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Journal of Chromatography. A Aug 2023Retention and separation of enantiomers of amine derivatives of indane and tetralin (rasagiline and its analogues) on chiral stationary phases (CSPs) Chiral-T and... (Review)
Review
Retention and separation of enantiomers of amine derivatives of indane and tetralin (rasagiline and its analogues) on chiral stationary phases (CSPs) Chiral-T and Chiral-V with teicoplanin and vancomycin antibiotics grafted onto superficially porous silica particles under conditions of reversed-phase and polar organic chromatography were studied. The mobile phases (MP) were water-methanol and acetonitrile-methanol solvents modified with triethylamine-acetic acid buffer. The effects of molecular structure and physical properties of the analytes on enantioselective retention are discussed. The retention mechanism is hypothesized to involve the ion-ion attraction between the positively charged amino group of an analyte and the carboxylate anion of either antibiotic. The binding occurs outside of the antibiotic's aglycon basket that accounts for relatively low enantioselectivity observed. The presence of a large substitute at the analyte's amino group complicates enantiorecognition. The effect of the MP solvent composition on retention and enantioseparation was investigated. It is a complex phenomenon combined of different oppositely directed influences that resulted in different shapes, increasing, decreasing, or U-shaped, of the retention factor vs. composition dependences. A model taking into account the interaction of both solvents of a binary MP with both an analyte and an adsorption site was successfully applied to approximate a majority of the studied systems. Pros and cons of the model are discussed.
Topics: Vancomycin; Teicoplanin; Porosity; Methanol; Anti-Bacterial Agents; Solvents; Stereoisomerism; Indicators and Reagents; Chromatography, High Pressure Liquid
PubMed: 37315444
DOI: 10.1016/j.chroma.2023.464120 -
The AAPS Journal Mar 2016The importance of appropriate sample management in regulated bioanalysis is undeniable for clinical and non-clinical study support due to the fact that if the samples... (Review)
Review
The importance of appropriate sample management in regulated bioanalysis is undeniable for clinical and non-clinical study support due to the fact that if the samples are compromised at any stage prior to analysis, the study results may be affected. Health authority regulations do not contain specific guidance on sample management; therefore, as part of the Global Bioanalysis Consortium (GBC), the A5 team was established to discuss sample management requirements and to put forward recommendations. The recommendations from the team concern the entire life span of the sample and include the following: 1. Sampling procedures should be described in the protocol or within the laboratory manual. This information should include the volume of the sample to be collected, the required anticoagulant, light sensitivity, collection and storage containers, and labeling with a unique identifier. 2. The correct procedures for processing and then storing the samples after collection at the clinical/non-clinical testing site and during shipment are also very important to ensure the analyte(s) stability and should be documented. 3. Chain of custody for the samples must be maintained throughout the complete life span of each sample. This is typically maintained via paper and electronic data systems, including Laboratory Information Management Systems (LIMS) where available. 4. Pre- and post-analysis storage location and conditions must also be clearly defined at the analytical laboratory. The storage temperature of the samples must be traceable and controlled by monitoring and warning alerts. The team suggests moving away from using temperatures and to adopt standard terminology of "room temperature," "refrigerator," "freezer," and "ultra-freezer" that have defined and industry-wide accepted temperature ranges. 5. At the end of the study, documentation of the samples' disposal is required.
Topics: Biological Specimen Banks; Congresses as Topic; Humans; Internationality; Medical Laboratory Science; Specimen Handling
PubMed: 26821803
DOI: 10.1208/s12248-016-9869-2 -
Veterinary Clinical Pathology Sep 2023Biological variation (BV) of urinary (U) biochemical analytes has not been described in absolute terms, let alone as a ratio of the U-creatinine or fractional excretion...
BACKGROUND
Biological variation (BV) of urinary (U) biochemical analytes has not been described in absolute terms, let alone as a ratio of the U-creatinine or fractional excretion in healthy dogs. These analytes are potential diagnostic tools for different types of kidney damage and electrolyte disorders in dogs.
OBJECTIVES
We aimed to investigate the BV of specific gravity, osmolality, creatinine, urea, protein, glucose, chloride, sodium, potassium, calcium, and phosphate in urine from healthy pet dogs.
METHODS
Blood and urine samples from 13 dogs were collected once weekly for 8 weeks. Samples were analyzed in duplicate and in randomized order. For each sample, U-analyte and serum concentrations were measured, and U-analyte/U-creatinine and fractional excretion (FE) were calculated. Components of variance, estimated by restricted maximum likelihood, were used to determine within-subject variation (CV ), between-subject variation (CV ), and analytical variation (CV ). Index of individuality (II) and reference change values were calculated.
RESULTS
CV for all urine analytes varied between 12.6% and 35.9%, except for U-sodium, U-sodium/U-Cr, and FE-sodium, which had higher CV s (59.5%-60.7%). For U-protein, U-sodium, U-potassium, U-sodium/U-creatinine, FE-urea, FE-glucose, FE-sodium, FE-potassium, and FE-phosphate II were low, indicating that population-based RIs were appropriate. The remaining analytes had an intermediate II, suggesting that population-based RIs should be used with caution.
CONCLUSION
This study presents information on the biological variation of urinary and serum biochemical analytes from healthy dogs. These data are important for an appropriate interpretation of laboratory results.
Topics: Dogs; Animals; Creatinine; Sodium; Potassium; Glucose; Urea; Phosphates; Reference Values
PubMed: 37316471
DOI: 10.1111/vcp.13225 -
The Analyst May 2017The ability to separate analytes with increasingly similar properties drives the field of separation science. One way to achieve such separations is using trapping and...
The ability to separate analytes with increasingly similar properties drives the field of separation science. One way to achieve such separations is using trapping and streaming dielectrophoresis (DEP), which directly exploits the subtle differences in the electrophysical properties of analytes. The non-uniform fields necessary for DEP can be formed using various insulator shapes in microchannels. Current insulator shapes include triangles, diamonds, circles, and rectangles. However, all of these insulators pose problems for trapping, streaming, and sorting (deflection) as the induced fields/gradients are not behaviorally consistent across the lateral dimension. This leads to analytes experiencing different forces depending on their pathline in the microchannel and result in low resolution separations. Based on an iterative process that explored approximately 40 different insulator shapes, a design was chosen that indicated improved particle streamlines, better trapping efficiency, and consistent electrical environments across the lateral dimension. The design was assessed by simulations where the electric field, gradient of the electric field squared, and the ratio of the two were plotted. The improved design includes a unique new multi-length scale element. The multi-length scale structure streamlines the analyte(s) and improves homogeneity in the lateral dimension, while still achieving high gradients necessary for analyte separation using DEP. The design is calculated to keep analytes on the centerline which should improve resolution, and eliminate extraneous trapping zones. Behaviors consistent with the features of the simulations were observed in proof of principle experiments using representative test probes.
PubMed: 28394391
DOI: 10.1039/c6an02509a -
Journal of Chromatography. A Jan 2022Pesticides are used extensively in a wide range of applications and due to their high rate of consumption, they are ubiquitous in the different media and samples like... (Review)
Review
Pesticides are used extensively in a wide range of applications and due to their high rate of consumption, they are ubiquitous in the different media and samples like environment, water sources, air, soil, biological materials, wastes (liquids, solids or sludges), vegetables and fruits, where they can persist for long periods. Pesticides often have hazardous side effects and can cause a range of harmful diseases like Parkinson, Alzheimer, asthma, depression and anxiety, cancer, etc, even at low concentrations. To this end, extraction, pre-concentration and determination of pesticides from various samples presents significant challenges caused by sample complexity and the low concentrations of them in many samples. Often, direct extraction and determination of pesticides are impossible due to their low concentrations and the complexity of samples. The main goals of sample preparation are removing interfering species, pre-concentrating target analyte/s and converting the analytes into more stable forms (when needed). The most popular approach is solid-phase extraction due to its simplicity, efficiency, ease of operation and low cost. This method is based on using a wide variety of materials, among which covalent organic frameworks (COFs) can be identified as an emerging class of highly versatile materials exhibiting advantageous properties, such as a porous and crystalline structure, pre-designable structure, high physical and chemical stability, ease of modification, high surface area and high adsorption capacity. The present review will cover recent developments in synthesis and applications of COFs and their composites for extraction of pesticides, different synthesis approaches of COFs, possible mechanisms for interaction of COFs-based adsorbents with pesticides and finally, future prospects and challenges in the fabrication and utilization of COFs and their composites for extraction of pesticides.
Topics: Adsorption; Metal-Organic Frameworks; Pesticides; Solid Phase Extraction; Vegetables
PubMed: 34844738
DOI: 10.1016/j.chroma.2021.462612 -
ACS Omega Jul 2022The use of immunodetection assays including the widely used enzyme-linked immunosorbent assay (ELISA) in applications such as point-of-care detection is often limited by...
The use of immunodetection assays including the widely used enzyme-linked immunosorbent assay (ELISA) in applications such as point-of-care detection is often limited by the need for protein immobilization and multiple binding and washing steps. Here, we describe an experimental and analytical framework for the development of simple and modular "mix-and-read" enzymatic complementation assays based on split luciferase that enable sensitive detection and quantification of analytes in solution. In this assay, two engineered protein binders targeting nonoverlapping epitopes on the target analyte were each fused to nonactive fragments of luciferase to create biosensor probes. Binding proteins to two model targets, lysozyme and Sso6904, were isolated from a combinatorial library of Sso7d mutants using yeast surface display. In the presence of the analyte, probes were brought into close proximity, reconstituting enzymatic activity of luciferase and enabling detection of low picomolar concentrations of the analyte by chemiluminescence. Subsequently, we constructed an equilibrium binding model that relates binding affinities of the binding proteins for the target, assay parameters such as the concentrations of probes used, and assay performance (limit of detection and concentration range over which the target can be quantified). Overall, our experimental and analytical framework provides the foundation for the development of split luciferase assays for detection and quantification of various targets.
PubMed: 35874239
DOI: 10.1021/acsomega.2c02319 -
Journal of Materials Chemistry. B Nov 2022In the last few decades, nanomaterials have made great advances in the biosensor field, thanks to their ability to enhance several key issues of biosensing analytical... (Review)
Review
In the last few decades, nanomaterials have made great advances in the biosensor field, thanks to their ability to enhance several key issues of biosensing analytical tools, namely, sensitivity, selectivity, robustness, and reproducibility. The recent trend of sustainability has boosted the progress of novel and eco-designed electrochemical paper-based devices to detect easily the target analyte(s) with high sensitivity in complex matrices. The huge attention given by the scientific community and industrial sectors to paper-based devices is ascribed to the numerous advantages of these cost-effective analytical tools, including the absence of external equipment for solution flow, thanks to the capillary force of paper, the fabrication of reagent-free devices, because of the loading of reagents on the paper, and the easy multistep analyses by using the origami approach. Besides these features, herein we highlight the multifarious aspects of the nanomaterials such as (i) the significant enlargement of the electroactive surface area as well as the area available for the desired chemical interactions, (ii) the capability of anchoring biorecognition elements on the electrode surface on the paper matrix, (iii) the improvement of the conductivity of the cellulose matrix, (iv) the functionality of photoelectrochemical properties within the cellulose matrix, and (v) the improvement of electrochemical capabilities of conductive inks commonly used for electrode printing on the paper support, for the development of a new generation of paper-based electrochemical biosensors applied in the biomedical field. The state of the art over the last ten years has been analyzed highlighting the various functionalities that arise from the integration of nanomaterials with paper-based electrochemical biosensors for the detection of biomarkers.
Topics: Reproducibility of Results; Nanostructures; Biosensing Techniques; Biomarkers; Cellulose
PubMed: 35899594
DOI: 10.1039/d2tb00387b -
Frontiers in Chemistry 2021Anodic stripping voltammetry (ASV) is a powerful electrochemical analytical technique that allows for the detection and quantification of a variety of metal ion species... (Review)
Review
Anodic stripping voltammetry (ASV) is a powerful electrochemical analytical technique that allows for the detection and quantification of a variety of metal ion species at very low concentrations in aqueous media. While early, traditional ASV measurements relied on macroscopic electrodes like Hg drop electrodes to provide surfaces suitable for plating/stripping, more recent work on the technique has replaced these electrodes with thin film metal electrodes generated . Such electrodes are plated alongside the analyte species onto the surface of a primary electrode, producing a composite metal electrode from which the analyte(s) can then be stripped, identified, and quantified. In this minireview, we will explore the development and use of these unique electrodes in a variety of different applications. A number of metals (e.g., Hg, Bi, Sn, etc.) have shown promise as thin film ASV electrodes in both acidic and alkaline media, and frequently multiple metals in addition to the analyte of interest are deposited together to optimize the plating/stripping behavior, improving sensitivity. Due to the relatively simple nature of the measurement and its suitability for a wide range of pH, it has been used broadly: To measure toxic metals in the environment, characterize battery materials, and enable biological assays, among other applications. We will discuss these applications in greater detail, as well as provide perspective on future development and uses of these thin film electrodes in ASV measurements.
PubMed: 35186893
DOI: 10.3389/fchem.2021.809535 -
ACS Sensors Oct 2021Potentiometric sensors induce a spontaneous voltage that indicates ion activity in real time. We present here an advanced self-powered potentiometric sensor with memory....
Potentiometric sensors induce a spontaneous voltage that indicates ion activity in real time. We present here an advanced self-powered potentiometric sensor with memory. Specifically, the approach allows for one to record a deviation from the analyte's original concentration or determine whether the analyte concentration has surpassed a threshold in a predefined time interval. The sensor achieves this by harvesting energy in a capacitor and preserving it with the help of a diode. While the analyte concentration is allowed to return to an original value following a perturbation over time, this may not influence the sensor readout. To achieve the diode function, the sensor utilizes an additional pair of driving electrodes to move the potentiometric signal to a sufficiently high base voltage that is required for operating the diode placed in series with the capacitor and between the sensing probes. A single voltage measurement across the capacitor at the end of a chosen time interval is sufficient to reveal any altered ion activity occurring during that period. We demonstrate the applicability of the sensor to identify incurred pH changes in a river water sample during an interval of 2 h. This approach is promising for achieving deployable sensors to monitor ion activity relative to a defined threshold during a time interval with minimal electronic components in a self-powered design.
Topics: Electrodes; Electronics; Potentiometry
PubMed: 34582164
DOI: 10.1021/acssensors.1c01273 -
Methods and Applications in Fluorescence Apr 2023The wavelength-ratiometric techniques demonstrate strong advantages in fluorescence sensing and imaging over techniques employing variations of intensity at single... (Review)
Review
The wavelength-ratiometric techniques demonstrate strong advantages in fluorescence sensing and imaging over techniques employing variations of intensity at single wavelength. We present different possibilities for realization of these advantages in different simplified, miniaturized and multiplexing devices. They include the smartphone-based detection systems and strips, in which the color changes are observed with naked eye. The array-based techniques and different immunoassays with-ratiometric detection demonstrate strongly increased stability and sensitivity. The application areas extend from on-site monitoring of environment and point-of-care diagnostics to testing in personal need. Selected examples of sensing different analytes in chemical and biological systems demonstrate multiple possibilities of coupling the analyte-sensor interaction with the generation of-ratiometric output signal. Among them, simultaneous detection of several analytes and performing logical operations that can be useful in analysis. Finally, the benefits of multicolor ratiometric fluorescence imaging are demonstrated by visualization the functionally important parameters of biological membranes.
Topics: Spectrometry, Fluorescence; Fluorescent Dyes; Fluorometry; Quantum Dots; Optical Imaging
PubMed: 36958041
DOI: 10.1088/2050-6120/acc715