Low Detection Limit Research Articles

Sequencing of Phosphopeptides Using a Sequential Charge Inversion Ion/Ion Reaction and Electron Capture Dissociation Workflow.

Protein phosphorylation, a common post-translational modification (PTM), is fundamental in a plethora of biological processes, most importantly in modulating cell signaling pathways. Matrix-assisted laser desorption/ionization (MALDI) coupled to tandem mass spectrometry (MS/MS) is an attractive method for phosphopeptide characterization due to its high speed, low limit of detection, and surface sampling capabilities. However, MALDI analysis of phosphopeptides is constrained by relatively low abundances in biological samples and poor relative ionization efficiencies in positive ion mode. Additionally, MALDI tends to produce singly charged ions, generally limiting the accessible MS/MS techniques that can be used for peptide sequencing. For example, collision induced dissociation (CID) is readily amendable to the analysis of singly charged ions, but results in facile loss of phosphoric acid, precluding the localization of the PTM. Electron-based dissociation methods (e.g., electron capture dissociation, ECD) are well suited for PTM localization, but require multiply charged peptide cations to avoid neutralization during ECD. Conversely, phosphopeptides are readily ionized using MALDI in negative ion mode. If the precursor ions are first formed in negative ion mode, a gas-phase charge inversion ion/ion reaction could then be used to transform the phosphopeptide anions produced via MALDI into multiply charged cations that are well-suited for ECD. Herein we demonstrate a multistep workflow combining a charge inversion ion/ion reaction that first transforms MALDI-generated phosphopeptide monoanions into multiply charged cations, and then subjects these multiply charged phosphopeptide cations to ECD for sequence determination and phosphate bond localization.

Silver nanopopcorns decorated on flexible membrane for SERS detection of nitrofurazone.

Thesynthesis of three-dimensional silver nanopopcorns (Ag NPCs) onto a flexible polycarbonate membrane (PCM) for the detection of nitrofurazone (NFZ) on the fish surface by surface-enhanced Raman spectroscopy (SERS)is presented. The proposed flexible Ag-NPCs/PCM SERS substrate exhibits significant Raman signal intensity enhancement with the measured enhancement factor of 2.36 × 106. This is primarily attributed to the hotspots created on Ag NPCs, including numerous nanoscale protrusions and internal crevices distributed across the surface of Ag NPCs. The detection of NFZ by this flexible SERS substrate demonstrates a low limit of detection (LOD) of 3.7 × 10-9M and uniform and reproducible Raman signal intensities with a relative standard deviation below 8.34%. It also exhibits excellent stability, retaining 70% of its efficacy even after 10days of storage. Notably, the practical detection of NFZ in tap water, honey water, and fish surfaces achieves LOD values of 1.35 × 10-8M, 5.76 × 10-7M, and 3.61 × 10-8M,respectively, which highlights its effectiveness across different sample types. The developed Ag-NPCs/PCM SERS substrate presents promising potential for sensitive SERS detection of toxic substances in real-world samples.

High-Coverage UHPLC-MS/MS Analysis of 67 Mycotoxins in Plasma for Male Infertility Exposure Studies.

Mycotoxins are a class of exogenous metabolites that are major contributors to foodborne diseases and pose a potential threat to human health. However, little attention has been paid to trace mycotoxin co-exposure situations in vivo. To address this, we devised a novel analytical strategy, both highly sensitive and comprehensive, for quantifying 67 mycotoxins in human plasma samples. This method employs isotope dilution mass spectrometry (IDMS) for approximately 40% of the analytes and utilizes internal standard quantification for the rest. The mycotoxins were classified into three categories according to their physicochemical properties, facilitating the optimization of extraction and detection parameters to improve analytical performance. The lowest limits of detection and quantitation were 0.001-0.5 μg/L and 0.002-1 μg/L, respectively, the intra-day precision ranged from 1.8% to 11.9% RSD, and the intra-day trueness ranged from 82.7-116.6% for all mycotoxins except Ecl, DH-LYS, PCA, and EnA (66.4-129.8%), showing good analytical performance of the method for biomonitoring. A total of 40 mycotoxins (including 24 emerging mycotoxins) were detected in 184 plasma samples (89 from infertile males and 95 from healthy males) using the proposed method, emphasizing the widespread exposure of humans to both traditional and emerging mycotoxins. The most frequently detected mycotoxins were ochratoxin A, ochratoxin B, enniatin B, and citrinin. The incidence of exposure to multiple mycotoxins was significantly higher in infertile males than in healthy subjects, particularly levels of ochratoxin A, ochratoxin B, and citrinin, which were significantly increased. It is necessary to carry out more extensive biological monitoring to provide data support for further study of the relationship between mycotoxins and male infertility.

Design of microfluidic fluorescent sensor arrays for real-time and synchronously visualized detection of multi-component heavy metal ions

The majority of the environmental heavy metal ions exist in the form of multi-components, and the current single-to-single rapid detection methods are unable to meet the needs of simultaneous multi-component detection. Here, we have designed a microfluidic fluorescence sensor array by combining microfluidic sensing and organic fluorescent switches for the real-time and simultaneous visual detection of multi-component heavy metal ions. A series of “light-up” organic molecular probes was designed and synthesized, exhibiting a strong ability to bind heavy metal ions and resulting in the opening of probe fluorescence. Meanwhile, we design microfluidic sensor plate, the patterned path of the microfluidic plate has drainage channel wall and 2.70° downward slope, which can enable the samples to quickly reach the detection area. By loading organic molecular probes into the detection area, the microfluidic sensor array achieves simultaneous detection of four heavy metal ions. Combined with intelligent terminal, read and analyze the RGB color mode (RGB) results of detection, obtain quantitative information. The microfluidic fluorescence sensor array developed here can meet the requirements for in situ and semi-quantitative detection of a range of heavy metal ions with a low detection limit, fast reaction speed, and without the need for pretreatment. It represents a novel engineering technology approach for real-time detection of multi-components in the environment.

Boron-Nitrogen-Edged Biomass-Derived Carbon: A Multifunctional Approach for Colorimetric Detection of H2O2, Flame Retardancy, and Triboelectric Nanogenerator.

Enhancing the concentration and type of nitrogen (N) dopants within the Sp2-carbon domain of carbon recycled from biomass sources is an efficient approach to mimic CNT, GO, and rGO to activate oxidants such as H2O2, excluding toxic chemicals and limiting reaction steps. However, monitoring the kind and concentration of N species in the Sp2-C domain is unlikely with thermal treatments only. A high temperature for graphitization reduces N moieties, leading to low electron density. This inhibits H2O2 adsorption and activation on catalyst surfaces. In this study, coffee waste (CW) is converted into B, N-doped biochar (BXNbY) using boric acid-assisted pyrolysis (H3BO3mass = X and carbonization temperature = Y) under N2 to overcome the challenge. The B dopant regulates the concentration and type of N, provides Lewis's acid sites, and converts graphitic-N to pyridine-N in BXNbY. The optimized B3Nb900 exhibits excellent colorimetric sensing performance toward H2O2 with a low detection limit (36.9nM) and high selectivity in the presence of many interferences and milk samples due to high pyridinic-N and Sp2 domain sizes. Interestingly, B enhances other properties of N-containing CW-derived carbon and introduces self-extinguishing and tribopositive properties. Hence, BXNbY-coated polyurethane foam shows excellent flame retardancy and energy harvesting performance.

Multienzyme Mimicking Cascade Mn3O4 Catalyst to Augment Reactive Oxygen Species Elimination and Colorimetric Detection: A Study of Phase Variation upon Calcination Temperature.

Over decades, nanozyme has served as a better replacement of bioenzymes and fulfills most of the shortcomings and intrinsic disadvantages of bioenzymes. Recently, manganese-based nanomaterials have been highly noticed for redox-modulated multienzyme mimicking activity and wide applications in biosensing and biomedical science. The redox-modulated multienzyme mimicking activity was highly in tune with their size, surface functionalization, and charge on the surface and phases. On the subject of calcination temperature to Mn3O4 nanoparticles (NPs), its phase has been transformed to Mn2O3 NPs and Mn5O8 NPs upon different calcination temperatures. Assigning precise structure-property connections is made easier by preparing the various manganese oxides in a single step. The present study has focused on the variation of multienzyme mimicking activity with different phases of Mn3O4 NPs, so that they can be equipped for multifunctional activity with greater potential. Herein, spherical Mn3O4 NPs have been synthesized via a one-step coprecipitation method, and other phases are obtained by direct calcination. The calcination temperature varies to 100, 200, 400, and 600 °C and the corresponding manganese oxide NPs are named M-100, M-200, M-400, and M-600, respectively. The phase transformation and crystalline structure are evaluated by powder X-ray diffraction and selected-area electron diffraction analysis. The different surface morphologies are easily navigated by Fourier transform infrared, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy analysis. Fortunately, for the mixed valence state of Mn3O4 NPs, all phases of manganese oxide NPs showed multienzyme mimicking activity including superoxide dismutase (SOD), catalase, oxidase (OD), and peroxidase; therefore, it offers a synergistic antioxidant ability to overexpose reactive oxygen species. Mn3O4 NPs exhibited good SOD-like enzyme activity, which allowed it to effectively remove the active oxygen (O2•-) from cigarette smoke. A sensitive colorimetric sensor with a low detection limit and a promising linear range has been designed to detect two isomeric phenolic pollutants, hydroquinone (H2Q) and catechol (CA), by utilizing optimized OD activity. The current probe has outstanding sensitivity and selectivity as well as the ability to visually detect two isomers with the unaided eye.

Extending the Range of Detectable Trace Species with the Fast Polarity Switching of Chemical Ionization Orbitrap Mass Spectrometry.

Chemical ionization (CI) atmospheric pressure interface mass spectrometry is a unique analytical technique for its low detection limits, softness to preserve molecular information, and selectivity for particular classes of species. Here, we present a fast polarity switching approach for highly sensitive online analysis of a wide range of trace species in complex samples using selective CI chemistries and high-resolution mass spectrometry. It is achieved by successfully coupling a multischeme chemical ionization inlet (MION) and an Orbitrap Fourier transform mass spectrometer. The capability to flexibly combine ionization chemistries from both polarities effectively extends the detectability compared to using only one ionization chemistry, as commonly used positive and negative reagent ions tend to be sensitive to different classes of species. We tested the performance of the MION-Orbitrap using reactive gaseous organic species generated by α-pinene ozonolysis in an environmental chamber and a standard mixture of 71 pesticides. Diethylammonium and nitrate are used as reagent ions in positive and negative polarities. We show that with a mass resolving power of 280,000, the MION-Orbitrap can switch and measure both polarities within 1 min, which is sufficiently fast and stable to follow the temporal evolution of reactive organic species and the thermal desorption profile of pesticides. We detected 23 of the 71 pesticides in the mixture using only nitrate as the reagent ion. Facilitated by polarity switching, we also detected 47 pesticides using diethylammonium, improving the total number of detected species to 59. For reactive organic species generated by α-pinene ozonolysis, we show that combining diethylammonium and nitrate addresses the need to measure oxygenated molecules in atmospheric environments with a wide range of oxidation states. These results indicate that the polarity switching MION-Orbitrap can promisingly serve as a versatile tool for the nontargeted chemical analysis of trace species in various applications.

The synthesis and application of L-cysteine graphene quantum dots for quantitative analysis of nitrite content in water

The limit standard of nitrite content in drinking water is an internationally recognized safety indicator. Some fluorescence analysis methods used for quantitative analysis of nitrite suffered from low anti-interference performance and inadequate specificity. In this article, L-cysteine graphene quantum dots have been synthesized and used to built a sensor system of ratiometric fluorescence with CdTe quantum dots. The L-cysteine graphene quantum dots were characterized by TEM and XPS. Results shown that the size of product is about 2 nm with homogeneous dispersion and a interplanar distance 0.235 nm, and there were hydroxyl, carboxyl, amino and sulfhydryl groups on its surface. Also, according to the linear association between nitrite concentrations and the ratio of fluorescence intensities at 421 and 570 nm (F421 nm/F570 nm), the quantitative analysis of nitrite in water has been realized, of which the linear range was 7.25–72.5 nmol/l, and the lowest detection limit was 3.012 nmol/l. This method with high sensitivity, selectivity, and anti-interference ability might be applied to analyze of nitrite in water quantitatively.

Nano-cerium zinc molybdate embedded with activated graphene for detection of levofloxacin in polluted water resources

Antibiotics have widespread applications in personal care, animal muscle growth, and aquaculture, yet their pervasive use gives rise to substantial risks for human health and the ecosystem. Consequently, the imperative lies in developing accurate and highly sensitive detection techniques for analyzing levofloxacin (LFX). This research focuses on the hydrothermal synthesis of unique three-dimensional cubical-like ternary cerium-doped zinc molybdate (Ce@ZnMoO4) nanostructures. Ultrasonic methods were used to integrate Ce@ZnMoO4 with activated graphene (AGr) for LFX detection. X-ray diffraction, Raman spectroscopy, and field emission scanning electron microscopy were used to carefully analyze the resultant Ce@ZnMoO4/AGr composite's physical characteristics. The covalent integration of cubic-like Ce@ZnMoO4 with AGr produced a four-fold increase in sensor response compared to a Ce@ZnMoO4-modified electrode and displayed remarkable electrocatalytic activity. Due to its unique electronic and catalytic properties, Ce@ZnMoO4 synergistically interacts with the AGr layers. This synergy enhances conductivity, facilitating efficient electron transfer during electrochemical processes. Additionally, the composite offers a high surface area and numerous active sites, enabling more significant interaction between the electrode and the target analyte, LFX, thereby enhancing sensor response. The sensor demonstrated outstanding lower limits of detection (0.0031 µM), good sensitivity (0.3327 µA/µM cm-2), and a quantification limit (0.0375 µM) under optimal conditions. Along with high specificity and outstanding storage stability, a broad linear range spanning from 0.025 to 845 µM was also found. The effectiveness of the sensor is further confirmed by the successful detection of LFX in aquatic samples.

2D Zn (II) Metal‐Organic Framework as a Highly Sensitive Luminescent Sensor for Detection of the Cr2O72− and Fe3+

AbstractIn this work, NH2‐containing organic ligand 5‐Aminoisophthalic acid (AIPA), and trans‐1,2‐bis(4‐pyridyl)ethene (bpe) were selected as organic ligands to construct a new two‐dimensional luminescent Zn(II) metal‐organic framework [Zn(AIPA)(bpe)1/2]⋅named MOF‐1. It is worth noting that MOF‐1 exhibited excellent thermal stability and chemical stability in common solvents and different pH aqueous solution. As we expected, the luminescence sensing investigations demonstrated that MOF‐1 could be deemed as a multifunctional fluorescence sensor toward Cr2O72− and Fe3+ via a “turn‐off” effect. Notably, MOF‐1 had high selectivity and sensitivity for Fe3+ and Cr2O72− with low detection limits of 9.72×10−5 M and 1.95×10−5 M, respectively. Furthermore, the possible quenching mechanisms were also explored in detail.

2D organic-inorganic lead perovskite: Advancing X-ray detection capability

Two-dimensional (2D) perovskite single crystals have risen to be prominent in the domain of optoelectronic materials due to their exceptional characteristics including notably low ion migration and defect density. A distinguishing feature is the strategic inclusion of larger organic amine spacer, alternately inserted between inorganic lead halide octahedral layers. This spacer effectively mitigates ion migration, even under higher bias voltages, which is particularly advantageous for X-ray detection. However, the simultaneous realization of multiple functions within this realm remains a formidable challenge. In this work, we have synthesized a high-quality organic spacer-incorporated single layered 2D perovskite single crystal of [CYP]PbBr4 (CYP = 1-cyclohexylpiperazine). Our findings reveal the impressive potential of [CYP]PbBr4 in the domain of X-ray detection, as evidenced by the ultrahigh X-ray sensitivity, long-term stability, and astonishingly low detection limit of 1.72 nGyairs-1. Notably, [CYP]PbBr4 also emits bright broadband yellow light with quantum yield of 30.3%, and the fabricated white LED achieves a high Color Rendering Index of 94.1, which surpasses that of commercially available white LED based on YAG: Ce3+ (< 80).

Pyrene based AIE-active probe for selective detection of picric acid through the inner filter effect channel in aqueous medium

The development of pyrene derivatives possessing the AIE feature have emerged as an intriguing area of research with potential applications in several domains. In the present study, we designed and developed an AIE active pyrene derivative for picric acid sensing in an aqueous medium. The design based on a single step condensation reaction and the product has been meticulously characterized by using NMR and Mass spectrometric techniques. In comparison to pristine pyrene, the synthesized pyrene derivative has a lower bandgap energy as a result of the intramolecular charge transfer between pyrene and 4-(methylthio)-2-oxo-2H-pyran-3-carbonitrile. The synthesized probe demonstrates a moderate level of fluorescence when dissolved in a solution, and it has exhibited a remarkable emission caused by aggregation at higher water percentages. The aggregates were meticulously characterized by DLS, SEM and TEM measurements. The spherically shaped aggregates have shown enhanced fluorescence quantum yield and lifetime, rendering them a more suitable option for sensor applications. The aggregates were effectively employed as a fluorescent probe for the detection of picric acid in an aqueous medium. The probe exhibited a notable level of selectivity and sensitivity towards picric acid, as evidenced by its low detection limit of 4.47 nM. Moreover, the quenching mechanism was ascribed to the inner filter effect, providing supporting evidence from both experimental and mathematical calculations. The findings indicate that the probe has potential as a feasible choice for a picric acid sensor.

A fluorescein conjugate as colorimetric and red-emissive fluorescence chemosensor for selective recognition Cu2+ ions

A derivative of fluorescein was designed, synthesized, and characterized by FT-IR, 1H, 13C NMR, mass spectrometry, and quantum chemical calculations. When applied to the set of solutions containing different cations, it has shown a selective colorimetric and fluorescence response for Cu2+. A visible color change from colorless to purple and from non-fluorescent to red fluorescence was observed. A linear relationship between Cu2+ concentration and absorbance or fluorescence intensity was demonstrated with low detection limits (0.64 and 0.24 μM, respectively) in the acetonitrile/water mixture. Test strips are made by impregnating filter paper with acetonitrile chemosensor 1 solution and used to detect Cu2+ in water. The strips noticeably change their color from colorless to purple.

An electrochemical sensing potential of cobalt oxide nanoparticles towards citric acid integrated with computational approach in food and biological media

Although citric acid (CA) has antioxidant, antibacterial, and acidulating properties, chronic ingestion of CA can cause urolithiasis, hypocalcemia, and duodenal cancer, emphasizing the need for early detection. There are very few documented electrochemical-based sensing methods for CA detection due to the challenging behavior of electrode fouling caused by reactive oxidation products. In this study, a novel, non-enzymatic, and economical electrochemical sensor based on cobalt oxide nanoparticles (CoOxNPs) is successfully reported for detection CA. The CoOxNPs were synthesized through a simple thermal decomposition method and characterized by SEM, FT-IR, EDX, and XRD techniques. The proposed sensing platform was optimized by various parameters, including pH (7.0), time (15 min), and concentration of nanoparticles (100 mM) etc. In a linear range of 0.05–2500 μM, a low detection limit (LOD) of 0.13 μM was achieved. Theoretical calculations (ΔRT), confirmed hydrogen bonding and electrostatic interactions between CoOxNPs and CA. The detection method exhibited high selectivity in real media like food and biological samples, with good recovery values when compared favorably to the HPLC method. To facilitate effective on-site investigation, such a sensing platform can be assembled into a portable device.

Magnetic dispersive solid-phase extraction of clarithromycin and azithromycin by Fe3O4@ionic salt g-C3N4 adsorbent and HPLC-UV

In this study, Fe3O4@ionic salt g-C3N4 was synthesized as a new adsorbent for magnetic dispersive solid phase extraction (MDSPE) of two antibiotics (clarithromycin and azithromycin) in biological samples followed by HPLC-UV. The new nanocomposite was characterized by Fourier-transform infrared (FT-IR), field emission-scanning electronic microscope (FE-SEM), transmission electron microscope (TEM), nitrogen adsorption–desorption analysis, X-ray powder diffraction (XRD), and vibrating sample magnetometer (VSM). Box-Behnken design (BBD) and response surface methodology (RSM) were used for the optimization and design of experiments. The method had a suitable linear range (1–300 µg/L), a high coefficient of determination (R2; 0.9988 and 0.9993), and a low detection limit (0.33 and 0.42 µg/L) for clarithromycin and azithromycin, respectively. The applicability of the method was evaluated by estimating the recovery of analytes from urine and blood serum samples. Recovery of more than 90.0 % and RSDs of less than 5.2 % show the acceptable accuracy and precision of the proposed method.

C. Halicacabum derived “turn-on-off” non-invasive molecularly imprinted polymer for selective profiling of 2-(3,4-dihydroxy phenyl) ethylamine in human fluid samples

A rationally designed “Turn on-off” molecularly imprinted fluorescent probe SCDs-MPs serves as a robust platform for the specific identification of aberrant dopamine (DA) levels. In this study, carbon dots (SCDs) were synthesized usingCardiospermum Halicacabum leaf extract as a carbon source via a step hydrothermal process. The synergistic integration of the synthesized fluorophore SCDs (QY–27.6 %) with molecularly imprinted elements via reverse micro-emulsion technique forms novel C. Halicacabum derived SCDs-MPs nanocomposite. The synthesized SCDs-MPs possess various inimitable properties such as hydrophilicity (WCA of 12.9°) suitability for detection in aqueous media, the narrow bandgap of 3.45 eV attributed to the electron-donating nature, and photostability. Fluorescence lifetime, from 6.38 ns to 6.17 ns after adding dopamine to SCDs-MPs, and zeta potential studies (–32.9 mV to –23.9 mV) validate the static fluorescence quenching mechanism in SCDs-MPs. Under various modifications and experimental conditions, SCDs-MPs consistently achieved a low dopamine detection limit of 6.4 pM within the range of 0–50 µM. Excellent recovery experiments in human fluid samples (98–102 %) confirm the fluorescent probe’s empirical reliability. The MTT assay confirms the superior biocompatibility of SCDs-MPs, with cell viability remaining at ± 24.03 % at a concentration of 200 µg/ml suggesting the safe usage for invitro administration. This opens new possibilities for utilizing C. Halicacabum derived SCDs-MPs material in biomedical contexts.

DNA-Functionalized Gold Nanorods for One-Step Simultaneous Determination of Multiple microRNAs Based upon Plasma-Enhanced Fluorescence

MicroRNAs (miRNAs) are endogenous, noncoding, and sequence-specific single-stranded RNA regulatory factors whose abnormal expression levels are closely related to various diseases, especially cancer, and are considered effective biomarkers for disease diagnosis and prognosis. Since the concentrations of miRNAs in the body are low and disease diagnosis by detecting single miRNAs may result in a high false positive, it is essential to construct a sensitive biosensor for the determination of multiple miRNAs. In this work, an enzyme-free signal amplification assay based on plasma-enhanced fluorescence (PEF) is reported for the one-step simultaneous determination of two miRNAs. Gold nanorods (AuNRs) were functionalized with fluorescein isothiocyanate (FAM)-tagged hairpin DNA1 (H1) and cyanine 5.5 (Cy5.5)-tagged hairpin DNA2 (H2). The fluorescence signals of FAM and Cy5.5 were quenched due to their proximity to the surface of the AuNRs. In the presence of target miRNA-21 and miRNA-155, H1 and H2 complemented miRNA-21 and miRNA-155, respectively, and the fluorescence signals of FAM and Cy5.5 were not only restored but amplified due to the plasma-enhanced fluorescence. A suitable linear range (0.1 to 10 nM) and low limits of detection for miRNA-21 (23 pM) and miRNA-155 (1.6 pM) were achieved. The developed assay for the one-step simultaneous measurement of two miRNAs is simple, fast and sensitive, exhibiting great potential for monitoring these biomarkers.

Whispers in the wind: Face mask sampling for Mycobacterium tuberculosis detection in children with pulmonary tuberculosis.

Recently, face mask sampling (FMS) confirmed detection of Mycobacterium tuberculosis DNA from exhaled breath in adults with TB. To date, no study has evaluated the use of FMS to detect pulmonary Tuberculosis (TB) in children. We developed a method for FMS of M. tuberculosis-specific DNA in children and performed a clinical exploration to assess feasibility in children. Face masks were spiked, analysed on GeneXpert-Ultra, qPCR, and tNGS. Children with pulmonary TB were asked to wear three modified FFP2 masks for 30 minutes as part of an exploratory clinical study. Experiments with H37Ra M. tuberculosis strain showed a limit of 95% detection of 3.75 CFU (4.85-3.11; 95%CI) on GeneXpert-Ultra. Ten children with pulmonary TB participated in the clinical study. M. tuberculosis-specific DNA was detected on none of the face masks. Paediatric FMS has a low limit of detection for M. tuberculosis-specific DNA in vitro. However, M. tuberculosis DNA was not detected in any of thirty masks worn by children with pulmonary TB. This suggests that FMS in this form may not be more effective for detecting M. tuberculosis in children with TB than existing methods.

Microsyringe-based slug-flow microextraction for rapid and accurate determination of antibiotics in highly saline seawater

BackgroundExtensive use of antibiotics leads to widespread environmental pollution, endangering ecosystems, and human health. It is particularly concerning, posing global threats requiring urgent attention and action. In this regard, the shift to mass spectrometry in determining antibiotics is highly desirable. Significant progress has been made in analyzing and optimizing the sensitivity of high-salt samples. However, the persistence of cumbersome operational procedures presents a significant challenge to this shift. Thus, the persistence of complex operational procedures needs to be addressed. ResultsIn this study, a rapid and direct method for determining antibiotics in highly saline environmental water samples using microsyringe-based slug-flow microextraction (MSFME)-droplet spray ionization (DSI) mass spectrometry (MS) has been described. The proposed method successfully detected clarithromycin, ofloxacin, and sulfadimidine in seawater within a linear range of 1–1200 ng mL−1, with low limits of detection of 0.19 ng mL−1, 0.17 ng mL−1, and 0.20 ng mL−1, respectively (Signal/Noise = 3). Additionally, spiked real seawater samples of all three antibiotics demonstrated satisfactory recoveries (95.1–107.5%) and precision (RSD≤8.8%). The MSFME–treated high-salt sample (3.5 wt%) showed a mass spectral response intensity 4–5 orders of magnitude higher than the untreated medium-salt sample (0.35 wt%). Furthermore, exploration of the applicability of MSFME showed that it is suitable not only for high-salinity (3.5 wt%) samples but also for salt-free or low-salt and hard water samples rich in calcium and magnesium ions. SignificanceComparisons with other methods, complex laboratory setups for sample processing are now simplified to a single step, completing the entire process, including desalination and detection, MSFME–DSI–MS provides faster results in less than 1 min while maintaining sensitivity comparable to that of other detection methods. In conclusion, this advancement provides an exceptionally simplified protocol for the rapid, highly sensitive, and quantitative determination of antibiotics in environmental water samples.

Spectrofluorometric determination of futibatinib in human plasma and pharmaceutical formulations

Futibatinib is a powerful inhibitor of fibroblast growth factor receptors that impedes its phosphorylation and subsequently leading to a reduction in in cell viability across various cell lines. Futibatinib was approved for initial use as an effective treatment for several diseases, including non-small cell lung cancer and breast cancer. Herein, a novel selective fluorescence probe was created for futibatinib quantification in various matrices, including pharmaceutical formulation and human plasma. The technique primarily depends on futibatinib’s chemical conversion into a fluorescent product through a reaction with trimethylamine and bromoacetyl bromide. The created fluorescent probe exhibits maximum emission peak at 338 nm upon excitation at 248 nm. The method provided a low detection limit of 0.120 ng/mL and maintained a linear concentration-dependent relationship across the range of 1–200 ng/mL. High sensitivity, accuracy and precision were demonstrated for futibatinib quantification in pharmaceutical formulation and spiked plasma matrix by the method, which was validated in accordance with ICH requirements.