UV-Vis Detection Research Articles

MAGNESIUM –PICRATE COMPLEXES AS COUPLING AGENTS TO ENHANCE UV-VISIBLE SPECTROPHOTOMETRIC DRUG ANALYSIS

This research investigates the production of magnesium-picrate complexes and their use as coupling agents to improve UV-Visible spectrophotometric detection and quantification of vital medicinal medicines. The analyzed pharmaceuticals comprise Diclofenac Sodium, Ciprofloxacin HCl, Levoceitrizine 2HCl, Levofloxacin Hemihydrate, Nimesulide, Piroxicam BCD, and Terbinafine HCl. The synthesized magnesium-picrate complexes, upon heating with medication solutions, exhibited substantial increases in absorbance at their specific characteristic wavelengths. The increases were documented as 70.82%, 47.95%, 64.11%, 64.05%, 39.24%, 81.16%, and 87.10%, respectively, reflecting increased molar absorptivity. The 90% yield of magnesium-picrate complexes and their capacity to improve spectrum detection highlight their promise in optimizing UV-Visible spectrophotometric techniques for pharmaceutical quality assurance.

High-performance liquid chromatography method for measuring Captopril: an empirical study on hydrogel film permeability test.

High-performance liquid chromatography (HPLC) has emerged as a highly sensitive and versatile analytical technique for quantifying antihypertensive drugs, such as Captopril (CAP). This study focused on the optimization and validation of an HPLC method for quantifying CAP in an in vitro hydrogel permeability test. The main objective of this study was to develop and validate an HPLC method for quantifying CAP in an in vitro hydrogel permeability test. The HPLC method employed a C18 column (Waters, Sunfire, 5μm; 250 × 4.6mm) and a mobile phase consisting of methanol-water (85% v/v orthophosphoric acid) in a 55:45 (v/v) ratio at a flow rate of 0.5 mL/min. The UV-Vis detector was configured to detect CAP at a wavelength of 220nm. The hydrogel film used in the permeability test was prepared using poly (vinyl alcohol)/poly (vinyl caprolactam) (PVA/PNVCL) with citric acid as a crosslinking agent. All results met the validation parameters according to ICH Guideline. The HPLC method showed consistent retention time (4.7-4.9min), linearity (1-50µg/mL; r = 0.9995), accuracy (98.11-101.78%), precision (RSD ≤ 2%), and LoD/LoQ (0.19/0.62µg/mL). The developed HPLC method was successfully applied to an in vitro permeability test using horizontal diffusion cells. The results demonstrated that CAP permeated through the swollen hydrogel film, with a cumulative drug permeation exceeding 30%. This highlighted the method's utility in assessing drug transport properties through hydrogels. The validated HPLC method demonstrates robustness and reliability for quantifying CAP in the hydrogel permeability test.

Advances in High-Performance Liquid Chromatography (HPLC) and Ultra-Performance Liquid Chromatography (UPLC)

High-Performance Liquid Chromatography (HPLC) and Ultra-Performance Liquid Chromatography (UPLC) are fundamental analytical techniques that have revolutionized chemical analysis across various fields. These chromatographic methods offer exceptional separation capabilities, high resolution, and precise quantification of complex mixtures. HPLC has evolved significantly since its inception, with improvements in column technology, detection systems, and automation. UPLC, introduced as an advancement to conventional HPLC, operates at significantly higher pressures using sub-2-μm particle sizes, resulting in enhanced resolution, speed, and sensitivity. Both techniques have found extensive applications in pharmaceutical analysis, environmental monitoring, food safety, clinical diagnostics, and biomedical research. The implementation of various detection methods, including UV-visible, fluorescence, mass spectrometry, and electrochemical detection, has expanded their analytical capabilities. Recent developments in column technology, such as core-shell particles and monolithic columns, have further improved separation efficiency. The integration of artificial intelligence and machine learning has enhanced method development and data analysis. This review discusses the fundamental principles, technological advancements, and diverse applications of HPLC and UPLC. Additionally, it discusses current challenges, emerging trends, and future prospects in chromatographic science, including green chromatography initiatives and miniaturization efforts. The continuous evolution of these techniques contributes significantly to analytical chemistry's advancement, promising even more sophisticated applications in various scientific disciplines.

Comparative efficacy of Knema retusa extract delivery via PEG-b-PCL, niosome, and their combination against Acanthamoeba triangularis genotype T4: characterization, inhibition, anti-adhesion, and cytotoxic activity.

Acanthamoeba spp. is a waterborne, opportunistic protozoan that can cause amebic keratitis and granulomatous amebic encephalitis. Knema retusa is a native tree in Malaysia, and its extracts possess a broad range of biological activities. Niosomes are non-ionic surfactant-based vesicle formations and suggest a future targeted drug delivery system. Copolymer micelle (poly(ethylene glycol)-block-poly(ɛ-caprolactone); PEG-b-PCL) is also a key constituent of niosome and supports high stability and drug efficacy. To establish Knema retusa extract (KRe) loading in diverse nanocarriers via niosome, PEG-b-PCL micelle, and their combination and to study the effect of all types of nanoparticles (NPs) on Acanthamoeba viability, adherent ability, elimination of adherence, and cytotoxicity. In this study, we characterized niosomes, PEG-b-PCL, and their combination loaded with KRe and tested the effect of these NPs on Acanthamoeba triangularis stages. KRe-loaded PEG-b-PCL, KRe-loaded niosome, and KRe-loaded PEG-b-PCL plus niosome were synthesized and characterized regarding particle size and charge, yield, encapsulation efficiency (EE), and drug loading content (DLC). The effect of these KRe-loaded NPs on trophozoite and cystic forms of A.triangularis was assessed through assays of minimal inhibitory concentration (MIC), using trypan blue exclusion to determine the viability. The effect of KRe-loaded NPs was also determined on A.triangularis trophozoite for 24-72 h. Additionally, the anti-adhesion activity of the KRe-loaded niosome on trophozoites was also performed on a 96-well plate. Cytotoxicity activity of KRe-loaded NPs was assessed on VERO and HaCaT cells using MTT assay. KRe-loaded niosome demonstrated a higher yielded (87.93 ±6.03%) at 286nm UV-Vis detection and exhibited a larger size (199.3 ±29.98 nm) and DLC (19.63±1.84%) compared to KRe-loaded PEG-b-PCL (45.2 ±10.07 nm and 2.15±0.25%). The EE (%) of KRe-loaded niosome was 63.67 ±4.04, which was significantly lower than that of the combination of PEG-b-PCL and niosome (79.67±2.08). However, the particle charge of these NPs was similar (-28.2 ±3.68 mV and -28.5 ±4.88, respectively). Additionally, KRe-loaded niosome and KRe-loaded PEG-b-PCL plus niosome exhibited a lower MIC at 24 h (0.25 mg/mL), inhibiting 90-100% of Acanthamoeba trophozoites which lasted 72 h. KRe-loaded niosome affected adherence by around 40-60% at 0.125-0.25 mg/mL and removed Acanthamoeba adhesion on the surface by about 90% at 0.5 mg/mL. Cell viability of VERO and HaCaT cells treated with 0.125 mg/mL of KRe-loaded niosome and KRe-loaded PEG-b-PCL plus niosome exceeded 80%. Indeed, niosome and niosome plus PEG-b-PCL were suitable nanocarrier-loaded KRe, and they had a greater nanoparticle property to test with high activities against A. triangularis on the reduction of adherence ability and demonstration of its low toxicity to VERO and HaCaT cells.

Effects of gamma and electron-beam irradiations on the stability of free radicals, bioactive compounds and microbial characteristics of turmeric powder

Turmeric is a functional ingredient commonly used in food, pharmaceutical, and cosmetic products due to its health benefits and bioactivity, including anti-inflammatory, antioxidant, and anticancer benefits. Irradiation is a common technique used to decontaminate microorganisms and extend the shelf life of spices. However, there are scientific debates over the use of irradiation in food products. This study aimed to assess the effects of ionizing radiation, including gamma rays and electron beams, on bioactive compounds and microbial characteristics of turmeric powder. Technically, high-performance liquid chromatography with UV–Vis detection was used to assess bioactive compounds. Another aim of the present study was to determine free radicals in irradiated and non-irradiated samples within one month of storage using electron paramagnetic resonance (EPR). Results showed that gamma and electron-beam irradiations could decrease microbial contamination of turmeric by approximately 5 and 6 log cfu/g, respectively. Contents of bioactive compounds increased in irradiated samples and curcumin contents in gamma and electron-beam irradiated samples were 232–248 and 215–266 mg/g dry weight (dw), respectively. Furthermore, the study detected that free radicals increased in all irradiated samples immediately after irradiation but decreased over time. Decrease in EPR signals was faster in gamma-irradiated samples during storage. Numbers of free radicals induced by gamma and electron-beam irradiations were 6.59–4.70, 2.69–1.60, 1.61–1.34, and 0.99–1.05 on days 0, 7, 14, and 21, respectively. After 21 days of storage, the numbers of free radicals in all non-irradiated and irradiated samples were similar. Therefore, free radicals induced by irradiations were degraded during storage and eliminated after 21 days.

Electroextraction of Large Volume Samples Using Paper Points Coupled With Hollow Fiber Membranes: Study of Parameters and Strategies to Enhance Analytical Performance.

Electroextraction (EE) encompasses a range of sample preparation methods whose effectiveness, selectivity, and efficiency are significantly influenced by the physical-chemical characteristics of analytes, samples, and instrumental conditions. This article explores, for the first time, various strategies aimed at enhancing the extraction efficiency of a recent approach of EE utilizing a paper point (PP) combined with a hollow fiber (HF) (abbreviated as PP-HF-EE) to extract various cationic and anionic model compounds from water samples. The study also explores, experimentally, the impact of agitation, organic filter composition, PP diameter, and PP brand on extraction performance, and proves that all these factors are quite important, especially when digital image analysis is utilized for determination. Furthermore, this work demonstrates the ease and feasibility of simultaneously extracting cations and anions using PP-HF-EE and proposes a straightforward method to enhance analyte concentration on the vertex of the PP through a base-to-vertex focusing. Lastly, it is demonstrated, using capillary electrophoresis coupled to a UV-Vis detector, that for PP-HF-EE, the extraction efficiency and pre-concentration factor are less dependent on other parameters when multiple PPs per sample are utilized, with signal enhancement values of up to 111 and 339 for nortriptyline and haloperidol, respectively. All the findings and strategies presented herein constitute significant contributions that can facilitate future research in method development, particularly in the utilization of PP-HF-EE and similar EE approaches.

Enzyme-Triggered Chromogenic and Fluorogenic Probes for Myrosinase Activity Detection.

Myrosinase, a thioglucosidase, is a key enzyme in the mechanism of defense of plants that hydrolyzes glucosinolates (GSLs) into isothiocyanates. These isothiocyanates are the main bioactive molecules exerting protective effect in Brassicales plants. These plants that contain this specific enzyme-substrate couple belong to our daily human diet and have demonstrated health benefits, such as chemopreventive effects. Thus, the detection of myrosinase activity is a key aspect of the production of isothiocyanates from glucosinolates. Two novel chromogenic and fluorogenic GSLs, GSL p-nitrophenoxy (GSL-pNP) and GSL-4-methylumbelliferone (GSL-4MU), were designed and synthesized to be used as simple and reliable molecular tools to spectrophotometrically detect myrosinase activity in simple and complex mixtures. Notably, the chromogenic GSL enabled the UV-vis detection and quantification of isolated myrosinase activity, while fluorogenic GSL could be used for in vitro activity monitoring of more complex plant materials, such as seeds.

Molecular architecture of a novel indoline-fused chromenylium-cyanine probe carrying methionine biomolecule for ultrasensitive analyzing Hg2+ ion in real samples

In this study, by decorating the chromenylium-cyanine structure with an indoline ring, a new sensor platform CSI with a highly rigid structure and improved photophysical properties was developed for the first time. The CSI platform was modified with glyoxal and L-methionine methyl ester to produce a new NIR, ratiometric, and switch-on probe (CIME). This probe is biocompatible, water soluble, and has a specific binding mode for Hg2+ ion selectivity. The crystal structure of CSI was determined by x-ray crystallography, and its electronic characteristics, including HOMO-LUMO energy levels were determined by quantum mechanical calculations. CIME is the first instance of an indoline-fused chromenylium-cyanine used for quantification of trace level of Hg2+ in both the living cells and the environment. The new probe has a high level of selectivity and sensitivity for Hg2+ in aqueous media, with broad linear ranges (0–300 μM for UV-Vis and 0–225 μM for fluorescence). It has a rapid response time of 30 seconds, and UV-Vis and fluorescence detection limits of 7.4 ng/mL and 0.13 ng/mL, respectively. Probe quantitatively detected Hg2+ in real samples using UV-Vis, fluorescence spectrophotometry and a smartphone. The interaction between CIME and Hg2+ was verified by FTIR, HRMS and DFT calculations. Furthermore, the ability of CIME to sense Hg2+ in living cells was confirmed in both MCF-7 cells and 3T3 cells.

Methods of L-Dopa Extraction by the Method of Analytical Determination for Parkinson’s Neurodegenerative Disease

Levodopa the majority of Parkinson's disease patients eventually require levodopa medication. The chemical dopamine, which is produced when levodopa is absorbed by brain nerve cells, is used for send messages from brain regions,neurons,and synaptic memberane. that regulate movement.this neurodegenerative disease can cause uncontrollable movements, shivering, and problem balancing and muscle control. Only a few plants in the Fabaceae family have substantial amounts of isolated L-dopa; the rest are either chemically synthesized or derived from natural sources.(HPLC) added with mass spectrometry else it can added with UV-visible detection. Most frequently, HPLC is utilized.

Storing liquid chromatographic separations on surface energy traps: decoupling the LC and the mass spectrometer.

We report a micro-fractionation device for high performance liquid chromatography-mass spectrometry to archive chromatographic separations on an array of optimized surface energy traps (SETs). The method has the potential to significantly alter nanoflow LC-MS workflow, decoupling separation and analysis. The wetting characteristics of the SETs cause the HPLC eluent stream to spontaneously split into droplet microfractions. The droplet mirofractions are then dried down to enable facile storage and transport of the archived separation. Discontinuously dewetting array parameters were explored to maximize array volume and resolution using a combination of SET design, shape, size, and spacing. Mass spectrometry analysis is performed utilizing a liquid micro-junction surface sampling probe to extract dried analytes from the surface of the SETs followed by electrospray ionisation. A reverse phase separation of pharmaceutical compounds is "recorded" using the micro-fractionation device followed by "reading" the chromatographic trace with a mass spectrometer 24 hours after the separation was performed/archived, demonstrating a true decoupling of LC, and MS. Additionally, we demonstrate the ability to collect microfractions with sub-one-second integration time, approaching the scan time of a mass spectrometer or UV-Vis detector. With further improvements to the device, sub-1-second micro-fractionation may enable seamless reconstruction of archived chromatograms indistinguishable from online LC-MS data, while also providing the benefits of easy storage and transport of archived separations.

Covalent Au-C Contact Formation and C-C Homocoupling Reaction from Organotin Compounds in Single-Molecule Junctions.

Formation of new chemical species has been achieved under an electric field by the use of the scanning tunneling microscope break junction technique, yet simultaneous implementation of catalytic reactions both at the organic/metal interface and in the bulk solution remains a challenging task. Herein, we show that n-butyl-substituted organotin-terminated benzene undergoes both an efficient cleavage of the terminal tributyltin group to form a covalent Au-C bond and a homocoupling reaction to yield biphenyl product when subjected to an electric field in the vicinity to Au electrodes. By using ex situ characterization of high-performance liquid chromatography with an UV-vis detector, we demonstrate that the homocoupling reaction can occur with high efficiency under an extremely low tip bias voltage of ∼5 mV. Additionally, we show that the efficiency of the homocoupling reaction varies significantly in different solvents; the choice of the solvent proves to be one of the methods for modulating this reaction. By synthesizing and testing varied molecular backbone structures, we show that an extended biphenyl backbone undergoes homocoupling to form a quarterphenylene backbone, and the C-C coupling reactions are prohibited when additional aurophilic or bulky chemical groups that exhibit a steric blockage are introduced.

Development of a certified reference material for D-phenylalanine with evaluation of enantiomeric purity.

D-Phenylalanine (D-Phe) is a small chiral organic molecule that is both an important pharmaceutical intermediate and used as a calibrator for quantifying amino acids in liquid chromatography-circular dichroism. We have developed a process for a national certified reference material (CRM) for D-Phe following ISO 17034:2016. The identity of D-Phe was confirmed using mass spectrometry (MS) and nuclear magnetic resonance (NMR), infrared, and ultraviolet (UV) spectroscopy. The absolute optical conformation was also determined using circular dichroism (CD) spectroscopy and optical rotation measurements. Impurities were identified via liquid chromatography (LC) with a UV-Vis detector and a charged aerosol detector (CAD) and LC-MS. Both mass balance and quantitative NMR were employed for value assessment, and the associated uncertainty was evaluated. The certified purity was determined to be 0.995 ± 0.003g/g, a validation that was confirmed by CD using L-Phe CRM as a calibrator. Twenty milligrams of raw material was packed in sealed brown glass tubes for storage, and no inhomogeneity was observed. Stability tests revealed that the D-Phe CRM remained stable at -20°C for at least 26months, at 4°C for at least 14days, and at 25°C and 60°C for at least 7days. The D-Phe CRM can be used to ensure the accuracy and reliability of D-Phe quantitation in the pharmaceutical field and also as a calibrator to ensure traceability to the International System of Units (SI) for L-Phe quantitation and protein purity analysis using LC-CD methods. The approach outlined in this paper also has potential for use in the development of other chiral CRMs.

Validación de un método de cromatografía líquida (HPLC-UV/Vis) para la cuantificación de aldehídos en agua de lluvia y aire

Aldehydes are compounds in the atmosphere formed by the photochemical degradation of other organic compounds in the troposphere and can be emitted by natural or anthropogenic sources. [Objective] An analytical method was implemented to quantify aldehyde samples in matrices such as air and rainwater. [Methodology] Aldehyde sampling and analysis were conducted using method TO-11 from the United States Environmental Protection Agency (EPA). Sampling was carried out by using adsorption cartridges coated with a 2,4-DNPH solution, forming a hydrazone with the aldehydes present in the rainwater and the air, which were tested using a liquid chromatograph coupled to a UV-visible detector (HPLC-UV/Vis). To validate the analysis technique and the analytical quality of the results, the following was determined: linearity, sensitivity, quantification limits, detection limits, repeatability, reproducibility, and recovery percentage. In the case of repeatability, the comparison of the Horwitz coefficient of variation was used with the percentages of relative standard deviation (% RSD) of the samples. [Results] The detection and quantification limits obtained range between 0.18 μg/m3 and 3.20 μg/m3 for acetaldehyde and acrolein, respectively, while quantification limits are between 0.62 μg/m3 for acetaldehyde and 4.70 μg/m3 for heptanal, data that characterizes the method’s analytical quality. [Conclusions] In general, the analysis method for aldehydes showed linearity, with R2 values equal to or greater than 0.9991 for each calibration curve, and relative deviation percentage values less than 2.25 %, indicating good precision in the analysis.

Primary alcohol-induced coacervation in alkyl polyglucoside micellar solution for supramolecular solvent-based microextraction and chromatographic determination of phthalates in baby food

This study reports for the first time the phenomenon of supramolecular solvent formation based on alkyl polyglucoside as an amphiphile and primary alcohol as a coacervation agent. The physical properties (density, kinematic viscosity, phase diagram for ternary system) of the supramolecular solvent were investigated, and a mechanism for its formation was proposed. A green and simple microextraction procedure for preconcentration and determination of phthalates in baby foods packaged in plastic packaging was developed as proof-of-concept example. The microextraction procedure assumed separation of analytes from solid phase sample in micellar solution of decyl glucoside and in situ formation of supramolecular solvent for analytes preconcentration after addition of n-heptanol. The determination of phthalates in obtained extracts was implemented by high-performance liquid chromatography with UV–Vis detection. The limits of detection, calculated from a blank test based on 3σ, were determined to be 10 μg kg−1 for dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, and di-n-octyl phthalate. The developed procedure did not require filtration of sample suspension, and assumed the use of green and biodegradable substances for the supramolecular solvent formation across a wide pH range.

Determination of Rhodamine 6G with direct immersion single-drop microextraction combined with an optical probe.

The combination of an optical probe and single-drop direct immersion microextraction (DI-SDME-OP) was used for the preconcentration and subsequent spectrophotometric determination of rhodamine 6G (Rh6G). The developed method is based on the formation of an ionic associate between Rh6G and picric acid at pH 3.0 and its extraction with amyl acetate. A microdrop of the organic phase was stably placed in the hole of an optical probe immersed in the sample solution. The absorbance of the extraction phase was monitored at 534 nm. The proposed method combines in a single step several stages of the analytical procedure, such as pre-concentration, phase separation, transfer of the extraction phase to the instrument and online measurement. The sensitivity of the proposed approach is not inferior to existing microextraction methods involving the combination of liquid-phase or solid-phase extraction with spectrophotometry or HPLC with a UV-Vis detector. The evaluation of the greenness of the developed method carried out by the AGREE method (0.58 points) showed that it outperforms other similar existing techniques using this parameter. The calibration plot for the determination of Rh6G by the DI-SDME-OP method was linear over the range of 10-500 nM with a correlation coefficient of 0.9956. The limit of detection was 3.4 nM. The accuracy and applicability of the method were evaluated by the determination of Rh6G in natural waters and lipstick.

Graphitic nitride co-doped with sodium and sulphur as fluorescent and UV–Vis probe for quercetin detection

This work described the synthesis of novel sodium and sulphur doped graphitic nitride (Na,S-g-CN) for the detection of quercetin by fluorimetry and UV–Vis absorption. By pyrolyzing melamine and 2-Mercaptoethanol, Na,S-g-CN was created and characterized by advanced techniques. The fluorophore's crystal structure, surface morphology, elemental composition, and photoluminescence activity have all been studied using a variety of characterization techniques. It was shown that adding quercetin through the Static quenching and IFE mechanism significantly reduced the fluorescence intensity of Na,S-g-CN. In comparison to single heteroatom doped graphitic nitride, it was discovered that Na and S co-doping considerably detects the quercetin. For both fluorescence and UV–Vis detection, the measured limit of detection (LOD) was 23.79 nM and 16.49 μM respectively, with corresponding linear ranges of 3–80 nM and 0–60 μM. The findings of this study show that the suggested nanomaterials have a comparatively consistent and noticeable photoluminescence activity, demonstrating their enormous potential for high-accuracy QC quantity detection in industrial, food, beverages, and biological applications.

Advancements in Dual-Function UV-Visible Light Detection

Abstract This research introduces a photodetector capable of differentiating between ultraviolet (UV) and visible light, employing the unique properties of zinc oxide (ZnO) and α-silicon (α-Si). The core of this innovative device is a pixel unit circuit, designed with three integral components: a delay circuit for precise timing, a photosensitive element composed of an α-Si thin film resistor and a ZnO thin film transistor (ZnO TFT) for respective light spectrum detection, and a source follower for effective signal transmission. Through simulations conducted in Cadence Virtuoso, the device’s responsiveness to varying intensities of UV and visible light was assessed. Adjustments to the α-Si resistance and ZnO TFT threshold voltage simulated realistic light conditions, demonstrating the device’s capability to generate distinct voltage changes in response to different light spectrums. These results underline the potential of the design for larger-scale implementations and highlight its adaptability and precision in detecting diverse light intensities. This research provides the basis for the development of simultaneous UV-visible detection and scalable light detection systems. In addition, taking advantage of the properties of ZnO TFT, which can also be used in the future in curved transparent environments.

The Development of Digital Colorimetric-Based Thiourea Receptor for Highly Sensitive Detection of Dihydrogen Phosphate

T his study aimed to synthesize a new chemosensor, namely 1,1’-(1,4-phenylene)bis(3-(4-nitrophenyl)thiourea), specifically designed for detection of H2PO4−. The compound was characterized using FTIR, LC-MS, 1H NMR, and 13C NMR, while the colorimetric sensing abilities were validated through various analyses. These include linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy using UV-Vis spectrophotometry, RGB, and HSV color components. Digital images of color changes were captured using a smartphone camera and Color Grab app was used to quantify color components. Subsequently, anions test (NO3−, Cl–, HSO4−, and H2PO4−) were conducted in acetonitrile, where the addition of H2PO4− induced a distinct color change from colorless to yellow. The results showed that detection of H2PO4− depended on pH of the solution, with no color change observed at pH 1-3 due to anions converting to acidic species. At pH 5, H2PO4− was detected as a yellow color change, and alkaline conditions led to different color responses. Furthermore, UV-Vis detection showed recovery values of 99.80% to 100.6%, indicating high accuracy. RGB and HSV color component-based sensors showed recovery values of 101.6% to 114.4% and 92.50% to 110.2%, respectively. The LOD of the UV-Vis, RGB, and HSV methods were 0.16 μM, 0.46 μM, and 0.18 μM, while LOQ values were 0.54 μM,1.52 μM, and 0.61 μM, respectively. In conclusion, the synthesized chemosensor showed potential for accurate and sensitive detection of H2PO4− using UV-Vis spectrophotometry and digital colorimetric-based image.

Improved UV-Vis Detector Performance Prepared via the Electrospinning Technique by Doping Polymer Solutions with Iron Oxide

The iron (III) oxide nanoparticles (NPs) were prepared by a solvent-controlled method when preparing the electrospinning solution. Nanofibers (NFs) were prepared from pure PVP and PVP doped with ratios 1 %wt., 2 %wt. and 3 %wt. of Fe2O3 NPs at room temperature by the electrospinning technique. Optical properties like absorbance and the band energy gap ([Formula: see text]g) were studied, and the direct band gap of pure PVP NFs is 4.07 eV and decreases slightly with increasing concentration of Fe2O3 NPs. The PVP NFs with Fe2O3 NPs were used as a UV-Vis light detector with good responsivity and specific detectives at a mixing rate of 3% Fe2O3 NPs, which was 12 A/W and 27.76 ×10[Formula: see text] Jones at wavelength 458.3 nm, and also had the lowest values for the rise-time and fall-time.

Natural deep eutectic solvent for the simultaneous derivatization and microextraction of isoniazid from human plasma

BackgroundPersonalized medicine is a rapidly revolving field that offers new opportunities for tailoring disease treatment to individual patients. The main idea behind this approach is to carefully select safe and effective medications and treatment plant based on each patient's unique pharmacokinetic profile. Isoniazid is a first-line anti-tuberculosis drug that has interindividual variability in its metabolic processing, leading to significant differences in plasma concentrations among patients receiving equivalent doses. This variability necessitates the creation of individualized treatment regimens as part of personalized medicine to achieve more effective therapy. ResultsIn this work, a deep eutectic solvent-based liquid-liquid microextraction approach for the separation and determination of isoniazid in human plasma by high-performance liquid chromatography with UV–Vis detection was developed for the first time. A new natural deep eutectic solvent based on thymol as a hydrogen bond donor and 4-methoxybenzaldehyde as a hydrogen bond acceptor was proposed as the extraction solvent. The developed microextraction procedure assumed two simultaneous processes during the mixing of the sample and extraction solvent: the derivatization of the polar analyte in the presence of 4-methoxybenzaldehyde (component of the natural deep eutectic solvent) with the formation of a hydrophobic Schiff base (1); mass transfer of the Schiff base from the sample phase to the extraction solvent phase (2). Under optimal conditions, the limits of detection and quantification were 20 and 60 μg L−1, respectively. The RSD value was <10 %, the extraction recovery was 95 %. SignificanceIn this work, the possibility of isoniazid derivatization in the natural deep eutectic solvent phase with the formation of the Schiff base was presented for the first time. The approach provided the separation and preconcentration of polar isoniazid without the use of expensive derivatization agents and solid-phase extraction cartridges. The formation of the Schiff base was confirmed by mass spectrometry.