in fluorescence sensing, encompassing both turn-off and turn-on mechanisms. Finally, it presents a systematic assessment of the current state of research on GQDs, along with discussions on challenges and prospects for expanding and improving their applications.

Andrea C. Mora, Alexandra K. Sogn, Allison J. Tierney et al.

Anass Hatim, Driss Khaddoudi, Fatima Abida et al.

Hydroxyapatite is a versatile material with strong potential for environmental remediation, yet its large-scale use is limited by the cost and purity requirements of conventional precursors. This study introduces a low-cost and sustainable synthesis route for hydroxyapatite using technical-grade phosphoric acid, highlighting the beneficial role of industrial impurities in tuning its structural, optical, and adsorption properties, thus promoting its broader use in environmental applications. Hydroxyapatite powders were synthesized from calcium hydroxide and technical-grade phosphoric acid (Ca/P = 1.67) at 25 °C in aqueous medium, then dried and calcined (500–1100 °C). Structural, chemical, and optical analyses revealed single-phase nano-hydroxyapatite (12.6–57.3 nm) with high surface area (176.95 m²·g-1) and strong wettability. The optical band gap decreased from 4.5 ± 0.4 eV to 3.2 ± 0.4 eV after calcination, indicating defect-induced electronic modification. The poorly crystallized hydroxyapatite exhibited excellent Cd²⁺ and Pb²⁺ adsorption (99 % and 97 % removal in 100 min) but limited bisphenol A elimination (2.73 % in 180 min).

María Agustina Pavicich, Stefano Compagnoni, Celine Meerpoel et al.

Cheese is vulnerable to contamination with mycotoxins, particularly ochratoxin A (OTA) and aflatoxin M1 (AFM1). This study aims to develop and validate an analytical method for the detection and quantification of OTA and AFM1 in cheese and to assess their prevalence and associated risks. A liquid chromatography–tandem mass spectrometry (LC-MS/MS) method was validated for detecting these mycotoxins in 41 cheese samples, including firm-ripened, spreadable, and plant-based alternatives. The results showed that OTA was detected exclusively in grated Parmigiano Reggiano cheese, while AFM1 was found in both Parmigiano Reggiano and Pecorino cheeses. This study goes beyond analytical method development by providing a preliminary exposure assessment and risk characterization for OTA and AFM1 in cheese, bridging the gap between analytical chemistry and public health implications. This study identified potential health risks associated with OTA, particularly for children and adolescents categorized as high consumers of Parmigiano Reggiano cheese. The findings underscore the need for monitoring of OTA and AFM1 in cheese and further research to establish regulatory limits for these contaminants.

Savarimuthu Paulraj Roseline, Chalakuzhiyil Abraham Mathew, S Sakthi Gnanavel et al.

Background and Objective: Inspite of advancements in material properties of heat cure acrylic resin, fracture of denture base and allergic reactions due to release of residual monomer is encountered frequently. To improve strength and to reduce residual monomer, different polymerization methods need to be investigated. The objective is to evaluate and compare transverse strength and residual monomer content of two different heat cured denture base resins polymerized by conventional water bath and by autoclave. Materials and Methods: Samples were prepared with Acralyn-H conventional heat cure resin and Acralyn-H super hi-impact resin using metal dies. Samples undergoing water bath polymerization were polymerized in water bath at 74°C for 2 hours followed by 100°C for 1 hour and samples undergoing autoclave polymerization were cured in an autoclave at 121°C and 210 kPa for 30 minutes as holding temperature. Transverse strength specimens were processed and then tested for transverse strength in a Universal testing machine. Specimens for residual monomer content estimation were weighed and each specimen’s residual monomer was extracted in methanol using Soxhlet extractor and then read at 230nm in Ultraviolet-Visible spectrophotometer. Concentrations of residual monomer were evaluated and weight fractions were calculated. Results: The results of this study showed a statistically significant difference in transverse strength of Acralyn-H conventional heat cure resin polymerized by autoclave, whereas all other groups showed a non-significant result. Conclusion: Autoclave can be used as an alternative polymerization technique as it has shown similar results when compared with water bath polymerization and the time required for polymerization was also reduced.

Shilpa A Warhekar, Gaurao M Pimpale, Ashish M Warhekar et al.

Objective: The aim of this cross-sectional study was to assess the oral health-related quality of life (OHRQoL) in a cohort of 500 patients diagnosed with precancerous lesions and conditions at a tertiary care hospital in Central India. Methods: 500 patients with confirmed precancerous oral lesions and conditions were recruited for the study. The Oral Health Impact Profile (OHIP-14) questionnaire, a validated instrument consisting of 14 items, was used to assess the OHRQoL of the participants. The OHIP-14 questionnaire scores were statistically analyzed using appropriate methods. Results: The majority of the participants were with a mean age of 48 years. The mean OHIP-14 score was calculated to be 45.1, indicating the overall impact of oral health on the quality of life of patients with precancerous lesions and conditions. The individual domains most affected were functional limitations and physical pain. Conclusion: This study demonstrates that promoting oral health awareness and regular screenings in the community is needed to prevent the progression of oral precancerous conditions and ultimately reduce the burden of oral cancer.

Jayashree Shanmugam, Manikandan Dhayalan, Mohammed Riyaz Savaas Umar et al.

The chemical content of plant excerpts can be efficiently employed to reduce the metal ions to nanoparticles in the one-pot green production method. Here, green production of silver nanoparticles (AC-AgNPs) is performed by means of <i>Allium cepa</i> var. <i>Aggregatum</i> (shallot) extract as a stabilizer and reducer. The shape, size, and morphology of resultant AC-AgNPs are examined by optical spectroscopy analysis such as UV for nucleation and coalescence processes of the AC-AgNPs. Through FTIR functional group is determined and through DLS size is defined, it was confirmed that metallic AgNPs were successfully synthesized through the green synthesis route, and these results agreed well with the results obtained in the XRD pattern along with TEM spectroscopy, where the TEM images confirm the formation of sphere-like nanostructures along with SAED analysis. The chemical characterization is performed with XPS; the obtained molecular species in the materials are determined from the energy profile. Antioxidant activity of AC-AgNPs versus DPPH substrate is carried out. Antibacterial activity is well established against Gram-negative and Gram-positive organisms. Cell viability is accomplished, followed by an MTT assay, and a cytotoxicity assay of AC-AgNPs on MCF—7 cell lines is also carried out. Highlights: (1). This study highlights the eco-friendly synthesis of silver nanoparticles from <i>Allium cepa</i> var. <i>Aggregatum</i> Natural Extract. (2). The synthesized AC-AgNPs were characterized by UV-VIS, FT-IR, XRD, TEM, and XPS. (3). The synthesized nanoparticles were well dispersed in nature and the size range of 35 ± 8 nm. (4). The anti-candidal activity of biosynthesized silver nanoparticles was evaluated against the following Gram-Negative organisms: <i>Escherichia coli</i> (<i>E. coli</i>), and the following Gram-positive organisms: <i>Staphylococcus aureus</i> strains. The biosynthesized AC-AgNPs showed enhanced antiseptic features anti both Gram-positive and negative organisms. (5). Besides, the in vitro cytotoxic outcomes of AC-AgNPs were assessed versus MCF-7 cancerous cells, and the reduction in the feasibility of cancer cells was established via MTT assay, which suggests potential biomedical applications.

Ana Correia, Ana Margarida Silva, Manuela M. Moreira et al.

This study aims to validate a new cosmetic ingredient from <i>Salicornia ramosissima</i> S J. Woods through in vitro and ex vivo assays. The halophyte extracts were obtained by subcritical water extraction (SWE) at different temperatures (110, 120, 140, 160 and 180 °C). The antioxidant/radical scavenging activities and the phenolic profile were screened for all extracts. The optimal extract was assessed in keratinocytes and fibroblasts, while permeation assays were performed in Franz cells. The inhibitory activity of hyaluronidase and elastase was also evaluated. The sample extracted at 180 °C presented the highest phenolic content (1739.28 mg/100 g of dry weight (dw)). Despite not being efficient in the sequestration of ABTS^•+, this extract scavenged the DPPH^• (IC₅₀ = 824.57 µg/mL). The scavenging capacity of superoxide (O₂^•−) and hypochlorous acid (HOCl) was also considerable (respectively, IC₅₀ = 158.87 µg/mL and IC₅₀ = 5.80 µg/mL). The cell viability assays confirmed the absence of negative effects on keratinocytes, while the fibroblasts’ viability slightly decreased. The ex vivo permeation of rutin, quercetin and syringic acid after 24 h was, respectively, 11, 20 and 11%. Additionally, the extract showed a good elastase and hyaluronidase inhibitory activity. The results obtained support the <i>S. ramosissima</i> bioactivity as a cosmetic ingredient.

Lambert Baij, Chun Liu, Jesse Buijs et al.

Abstract Evolon $$^\circledR$$ ® CR is increasingly used in paintings conservation for varnish removal from oil paintings. Its key benefits over traditional cotton swabs are limiting solvent exposure and reducing mechanical action on the paint surface. However, this non-woven microfilament textile was not originally engineered for conservation use and little is known about its chemical stability towards organic solvents. Moreover, the physical processes of solvent loading and release by Evolon $$^\circledR$$ ® CR, as well as solvent retention inside paint after cleaning, have not been studied. These three topics were investigated using a multi-analytical approach, aiming for an improved understanding and optimized use of Evolon $$^\circledR$$ ® CR for varnish removal. Our results show that the tissue is generally chemically and physically stable to organic solvents when exposed on timescales that are typical in conservation practice. However, a pre-treatment step of Evolon $$^\circledR$$ ® CR is necessary to avoid the release of unwanted saturated fatty acids into the paint during varnish removal. We show that the primary mechanism of solvent uptake by the fibers is adsorption rather than absorption and that the dominant factor dictating the maximum solvent load is the volume of the voids between the fibers. Finally, solvent induced dynamics after application of solvent-loaded Evolon $$^\circledR$$ ® CR within the paint film was monitored using portable laser speckle imaging on model paints. A method to quantify solvent-retention in real-time was developed and revealed that the presence of varnish on paintings results in lower dynamics of solvents within the paint in comparison to unvarnished paint. Comparing various solvents, it was found that cleaning with acetone resulted in a roughly six-fold increase in dynamics compared to ethanol and isopropanol.

Ingrid Hagarová

The widespread use of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) in a wide variety of industrial as well as medical sectors is indisputable. This leads to a new concern about their presence in various environmental compartments. Since their negative effect and potential toxicity impact have been confirmed, analytical chemists focus on the development of different procedures for their reliable detection, identification, characterization, and quantification, not only in homogenous and simple matrices but also in complex environmental matrices. However, nanoparticles and their ionic species can coexist and their toxicity may differ; therefore, novel analytical approaches are necessary to monitor not only the nanoparticles but also their ionic species. The aim of this article is to bring a review of recent works where magnetic solid-phase extraction (MSPE) procedures in connection with spectrometric methods were used for separation/preconcentration and quantification of (1) silver and gold ions in various environmental samples, (2) AgNPs and AuNPs in real water samples in the presence of various coexisting ions, and (3) both species (it means Ag ions and AgNPs; Au ions and AuNPs) in real water samples. The results presented herein show the great analytical potential of MSPE procedures in connection with spectrometric methods used in these fields and can be helpful in guiding analytical chemists who aim to work on this subject.

Pavel Řezanka, Denisa Macková, Radek Jurok et al.

Mephedrone, a psychoactive compound derived from cathinone, is widely used as a designer drug. The determination of mephedrone and its metabolites is important for understanding its possible use in medicine. In this work, a method of capillary electrophoresis for the chiral separation of mephedrone and its metabolites was developed. Carboxymethylated β-cyclodextrin was selected as the most effective chiral selector from seven tested cyclodextrin derivates. Based on the simplex method, the optimal composition of the background electrolyte was determined: at pH 2.75 and 7.5 mmol·L⁻¹ carboxymethylated β-cyclodextrin the highest total resolution of a mixture of analytes was achieved. For mephedrone and its metabolites, calibration curves were constructed in a calibration range from 0.2 to 5 mmol·L⁻¹; limits of detection, limits of quantification, precision, and repeatability were calculated, and according to Mandel’s fitting test, the linear calibration ranges were determined.

Irina Petroviciu, Iulia Teodorescu, Florin Albu et al.

Abstract Liquid chromatography with UV–Vis and mass spectrometric detection (LC–DAD–MS) was applied to the identification of dyes and biological sources in samples from nineteenth to twentieth century ethnographic textiles from ASTRA National Museum Complex, Sibiu, Transylvania. The objects are part of the Romanian traditional costume and are among the first to be acquired for the museum collections, around 1905. Oral and written information mention such objects as homemade, with nearby materials, while literature mentions a significant number of local vegetal sources as being used for textile dyeing. The analytical protocol developed, based on the combined use of the UV–Vis and mass spectrometric detectors to associate the information and distinguish between major and minor dyes, facilitates a clear attribution of the dyes and biological source/sources used. Other techniques, such as X-ray spectroscopy and FTIR-ATR were successfully used to identify inorganic dyes, which may not be detected by LC–DAD–MS, as was the case of Prussian blue. A large number of biological sources was identified in the studied objects, both local and imported. The local sources identified include dyer’s broom (Genista tinctoria L.), sawwort (Serratula tinctoria L.), young fustic (Cotinus coggygria Scop.), Rhamnus berries, emodin based dyes (Rhamnus, Rheum, Rumex sp.) and woad (Isatis tinctoria L.), in perfect correlation with literature which states that local dyes were still in use in the period under discussion. Carminic acid containing insects (Dactylopius coccus Costa and Porphyrophora sp.) and redwood type Caesalpinia species should be considered a result of trade. Almost all the natural and synthetic dyes detected are frequently mentioned in a collection of recipes published by the Romanian Academy, in 1914. The richness in colours in belts, the use of insect dyes in shirts decoration and the large amount of cotton in shirts are illustrative for the owners’ status. The study provides a better valorisation of the Romanian traditional costume as witness of the rural society at the end of the nineteenth to beginning of the twentieth century and emphasizes the usefulness of chemistry in cultural heritage dedicated applications.

Hai-Long Qian, Cheng-Xiong Yang, Xiu-Ping Yan

This Article contains an error in Fig. 1, in which the structures of ‘(+)-Ac-L-Ta’ and ‘CTp’ are drawn incorrectly. The correct version of Fig. 1 is shown below. The error has not been fixed in the original PDF and HTML versions of the Article.

Showkat Ahmad Bhawani, Sim Siong Fong, Mohamad Nasir Mohamad Ibrahim

The nature of caffeine reveals that it is a bitter white crystalline alkaloid. It is a common ingredient in a variety of drinks (soft and energy drinks) and is also used in combination with various medicines. In order to maintain the optimum level of caffeine, various spectrophotometric methods have been developed. The monitoring of caffeine is very important aspect because of its consumption in higher doses that can lead to various physiological disorders. This paper incorporates various spectrophotometric methods used in the analysis of caffeine in various environmental samples such as pharmaceuticals, soft and energy drinks, tea, and coffee. A range of spectrophotometric methodologies including chemometric techniques and derivatization of spectra have been used to analyse the caffeine.

Fuqiu Wang, Jiao Han, Qing He et al.

Monitoring physical training is important for the health and performance of athletes, and real-time assessment of fatigue is crucial to improve training efficiency. The relationship between key biomarkers and exercise has been reported. The aim of this study was to determine the effects of different levels of training exercises on the urine metabolome. 1H NMR-based metabolomics analysis was performed on urine samples from half-pipe snowboarders, and spectral profiles were subjected to PCA and PLS-DA. Our results show that metabolic profiles varied during different stages of exercises. Lactate, alanine, trimethylamine, malonate, taurine, and glycine levels decreased while TMAO and phenylalanine levels increased in the stage with higher amount and intensity of exercise. Although the amount of exercise was reduced in subsequent stage, no significant variations of metabolic profile were found. Metabolic changes induced by training level were analyzed with related metabolic pathway. Studying metabolome changes can provide a better understanding of the physiology of athletes and could aid in adjusting training.

Gautham Hegde, Nanditha Hegde, Anil Kumar et al.

Objective: Orthodontic diagnosis and treatment planning for growing children must involve growth prediction, especially in the treatment of skeletal problems. Studies have shown that a strong association exists between skeletal maturity and dental calcification stages. The present study was therefore taken up to provide a simple and practical method for assessing skeletal maturity using a dental periapical film and standard dental X-ray machine, to compare the developmental stages of the mandibular canine with that of developmental stages of modified MP3 and to find out if any correlation exists, to determine if the developmental stages of the mandibular canine alone can be used as a reliable indicator for assessment of skeletal maturity. Materials and Methods: A total of 160 periapical radiographs, of the mandibular right canine and the MP3 region was taken and assessed according to the Dermirjian′s stages of dental calcification and the modified MP3 stages. Results and Discussion: The correlation coefficient between MP3 stages and developmental stages of mandibular canine was found to be significant in both male and female groups. When the canine calcification stages were compared with the MP3 stages it was found that with the exception of the D stage of canine calcification the remaining stages showed a very high correlation with the modified MP3 stages. Conclusion: The correlation between the mandibular canine calcification stages, and the MP3 stages was found to be significant. The canine calcification could be used as a sole indicator for assessment of skeletal maturity.