Peak Assignments Research Articles

Utilizing surface-enhanced Raman spectroscopy for the adjunctive diagnosis of osteoporosis

Osteoporosis (OP) is a chronic disease characterized by diminished bone mass and structural deterioration, ultimately leading to compromised bone strength and an increased risk of fractures. Diagnosis primarily relies on medical imaging findings and clinical symptoms. This study aims to explore an adjunctive diagnostic technique for OP based on surface-enhanced Raman scattering (SERS). Serum SERS spectra from the normal, low bone density, and osteoporosis groups were analyzed to discern OP-related expression profiles. This study utilized partial least squares (PLS) and support vector machine (SVM) algorithms to establish an OP diagnostic model. The combination of Raman peak assignments and spectral difference analysis reflected biochemical changes associated with OP, including amino acids, carbohydrates, and collagen. Using the PLS-SVM approach, sensitivity, specificity, and accuracy for screening OP were determined to be 77.78%, 100%, and 88.24%, respectively. This study demonstrates the substantial potential of SERS as an adjunctive diagnostic technology for OP.

Can X-ray Photoelectron Spectroscopy Characterize Photocatalytically Relevant Defects in Graphitic Carbon Nitride? Re-examining Peak Assignment and Quantification Using Model Compounds

Can X-ray Photoelectron Spectroscopy Characterize Photocatalytically Relevant Defects in Graphitic Carbon Nitride? Re-examining Peak Assignment and Quantification Using Model Compounds

Schiff base substituted non-peripheral symmetrical cupper, cobalt, and manganese phthalocyanines: Synthesis, design, electrochemistry, and spectroelectrochemistry

Novel CoII (nANTHCoPc), CuII (nANTHCuPc), and MnIIICl (nANTH-MnClPc) phthalocyanines were obtained by substituting the 3-(4-((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-ylimino)methyl)phenoxy) Schiff base compound (nANTHOH) obtained by the acid-catalyzed condensation reaction of 4-aminoantipyrine and 4-hydroxybenzaldehyde at non-peripheral positions. By using various spectroscopic techniques, (NMR, MALDI-TOF, FT-IR, and UV–Vis), the structures of green-colored phthalocyanine compounds and precursor phthalonitrile compounds were identified. The electrochemical responses of cobalt (II) (nANTHCoPc), cupper (II) (nANTHCuPc), and manganese (III) (nANTH-MnClPc) phthalocyanines were determined, and their redox responses were analyzed based on the different metal centers. The results indicated that using redox-active Co2+ and Mn3+ cations instead of Cu2+enhanced the redox richness of the complexes due to the observation of extra metal-based electron transfer reactions in addition to the Pc-based ones. In-situ spectroelectrochemical analyses of the complexes were used to support the peak assignments of the redox processes and the spectrum and color of the electrogenerated species during the redox reactions. Supported these redox mechanisms. Multi-electron transfer processes and distinct color changes during these processes indicate the possible usage of these complexes in various electrochemical and opto-electrochemical processes. Metal-based electron transfer reactions illustrated different spectral changes than those of the Pc-based ones, and these spectral changes significantly differed the color of the anionic and cationic species.

How Many Glucan Chains Form Plant Cellulose Microfibrils? A Mini Review.

Assessing the number of glucan chains in cellulose microfibrils (CMFs) is crucial for understanding their structure-property relationships and interactions within plant cell walls. This Review examines the conclusions and limitations of the major experimental techniques that have provided insights into this question. Small-angle X-ray and neutron scattering data predominantly support an 18-chain model, although analysis is complicated by factors such as fibril coalescence and matrix polysaccharide associations. Solid-state nuclear magnetic resonance (NMR) spectroscopy allows the estimation of the CMF width from the ratio of interior to surface glucose residues. However, there is uncertainty in the assignment of NMR spectral peaks to surface or interior chains. Freeze-fracture transmission electron microscopy images show cellulose synthase complexes to be "rosettes" of six lobes each consistent with a trimer of cellulose synthase enzymes, consistent with the synthesis of 18 parallel glucan chains in the CMF. Nevertheless, the number of chains in CMFs remains to be conclusively demonstrated.

Fourier-Transform Infrared Spectral Library of MXenes.

Fourier-transform infrared (FTIR) spectroscopy characterization is a powerful and easy-to-use technique frequently employed for the characterization and fingerprinting of materials. Although MXenes are a large and fastest growing family of inorganic 2D materials, the lack of systematic FTIR spectroscopy studies hinders its application to MXenes and often leads to misinterpretation of the results. In this study, we report experimental and calculated FTIR spectra of 12 most typical carbide and carbonitride MXenes with different compositions (5 transition metals) and all four basic structures, including Ti2CT x , Nb2CT x , Mo2CT x , V2CT x , Ti3C2T x , Ti3CNT x , Mo2TiC2T x , Mo2Ti2C3T x , Nb4C3T x , V4C3T x , Ta4C3T x , and Mo4VC4T x . The measurements were performed on delaminated MXene flakes incorporated in KBr pellets in the 4000-400 cm-1 range. We provide detailed instructions for sample preparation, data collection, and interpretation of FTIR spectra of MXenes. Background correction and spectra smoothing are applied to obtain clear FTIR peaks corresponding to bond vibrations in MXenes. Density functional theory calculations were used for the precise assignment of all characteristic FTIR peaks and an in-depth analysis of the vibration modes. This work aims to provide the 2D material community with the FTIR spectroscopy technique as a reliable method for identifying and analyzing MXenes.

LAMAIS: A library-aided approach for efficient 1D 1H NMR qualitative analysis in plant metabolomics

BackgroundOne-dimensional proton nuclear magnetic resonance (1D 1H NMR) spectroscopy is a non-destructive, non-targeted analytical technique providing both qualitative and quantitative insights, particularly beneficial for mixture analysis. However, the qualitative analysis of 1D 1H NMR spectra for mixture samples is laborious and time-consuming, involving extensive database searches and verification experiments like spiking. This process heavily relies on the analyst's expertise, leading to efficiency discrepancies. There is a pressing need for a reliable method to streamline operations and enhance the efficiency of qualitative analysis in complex mixtures. ResultsWe introduce a library-aided method for spectral profiling, named LAMAIS. This method achieves compound identification through similarity assessment between samples and template data, allowing rapid, automatic compound identification and full-spectrum peak assignment without the need for fitting. LAMAIS correctly identifies over 90 % of components in synthetic mixtures and more than 75 % in experimental mixtures, surpassing other representative methods with a higher F2 score. Our reference library, which currently includes 71 compounds, is tailored to capture the commonality of primary metabolites across diverse plant species. The analysis of real-world samples yielded encouraging results, underscoring LAMAIS's versatility as an auxiliary tool suitable for a variety of botanical sources. For analyst convenience, interactive graphics are utilized as the output format. SignificanceLAMAIS excels, demonstrating competitiveness and reliability. The approach minimizes repetitive tasks and sample wastage, improving the efficiency of 1D 1H NMR qualitative analysis. Constructing a reference library effectively preserves knowledge, mitigates reliance on human experience, and addresses gaps in the analysis of plant source samples.

Quantifying Covalency and Environmental Effects in RASSCF-Simulated O K-Edge XANES of Uranyl.

A RASSCF approach to simulate the O K-edge XANES spectra of uranyl is employed, utilizing three models that progressively improve the representation of the local crystal environment. Simulations successfully reproduce the observed three-peak profile of the experimental spectrum and confirm peak assignments made by Denning. The [UO2Cl4]2- model offers the best agreement with experiment, with peak positions (to within 1 eV) and relative peak separations accurately reproduced. Establishing a direct link between a specific electronic transition and peak intensity is complicated, as a large number of possible transitions can contribute to the overall peak profile. Furthermore, a relationship between oxygen character in the antibonding orbital and the strength of the transition breaks down when using a variety of orbital composition approaches at larger excitation energy. Covalency analysis of the U-O bond in both the ground- and excited-state reveals a dependence on the crystal environment. Orbital composition analysis reveals an underestimation of the uranium contribution to ground-state bonding orbitals when probing O K-edge core-excited states, regardless of the uranyl model employed. However, improving the environmental model provides core-excited state electronic structures that are better representative of that of the ground-state, validating their use in the determination of covalency and bonding.

Photochemical Synthesis and Characterization of a Uranyl Peroxide Triethylamine N‐OxideDimer

A µ‐peroxido‐bis[di‐triethylamine N‐oxide‐dichloro‐dioxouranium] complex with the formula [(UO2)2O2(ON(CH2CH3)3)4Cl2] (complex 1) was synthesized photochemically from a reaction containing uranyl chloride, triethylamine, and H2O2. The photochemical breakdown of H2O2 yielded •OH radicals that reacted with triethylamine to form triethylamine N‐oxide (TEAO) in situ, which subsequently coordinated to UO22+ cations in a monodentate fashion via the N‐oxide functional groups. Structure determination using single crystal X‐ray diffraction revealed that TEAO ligands also formed intermolecular and intramolecular hydrogen bonds with UO22+ and peroxide moieties, and the intermolecular H‐bonding interactions displayed a temperature dependence with Oyl ‐ ‐ H – C and Oper ‐ ‐ H – C distances shortening at 100(2) K by ca. 0.1 Å. Raman spectroscopy data were collected on single crystals of 1 and peak fitting of these results allowed for assignments of peaks including C‐N stretches for TEAO ligands bound to UO22+ cations at 696.8 cm‐1, 717.8 cm‐1, and 776.5 cm‐1, which are redshifted by approximately 30 cm‐1 when compared to free triethylamine. UO22+ν1 and O22‐ν1 stretches, U‐Oper stretches, and notably, U‐Cl stretches were all identified as well, with U‐Cl modes at 198.9 cm‐1 and 212.1 cm‐1 substantially redshifted compared to the uranyl chloride starting material.

Enhanced Declustering Enables Native Top-Down Analysis of Membrane Protein Complexes using Ion-Mobility Time-Aligned Fragmentation.

Native mass spectrometry (MS) is proving to be a disruptive technique for studying the interactions of proteins, necessary for understanding the functional roles of these biomolecules. Recent research is expanding the application of native MS towards membrane proteins directly from isolated membrane preparations or from purified detergent micelles. The former results in complex spectra comprising several heterogeneous protein complexes; the latter enables therapeutic protein targets to be screened against multiplexed preparations of compound libraries. In both cases, the resulting spectra are increasingly complex to assign/interpret, and the key to these new directions of native MS research is the ability to perform native top-down analysis, which allows unambiguous peak assignment. To achieve this, detergent removal is necessary prior to MS analyzers, which allow selection of specific m/z values, representing the parent ion for downstream activation. Here, we describe a novel, enhanced declustering (ED) device installed into the first pumping region of a cyclic IMS-enabled mass spectrometry platform. The device enables declustering of ions prior to the quadrupole by imparting collisional activation through an oscillating electric field applied between two parallel plates. The positioning of the device enables liberation of membrane protein ions from detergent micelles. Quadrupole selection can now be utilized to isolate protein-ligand complexes, and downstream collision cells enable the dissociation and identification of binding partners. We demonstrate that ion mobility (IM) significantly aids in the assignment of top-down spectra, aligning fragments to their corresponding parent ions by means of IM drift time. Using this approach, we were able to confidently assign and identify a novel hit compound against PfMATE, obtained from multiplexed ligand libraries.

Method for Surface Characterization Using Solid-State Nuclear Magnetic Resonance Spectroscopy Demonstrated on Nanocrystalline ZnO:Al.

Nanoscale zinc-oxide doped with aluminum ZnO:Al is studied by different techniques targeting surface changes induced by the conditions at which ZnO:Al is used as support material in the catalysis of methanol. While it is well established that a variety of 1H and 27Al resonances can be found by solid-state NMR for this material, it was not clear yet which signals are related to species located close to the surface of the material and which to species located in the bulk. To this end, a method is suggested that makes use of a paramagnetically impregnated material to suppress NMR signals close to the particle surface in the blind sphere around the paramagnetic metal atoms. It is shown that it is important to use conditions that guarantee a stable reference system relative to which it can be established whether the coating procedure is conserving the original structure or not. This method, called paramagnetically assisted surface peak assignment, helped to assign the 1H and 27Al NMR peaks to the bulk and the surface layer defined by the blind sphere of the paramagnetic atoms. The assignment results are further corroborated by the results from heteronuclear 27Al{1H} dipolar dephasing experiments, which indicate that the hydrogen atoms are preferentially located in the surface layer and not in the particle core.

Structural and retrospective bio-dosimetric study of gamma-irradiated human fingernails

Emergency involving ionising radiation is a rare occurrence, yet it can leave severe damage if a population is not equipped with necessary preparation. In such a situation, there is no viable way to know how much radiation dose is received by human beings. However, in present time only personnel of rescue teams have accessed to active dosimetry such as a personal dosimeter. Preliminary study has been made of human fingernails, a model in examining the potential of nails of the human fingers in retrospective and emergency bio-dosimetry applications, also offering effective atomic number near to that of soft human tissues at 7.4. Human fingernails were sampled from different age groups and exposed to 60Co gamma rays, delivering doses from 2 to 10 Gy. Structural alterations were observed, use being made of Raman spectroscopy and the crystalline structure of alpha keratin is studied using X-ray diffraction (XRD), while the elemental composition of the sample is determined by energy dispersive x-ray (EDX) analysis. Raman shows the ‘fingerprint’ of nail sample is identical in which the peak assignment concerns on the disulfide (S–S) bond and the alpha helix content at the amide 1 region. These are the few regions which displayed major Raman shift and intensity difference from a normal nail sample and an effected nail which have the same analogy as a non-irradiated nail and an irradiated nail sample. XRD shows the molecular structure of hard α-keratin from different age groups of fingernails, examining crystallite diameters (D) and crystallinity index (C.I.). The α-keratin characteristic bands can be seen in all groups of fingernails, albeit they become much weaker and shift to smaller angles with higher gamma doses. The results obtained by Raman spectroscopy and X-ray diffraction are complementary and suggest that the α-helix structure of keratin is partially destroyed by the presence of radiation.

ZIF-8 Vibrational Spectra: Peak Assignments and Defect Signals.

Zeolitic imidazolate framework (ZIF-8) is a promising material for gas separation applications. It also serves as a prototype for numerous ZIFs, including amorphous ones, with a broader range of possible applications, including sensors, catalysis, and lithography. It consists of zinc coordinated with 2-methylimidazolate (2mIm) and has been synthesized with methods ranging from liquid-phase to solvent-free synthesis, which aim to control its crystal size and shape, film thickness and microstructure, and incorporation into nanocomposites. Depending on the synthesis method and postsynthesis treatments, ZIF-8 materials may deviate from the nominal defect-free ZIF-8 crystal structure due to defects like missing 2mIm, missing zinc, and physically adsorbed 2mIm trapped in the ZIF-8 pores, which may alter its performance and stability. Infrared (IR) spectroscopy has been used to assess the presence of defects in ZIF-8 and related materials. However, conflicting interpretations by various authors persist in the literature. Here, we systematically investigate ZIF-8 vibrational spectra by combining experimental IR spectroscopy and first-principles molecular dynamics simulations, focusing on assigning peaks and elucidating the spectroscopic signals of putative defects present in the ZIF-8 material. We attempt to resolve conflicting assignments from the literature and to provide a comprehensive understanding of the vibrational spectra of ZIF-8 and its defect-induced variations, aiming toward more precise quality control and design of ZIF-8-based materials for emerging applications.

Vinyl and methyl-ester groups in the insoluble polymer drug patiromer identified and quantified by solid-state NMR

Patiromer (Veltassa®) is a crosslinked, insoluble co-polymer drug used as a nonabsorbent potassium binder, approved for treatment of hyperkalemia. Quantitative solid-state 13C nuclear magnetic resonance (NMR) analysis with comprehensive peak assignment, component quantification, and calculation of mole and weight fractions of monomer units was performed on three doses of patiromer. The workflow is documented in detail. Spectrally edited solid-state 13C NMR spectra of patiromer show =CHn peaks of matching intensity at 116 and 141 ppm, characteristic of -CH=CH2 vinyl groups. Similar spectral features can be observed in earlier studies but were previously ignored. In this study, the vinyl signals are well-resolved in a 2-s direct polarization (DP) spectrum without and with dipolar dephasing, which confirms that these sp2-hybridized carbons are bonded to hydrogen and partially mobile, consistent with vinyl side groups from incompletely reacted divinyl crosslinkers. The vinyl groups account for 1.6% of all carbon, 3% of the monomer units, and nearly 1/3 of the crosslinkers. Furthermore, an unexpected OCH3 moiety accounting for ∼1.2% of all carbons was identified by spectral editing; its chemical shift of 54 ppm is more consistent with a methyl ester than with a methyl ether. It can originate from incomplete hydrolysis of ∼6% of methyl-2-fluoroacrylate, the main monomer of patiromer. Characteristic cross peaks in two-dimensional 1H–13C heteronuclear correlation NMR confirm the presence of the vinyl and OCH3 groups. Trace amounts of xanthan gum are also detected. The quantitative 13C NMR spectrum of patiromer has been matched in a simulation using a model with five monomer units.

Relaxation Editing in NMR Using a New Two-Dimensional Long-Lived Coherence Method for Mixture Analysis.

The exploration of metabolomics and targeted segments of proteins stands as a pivotal facet of Nuclear Magnetic Resonance (NMR) analysis, furnishing valuable insights into molecular architectures and potential therapeutic applications. The issue of spectral congestion frequently presents challenges in ascribing distinct peaks within the confines of both one-dimensional (1D) and two-dimensional (2D) NMR spectra. Numerous strategies have been proposed to resolve specific resonances in NMR spectra differentially. Among these approaches, relaxation editing emerges as a viable solution. In the realm of relaxation phenomena within NMR, Long-Lived States (LLS) and Long-Lived Coherences (LLC) manifest as promising phenomena, offering enhanced relaxation lifetimes in comparison to the traditional longitudinal (T1) and transverse (T2) relaxation times for coupled nuclear spins. Notably, LLC presents a pathway to attenuate uncoupled high-intensity peaks, effectively diminishing their impact. The foundation of this technique rests upon the premise that the relaxation lifetime in the rotating frame (T1ρ) remains smaller than TLLC. In pursuit of refining spectral assignments within complex mixtures, we introduce a new pulse sequence tailored for LLC Total Correlation Spectroscopy (LLC-TOCSY). This demonstrates efficacy in extracting LLC signals within configurations involving multiple coupled spins, thereby decluttering the spectrum and enhancing the accuracy of peak assignments. To validate the effectiveness of this method, a collection of samples was subjected to scrutiny, yielding compelling results.

Screening Disinfection Byproducts in Arid-Coastal Wastewater: A Workflow Using GC×GC-TOFMS, Passive Sampling, and NMF Deconvolution Algorithm.

Disinfection during tertiary municipal wastewater treatment is a necessary step to control the spread of pathogens; unfortunately, it also gives rise to numerous disinfection byproducts (DBPs), only a few of which are regulated because of the analytical challenges associated with the vast number of potential DBPs. This study utilized polydimethylsiloxane (PDMS) passive samplers, comprehensive two-dimensional gas chromatography (GC×GC) coupled with time-of-flight mass spectrometry (TOFMS), and non-negative matrix factorization (NMF) spectral deconvolution for suspect screening of DBPs in treated wastewater. PDMS samplers were deployed upstream and downstream of the chlorination unit in a municipal wastewater treatment plant located in Abu Dhabi, and their extracts were analyzed using GC×GC-TOFMS. A workflow incorporating a multi-tiered, eight-filter screening process was developed, which successfully enabled the reliable isolation of 22 candidate DBPs from thousands of peaks. The NMF spectral deconvolution improved the match factor score of unknown mass spectra to the reference mass spectra available in the NIST library by 17% and facilitated the identification of seven additional DBPs. The close match of the first-dimension retention index data and the GC×GC elution patterns of DBPs, both predicted using the Abraham solvation model, with their respective experimental counterparts-with the measured data available in the NIST WebBook and the GC×GC elution patterns being those observed for the candidate peaks-significantly enhanced the accuracy of peak assignment. Isotopic pattern analysis revealed a close correspondence for 11 DBPs with clearly visible isotopologues in reference spectra, thereby further strengthening the confidence in the peak assignment of these DBPs. Brominated analogues were prevalent among the detected DBPs, possibly due to seawater intrusion. The fate, behavior, persistence, and toxicity of tentatively identified DBPs were assessed using EPI Suite™ and the CompTox Chemicals Dashboard. This revealed their significant toxicity to aquatic organisms, including developmental, mutagenic, and endocrine-disrupting effects in certain DBPs. Some DBPs also showed activity in various CompTox bioassays, implicating them in adverse molecular pathways. Additionally, 11 DBPs demonstrated high environmental persistence and resistance to biodegradation. This combined approach offers a powerful tool for future research and environmental monitoring, enabling accurate identification and assessment of DBPs and their potential risks.

Detection of microplastics based on splicing grating spatial heterodyne Raman spectroscopy

As a new type of persistent pollutant, microplastics pose a serious threat to the earth’s ecological environment and human health. Efficient and reliable microplastic detection technology is of great significance in the management of microplastic pollution. Aiming at the problems of low signal-to-noise ratio (SNR), narrow spectral range and low spectral resolution in traditional microplastic detection technology, a splicing grating spatial heterodyne Raman spectroscopy (SG-SHRS) is proposed in this paper. The splicing grating is composed of four sub-gratings with groove densities of 320, 298, 276 and 254 gr / mm, respectively. Each sub-grating has an independent sub-filter to improve the SNR of the system. The system is simulated, built and calibrated. The actual resolution of the SG-SHRS system is 0.7 cm−1, and the spectral detection range of a single sub-grating is 2947.2 cm−1. Four kinds of microplastics, polyamide (PA), polystyrene (PS), polycarbonate (PC), and polyphenylene sulfide (PPS), were detected by the SG-SHRS system. The complete Raman spectral information of microplastics was obtained, and the peak assignment of Raman characteristic peaks of the four kinds of microplastics was analyzed. By comparing the test results with a commercial dispersion spectrometer, it has been proven that the SG-SHRS system has the advantages of high spectral resolution, wide spectral range, and high SNR, and has good application prospects in the field of microplastic detection.

Far Infrared/Terahertz Spectroscopy as a Complementary Method for the Analysis of the Spectral Features of Thymol and Carvacrol Structural Isomers

Objective: The conventional method for the characterization of volatile compounds has been mostly limited to the use of gas chromatography. This work offers an alternative method to address the limitations that might be encountered with the use of the gas chromatography method. Furthermore, this work addresses the scarcity of the analysis of these materials in the far infrared/terahertz region as previous studies have been focused mainly on the mid-infrared region. Methods: The far infrared/terahertz spectra of carvacrol and thymol were analyzed using the Fourier transform infrared (FTIR) and gas chromatography-mass spectroscopy (GC-MS). Density function theory (DFT) calculations were employed for the interpretation of the FTIR experimental spectra. Results: Thymol and carvacrol spectra were characterized by distinct absorption bands in the 200-600 cm−1 (6-18 THz). There were appearances of bands at similar energies for these isomers. These bands appeared at 320.7 cm−1 (9.6 THz), 439.2 cm−1 (13.2 THz), 525.2 cm−1 (15.8 THz), and 586.8 cm−1 (17.6 THz) for thymol and at 313.6 cm−1 (9.4 THz), 419.8 cm−1 (12.6 THz), 521.2 cm−1 (15.7 THz), and 566.9 cm−1 (17.0 THz) for carvacrol. Despite these similarities, there were also significant differences in the spectra of these materials. The theoretical peak frequencies were in agreement with the experimental absorption band frequencies. Two seemingly common absorption bands were observed in the spectra of thymol and carvacrol. However, peak assignments revealed that these bands have different vibrational modes. The GC-MS results show that the retention time of thymol and carvacrol are very close at 18.5 and 18.8 respectively. Conclusion: This work underscores the ability of far infrared/terahertz waves in identifying materials with similar structural features. Furthermore, it supplements the limited studies of these isomers in the far infrared/terahertz region. The GC-MS results emphasize the need for a complementary method that can improve the characterization of these materials.

Methylation-GC-MS/FID-Based Glycosidic Linkage Analysis of Unfractionated Polysaccharides in Red Seaweeds.

Glycosidic linkage analysis was conducted on the unfractionated polysaccharides in alcohol-insoluble residues (AIRs) prepared from six red seaweeds (Gracilariopsis sp., Prionitis sp., Mastocarpus papillatus, Callophyllis sp., Mazzaella splendens, and Palmaria palmata) using GC-MS/FID analysis of partially methylated alditol acetates (PMAAs). The cell walls of P. palmata primarily contained mixed-linkage xylans and small amounts of sulfated galactans and cellulose. In contrast, the unfractionated polysaccharides of the other five species were rich in galactans displaying diverse 3,6-anhydro-galactose and galactose linkages with varied sulfation patterns. Different levels of cellulose were also observed. This glycosidic linkage method offers advantages for cellulose analysis over traditional monosaccharide analysis that is known for underrepresenting glucose in crystalline cellulose. Relative linkage compositions calculated from GC-MS and GC-FID measurements showed that anhydro sugar linkages generated more responses in the latter detection method. This improved linkage workflow presents a useful tool for studying polysaccharide structural variations across red seaweed species. Furthermore, for the first time, relative linkage compositions from GC-MS and GC-FID measurements, along with normalized FID and total ion current (TIC) chromatograms without peak assignments, were analyzed using principal component analysis (PCA) as a proof-of-concept demonstration of the technique's potential to differentiate various red seaweed species.

Phytochemical Analysis of Silver Nanoparticles of Psidium guajava Leaf Extract and Evaluation for Its Antibacterial Property.

Nonessential heavy metals are toxic to human health. In this study, mercury, a hazardous metal, was detected by colorimetric analysis using Murraya koenigii. The eco-friendliness of this method was also emphasized. UV spectrum is a broad peak observed at 200-250 nm in P. guajava leaf extracts. The UV spectrum of green synthesized P. guajava exhibited an absorption band of 418 nm, which confirms the nanoparticle synthesis. FTIR analysis of the vibrational peak around 3307 cm-1 is assigned to ν(O-H) stretching that could possibly emanate from carbohydrates or phenolics. The peaks found around 2917 and 2849 cm-1 are ascribed to the -C-H stretch of the alkyl group, and the peak around 1625 cm-1 is due to the enolic β-diketones or -C = O stretch of carboxylic acids, while the corresponding -C-O stretch is observed around 1375 and 1029 cm-1. The assignment of peaks is similar. It is clear from the SEM image that the constituent parts were non-uniform sphere-shaped, agglomerated, and of an average size of 30.9 nm. XRD analysis was utilized to determine the structural characteristics and crystalline nature of P. guajava. The observed intensity peaks at 32.35°, 36.69°, 39.24°, 44.76°, 59.42°, and 67.35° represent the 2θ values for P. guajava in the diffraction pattern, aligning with the values in the standard database. The synthesized AgNPs tested antibacterial properties against various strains of microorganisms, including Escherichia coli, 25 μg/mL 6.02 ± 0.17 and 100 μg/mL 7.3 ± 0.05, Staphylococcus aureus, 25 μg/mL 05.02 ± 0.07 and 100 μg/mL 11.3 ± 1.12, Streptococcus mutans, 25 μg/mL 04.02 ± 0.19 and 100 μg/mL 11.1 ± 0.11, Enterococcus faecalis, 25 µg/mL 0.8.05 ± 0.11 and 100 µg/mL 11.7 ± 0.02. The short novelty of Psidium guajava (guava) lies in its potential relevance to human health, as it has been found to possess bioactive compounds with various medicinal properties, such as antimicrobial, antioxidant, and anti-inflammatory activities, making it a promising natural resource for therapeutic applications.

Phytochemical Analysis of Silver Nanoparticles of Zingiber officinale and Evaluation for Its Antibacterial Property.

Nonessential heavy metals are toxic to human health. In this study, mercury, a hazardous metal, was detected by colorimetric analysis using Zingiber (Z.) officinale. The eco-friendliness of this method was also emphasized. The ultraviolet (UV) spectrum is a broad peak observed at 200-250 nm in Z. officinale leaf extracts. The UV spectrum of green synthesized Z. officinale exhibited an absorption band of 286 nm, which confirms the nanoparticle (NP) synthesis. Fourier transform infrared (FTIR) analysis of the vibrational peak around 3307 cm-1 is assigned to ν(O-H) stretching that could possibly emanate from carbohydrates or phenolics. The peaks found around 2917 and 2849 cm-1 are ascribed to the -C-H stretch of the alkyl group, and the peak around 1625 cm-1 is due to the enolic β-diketones or -C = O stretch of carboxylic acids, while the corresponding -C-O stretch is observed around 1375 and 1029 cm-1. The assignment of peaks is similar. It is clear from the scanning electron microscope (SEM) image that the constituent parts were nonuniform, sphere-shaped, agglomerated, and of an average size of 30.9 nm. X-ray diffraction (XRD) analysis was used to determine the structural characteristics and crystalline nature of Z. officinale. The observed intensity peaks at 32.35°, 36.69°, 39.24°, 44.76°, 59.42°, and 67.35° are, respectively, of the Z. officinale diffraction 2θ values, which correspond to the standard database values. The synthesized copper NPs synthesized tested antibacterial properties against various strains of microorganisms, including Escherichia coli: 25 μg/mL 2.01 ± 0.11 and 100 μg/mL 5.37 ± 0.12, Staphylococcus (S.) aureus: 25 μg/mL 1.05 ± 0.71 and 100 μg/mL 11.43 ± 1.27, Streptococcus mutans: 25 μg/mL 02.01 ± 0.1 and 100 μg/mL 15.67 ± 0.17, and Enterococcus faecalis: 25 μg/mL 03.11 ± 0.7 and 100 μg/mL 18.32 ± 0.2. The short novelty of Z. officinale lies in its potential relevance to human health, as it has been found to possess bioactive compounds with various medicinal properties, such as antimicrobial, antioxidant, and anti-inflammatory activities, making it a promising natural resource for therapeutic applications.