Detection Limit Of Method Research Articles

Method Development and Validation of Luliconazole Bulk Drug Using Reverse Phase - HPLC Technique

Objective: To develop and validate the RP- HPLC method for determining Luliconazole in bulk and pharmaceutical formulations. Methods: Following the International Conference on Harmonization (ICH) guidelines, a sensitive, accurate, and specific reversed-phase HPLC technique was created and validated for the detection of Luliconazole. Using high-performance liquid chromatography, this drug was examined. A better separation of the drug was achieved by using Agilent Eclipse XDB C (4.6mm x 250mm, 5µm) with a mobile phase consisting of a mixture of Acetonitrile and Buffer in HPLC water. The ratio of 30:70 v/v (Formic acid and Acetonitrile) at a flow rate of 1.0 ml/ min and the detection was at the wavelength 295 nm using a Photodiode Arrays Detector. The planned method was able to produce good quality separation of the drug and its degradation products with sharp peaks. Findings: Luliconazole had a retention time of 2.38 ± 0.127 minutes. The technique was linear in the range of 10-100 µg/ml, with a correlation (r2) of 0.9995 and a run duration of 4 minutes. The method limit of detection (LOD) and limit of quantification (LOQ) were set at 0.1 and 1 g/ml, respectively. The method accuracy and system precision were estimated, and the findings were calculated as percentage RSD values, which were found to be limitations. Luliconazole recovery was 100% confirming the method's efficiency. Novelty: The presented approach was innovative and successfully fulfilled all validation requirements, including linearity, robustness, accuracy, reduced retention, and run time. This suggests that the method is appropriate for identifying the stability of luliconazole in bulk and pharmaceutical formulations. Keywords: RP-HPLC, Transferosome, ICH guidelines, Validation, Luliconazole

Accurate and stable detection of p-phenylenediamine antioxidants and their transformation products in aquatic products using antioxidant protection – Analysis of actual aquatic products

Given the high toxicity of N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) derivatives, such as 6PPD quinone (6PPDQ) to salmon, as well as their ubiquitous presence in the environment, the contaminant of aquatic food products has drawn significant attention. However, analytical methods for p-Phenylenediamines (PPDs) and their transformation products (TPs) in aquatic products remain underdeveloped. In particular, the degradation of some compounds and strong matrix effects complicate detection. In this study, we present a stable, rapid, and sensitive method combining salt-out assisted extraction, antioxidant protection, and multi-plug filtration clean-up (m-PFC) to detect two PPDs and five TPs in aquatic products. Crucially, the appropriate selection of antioxidants prevented the degradation of the easily oxidized target compounds. Further, the m-PFC method significantly enhanced the purification efficiency, achieving satisfactory recoveries (62.1–115 %), and method detection limits (MDLs) ranging from 0.00300 to 0.400 μg/kg. Subsequently, the method was applied to monitor PPDs and their TPs in aquatic products systematically, revealing the presence of 6PPD and N-isopropyl-N′-phenyl-1,4-phenylenediamine (IPPD) in white shrimp from aquafarms, whereas none of the seven target analytes were detected in fish and crab samples. These findings contribute to the detection of PPDs, their TPs and other unstable chemicals in aquatic products, thereby providing insights into their concentrations in these products.

Bioaccumulation potentials of per-and polyfluoroalkyl substances (PFAS) in recreational fisheries: Occurrence, health risk assessment and oxidative stress biomarkers in coastal Biscayne Bay

Per-and polyfluoroalkyl substances (PFAS) are a group of synthetic, highly fluorinated, and emerging chemicals that are reported to be used for both industrial and domestic applications. Several PFAS have demonstrated persistent, bioaccumulative and toxic tendencies in marine organisms. Therefore, this research aims to characterize and quantify these compounds in both recreational fisheries and surface water samples, including estimating their bioaccumulation potentials. In addition, we assessed the potential contribution of biomonitoring tools such as oxidative stressors and morphological index on fish and ecological health. Finally, human health risk assessment was performed based on available toxicological data on limited PFAS. All PFAS were detected in at least one sample except for N-EtFOSAA in lobster which was below the method detection limit. ƩPFAS body burden ranged from 0.15 to 3.40 ng/g wet weight (ww) in blackfin tuna samples and 0.37–5.15 ng/g ww in lobster samples, respectively. Wilcoxon rank paired test (α = 0.05) shows that there is statistical significance (ρ < 0.05) of ƩPFAS between species. Bioaccumulation factors (BAF) suggest an increasing trend in PFAS classes (PFCAs < PFSAs < FTSs), with higher BAFs observed in tuna compared to lobster. Long-chain PFESAs and FASAA were reported at higher concentrations in lobster compared to Blackfin tuna due to their bioavailability through sediment-sorption interactions. Although Fulton’s condition factor (FCF) indicates healthy fish conditions, oxidative stress biomarkers suggest that tuna and lobster might be under stress, which can weaken their immune system against exposure to emerging contaminants such as PFAS. Hazard risk (HR) suggests a low risk to human health based on the consumption of the studied species; however, the risk of contaminant exposure may be higher than estimated. This study is aimed at improving food safety by providing better understanding of how PFAS infiltrate into human diet and incorporating data on influence of contaminant exposure and environmental stressors on marine health.

4D-printed shape-programmable [H+]-responsive needles for determination of urea

Four-dimensional printing (4DP) technologies are revolutionizing the fabrication, functionality, and applicability of stimuli-responsive analytical devices. More practically, 4DP technologies are effective in fabricating devices with complex geometric designs and functions, and the degree of shape programming of 4D-printed stimuli-responsive devices can be optimized to become a reliable analytical strategy. Although shape-programming modes play a critical role in determining the analytical characteristics of 4D-printed stimuli-responsive sensing devices, the effect of shape-programming modes on the analytical performance of 4D-printed stimuli-responsive devices remains an unexplored subject. We employed digital light processing three-dimensional printing (3DP) with acrylate-based photocurable resins and 2-carboxyethyl acrylate (CEA)-incorporated photocurable resins for 4DP of the bending, helixing, and twisting needles. Upon immersion in samples with pH values above the pKa of CEA, the electrostatic repulsion among the dissociated carboxyl groups of polyCEA caused swelling of the CEA-incorporated part and [H+]-dependent shape programming. When coupling with the derivatization reaction of the urease-mediated hydrolysis of urea, the decline in [H+] induced shape programming of the needles, offering reliable determination of urea based on the shape-programming angles. After optimizing the experimental conditions, the helixing needles provided the best analytical performance, with the method's detection limit of 0.9 μM. The reliability of this analytical method was validated by determining urea in samples of human urine and sweat, fetal bovine serum, and rat plasma with spike analyses and comparing these results with those obtained from a commercial assay kit. Our demonstration and analytical results suggest the importance of optimizing the shape-programming modes to improve the analytical performance of 4D-printed stimuli-responsive shape-programming sensing devices and emphasize the benefits and applicability of 4DP technologies in advancing the development and fabrication of stimuli-responsive sensing devices for chemical sensing and quantitative chemical analyses.

Determining personal exposure to high production volume chemicals (HPVCs) and polycyclic aromatic hydrocarbons (PAHs) with silicone wristbands: A pilot study

High production volume chemicals (HPVCs) and polycyclic aromatic hydrocarbons (PAHs) are semi-volatile organic compounds (semi-VOCs) of great environmental concern because of their presence worldwide and health problems resulting from long-term exposure to some of them. It is essential to have robust analytical methods to monitor the concentrations of these compounds not only in environmental samples but also individual exposure. In this pilot study we develop and validate a multiresidue analytical method based on ultrasound-assisted extraction and gas-chromatography mass spectrometry for the simultaneous determination of 56 semi-VOCs using silicone wristbands (SWBs) as personal passive samplers. The developed method provided recoveries between 43% and 114% on sampled SWBs and method detection and quantification limits in the range of 0.1–35 ng/g and 0.3–119 ng/g, respectively. A preliminary study was performed with a small group of adults living in the industrial city of Tarragona (north-eastern Spain) to evaluate the applicability of SWBs for monitoring individual exposure to the studied HPVCs and PAHs. Benzothiazoles, benzenesulfonamides, UV stabilisers and phenolic antioxidants were determined for the first time in SWBs. Phthalates (PAEs), stood out above the rest, accounting for 52% of the total concentrations. Diethylhexyl phthalate was the compound found at the highest concentrations with values between 1.1 and 82 μg/g. Carcinogenic and non-carcinogenic dermal risk assessment was performed for adults and considering two scenarios (low and high). PAHs were the compounds with the highest carcinogenic and non-carcinogenic dermal risk regardless of the exposure scenario. The second family of compounds that contributed the most to the total risk were PAEs but high punctual concentrations of these compounds caused significant differences between exposure scenarios.

Implementation of gas chromatography tandem mass spectrometry for the analysis of six high boiling point polyhydric alcohols in cosmetics and toothpaste based on precolumn derivatization

Based on precolumn derivatization, an analytical method has been developed for the determination of six high boiling point polyhydric alcohols (HBPAs, b.p. > 300 ℃) in cosmetics and toothpaste, including erythritol, xylitol, Pro-Xylane-S, inositol, mannitol, and sorbitol. The water dispersion and oil in water samples were extracted by distilled water. The water in oil sample was firstly pre-dispersed with acetone, and then extracted by distilled water. The extract was concentrated to dry under nitrogen, and derivatized with acetic anhydride under the dispersion and catalysis of anhydrous pyridine. The derivatives were detected by gas chromatography-tandem mass spectrometry in the selected reaction monitoring mode, and quantified using arabinitol as internal standard. The experimental conditions such as the selection of columns, extraction procedures, and derivative conditions were optimized. This method was properly validated under the optimized conditions, and obtained excellent analytical features. Specifically, the correlation coefficients in the range of 0.02 ∼ 0.5 mg/L all exceed 0.992. The method limits of detection and quantification were 0.25 and 0.8 mg/kg, respectively. The average recoveries in toothpaste, cosmetics with oil in water and water in oil were 81.8 ∼ 107.1 %, with the relative standard deviation were 3.1 ∼ 7.2 %. The established method was successfully applied to commercial samples of different matrices, showing the advantages of simplicity, sensitivity, and good reproducibility, and can be used for the determination of HBPAs in cosmetics and toothpaste. The proposed methodology solves the problem that there is no detection method for HBPAs in cosmetics.

Multielement electrochemical vapor generation system coupled with atomic fluorescence spectrometer for simultaneous measurement of trace levels of As and Hg in coastal seawater samples

BackgroundToxic elements As and Hg in coastal waters affect human health through the food chain even at trace levels. The simultaneous determination of As and Hg in seawater using electrochemical vapor generation (ECVG) with atomic fluorescence spectrometer (AFS) currently has technical bottlenecks. One is the need for a simple and efficient chemical reaction cell and corresponding parameters to generate both AsH3 and Hg vapors, and the other is a suitable preservation method of the mixed standard solutions. ResultsA novel, efficient, online ECVG device was developed and interfaced with a laboratory-built multichannel AFS. The electrolytic cell adopted Sn–Pb alloy as the cathode material to generate both AsH3 and Hg vapors by electrolysis, replacing the unstable reagent tetrahydroborate (THB) usually used in most traditional vapor generation methods. The AFS was equipped with a built-in H2 generator for fuel supply, instead of the conventional acid-THB system. A mixed standard solution of As and Hg was prepared and preserved using thiourea-ascorbic acid as a fixing agent for Hg and a prereduction agent for As(V). The method detection limits (LOD, 3σ) were 0.005 and 0.003 μg/L for As and Hg, respectively. The relative standard deviations (RSD, n = 8) of the spiked samples were 2.8 % (0.50 μg/L As) and 3.1 % (0.05 μg/L Hg), respectively. The recoveries of standard spiked seawater samples with different salinities ranged from 86.1 % to 115.3 %. SignificanceThe system has been successfully applied to the simultaneous analysis of As and Hg in the seawater samples collected from the Xiamen coastal area. The study results provide a sensitive, accurate, and efficient method to promote the development and utilization of simultaneous analysis of multielement in seawaters.

Smart paper-based materials incorporating nitrogen and boron co-doped MXene quantum dots for rapid adsorption and sensitive detection of Cr2O72−

Dichromate ion (Cr2O72−) is a highly toxic chromium-containing compound that poses significant hazards to the digestive, respiratory systems, skin, and mucous membranes. Currently, the detection and adsorption of Cr2O72− face significant challenges, including the time-consuming and low sensitivity nature of traditional analytical methods. The limited efficiency and capacity of existing adsorbents hinder their practical application in real-time water quality monitoring and environmental remediation. Herein, using polyethyleneimine-functionalized (PEI) pulp fiber paper as the substrate, we developed smart paper-based materials (designated as NB-MQDs@PP) incorporated with nitrogen and boron co-doped MXene quantum dots (NB-MQDs) for rapid adsorption and sensitive detection of Cr2O72−. Compared to undoped MQDs, NB-MQDs exhibited longer excitation wavelength and enhanced oxidation stability. As anticipated, NB-MQDs achieved rapid (response time of 10 s) and sensitive (detection limit of 1.2 μM) recognition of Cr2O72− within a wide pH range with a quenching efficiency of 99.9%. Simultaneously, two on-site detection methods, immersion and cyclic filtration, were constructed based on NB-MQDs@PP. The detection limit of the immersion method was 17.0 nM, while the cyclic filtration method had a detection limit as low as 3.8 nM, surpassing the majority of those reported literatures. Remarkably, NB-MQDs@PP exhibited outstanding enrichment capacity towards Cr2O72−, with an adsorption capacity of up to 162.4 mg/g. This work provides a novel strategy for creating unique paper-based materials with excellent capture and monitoring dual-function, which can be customized according to the requirements of various application scenarios.

Simultaneous determination of picroside I and picroside II in dietary supplements by high performance liquid chromatography with PDA detector

Picroside I and picroside II are two compounds found in the Picrorhiza Kurroa plant, which have anti-cirrhosis, antioxidant, anti-inflammatory, fever, and asthma effects, etc. They are included in the ingredients of many dietary supplement products that help protect the liver and bile, prevent oxidation, etc. Therefore, determining the content of these two active ingredients in dietary supplements is necessary to evaluate product quality. In this study, highperformance liquid chromatography (HPLC-PDA) was used to simultaneously determine picroside I and picroside II in dietary supplements. The analytes in the samples were extracted with methanol for 60 min using a horizontal shaking technique. The extract was then filtered and determined by the HPLC&amp;ndash;PDA method with the following conditions: C18 Column (250 mm x 4.6 mm; 5 &amp;micro;m) and a corresponding pre-column (3.9 mm x 5 mm; 5 &amp;micro;m), the mobile phase consists of a solvent mixture of acetonitrile and water according to the gradient program, detection wavelength 265 nm. The method has good specificity, the calibration curve of picroside I and picroside II has a linear coefficient R2 &amp;gt; 0.9999 and the repeatability and recovery meet the AOAC requirements. The method limits of detection (MDL) for these two substances were 4.3 mg/kg and 3.2 mg/kg, respectively. The method was applied to simultaneously determine picroside I and picroside II in 30 different dietary supplement products. The results detected analytes in 3 samples positive with picroside I and picroside II concentrations ranging from 98.8 to 148 mg/kg.

Study on determination of cynarin in dietary supplement containing artichoke by high performance liquid chromatography

There has been no announcement on the standardization and testing of cynarin in dietary supplements containing artichokes in Vietnam. The high-performance liquid chromatography (HPLC) method was developed to determine cynarin in dietary supplements containing artichokes. The sample was extracted twice with 80% methanol solvent and ultrasonicated at 50&amp;deg;C for 20 minutes. Centrifuge at 6000 rpm for 5 minutes, filter, and inject into HPLC system with XBridge C18 column (250 mm x 4,6 mm, 5 &amp;micro;m) and corresponding pre-column, mobile phase consisting of two solvents phosphoric acid 0,1% and acetonitrile eluted according to gradient program, flow rate 1mL/min, detection wavelength 322nm. The calibration curves for cynarin had R2 = 1, and the validation parameters met AOAC standards. The method detection limits and the limit of quantification were 3.00 mg/kg and 10.0 mg/kg, respectively. The validated method was applied to determine cynarin in 15 dietary supplement samples. The content of cynarin varied depending on the manufacturer

Determination of deoxynivalenol and metabolites in maize samples by LC-MS/MS

In Vietnam, the regulation QCVN 8-1:2011/BYT has been issued to control mycotoxin content in food products. However, there are currently no regulations or studies on their derivatives and metabolites. Deoxynivalenol-3-glucoside (D3G) and two acetylated derivatives of deoxynivalenol (DON), namely 15-acetyldeoxynivalenol (15-AcDON) and 3- acetyldeoxynivalenol (3-AcDON), have been frequently detected in naturally contaminated grains such as wheat, barley, and corn. This study developed and applied a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine deoxynivalenol (DON) and its metabolites, including deoxynivalenol-3-glucoside (D3G), 3- acetyldeoxynivalenol (3-AcDON), and 15-acetyldeoxynivalenol (15-AcDON) in maize. The instrumental conditions comprised a C18 HSS SB (150 mm &amp;times; 2.1 mm &amp;times; 1.7 &amp;micro;m) column for separation and an MS/MS detector in positive and negative electrospray ionization (ESI) source, employing multi-reactive ion monitoring mode, with an injection volume of 2 &amp;micro;L. The method has been fully validated and meets the performance requirements of AOAC, demonstrating high specificity. The linearity range was established from 100 &amp;micro;g/kg to 1000 &amp;micro;g/kg, with a method detection limit (MDL) of 30 &amp;micro;g/kg. The repeatability and recovery rates were determined to be between 1.45% to 4.31% and 90% to 110%, respectively. The validated method was applied to analyze 50 maize samples. Deoxynivalenol (DON) was detected in 10 samples (20%), while deoxynivalenol-3-glucoside (D3G), 3- acetyldeoxynivalenol (3-AcDON), and 15-acetyldeoxynivalenol (15-AcDON) were not detected in any of the samples.

Isotopic spike 190Os as internal standard and empirical coefficient LA-ICP-MS combined with Sb fire assay for the determination of ultra-trace platinum group elements in geochemical samples

In this work, a novel method of antimony fire assay (Sb-FA) enrichment combined with laser ablation ICP-MS (LA-ICP-MS) for the determination of ultra-trace platinum group elements (PGEs) in geological samples was established. The purification and recycling technology of ultra-clean and high-purity fire assay collector Sb2O3 was proposed, in addition, high-purity quartz crucible was developed to replace the usual clay crucible, then the blank values of PGEs were as low as 0.0007–0.0028 ng g−1 (for 20 g sample). 190Os isotopic diluent was used as internal standard (IS) and quantitatively added into the fire assay ingredients, and fully mixed and balanced with the PGEs in the real samples by means of high temperature melting, cupellation and horizontal rotation of crucible and dish. Both 190Os and PGEs in the real sample were pre-concentrated in microgram level Sb granules (100 mg) through Sb-remaining cupellation. After grinding and polishing, 195Pt, 105Pd, 101Ru, 103Rh, 193Ir, total 189Os and 190Os enriched in Sb slices were determined by LA-ICP-MS, 190Os in the internal standard was calculated by isotope dilution equations. The Certified Reference Materials (CRMs) for PGEs were treated by the same procedure to obtain completely matrix matched Sb slices to solve the problem of no internationally recognized uniform PGEs standard materials for LA-ICP-MS determination. Due to the similar distribution trends of different PGEs in Sb slices by LA-ICP-MS imaging, then matrix-matched internal standard calibration strategy was used to reduce the element fractionation effect and improve the determination precision and accuracy of LA-ICP-MS. The laser frequency, energy density, denudation diameter and dwell times were optimized. Under the optimal conditions, empirical coefficient method was used to fit the standard curve and excellent curve fitting of PGEs were obtained with the correlation coefficient between 0.9990 and 0.9999. The method detection limits (LODs) for PGEs ranged from 0.00042 to 0.010 ng g−1. The established method was successfully applied to analyze real geochemical samples and various matrix Certified Reference Materials (CRMs) domestic and international, the determined values were in good agreement with the results of Sb-FA ICP-MS and the certified values.

High Luminescent Carbon Dots Derived from Fermented Beverages for Sensitive Sensing of Tartrazine in Foods.

Highly luminescent carbon dots (CDs) derived from fermented beverages-kvass (K-CDs) were synthesized through a one-step hydrothermal method with ethylenediamine (EDA) as a surface passivation reagent. Purified K-CDs with a fluorescent quantum yield of 35.1% were obtained after a dialysis process. The K-CDs were characterized by TEM, FT-IR, XPS, fluorescence and UV-vis spectroscopy. The results indicated that K-CDs possess typical excitation wavelength-dependent blue fluorescence emission, and the strongest excitation and emission wavelengths are 350nm and 440nm, respectively. The great spectral overlap between the emission peak (440nm) of K-CDs and the absorption peak (430nm) of tartrazine (TAR) leads to an effective fluorescence quenching phenomenon by TAR through inner filter effect (IFE) and the calculated (lg(I0/I)) showed a linear response to TAR concentration in the range of 0.1-70 µM. The detection limit of the developed method is 23 nM for TAR, and the relative standard deviation (RSD) is 3.9% (c = 10 µM, n = 7). The fluorescent sensor for TAR based on K-CDs through the IFE mechanism possesses the characteristics of rapid, sensitive, and high selectivity. It has been successfully applied to detect of trace TAR in foods.

Development and Validation of an ICP‐OES Method to Determine Extractable and Leachable Metals in HDPE (Plastic) Pharmaceutical Packaging Material

ABSTRACTThe safety and effectiveness of pharmaceutical medicines depend heavily on extractables and leachables. Patients may be adversely affected by contaminants that enter drug products through packing materials. As a result, regulatory organizations like the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) have set standards and regulations for evaluating and managing extractables and leachables. Characterizing the packing materials, carrying out extraction experiments and checking the extracted solutions for contaminants are all parts of this research. As part of the process for approving new drugs, regulatory agencies make use of these data. In present work, an inductively coupled plasma optical emission spectroscopy (ICP‐OES) method is developed and validated for quantifying trace elements from a high‐density polyethylene (HDPE) packaging material. The approach delineated in accordance with United States Pharmacopoeia (USP) &lt;661.1&gt; and &lt;661.2&gt; for the comprehensive analysis of 16 metallic elements including aluminium, arsenic, cadmium, chromium, cobalt, lead, mercury, nickel, titanium, vanadium, zinc, zirconium, barium, manganese, calcium and tin is applicable for evaluating the efficacy of packaging materials. The method detection limits (MDLs) complied as per USP 39‐NF 34 &lt;661.1&gt; along with relative standard deviations (RSDs) obtained were ranging from 0.3% to 3.1% and recoveries of all elements spiked at two different trace levels in HDPE samples were within 97%–110%, providing sensitive, accurate and reproducible methodology.

Overcoming strong retention barriers of A- and V-series nerve agents on silica sorbents

The present study explores the potential of silica solid phase extraction for gas chromatography mass spectrometric analyses of A- and V-series nerve agents. Owing to the presence of basic amidine and amine moieties, these analyte undergo strong ionic interactions with inherently acidic silica surfaces, producing poor recoveries. Subtle optimizations in the elution composition empowered the analytes to overcome the retention barriers from sorbent surfaces. Acetone containing 10 % (v/v) NH4OH effectively minimized strong analyte-sorbent interactions allowing good to excellent recoveries. Recoveries for A-series agents ranged from 88 to 96 %. VX, which is reported to be poorly recoverable from such sorbent matrices offered best data so far, reaching up to 74 % under optimized conditions. The method detection limits for the selected analytes in mass spectrometric analysis ranged from 47 to 171 ng/ml. Strong affinities of analytes towards silica sorbent were further exploited to expand the scope of analysis and establish the method's efficacy for a wide range of organic matrices. The applicability of the method to the real world applications was also validated in blind spiking exercises in diverse organic liquid samples received in 48th, 50th and 52nd proficiency tests conducted by the Organization for the Prohibition of Chemical Weapons (OPCW).

A simple and accurate method for the determination of Rh, Pd, and Pt in e-waste and spent automotive catalysts using HR-CS FAAS for assessing the value of secondary raw materials

This work presents a simple and accurate method for the fast sequential determination of Rh, Pd, and Pt in spent automotive catalysts and e-wastes using high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). Extensive research was carried out in model systems on the impact of potential interfering substances on analyte's signals measured in two types of flame (air-C2H2 and N2O–C2H2). Mutual analyte interactions were also taken into account. Different background corrections offered by the HR-CS AAS spectrometer were tested to obtain interference-free analyte signals and the best detectability. Using an air-C2H2 flame and 1 % La solution as a spectrochemical buffer provided good sensitivity and accurate determinations of Rh, Pd, and Pt using a simple calibration graph. Microwave-assisted leaching of PGE from waste samples with aqua regia at 240 °C for 60 min efficiently leached all target metals, which significantly simplified and shortened the sample preparation step. The detectability of the method (detection limit of 0.4, 0.6, and 5 mg kg−1 for Rh, Pd, and Pt, respectively) and precision (< 7 %) were satisfactory. The accuracy of the method was confirmed by analysis of certified reference materials (spent automotive catalyst (ERM-EB504), electronic scrap (BAM-M505a)), and calculated zeta score values. The recoveries for Rh, Pd, and Pt in ERM-EB504 were 93, 101, and 96 %, respectively, and for Pd in BAM-M505a, 97 %. The developed method can be used to assess the value of secondary raw materials, such as various types of spent catalysts and e-waste containing Rh, Pd, and Pt.

3D-printed thermally expanded monolithic foam for solid-phase extraction of multiple trace metals.

Digital light processing (DLP) 3DP, commercial acrylate-based photocurable resins, and thermally expandable microspheres-incorporated flexible photocurable resins were employedto fabricate an SPE column with athermally expanded monolithic foam for extracting Mn, Co, Ni, Cu, Zn, Cd, and Pb ions prior to the determination using inductively coupled plasma mass spectrometry. After optimizationofthe thermally activated foaming, the design and fabrication of the SPE column, and the automatic analytical system, the DLP 3D-printed SPE column with the thermally expanded monolithic foam extracted the metal ions with up to 14.8-fold enhancement (relative to that without incorporating the microspheres), with absolute extraction efficiencies all higher than 95.6%, and method detection limits in the range from 0.5 to 5.2ng L-1. We validated the reliability and applicability of this method by determination ofthe metal ions in several reference materials (CASS-4, SLRS-5, 1643f, and Seronorm Trace Elements Urine L-2) and spikedseawater, river water, ground water, and human urine samples. Theresults illustrated that to incorporate the thermally expandable microspheres into the photocurable resins with a post-printing heating treatment enabled the DLP 3D-printed thermally expanded monolithic foam to substantially improve the extraction of the metal ions, thereby extending the applicability of SPE devices fabricated by vat photopolymerization 3DP techniques.

A Rapid Detection Method for H3 Avian Influenza Viruses Based on RT-RAA.

The continued evolution of H3 subtype avian influenza virus (AIV)-which crosses the interspecific barrier to infect humans-and the potential risk of genetic recombination with other subtypes pose serious threats to the poultry industry and human health. Therefore, rapid and accurate detection of H3 virus is highly important for preventing its spread. In this study, a method based on real-time reverse transcription recombinase-aided isothermal amplification (RT-RAA) was successfully developed for the rapid detection of H3 AIV. Specific primers and probes were designed to target the hemagglutinin (HA) gene of H3 AIV, ensuring highly specific detection of H3 AIV without cross-reactivity with other important avian respiratory viruses. The results showed that the detection limit of the RT-RAA fluorescence reading method was 224 copies/response within the 95% confidence interval, while the detection limit of the RT-RAA visualization method was 1527 copies/response within the same confidence interval. In addition, 68 clinical samples were examined and the results were compared with those of real-time quantitative PCR (RT-qPCR). The results showed that the real-time fluorescence RT-RAA and RT-qPCR results were completely consistent, and the kappa value reached 1, indicating excellent correlation. For visual detection, the sensitivity was 91.43%, the specificity was 100%, and the kappa value was 0.91, which also indicated good correlation. In addition, the amplified products of RT-RAA can be visualized with a portable blue light instrument, which enables rapid detection of H3 AIV even in resource-constrained environments. The H3 AIV RT-RAA rapid detection method established in this study can meet the requirements of basic laboratories and provide a valuable reference for the early diagnosis of H3 AIV.

Development of analytical methods and method validation for the qualitative and quantitative determination of Carboxymethyl Cellulose (CMC) in yogurt and ayran

This study presents the development and validation of analytical methods for the qualitative and quantitative determination of Carboxymethyl Cellulose (CMC) in yogurt and ayran. The methods were evaluated for their detection limit (LOD), quantification limit (LOQ), and method detection limit (MDL) across multiple samples, demonstrating robust sensitivity with MDL and LOD values of 0.03% for both yogurt and ayran. Recovery studies showed high accuracy, with recovery rates between 98% and 100%, and consistent recovery within the acceptable range of 97–103%, reinforcing the methods' reliability. The quantitative analysis exhibited strong repeatability and reproducibility, with low relative standard deviations (RSDr and RSDR), confirming minimal intra-day and inter-day variability. The calibration curves for CMC analysis demonstrated excellent linearity with high coefficients of determination (R2 = 0.9985 for yogurt and 0.9951 for ayran), ensuring accurate quantification over a wide concentration range. Measurement uncertainty analysis further validated the methods' precision and accuracy, showing low relative uncertainties for trueness, repeatability, and reproducibility. Robustness evaluations indicated that the methods maintained consistent recovery rates despite variations in pH, heating time, and sample quantity, highlighting their reliability under different conditions. For qualitative analysis, the visual images method showed exceptional performance with perfect sensitivity and specificity, accurately identifying all positive and negative samples without any false positives or negatives. This high level of accuracy makes the visual images method a valuable tool for ensuring product safety and compliance with quality standards in the dairy industry. Overall, the validated analytical methods for CMC detection in yogurt and ayran demonstrated high precision, accuracy, and reliability, making them essential for quality control and regulatory compliance in dairy production.

Analysis of sulfur in soil and plant digests using methane as a reaction gas for ICP-MS

Quantitation of sulfur (S) is vitally important for analysis of agricultural soil and plant samples due to the requirement of S in living organisms. Although inductively coupled plasma mass spectrometry (ICP-MS) is a commonly used and robust instrument for multi-elemental detection, S is usually analysed by ICP-optical emission spectroscopy (OES) since S quantitation poses a particular challenge for ICP-MS due to interferences on all S isotopes. The requirement for analysis by two instruments increases time and cost for sample analysis, hence analysis by one instrument is desirable. The use of reaction gases in ICP-MS can improve the performance by shifting S to a mass for detection where no interference is present. This work explored the potential of methane as a reaction gas for analysis of S in soil and plant samples to give users an alternative option to oxygen. The product ion clusters CH2SH+ were monitored (m/z 47 and 49 on ICP-MS and with mass shift of +15 from Q1 → Q2 using 32 → 47 and 34 → 49 on triple quadrupole ICP-MS). As expected, triple quadrupole ICP-MS performed better than single quadrupole ICP-MS containing a reaction cell due to the ability to preselect the m/z of choice and remove ions that may react with methane in the reaction cell. The method detection limit (MDL) was 150 mg kg−1 S for plants and 53 mg kg−1 S for soils which is fit for requirements. This is the first-time methane has been reported as a reaction gas for analysis of S and shows promising results for agricultural samples when using a triple quadrupole ICP-MS. Results compared well to those obtained via the more commonly used ICP-optical emission spectroscopy (OES) method with results <20 % for all samples. Interlaboratory comparison samples were within 2 Z-scores of the consensus mean. In the absence of ICP-MS/MS, Q-ICP-MS with detection of cluster m/z 47 was deemed to be suitable for detection of S in plant samples, with acceptable MDL (250 mg kg−1 S), acceptable precision (<20 % RSD) and <20 % variation to the reported ICP-OES result.