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Journal of AOAC International Mar 2023Laboratory sampling is a significant source of error in feed testing. Proficiency testing programs such as the Association of American Feed Control Officials Proficiency...
BACKGROUND
Laboratory sampling is a significant source of error in feed testing. Proficiency testing programs such as the Association of American Feed Control Officials Proficiency Testing Program are an effective means of assessing error in and among analytical methods. However, all proficiency test items are comminuted and blended to control variability among items, effectively minimizing sampling error. Currently there is no mechanism for monitoring sampling error among laboratories.
OBJECTIVE
The objective of this work was to investigate the feasibility of a proficiency testing program for laboratory sampling methods and provide insight into a program to advance the performance of sampling in laboratories.
METHODS
The study involved the fabrication of identical feed test items from feed ingredients and shipping the uncomminuted materials to volunteer laboratories. The volunteer laboratories followed in-house procedures for selecting test portions for routine feed tests. Tests on all the test portions for a single analyte were performed by a single laboratory, so that the variability in test results could be attributed to laboratory sampling processes to select test portions.
RESULTS
The average RSD, %, for Item A and Item B, respectively, were as follows: protein, 5.08 and 5.23; non-protein nitrogen, 8.90 and 16.6; crude fat, 3.45 and 5.67; vitamin A, 33.9 and 26.9; calcium, 21.9 and 23.6; zinc, 17.9 and 27.9; and copper, 17.4 and 27.9.
CONCLUSION
This study suggests that a proficiency testing program for laboratory sampling is feasible with manual manufacture of the test items, and data can be used to monitor laboratory sampling proficiency and also to compare the performance of different laboratory sampling methods.
HIGHLIGHTS
The data illustrates that each analyte has unique distributional and compositional heterogeneity, thus unique sampling error, even when multiple analytes are determined from a single test portion.
Topics: United States; Laboratories; Laboratory Proficiency Testing; Specimen Handling; Animal Feed
PubMed: 36156140
DOI: 10.1093/jaoacint/qsac117 -
Bioanalysis Feb 2022Analyzing unstable small molecule drugs and metabolites in blood continues to be challenging for bioanalysis. Although scientific countermeasures such as immediate... (Review)
Review
Analyzing unstable small molecule drugs and metabolites in blood continues to be challenging for bioanalysis. Although scientific countermeasures such as immediate cooling, immediate freezing, addition of enzyme inhibitors, pH adjustment, dried blood spot or derivatization have been developed, selecting the best practices has become an issue in the pharmaceutical industry as the number of drugs with such problems is increasing, even for generic drugs. In this study, we conducted a comprehensive literature review and a questionnaire survey to determine a suitable practice for evaluating instability and implementing countermeasures. Three areas of focus, matrix selection, effect of hemolysis and selection of esterase inhibitors, are discussed.
Topics: Biological Assay; Chemistry, Analytic; Humans; Japan; Surveys and Questionnaires
PubMed: 34894755
DOI: 10.4155/bio-2021-0229 -
Analytica Chimica Acta Jan 2023Noble metal nanoparticles (MNPs), have represented the keystone of a plethora of (bio)sensing analytical strategies because of their unique physicochemical features,... (Review)
Review
Noble metal nanoparticles (MNPs), have represented the keystone of a plethora of (bio)sensing analytical strategies because of their unique physicochemical features, becoming unique tools in the analytical scenario; in particular, MNPs localized surface plasmon resonance (LSPR) offers infinite analytical possibilities. In this work, the scaling-up from colloidal MNPs to their integration in solid substrates is overviewed, and the relative sensing and biosensing optical strategies based on LSPR changes are systematically treated in accordance with the supporting substrate employed. Recent literature and key papers reporting MNPs integration into solid substrates are considered, paying particular attention to the MNPs-based event into/onto the solid support and the related plasmonic change used as analytical signal. The review is organized in sections according to the solid support nature (glass, polymers, cellulose) and the papers are discussed according to the sensing strategy. The strategies have been classified in MNPs synthesis, growth, etching, displacement/aggregation directly or indirectly mediated by the analyte(s); only works that rely on plasmonic-transduction principles are taken into account, MNPs used as catalysts or in lateral flow systems are not considered. The review demonstrates that MNPs decorated/integrated substrates are now mature analytical tools, able to overcome the limitations of MNPs colloidal suspensions; this results in new analytical opportunities, particularly the realization of integrated systems, lab-on-chip/lab-on-strip and flexible devices, paving the way for a new generation of plasmonic (bio)sensors for point-of-need applications.
Topics: Nanostructures; Surface Plasmon Resonance; Metal Nanoparticles; Cellulose; Polymers
PubMed: 36442936
DOI: 10.1016/j.aca.2022.340594 -
Current Issues in Molecular Biology Oct 2023An immunoassay is an analytical test method in which analyte quantitation is based on signal responses generated as a consequence of an antibody-antigen interaction.... (Review)
Review
An immunoassay is an analytical test method in which analyte quantitation is based on signal responses generated as a consequence of an antibody-antigen interaction. They are the method of choice for the measurement of a large panel of diagnostic markers. Not only are they fully automated, allowing for a short turnaround time and high throughput, but offer high sensitivity and specificity with low limits of detection for a wide range of analytes. Many immunoassay manufacturers exploit the extremely high affinity of biotin for streptavidin in their assay design architectures as a means to immobilize and detect analytes of interest. The biotin-(strept)avidin system is, however, vulnerable to interference with high levels of supplemental biotin that may cause elevated or suppressed test results. Since this system is heavily applied in clinical diagnostics, biotin interference has become a serious concern, prompting the FDA to issue a safety report alerting healthcare workers and the public about the potential harm of ingesting high levels of supplemental biotin contributing toward erroneous diagnostic test results. This review includes a general background and historical prospective of immunoassays with a focus on the biotin-streptavidin system, interferences within the system, and what mitigations are applied to minimize false diagnostic results.
PubMed: 37998726
DOI: 10.3390/cimb45110549 -
Equine Veterinary Journal May 2021Measurement of hypoglycin A (HGA) and its toxic metabolite, methylenecyclopropylacetic acid (MCPA), in equine serum confirms a diagnosis of atypical myopathy (AM), a...
BACKGROUND
Measurement of hypoglycin A (HGA) and its toxic metabolite, methylenecyclopropylacetic acid (MCPA), in equine serum confirms a diagnosis of atypical myopathy (AM), a pasture-associated toxic rhabdomyolysis with high mortality linked to the ingestion of Acer trees plant material. Supportive diagnostic tests include plasma acyl-carnitine profiling and urine organic acid testing, but these are not specific for AM. Previously reported HGA and MCPA analytical techniques used liquid chromatography-mass spectrometry (LC-MS) with a derivatising step, but the latter prolongs testing and increases costs.
OBJECTIVES
To develop a rapid LCMS method for detection of serum and tissue HGA and MCPA that enables expedited diagnosis for horses with AM.
STUDY DESIGN
Analytical test validation.
METHODS
Validation parameters to industry standards using as criteria precision, accuracy, linearity, reproducibility and stability in analyte-spiked samples were calculated on 9-calibration points and 3 different validation concentrations in both serum and muscle tissue.
RESULTS
The test was successfully validated for the detection of HGA and MCPA-carnitine in equine serum and muscle. Test linearity was excellent (r = .999), accuracy was very good for both analytes (93%-108%), precision did not exceed 10% coefficient of variation and reproducibility met the requirements of the Horwitz equation. Stability was unaffected by storage at a range of temperatures.
MAIN LIMITATIONS
The spectrum of the tested analytes was limited to only two relevant analytes in favour of a quick and easy analysis. Linearity of the muscle method was not evaluated as calibration curves were not produced in this matrix.
CONCLUSION
We report an optimised, simplified and validated method for detection of HGA and MCPA-carnitine in equine serum and muscle suitable for rapid diagnosis of suspected AM cases. The serum-based test should also enable risk assessment of toxin exposure in cograzing horses and assessment of horses with undiagnosed myopathies, while the tissue detection test should help to confirm cases post-mortem and to determine toxin distribution, metabolism and clearance across different tissues.
Topics: Animals; Carnitine; Chromatography, Liquid; Cyclopropanes; Horse Diseases; Horses; Hypoglycins; Muscles; Reproducibility of Results; Tandem Mass Spectrometry
PubMed: 32525217
DOI: 10.1111/evj.13303 -
Journal of Pharmaceutical and... Feb 2021Thyroid hormones act on almost every tissue in the body to promote catabolism in cells and are important for regulating many biological processes. Accurate...
Thyroid hormones act on almost every tissue in the body to promote catabolism in cells and are important for regulating many biological processes. Accurate quantification of endogenous thyroid hormones has become essential for clinical and non-clinical applications in the development of new drugs according to the OECD Guideline (2018). However, there are difficulties in quantitative analysis of thyroid hormones because no analyte-free biological matrices are available for analysis of endogenous substances. In this study, surrogate matrix and surrogate analyte methods were compared and validated to quantify endogenous triiodothyronine (T) and thyroxine (T) in rat serum using LC-MS/MS. Separation of analytes was performed using an Xbridge™ C18 (2.1 × 50 mm, 2.5 μm) column. In the surrogate matrix, 3,3'5-triiodo- l-thyronine-C (cT) and l-thyroxine-C (cT) were used as the internal standard (IS), and in the surrogate analyte, l-3,3'-diiodothyronine-C (cT) was used as the IS. The mobile phases consisted of 0.1 % acetic acid in purified water (A) and 0.1 % acetic acid in acetonitrile (B). Both analytical methods were suitable for selectivity, matrix effect, carryover, lower limit of quantification, linearity, accuracy, precision, recovery, stability and parallelism. The surrogate matrix method was more accurate than using the surrogate analyte method, including evaluation of parallelism at low concentrations. Additionally, the surrogate matrix is cost-effective for T and T analysis in biological samples because it consists only of deionized water. However, surrogate analytes difficult to evaluate parallelism by obtaining response factors for mass spectrometric signal differences between the actual and surrogate analytes. Therefore, the results of this study indicate that it is more cost-effective to use the surrogate matrix method for endogenous thyroid hormone, T and T, analysis in biological samples.
Topics: Animals; Chromatography, Liquid; Rats; Reproducibility of Results; Tandem Mass Spectrometry; Thyroid Hormones; Thyroxine; Triiodothyronine
PubMed: 33383502
DOI: 10.1016/j.jpba.2020.113840 -
Materials Today. Bio Jun 2023Gold nanozymes (GNZs) have been widely used in biosensing and bioassay due to their interesting catalytic activities that enable the substitution of natural enzyme. This... (Review)
Review
Gold nanozymes (GNZs) have been widely used in biosensing and bioassay due to their interesting catalytic activities that enable the substitution of natural enzyme. This review explains different catalytic activities of GNZs that can be achieved by applying different modifications to their surface. The role of Gold nanoparticles (GNPs) in mimicking oxidoreductase, helicase, phosphatase were introduced. Moreover, the effect of surface properties and modifications on each catalytic activity was thoroughly discussed. The application of GNZs in biosensing and bioassay was classified in five categories based on the combination of the enzyme like activities and enhancing/inhibition of the catalytic activities in presence of the target analyte/s that is realized by proper surface modification engineering. These categories include catalytic activity enhancer, reversible catalytic activity inhibitor, binding selectivity enhancer, agglomeration base, and multienzyme like activity, which are explained and exemplified in this review. It also gives examples of those modifications that enable the application of GNZs for biosensing and bioassays.
PubMed: 37214551
DOI: 10.1016/j.mtbio.2023.100656 -
The Journal of Physical Chemistry... Aug 2023Nanoparticle-assisted nuclear magnetic resonance (NMR) chemosensing exploits monolayer-protected nanoparticles as supramolecular hosts to detect small molecules in...
Nanoparticle-assisted nuclear magnetic resonance (NMR) chemosensing exploits monolayer-protected nanoparticles as supramolecular hosts to detect small molecules in complex mixtures via nuclear Overhauser effect experiments with detection limits down to the micromolar range. Still, the structure-sensitivity relationships at the basis of such detection limits are little understood. In this work, we integrate NMR spectroscopy and atomistic molecular dynamics simulations to examine the covariates that affect the sensitivity of different NMR chemosensing experiments [saturation transfer difference (STD), water STD, and high-power water-mediated STD]. Our results show that the intensity of the observed signals correlates with the number and duration of the spin-spin interactions between the analytes and the nanoparticles and/or between the analytes and the nanoparticles' solvation molecules. In turn, these parameters depend on the location and dynamics of each analyte inside the monolayer. This insight will eventually facilitate the tailoring of experimental and computational setups to the analyte's chemistry, making NMR chemosensing an even more effective technique in practical use.
PubMed: 37498189
DOI: 10.1021/acs.jpclett.3c01005 -
Journal of Chromatographic Science Apr 2021Solid-phase microextraction (SPME) is an analytical method for microextraction of analytes, in which the analytes bind to the sorbent on the surface of the SPME fiber....
Plant Extract and Herbal Products as Potential Source of Sorbent for Analytical Purpose: An Experimental Study of Morphine and Codeine Determination Using HPLC and LC-MSMS.
Solid-phase microextraction (SPME) is an analytical method for microextraction of analytes, in which the analytes bind to the sorbent on the surface of the SPME fiber. Many types of chemical agents are used as sorbent; however, many of these sorbents cause secondary contamination or are not cost-effective. Here, aqueous extract of Ferula gummosa was evaluated as potential source of sorbent for simultaneous microextraction of morphine and codeine. For this purpose, multiwalled carbon nanotubes were carboxylated with H2SO4/HNO3 (3:1) and then functionalized with aqueous extract of F. gummosa. Functionalization was confirmed by Fourier transform infrared and Raman spectroscopy measurements as well as scanning electron microscopy analysis. Porous polypropylene hollow fibers were filled with the functionalized carbon nanotubes (CNTs) and used for analyte extraction in urine sample at 40°C and pH 6 for 2 min. Reversed-phase high-performance liquid chromatography (RP-HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis showed that the fiber could preconcentrate 1 ng/mL of morphine and 0.75 ng/mL codeine in urine sample and was successfully used for 30 times with no significant loss in the extraction efficiency. Limit of detection (LOD) and limit of quantification (LOQ) for morphine were 1 and 3.3 ng/mL, respectively. LOD and LOQ for codeine were determined 0.75 and 2.47 ng/mL, respectively. Recovery of the fiber was 80% and 93% for morphine and codeine, respectively. SPME fiber using extract of F. gummosa plant was used for the detection of a small amount of morphine in urine sample. Therefore, plants can be considered as abundant and cheap sources of sorbent for various analytical purposes.
Topics: Adsorption; Chromatography, High Pressure Liquid; Chromatography, Liquid; Codeine; Ferula; Humans; Limit of Detection; Morphine; Nanotubes, Carbon; Plant Preparations; Solid Phase Microextraction; Tandem Mass Spectrometry
PubMed: 33388745
DOI: 10.1093/chromsci/bmaa108 -
Soft Matter Nov 2023Nanoparticle aggregation is a driving principle of innovative materials and biosensing methodologies, improving transduction capabilities displayed by optical,...
Nanoparticle aggregation is a driving principle of innovative materials and biosensing methodologies, improving transduction capabilities displayed by optical, electrical or magnetic measurements. This aggregation can be driven by the biomolecular recognition between target biomolecules (analytes) and receptors bound onto nanoparticle surface. Despite theoretical advances on modelling the entropic interaction in similar systems, predictions of the fractal morphologies of the nanoclusters of bioconjugated nanoparticles are lacking. The morphology of resulting nanoclusters is sensitive to the location, size, flexibility, average number of receptors per particle , and the analyte-particle concentration ratio. Here we considered bioconjugated iron oxide nanoparticles (IONPs) where bonds are mediated by a divalent protein that binds two receptors attached onto different IONPs. We developed a protocol combining analytical expressions for receptors and linker distributions, and Brownian dynamics simulations for bond formation, and validated it against experiments. As more bonds become available (, by adding analytes), the aggregation deviates from the ideal Bethe's lattice scenario due to multivalence, loop formation, and steric hindrance. Generalizing Bethe's lattice theory with a (not-integer) effective functionality leads to analytical expressions for the cluster size distributions in excellent agreement with simulations. At high analyte concentration steric impediment imposes an accessible limit value to , which is bounded by < < . A transition to gel phase, is correctly captured by the derived theory. Our findings offer new insights into quantifying analyte amounts by assessing nanocluster size, and predicting nanoassembly morphologies accurately is a first step towards understanding variations of physical properties in clusters formed after biomolecular recognition.
Topics: Particle Size; Nanoparticles; Molecular Dynamics Simulation
PubMed: 37530392
DOI: 10.1039/d3sm00536d