Hasil untuk "Analytical chemistry"

Mohamed A. Farag, Sherif M. Eid, Sherine El-Shamy

Background Milk is an important dietary source for a healthy and balanced diet, owing to its rich content of proteins, fats, sugars, vitamins, and minerals. Due to the importance of milk macronutrient content for consumers’ preferences, a multiplex metabolomics-based approach using Fourier-transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) fingerprinting platforms was employed for the characterization of metabolites in different types of buffalo (BM), cow (CM), goat (GM), and camel (LM) milk. Methods GC-MS and FTIR coupled to chemometric tools (multivariate data analysis) were employed for the discriminative qualitative and quantitative analysis of BM, LM, CM, and GM milk, targeting their primary metabolites. A side-by-side comparative assessment of the performance of both the FTIR and GC-MS methods was implemented in the light of green analytical chemistry principle (GAC) and white analytical chemistry principles (WAC) using the 12 green analytical chemistry principles (12 GAC), analytical greenness metric approach (AGREE), national environmental methods index (NEMI), eco-scale assessment (ESA) and complementary green analytical procedure index (ComplexGAPI), and the red green blue (RGB) 12 algorithms. Results The milk types were qualitatively identified by visual inspection of their characteristic FTIR spectra as a fingerprint for each milk type. Quantitatively, GC-MS revealed the presence of 87 peaks belonging to alcohols, amino acids/nitrogenous compounds, fatty acids, organic acids, sterols, sugars, and vitamins. Sugars, mainly lactose, appeared as the major component in all milk types. The highest lactose content was detected in CM 1.07-fold higher than LM making LM a potential alternative for lactose intolerance. Both BM and CM were found to contain the highest organic acid content 5.2-fold higher than that in LM, accounting for their acidity (sourness), while the lowest level was found in LM. On the other hand, LM had the highest vitamins content compared to other milks. Lastly, FTIR outperformed GC-MS in terms of greenness and whiteness, suggesting its utilization as an alternative to traditional chromatographic techniques such as GC-MS.

Stelios Loukopoulos, Elias Sakellis, Polychronis Tsipas et al.

Titanium dioxide (TiO₂) is a benchmark photocatalyst for environmental applications, but its limited visible-light activity due to a wide band gap and fast charge recombination restricts its practical efficiency. This study presents the development of heterostructured Ag (Au)/MoS₂-TiO₂ inverse opal (IO) films that synergistically integrate photonic, plasmonic, and semiconducting functionalities to overcome these limitations. The materials were synthesized via a one-step evaporation-induced co-assembly approach, embedding MoS₂ nanosheets and plasmonic nanoparticles (Ag or Au) within a nanocrystalline TiO₂ photonic framework. The inverse opal architecture enhances light harvesting through slow-photon effects, while MoS₂ and plasmonic nanoparticles improve visible-light absorption and charge separation. By tuning the template sphere size, the photonic band gap was aligned with the TiO₂-MoS₂ absorption edge and the localized surface plasmon resonance of Ag, enabling optimal spectral overlap. The corresponding Ag/MoS₂-TiO₂ photonic films exhibited superior photocatalytic and photoelectrocatalytic degradation of tetracycline under visible light. Ultraviolet photoelectron spectroscopy and Mott–Schottky analysis confirmed favorable band alignment and Fermi level shifts that facilitate interfacial charge transfer. These results highlight the potential of integrated photonic–plasmonic-semiconductor architectures for efficient solar-driven water treatment.

Safa M. Megahed, Mona M. Amer

This study introduces three innovative green spectroscopic methods, each mathematically manipulated, for the simultaneous quantification of ciprofloxacin hydrochloride (CIP) and tinidazole (TIN) in their raw form and within a combined tablet product. Utilizing ratio spectra manipulation, CIP ratio spectra were derived by employing TIN at 8µg/mL as the divisor, and conversely, TIN ratio spectra were obtained using CIP at 4µg/mL as the divisor. The ratio difference spectrophotometric approach identified a correlation between the amplitude differences in the ratio spectra at ∆P272nm-237nm, ∆P331nm-273nm and the concentrations of CIP and TIN, respectively. Additionally, the first derivative of the ratio spectra was computed (1DD), revealing that the peak amplitudes at 283 nm for CIP and 294.2 nm for TIN were directly related to their respective concentrations. The Area Under Curve (AUC) method involved integrating the area within zero order absorption spectra over selected wavelength intervals, specifically 268–288 nm for CIP and 300–330 nm for TIN. The proposed methods demonstrated linearity within the concentration ranges of 1–16 µg/mL for CIP and 2–20µg/mL for TIN. The proposed spectrophotometric methods were validated according to ICH guidelines and effectively applied to the simultaneous analysis of CIP and TIN in Tinifloxacin® tablets. A statistical comparison with the reported HPLC method was conducted using F and t-tests. The greenness of the methods was also assessed and verified using the Eco-scale, complex GAPI, and AGREE assessment tools.

Maram Attia, Randa A. Abdel Salam, Ghada M. Hadad et al.

Abstract This study has been proposed new, sensitive, straightforward, and validated spectrophotometric and spectrofluorimetric methods for estimating of amprolium (AMP) and triclabendazole (TCB) in laboratory prepared pharmaceutical wastewater. Both methods were based on the reaction of AMP and TCB with Eosin-Y in acidic medium, targeting the tertiary amino groups of the concerned analytes, generating an orange-red ion pair complexes. The resulting products were measured by spectrophotometric (Method I) and spectrofluorimetric (Method II) tools. Regarding method I, the absorbance was measured at 547 nm with a lower detection limit of 45 ng/mL and quantitation limit of 136 ng/mL for AMP with corresponding values of 191 ng/mL and 579 ng/mL for TCB. The proposed method exhibited a linear pattern over the concentration range of 100–5000 and 1500–10,000 ng/mL for amprolium and triclabendazole, respectively. Meanwhile in method II, the produced complex was measured at λem 552 nm for AMP or 555 nm for TCB after excitation at λex 470 nm with a lower detection limit of 142 ng/mL and quantitation limit of 429 ng/mL for AMP with corresponding values of 67 ng/mL and 202 ng/mL for TCB. The proposed method exhibited a linear pattern over the concentration range with linearity ranges of 500–2000 and 100–1500 ng/mL for amprolium and triclabendazole, respectively. The International Conference on Harmonization (ICH) requirements for linearity, accuracy, precision, specificity, and robustness were followed in the comprehensive validation of the proposed methods, allowing its application successfully to determine the studied analytes in wastewater samples.

Niyaz Yagafarov, Yujia Liu, Naoto Adachi et al.

A highly efficient method was successfully applied for the first time to the functionalization of well-defined chlorinated silsesquioxanes with a range of thiols. Thiolation was rapid (2 to 4 h), quantitative, with complete conversion of the reactants and full chemoselectivity, and proceeded under mild conditions (room temperature). This “click chemistry” approach facilitated the preparation of nine novel compounds, with good to excellent isolated yields (64–92%). The structures and purities of these compounds were comprehensively confirmed using multiple analytical techniques, including ¹H, ¹³C, and ²⁹Si NMR spectroscopy, elemental analysis, and mass spectrometry. Thermogravimetric analysis (TGA) further demonstrated that the synthesized compounds exhibited excellent thermal stability. These characteristics suggest their potential for applications in various domains of science, technology, and medicine.

Ziheng Liang, Meng Ning, Chenqing Li et al.

Abstract Stromatolites archive critical information on Precambrian marine environments, but their geochemical signals are often obscured using complex diagenetic processes. Tonian stromatolites from the Weiji Formation, North China, show selective dolomitization in dark stromatolitic laminae, forming zoned dolomites. The zoned dolomite crystals with well‐preserved growth zoning record the evolution of diagenetic fluid, yet their genesis remains controversial. To constrain selective dolomitization processes and zoned dolomite formation in stromatolites, and further assess their reliability as paleoceanographic proxies, we use LA‐ICP‐TOF‐MS elemental mapping to reveal crystallization mechanisms and early diagenetic controls in stromatolitic carbonates. Results show distinct geochemical distribution patterns between dark and light stromatolitic laminae, reflecting complex microbial‐induced diagenetic reactions during early diagenesis. Fe is preferentially concentrated in dark stromatolitic layers, while Mn anomalously accumulates in light layers (with Mn/Fe ratio up to ∼2). Meanwhile, high terrigenous‐indicative elemental contents (Al‐Si‐K) are observed in dark laminae and the adjacent clay‐rich matrix. The anomalous Fe‐Mn distribution is attributed to the redox oscillations and terrigenous pulses (ROTP) model. Selective dolomitization proceeds through an Ion‐Exchange Motor mechanism during penecontemporaneous to early diagenesis, where Mg2+ derived from seawater undergoes dehydration via clay mineral adsorption and/or microbial mediation. Within ferroan zoned dolomite, elemental zoning exhibits alternating Mn‐enriched bands and Fe‐rich zones, indicating redox‐controlled diagenesis with preferential Mn(IV) reduction prior to Fe(II) mobilization. While Precambrian stromatolites remain valuable proxies for paleo‐ocean chemistry, our results emphasize the critical need for in situ analytical approaches to distinguish primary signals from diagenetic overprints in Precambrian carbonate systems.

Sergio Nogales-Delgado, Agustina Guiberteau Cabanillas, Juan Pedro Moro et al.

The use of alternatives for petroleum-based products is becoming more and more important, especially considering the new and constantly changing geopolitical context, where excessive energy dependence is not desirable. Thus, biodiesel could play an important role in contributing to the implementation of biorefineries, which represent desirable goals in terms of sustainability, green chemistry and the circular economy. However, one challenge related to biodiesel based on vegetable oils is its low oxidative stability, which can alter the properties of these products during storage. To avoid this problem, interesting antioxidants, such as propyl gallate (PG), could be added to biodiesel to allow it to keep its main properties during oxidation. Additionally, monitoring PG content during oxidation is interesting, and the use of voltammetry could be suitable for this purpose. The aim of this work was to assess the effectiveness of PG during cardoon biodiesel oxidation, while monitoring the process through cyclic voltammetry (CV). As a result, it was proven that PG was highly effective, increasing the length of oxidative stability to more than 10 h at low concentrations (600 mg·L⁻¹) and retaining its main properties (viscosity and acidity) during oxidation. Regarding CV, this technique was successfully optimized to determine PG concentration in cardoon biodiesel during oxidation.

Ainoa Morillas-España, Ruperto Bermejo, Roberto Abdala-Díaz et al.

In this study, a biorefinery based on <i>Oscillatoria</i> sp. is developed to produce high-value compounds such as C-phycocyanin, used in food colourant applications, and biostimulants, used in agriculture-related applications. First, the <i>Oscillatoria</i> biomass production was optimized at a pilot scale in an open raceway reactor, with biomass productivities equivalent to 52 t/ha·year being achieved using regular fertilizers as the nutrient source. The biomass produced contained 0.5% C-phycocyanins, 95% of which were obtained after freeze–thawing and extraction at pH 6.5 and ionic strength (FI) 100 mM, with a purity ratio of 0.71 achieved in the final extract. This purity ratio allows for use of the extract directly as a food colourant. Then, the extract’s colourant capacity on different beverages was evaluated. The results confirm that C-phycocyanin concentrations ranging from 22 to 106 mg/L produce colours similar to commercial products, thus avoiding the need for synthetic colourants. The colour remained stable for up to 12 days. Moreover, the safety of the extracted C-phycocyanin was confirmed through toxicity tests. The waste biomass was evaluated for use as a biostimulant, with the results confirming a relevant auxin-like positive effect. Finally, an economic analysis was conducted to evaluate different scenarios. The results confirm that the production of both C-phycocyanin and biostimulants is the best scenario from an economic standpoint. Therefore, the developed biomass processing scheme provides an opportunity to expand the range of commercial applications for microalgae-related processes.

Wen-Xin Liu, Shuang Song, Ming-Li Ye et al.

Sample pretreatment in analytical chemistry is critical, and the selection of materials for sample pretreatment is a key factor for high enrichment ability, good practicality, and satisfactory recoveries. In this review, the recent progress of the sample pretreatment methods based on various nanomaterials (i.e., carbon nanomaterials, porous nanomaterials, and magnetic nanomaterials) with excellent adsorption efficiency, selectivity, and reproducibility, as well as their applications, are presented. Due to the unique nanoscale physical–chemical properties, magnetic nanomaterials have been used for the extraction of target analytes by easy-to-handle magnetic separation under a magnetic field, which can avoid cumbersome centrifugation and filtration steps. This review also highlights the preparation process and reaction mechanism of nanomaterials used in the sample pretreatment methods, which have been applied for the extraction organophosphorus pesticides, fluoroquinolone antibiotics, phenoxy carboxylic acids, tetracycline antibiotics, hazardous metal ions, and rosmarinic acid. In addition, the remaining challenges and future directions for nanomaterials used as sorbents in the sample pretreatment are discussed.

Marie Denat, Dolores Pérez, José María Heras et al.

This study aimed at determining the changes induced by two S. cerevisiae strains, (IONYS wf™ and Lalvin ICV D254™) on the sensory and chemical aroma profiles of Tempranillo wine, after fermentation and after ageing. The 64 aroma molecules determined were grouped attending to sensory and chemical similarity into 17 aroma vectors. Sensory studies included a sorting task and a descriptive analysis by flash profile with a trained panel. Results revealed that, even if ageing is the dominant factor, the strain of yeast introduces significant and consistent differences, both in sensory and aroma vector profiles (11 out of 17 affected). Wines made with D254 contained higher levels of ethyl esters, acetic acid, cinnamates and ethyl acetate and lower levels of linear fatty acids, β-damascenone, acetaldehyde, higher alcohols and lactones than those made with IONYS. The first profile was related to black and fresh fruit notes, while the second to white and compote fruits.

Jie Peng, Jing Xie, Silin Shi et al.

Inula cappa (Buch.-Ham. ex D. Don) DC has been used in traditional Chinese medicine to treat malaria, dysentery, and hepatitis. Previous studies have shown that chlorogenic acid is the effective ingredient of plants in this family. And the research of the chlorogenic acid in Inula cappa will help to further improve the effective resource utilization rate of this plant. Therefore, it is necessary to establish an accurate method to characterize the chlorogenic acid components in Inula cappa. In this study, a simple, fast, and sensitive UHPLC-Q-Exactive Orbitrap mass spectrometry method was established, which can simultaneously analyze known and unknown ingredients in a short time (within 30 minutes) in Inula cappa. According to the diagnosis fragmentation ions, retention time, and bibliography, 68 chlorogenic acid derivatives were identified in Inula cappa. The results of this experiment lay the foundation for the active substances and quality control of Inula cappa and provide a theoretical basis for whether Inula cappa can be an alternative to the endangered wild medicinal materials of the same family.

Effie Edsor, G Agnes Golda Priyadarshini, P Gowri Shankar et al.

Aim: The aim of this study was to evaluate the efficacy of preoperative prophylactic antibiotics of 2 g of oral amoxicillin on bacteremia following extraction of teeth with periodontal and periapical pathology. Materials and Methods: This study was carried out on 160 patients. The patients were divided into four groups of forty patients each: two antibiotic groups, with periodontal and periapical pathology, receiving 2 g of oral amoxicillin preoperatively and two control groups, with periodontal and periapical pathology, receiving no amoxicillin preoperatively. Blood samples were collected before the start of the procedure, intraoperatively, and immediately following extraction of teeth. The collected blood samples were cultured and studied for bacterial growth. Results: In the control group patients with periodontal pathology, 17 out of 40 blood samples showed growth of Streptococcus viridans along with Staphylococcus epidermidis. In the control group patients with periapical pathology, 14 out of 40 blood samples showed growth of S. viridans and Staphylococcus aureus. No growth was observed in both the groups on prophylactic antibiotics with 2 g of oral amoxicillin. Conclusion: Bacteremia was found in 40% of the control group patients, while there was no bacteremia present in patients with preoperative administration of 2 g of oral amoxicillin.

Anais Izquierdo-Llopart, Javier Saurina

This paper is focused on the assessment of a multi-sensor approach to improve the overall characterization of sparkling wines (cava wines). Multi-sensor, low-level data fusion can provide more comprehensive and more accurate vision of results compared with the study of simpler data sets from individual techniques. Data from different instrumental platforms were combined in an enriched matrix, integrating information from spectroscopic (UV/Vis and FTIR), chromatographic, and other techniques. Sparkling wines belonging to different classes, which differed in the grape varieties, coupages, and wine-making processes, were analyzed to determine organic acids (e.g., tartaric, lactic, malic, and acetic acids), pH, total acidity, polyphenols, total antioxidant capacity, ethanol, or reducing sugars. The resulting compositional values were treated chemometrically for a more efficient recovery of the underlaying information. In this regard, exploratory methods such as principal component analysis showed that phenolic compounds were dependent on varietal and blending issues while organic acids were more affected by fermentation features. The analysis of the multi-sensor data set provided a more comprehensive description of cavas according to grape classes, blends, and vinification processes. Hierarchical Cluster Analysis (HCA) allowed specific groups of samples to be distinguished, featuring malolactic fermentation and the chardonnay and red grape classes. Partial Least Squares-Discriminant Analysis (PLS-DA) also classified samples according to the type of grape varieties and fermentations. Bar charts and complementary statistic test were performed to better define the differences among the studied samples based on the most significant markers of each cava wine type. As a conclusion, catechin, gallic, gentisic, caftaric, caffeic, malic, and lactic acids were the most remarkable descriptors that contributed to their discrimination based on varietal, blending, and oenological factors.

Bhuvaneswari Mani, Muralimani Mani, Selvakumar Ramar et al.

Aim: The aim of the current survey was conducted to assess the knowledge, attitude, and awareness regarding orthognathic surgery among orthodontic patients. Materials and Methods: This is cross-sectional web-based questionnaire survey conducted among orthodontic patients in Tamil Nadu. The self-administered questions related to awareness of orthognathic surgery were collected from 500 subjects. The statistical analysis was done using the Statistical Package for the Social Sciences (V 22.0). The frequency distribution was computed. Results: This survey revealed that 466 (93.2%) respondents had awareness about the role of orthognathic surgery. 332 (66.4%) had given the correct responses related to differentiating skeletal and dental malocclusion, 454 (90.6%) had the awareness of risk factors associated with orthognathic surgery and 40 (7.0%) were experienced regarding the procedure. Conclusion: The result of the current study showed that it clearly implies that the population was aware of orthognathic surgery as a treatment modality for correcting skeletal deformities.