Linear Dynamic Range Research Articles

Development of Zeolite Imidazole Framework-Based Adsorbent for Effective Microextraction and Preconcentration of Histamine in Food Samples.

This study is the first to focus on the preconcentration and determination of histamine (HIS) in food samples using zeolite imidazole frameworks (ZIFs) on a solid-phase microextraction (SPME) platform. ZIF was developed on a polypropylene hollow fiber (PPHF) substrate (ZIF@PPHF) and characterized. The extraction performance was optimized by adjusting several parameters, including pH, contact time for adsorption, and desorption conditions. Under the optimized conditions, a wide linear dynamic range (0.05-250 mg/L) with high R2 values (0.9989), low limit of detection (0.019 mg/L), and low limit of quantification (0.050 mg/L) were determined as analytical figures of merit. Additionally, a reusability study confirmed that ZIF@PPHF preconcentrated 83% of the HIS up to the fourth cycle. The developed method was used to preconcentrate HIS in fish and cheese samples. The spiked real samples confirmed the validity and accuracy of this method. The percentage mean recoveries ± relative standard deviation (% RSD, n = 3) at the concentration levels of 5, 10, and 50 mg/L of HIS and the sample amount of 5 g for intra- and inter days ranged from 97 ± 1.10 to 102.80 ± 0.90 and from 96.40 ± 1.82 to 103.40 ± 0.79, respectively. The results suggest that the analytical method validation parameters were acceptable, indicating the repeatability and sensitivity of the method.

Voltammetric Assessment of Paracetamol on a CuONPs – MWCNTs Modified Glassy Carbon Electrode

In this work, an electrochemical sensor using differential pulse voltammetric method for the assessment of antipyretic and analgesic drug, paracetamol was developed. The CuO nanoparticles were synthesized and characterized. A glassy carbon electrode (GCE) fabricated with the suspension of CuO nanoparticles (CuONPs) and multi-walled carbon nanotubes (MWCNTs) were used. The fabricated electrode was characterized using Potassium ferricyanide as a redox probe, which showed increase in the electro active area in the modified electrode. The modified electrode showed improved anodic peak current enhancement in phosphate buffer solution. The consequence of pH of supporting electrolyte and amount of nanoparticles suspension were investigated at a physiological pH of 7.4. Using differential pulse voltammetry, the fabricated electrode showed linear dynamic range from 9 to 160 nM of paracetamol concentration. From the calibration plot, the computed detection limit was 5.06nM and quantification limit was16.88 nM. The developed method was checked for its reproducibility and assay during a day and intraday as well and the results were good with permitted range of errors. The developed process was fruitfully applied to detect paracetamol in pharmaceutical formulations.

Development of pivalic acid conjugated Nafion modified glassy carbon electrode for sensitive detection of Cu(II) by electrochemical approach

In this work, pivalic acid (pivH) molecule is employed for an electrochemical sensing of copper cations in an aqueous medium. For sensitive as well as selective potential sensor application, pivH was fabricated onto a glassy carbon electrode (GCE) facilitated by adhesive conducting binder, nafion, so as make it selective and effective electrochemical probe (pivH/Nafion/GCE) towards specific heavy metal cations. This newly fabricated pivH/Nafion/GCE reveals enhance electrochemical activity toward copper ions in the presence of other interfering heavy metal cations in phosphate buffer solution (PBS) of pH=7. The calibration plot was linear (r2 = 0.9879) across broad linear dynamic range (LDR) spanning Cu2+ concentration from 0.1 nM to 0.01 M. The sensitivity and detection limit was found to be 0.0212 × 10−2 µAµM−1cm−2 and 0.014 nM, respectively. So, this newly fabricated GCE as selective electrochemical probe offers a sensitive as well as selective detection of Cu2+ cations in real environmental samples using a novel electrochemical, current–potential (I-V), approach, for the first time. Further, we explored pivalic acid for the preparation of new di-nuclear copper complex, [Cu2(piv)4(pivH)2] (where piv = pivalate; pivH=pivalic acid) and characterized by Fourier transform infrared spectroscopy (FTIR) spectroscopy, elemental analysis and single crystal X-ray diffractometry. Density functional theory (DFT) calculations were carried out to confirm the interactions and these calculations well-support to experimental data. In case of deprotonated form of pivH, Molecular Electrostatic Potential (MEP) analysis exhibits electrostatic potential equals to −148.4 kcal/mol which suggest about the strong interaction of –COOH with copper centers. Similarly, interaction energies, the quantum theory of atoms in molecules (QTAIM) study and Natural Bond Orbital (NBO) analysis also favor to experimental work. Thus, this novel study demonstrates an excellent approach for highly selective and sensitive detection of Cu2+ cations in short response time with low detection limit and good reproducibility by using I-V method based on newly designed pivH/Nafion/GCE as selective Cu2+ cationic electrochemical sensor. The experimental data was compactable with theoretical calculations.

Samarium, nitrogen co-Doped carbon dots for detection of Epinephrine: Theoretical and experimental

In this study we have developed a highly sensitive optical sensor for the detection of epinephrine using carbon dots co-doped with samarium and nitrogen (Sm,N-CDs) with a very low detection limit of 28.1 nM and a broad linear dynamic range from (0–105 nM). Various techniques were employed to characterize the synthesized material, aiming to understand its morphological and physicochemical characteristics. The synergistic effect of the synthesized Sm,N-CDs demonstrated excellent optical performance, high selectivity and photostability. Additionally, good recovery findings were obtained when the sensor’s viability for Epinephrine detection in biological fluid samples that had been spiked was evaluated. In addition, we have developed an smartphones-based sensor to record the solution’s fluorescent color shift as it is being sensed. Using a mobile phone application to examine the green, red, and blue values from these photos, the comparable LOD was found to be 17.21 μM in a (0–90 μM) wide linear range of concentration. This straightforward, affordable, and quick screening device is highly demanding for the on-the-spot identification of the analytes at remote locations where advanced instrumentation is typically unavailable. Density functional theory was used to examine energy, stability, band gap, and how Ep interacted with the Sm,N-CDs nanoparticles.

Synergistic Effects of V2O5 Nanoparticles Decorated By 2-Amino-1,3,4-Thiazole Derivatives Based Schiff Bases for High-Performance D-Glucose Sensing

V2O5 lamellar structure modifies its adsorption and conduction characteristics that makes it an extensively used biosensor for the detection of D-Glucose but its faster recombination rate limits its sensitivity. Here, V2O5 nanoparticles (NPs) decorated with 2-Amino-1,3,4-thiazole derivatives-based Schiff bases have been fabricated to enhance the sensing performance for D-Glucose detection. Decorated NPs exhibits unique physicochemical properties with enhanced surface area that attributes towards its better catalytic properties. Furthermore, modified V2O5 NPs surface with 2-Amino-1,3,4-thiazole derivatives facilitate efficient electron transfer and provides enhanced selectivity, sensitivity and repeatability towards glucose molecules that had been analyzed via. cyclic voltammetry and amperometry. Effect of different glucose concentration and scan rate at different time interval had been studied that illustrates the stability and sensitivity of NPs. Limit of detection (LOD), limit of quantification (LOQ), linear dynamic range (LDR), and durability has been acquired by a dependable current–voltage (I–V) process. Fabricated NPs shows potential for use in glucose sensing applications and advances biosensor technology to support the enzyme-free sensing technology.

Graphene-based field-effect transistor biosensor for prostate-specific antigen detection

The development of a graphene-based field-effect transistor (GFET) aptasensor for prostate-specific antigen (PSA) detection. We present the novel use of 1-pyrenebutyric acid N-hydroxysuccinimide ester (PBASE) to functionalize the graphene surface, enabling covalent bonding of amine-functionalized PSA-binding aptamers. Under optimized conditions, the shift of the GFET aptasensor’s Dirac point voltage exhibited a systematic variation with PSA concentrations. The sensor demonstrated a relatively wide linear dynamic range spanning from 100 fM to 100 nM, with a detection limit of 3.5 pM. Importantly, it displayed satisfactory specificity against potential interfering proteins and demonstrated good reproducibility and stability. Furthermore, we successfully applied the proposed method for the quantification of PSA in human serum samples, indicating its potential for bioanalysis and clinical diagnostics. The GFET aptasensor’s potential in medical diagnostics and personalized healthcare, positioning it as a promising tool for rapid and accurate biomarker detection.

Insights into Spectral Distortion and Nonlinearity in UV-Vis and Fluorescence Spectroscopy of Molecular Fluorophore Solutions: Effects of Cascading Optical Processes (Part IV).

Reproducibility and linearity are crucial benchmarks for any measurement technology. However, UV-vis and fluorescence spectral distortion and nonlinearity are prevalent, even in seemingly simple fluorescent solutions that comprise only one dissolved molecular fluorophore, without exogenous absorbing or scattering species. In this report, we introduce an analytical model for the quantification of fluorescence interference on UV-vis measurements and a conceptual model for mechanistically understanding the impacts of higher-order cascading optical processes on fluorescence measurements. The experimental UV-vis transmittance can be dominated by interfering fluorescence, even for fluorophore solutions with theoretical absorbance values far below the instrument's linear dynamic range (LDR). Absorption-inner-filter-effect (aIFE) correction drastically improves the fluorescence LDR. However, the efficacy of aIFE correction hinges on two competing factors that strongly depend on the fluorophore's optical properties: the degree of fluorescence interference in UV-vis and the significance of secondary or higher-order emission triggered by fluorophore absorption of emitted photons. Our research sheds light on the remarkable complexity of cascading optical processes that can occur even in the simplest fluorescent solutions. It emphasizes the necessity of critically evaluating optical spectroscopic measurements of fluorescent solutions to improve the reliability of analyzing and interpreting optical spectra. Moreover, it lays the groundwork for future development of methods capable of handling challenging samples that exceed the capabilities of the current tools.

Detection of volatile primary aliphatic amines: Highly selective and sensitive vapoluminescent sensing of n-butylamine

Detection of volatile amines is of great interest for environmental and industrial monitoring for the protection of human health from exposure to toxic substances. This contribution describes the vapochromic and vapoluminescent properties of a Lewis acidic Zn(salen)-type Schiff-base complex and its application as a chemosensor for detection of n-butylamine (BA) vapors. Annealed films of the complex were initially involved for vapochromic and vapoluminescence screening experiments to evaluate their response towards compounds representative of each of the different chemical classes of volatile organic compounds (VOCs). Then, a cost-effective, disposable paper-based vapoluminescent sensor, characterized by high optical uniformity and repeatability, was developed for the selective and sensitive direct in-situ detection of BA vapors. Under static exposure conditions, the sensor allows a sensitive vapoluminescent detection of BA, with a LOD down to 2.0 ppm, below the permissible exposure limit of 5 ppm established by OSHA for BA, and a linear dynamic range up to 50 ppm. The sensor response is not affected by the exposure temperature, only a different exposure time is required as the temperature varies, while average relative humidity levels lead to almost negligible changes in the sensor response. The sensor is highly selective for BA with respect to ammonia and the different chemical classes of VOCs, including relevant primary aliphatic amines, with the exception of propylamine and sec-butylamine, especially at low concentrations (tens of ppm). Selectivity for BA is also demonstrated by competitive experiments in the presence of a 10-fold ppm amount of all representative VOCs of each class as potential interferents.

Investigating the synergistic effect of RuO2 nanoparticle-decorated V2O5 nanoflakes for sensitive detection of 2,4-dinitrophenol and 2,4-dinitrotoluene

The dinitroaromatic compounds 2,4-Dinitrophenol (2,4-DNP) and 2,4-Dinitrotoluene (2,4-DNT) are prevalent contaminants in various water sources due to their extensive use in explosive synthesis and other industrial applications. The highly toxic and carcinogenic nature of these compounds poses significant risks to human health and environment, making the development of facile, rapid, cost-effective, and selective detection methods crucial. This research presents the one-step hydrothermal synthesis of RuO2 nanoparticle-decorated V2O5 nanoflakes to fabricate an electrochemical sensor for the detection of 2,4-DNP and 2,4-DNT. The synthesized materials were characterized using XRD, Raman spectroscopy, FESEM, HRTEM, and XPS techniques. The electrochemical behavior of 2,4-DNP and 2,4-DNT was investigated using cyclic voltammetry, square wave voltammetry and chronoamperometry. Under optimized conditions, 2,4-DNP and 2,4-DNT exhibited two reduction peaks corresponding to the nitro-functional groups on the aromatic ring. Notably, the 7 wt% RuO2 in V2O5 nanocomposite-modified glassy carbon electrode (RV7/GCE) demonstrated the lowest detection limits of 1.07 nM and 1.01 nM within the linear dynamic range (LDR) of 5.0 nM–35.0 µM for 2,4-DNP, and 2,4-DNT, respectively. Furthermore, the sensor exhibited excellent reusability and reproducibility, delivering consistent results for both laboratory-controlled and real-world samples. This advancement offers efficient detection and monitoring of these hazardous compounds in environmental and industrial settings.

High-Detectivity All-Polymer Photodiode Empowers Smart Vitality Surveillance and Computational Imaging Rivaling Silicon Diodes.

Near-infrared (NIR) organic photodetectors (OPDs), particularly all-polymer-based ones, hold substantial commercial promise in the healthcare and imaging sectors. However, the process of optimizing their active layer composition to achieve highly competitive figures of merit lacks a clear direction and methodology. In this work, celebrity polymer acceptor PY-IT into a more NIR absorbing host system PBDB-T:PZF-V, to significantly enhance the photodetection competence, is introduced. The refined all-polymer ternary broadband photodetector demonstrates superior performance metrics, including experimentally measured noise current as low as 6 fA Hz-1/2, specific detectivity reaching 8×1012 Jones, linear dynamic range (LDR) of 145 dB, and swift response speed surpassing 200 kHz, striking a fair balance between sensitivity and response speed. Comprehensive morphological and photophysical characterizations elucidate the mechanisms behind the observed performance enhancements in this study, which include reduced trap density, enhanced charge transport, diminished charge recombination, and balanced electron/hole mobilities. Moreover, the practical deployment potential of the proof-of-concept device in self-powered mode is demonstrated through their application in a machine learning-based cuffless blood pressure (BP) estimation system and in high-resolution computational imaging across complex environments, where they are found to quantitatively rival commercial silicon diodes.

High‐Performance P‐N Junction Heterostructure with Carbon Quantum Dot and Nitrogen Self‐Doped Graphitic Carbon Nitride for Visible Light Photodetection

AbstractOrganic photodetectors (OPDs) hold immense promise for optoelectronic applications. Here a zero‐biased, high‐performance organic photodetector employing a 2D organic heterostructure is introduced. The structure combines carbon quantum dots (CQDs) with nitrogen self‐doped graphitic carbon nitride (g‐C3N4+) and is tested for alternating current (AC) photodetection on an interdigitated electrode platform. The study reveals extraordinary performance driven by the synergistic effects of efficient charge excitation, separation, and emission within the 2D/2D CQD/g‐C3N4+ heterostructure, leveraging mechanisms of photoconduction, photogating, and fluorescence. A unique convergence to similar rise and decay times in the order of 2.9 ms is observed at higher frequencies in the visible (Vis) spectrum. Benchmarking against state‐of‐the‐art OPDs shows ultrahigh specific detectivity (4.60 × 1018 Jones), ultrahigh responsivity (1.43 × 107 A W−1), high external quantum efficiency (43 × 107%) at an optical intensity of 3.56 × 10−4 mW cm−2 and a wavelength of 405 nm while delivering competitive performance at 532 and 635 nm as well. Moreover, a large linear dynamic range of 86–162 dB in the Vis spectrum is obtained. These enhancements promise development of a new generation of OPDs to advance light sensing and imaging applications at high frequency, marking a significant milestone in optoelectronic device engineering.

Reversible Hydrophobic Deep Eutectic Solvent-Based Uranyl-Sensing Optode Film in Aqueous Streams: Color Transformation and Reusability.

A hydrophobic deep eutectic solvent (HDES)-based optode was designed for the preconcentration and determination of the UO22+ ion in aqueous media using spectroscopic techniques [energy-dispersive X-ray fluorescence (EDXRF) and solid-state absorption]. The optode was developed by incorporation of HDES (tri-n-octyl phosphine oxide and decanoic acid in an equimolar ratio), tri-(2-ethylhexyl) phosphate, and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol into a cellulose triacetate matrix. Characterization studies were carried out using different techniques to understand the roles of HDES as a plasticizer, UO22+ extractant, and Br-PADAP immobilizer. Uptake studies revealed that the optimal pH was 3 and sorption followed the type II adsorption isotherm. Uranium in the U-sorbed optode can be directly analyzed over a large concentration range of 0.021 × 10-3-2.1 × 10-3 Mol L-1 using EDXRF. The optode film exhibited a linear dynamic range of 0.84 × 10-6-84 × 10-6 Mol L-1 for uranium, with a lowest limit of detection of 0.084 × 10-6 Mol L-1 by colorimetric analysis. This optode-based method was employed for seawater analysis for its UO22+ concentration without any matrix separation, and the concentration was found to be 1.30 ± 0.06 × 10-8 Mol L-1. The optode exhibited better selectivity for UO22+ in the presence of various cations including Sr2+ and Cs+ in an aqueous medium. Compared to other prevailing optical sensors, this optode performed better in terms of key factors like pH, equilibration time, reusability, and detection limit.

Electrostatic Force-Assisted Transfer of Flexible Silicon Photodetector Focal Plane Arrays for Image Sensors.

Flexible photodetectors are pivotal in contemporary optoelectronic technology applications, such as data reception and image sensing, yet their performance and yield are often hindered by the challenge of heterogeneous integration between photoactive materials and flexible substrates. Here, we showcase the potential of an electrostatic force-assisted transfer printing technique for integrating Si PIN photodiodes onto flexible substrates. This clean and dry process eliminates the need for chemical etchants, making it a highly desirable method for manufacturing high-performance flexible photodetector arrays, expanding their widespread applications in electronic eyes, robotics, and human-machine interaction. As a demonstration, a 5 × 5 flexible Si photodetector focal plane array is constructed for imaging sensors and shaped into a convex semicylindrical form to achieve a π field of view with long-term mechanical and thermal stability. Such an approach provides a high yield rate and consistent performance, with the single photodetector demonstrating exceptional characteristics, including a responsivity of 0.61 A/W, a response speed of 39.77 MHz, a linear dynamic range of 108.53 dB, and a specific detectivity of 2.75 × 1012 Jones at an applied voltage of -3 V at 940 nm.

An efficient microchip electromembrane extraction online with high-performance liquid chromatography for the measurement of nicotine in high consumption vegetables.

Nicotine, a highly addictive substance, is naturally produced in the Solanaceae family of plants, particularly tobacco. The presence of nicotine in plant foods has adverse effects on the lungs, kidneys, heart, and reproductive system. A novel three-phase microchip flat electromembrane coupled with online high-performance liquid chromatography (HPLC) was developed to analyze nicotine in tomato, mushroom, eggplant, bell pepper, and red pepper. The microchip was connected to the HPLC in online mode. All effective variables were optimized to achieve the best extraction response. The use of electric potential and 2-nitrophenyl octyl ether -5% di(2-ethylhexyl) phosphate as a modified supported liquid membrane (SLM) increased the sensitivity and selectivity. The optimal extraction voltage, extraction time, and ion balance were 40 V, 10 min and 0, respectively. The dynamic linear range was 0.5-1000 ng g-1. The obtained recovery, relative standard deviation, and enrichment factor were 98%, 7%, and 35, respectively. The limits of detection 0.4 ng g-1 and the limits of quantification were obtained 1.3 ng g-1. The highest (105.0 ng g-1) and lowest (3.4 ng g-1) concentrations of nicotine were obtained for eggplant and tomato, respectively. Selective electromembrane extraction of nicotine from the donor phase to the acceptor phase was performed by optimizing the main variables influencing the method mechanism. The new channel design in this analytical system and online injection increased efficiency, stability, and repeatability. The results revealed that this method is capable for the efficient determination of trace amount of nicotine in edible vegetables.

Novel pore confinement enhanced europium functionalized porphyrin covalent organic framework electrochemiluminescence microreactor and its application to microRNA-21 detection

Here, an electrochemiluminescence (ECL) microreactor lanthanide europium functionalized porphyrin covalent organic framework (Eu@TAPP-COF) was developed through Schiff base condensation between 1,3,5-benzenetricarboxaldehyde (BTCA) and 5,10,15,20-tetrakis(4-aminophenyl)-porphyrin (TAPP) with the coordination reaction between the COF skeleton and Eu3+. Compared with O2/S2O82− and TAPP-COF/S2O82− systems, the ECL intensity of Eu@TAPP-COF/S2O82− is significantly enhanced by 5.1 and 1.3 times, respectively. It can be attributed to the positively charged micropore structure of the Eu@TAPP-COF, providing a relatively independent reaction environment for the electrochemical oxidation of S2O82− and the intermediate SO4•−, moreover shortening the distance among the ECL luminophore TAPP, the co-reaction accelerator Eu3+, and the co-reaction reagent S2O82−. Based on this novel emitter, an ECL biosensor was developed for microRNA-21 detection via the signal amplification strategy of catalytic hairpin assembly (CHA). The as-prepared biosensor displayed high sensitivity for target with a dynamic linear response range from 100 aM to 100 pM, and a lower detection limit of 21 aM (S/N = 3). This work provides an idea for the sensing application of weak luminophore and a simple, effective and accurate detection platform for tumor markers.

The Carrier Proteome Should Be Reassessed for Each Mass Analyzer Architecture.

A clever utilization of classic proteomics reagents now allows the effective amplification of the peptide sequencing potential in shotgun proteomics. The application of this method has helped usher in the exciting new field of single cell proteomics. While it was easy to first think that this approach was finally the answer for the polymerase chain reaction in protein chemistry, limitations were carefully described by the authors and others. A study by Cheung et al. systematically identified the consequences of higher concentration carrier proteomes and defined the "carrier proteome limit" [Cheung et al. Nat. Methods 2021, 18, 76]. While this work has been replicated by others, every analysis published to date has used a variation of the same mass analyzer. When the same analysis is performed on alternative instruments, these limits appear to be very different and can be attributed to defined characteristics of each mass analyzer. Specifically, in mass analyzers with a higher relative intrascan linear dynamic range, increased carrier channels appear less detrimental to quantitative accuracy. As such, we may be limiting the power of isobaric peptide signal "amplification" by restricting ourselves to traditional mass analyzer options for shotgun proteomics.

Copper Micro-Flowers for Electrocatalytic Sensing of Nitrate Ions in Water.

The progressive increase in nitrate's (NO3-) presence in surface and groundwater enhances environmental and human health risks. The aim of this work is the fabrication and characterization of sensitive, real-time, low-cost, and portable amperometric sensors for low NO3- concentration detection in water. Copper (Cu) micro-flowers were electrodeposited on top of carbon screen-printed electrodes (SPCEs) via cyclic voltammetry (with voltage ranging from -1.0 V to 0.0 V at a scan rate of 0.1 V s-1). The obtained sensors exhibited a high catalytic activity toward the electro-reduction in NO3-, with a sensitivity of 44.71 μA/mM. They had a limit of detection of 0.87 µM and a good dynamic linear concentration range from 0.05 to 3 mM. The results were compared to spectrophotometric analysis. In addition, the devices exhibited good stability and a maximum standard deviation (RSD) of 5% after ten measurements; reproducibility, with a maximum RSD of 4%; and repeatability after 10 measurements with the RSD at only 5.63%.

Dielectric‐Doped 2D Tellurium Diodes for Zero‐Bias Radio Frequency Power Detection

AbstractThis work presents a 2D tellurium (Te)‐based diode that exploits the doping achieved by atomic layer deposited (ALD) Al2O3 to enhance its rectifying performance. The proposed device comprises a Schottky junction that is dielectric‐doped to significantly reduce the reverse bias current. A boosted current responsivity four times higher compared to that of undoped devices is achieved, maximizing the performance for radio frequency (RF) power detectors. The application measurement results demonstrate sensitivities as low as −45 dBm, and at −30 dBm RF input power outstanding tangential responsivities up to 6.5 kV W–1, 4.3 kV W–1, and 650 V W–1 at 0.5, 1, and 2.5 GHz, respectively, while reaching linear dynamic range (DR) of over 30 dB. These are the highest reported values for 2D‐based material devices by almost two orders of magnitude. Furthermore, the DR is ≈10 dB larger compared to state‐of‐the‐art power detectors based on bulk semiconductors.

Improved high-performance liquid chromatography tandem mass spectrometry method for quantification of infliximab in pediatric plasma and its application in therapeutic drug monitoring.

The application of infliximab (IFX) to immune-mediated disease is limited by the significant individual variability and associated clinical nonresponse, emphasizing the importance of therapeutic drug monitoring (TDM). Because of the cross-reactivity, limited linear range, and high costs, the clinical application of the previous reported methods was limited. Here, an improved high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method was developed to address the issues. This study developed an improved bioanalytical HPLC-MS/MS method coupling nanosurface and molecular-orientation limited proteolysis technology. The commercially available compound P14R was selected as the internal standard. This method was developed with fewer volume of reagents and was thoroughly validated. The validated method was applied to TDM in pediatric inflammatory bowel disease (IBD). Chromatography was performed using a Shim-pack GISS-HP C18 metal-free column (3 μm, 2.1 × 100 mm) with a gradient elution of 0.1% formic acid in water and acetonitrile at 0.4 mL/min. Detection and quantitation were performed using electrospray ionization (ESI) and multiple reaction monitoring in the positive ion mode. The method was validated to demonstrate its selectivity, linearity, accuracy, precision, recovery, matrix effect, and stability. The method exhibited a linear dynamic range of 0.3-100 μg/mL, with intra- and inter-day precision and relative errors below 15%. The recovery and matrix effect were measured as 87.28%-89.72% and 41.98%-67.17%, respectively, which were effectively compensated by the internal standard. A total of 32 samples collected from 24 pediatric patients with IBD were analyzed using the validated method, and only 46.9% achieved the reported targeted trough level. This study developed an improved HPLC-MS/MS method for the quantitative determination of IFX concentration in human plasma. The accurate, reliable, and cost-effective method was validated and utilized in the analysis of clinical samples. The results confirmed the importance of TDM on IFX and the clinical application prospects of the improved method.

A highly sensitive and selective electrochemical sensing probe for detection of Edoxaban anticoagulant drug residue in environmental water and drug formulations

ABSTRACT Anticoagulant drugs currently play a crucial role in preventing severe deep vein thrombosis, heart attacks, heart valve diseases and contribute to the regulation of blood flow. Thus, the existing study reports the redox behaviour of Edoxaban (EDX) anticoagulant drug at bare glassy carbon electrode (GCE) for establishing sensitive, and selective adsorptive square wave – cathodic stripping voltammtric (Ads SW-CSV) probe for EDX detection. Under the optimal analytical parameters, the probe displayed good linear dynamic range (LDR) of EDX from 1.0 × 10−6 − 1.0 × 10−5 M. The probe displayed probe sensitivity, limits of detection (LOD) and quantification (LOQ) of 18.5 µA µM−1 cm−2, 3.3 × 10−7 and 1.0 × 10−6 M, respectively. The probe offered quick response, good anti-interference ability towards multiple co-existing species, good recovery (99.21 ± 5.02), reproducibility, and repeatability with relative standard deviation (RSD) of ± 3.0% at 1.0 × 10−6 M of EDX (n = 3). Intraday and interday precisions of the probe were 99.8 ± 1.74 and 99.54 ± 2.08% at 1.0 × 10−6 M of EDX, respectively. The probe was fruitfully applied for EDX detection in its formulations and its residue in water samples with good recovery (99.76 ± 3.768–101.43 ± 0.09) and precision (RSD < 3%) at low and high EDX levels. The tabulated Student t test (t tab =2.78) was higher than the experimental t exp = 1.3–1.7 at 95% probability (n = 5). The probe exhibited good sensitivity and selectivity towards EDX detection in drug formulation and environmental water samples. The probe has long-term stability and high level of anti-interference performance towards EDX detection.