Limit Of Quantitation Research Articles

Per- and Polyfluoroalkyl Substances in Surface Water of Fuyang River (Handan Section): Occurrence, Source Apportionment, and Risk Assessment

Perfluorinated and polyfluoroalkyl substances (PFASs), as an emerging type of pollutant, always pollute water quality to a certain extent. The occurrence, source, and risk of PFASs in the Fuyang River are not well understood. For the first time, the state of PFASs in the upper Fuyang River (Handan section) was investigated. The results showed that there were 10 types of PFASs with concentrations higher than the limit of quantitation in the surface water of the Fuyang River. The surface water ρ (∑PFASs) ranges from 13.80 to 22.88 ng·L−1. The highest quality score is perfluorooctane sulfonate (PFOS), which is 59.40%. PFASs are mainly composed of long-chain substances. PFASs generally show a trend of gradually increasing downstream. PFASs have the same source, mainly from industrial activities around rivers and rainfall inputs. Principal component analysis shows that PFASs mainly come from the leather and textile manufacturing industries, fluoropolymer production, and electroplating metal industries. The concentration of PFASs in the Fuyang River has not yet affected ecology and health.

A Phase 1 Study to Evaluate the Absorption, Metabolism, and Disposition of Dordaviprone in Healthy Adult Participants.

Dordaviprone (ONC201) is a novel, small-molecule imipridone with antitumor activity in patients with a glioma. Six healthy male participants received a single 625-mg (100-µCi) oral dose of [14C]-dordaviprone. Blood, plasma, urine, and feces were collected up to 288hours after dosing and analyzed by liquid scintillation counting. Metabolite profiles were evaluated using liquid chromatography-radiometric detection, and metabolite identification was accomplished by liquid chromatography with tandem mass spectrometry. Concentrations of drug-derived radioactivity in blood and plasma peaked at 1 hour after dosing and were below the limit of quantitation by 72hours (whole blood) to 96hours (plasma) after dosing. Seventy-one percent of the administered radioactivity was recovered in urine and 20% in feces. In plasma, the major circulating compounds were dordaviprone and the inactive metabolite ONC207, each contributing approximately one third of the total radioactivity area under the curve. Of the 19 metabolites identified in plasma, no other single metabolite contributed more than 10% to the total radioactivity area under the curve. Unchanged dordaviprone was a minor component in excreta (less than 0.3%), with multiple metabolites identified in urine and feces. Given the lack of dordaviprone in excreta and the metabolites formed, the primary route for dordaviprone elimination was through urinary excretion of oxidative metabolites.

Determination of neomycin B residue in bovine edible tissues and milk by ion-pair liquid chromatography-tandem mass spectrometry

AbstractAn analytical method based on ion-pair liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed to accurately determine neomycin B in bovine edible tissues (muscle, kidney, liver, fat) and milk. The pre-treatment procedure, including protein precipitation and solid phase extraction, was investigated to extract the analytes of interest better and remove matrix interferences. After sample pre-treatment, the 1% heptafluorobutyric acid 20 μL was added to the final extract. Then, the chromatography and mass spectrometry conditions were optimized, and the established method was validated. Good linearity (r > 0.999) was obtained at five matrices. The limit of detection, and the limit of quantitation were 10 and 20 μg kg−1, respectively. Trueness and repeatability at 0.5× maximum residue limit (MRL), MRL, and 2× MRL ranged from 96.67 to 109.54% and 3.36 to 9.01%, respectively. Adding the ion-pair agent to the extracts, rather than the mobile phase, ensures that neomycin B is efficiently retained on the reverse-phase column without contaminating the ion source. This simple and sensitive LC-MS/MS method is suitable for regularly monitoring neomycin residue in bovine edible tissues and milk.

Development and validation of a novel fluorometric approach utilizing flow injection analysis for the measurement of vilazodone: application to dosage form and spiked human plasma

A direct, precise, rapid and simple flow injection approach has been applied to determine vilazodone HCl (VZN) in pharmaceutical dosage forms and biological fluids. VZN has an indole ring as part of its structure, which gives it a significant native fluorescence. The study was based on determining the strong intrinsic fluorescence of VZN, which was measured at 486 nm after excitation at 241 nm. Phosphate buffer (pH 5, 10 mM): Acetonitrile (40:60, v/v) was utilized as the carrier solution, with a flow rate of 0.5 mL min− 1. Based on peak area, the calibration graph was linear over a concentration range of 10–300 ng mL− 1 of VZN with a correlation coefficient (r) of 0.9999. The quantitation limit was 9.62 ng mL− 1, while the detection limit was 3.17 ng mL− 1. Moreover, the suggested method was used to accurately measure VZN in its tablet dosage form. Additionally, the studied drug was also satisfactorily measured in blood using the suggested flow injection methodology. The approach was validated according to ICH specifications.

Detection of hexavalent chromium in solutions using optode membrane: fabrication and methods validation

Abstract Heavy metal pollution, such as chromium hexavalent in water, can pose a threat to human health, thus requiring a fast and efficient detection method. This research aims to build an alternative method and validate it through a cellulose triacetate (CTA)-based optode membrane that is selective for Cr(VI). The optode membrane was prepared by mixing CTA, plasticizers, aliquat 336, and selective reagents 1,5-diphenylcarbazide for Cr(VI). The optode membrane was evaluated based on validation parameters. The Cr(VI) optode membrane had average thickness of 0.028 mm, determination coefficient of 0.992 ± 0.003 at a concentration range of 0.02–0.40 mg/L, with a detection limit of 0.006 mg/L and quantitation limit of 0.017 mg/L, RSD for precision 3.03 ± 4.00 × 10−3 %, an accuracy of 96.10 ± 5.45 %. The optode membrane exhibited good sensitivity, selectivity, and stability with sensitivity 7.8 × 106 M−1 cm−1, selectivity to Fe3+ −0.037 and Pb2+ −0.049, stability of colour result %RSD 4.52 %. Application on water samples showed no significant difference between the results of the standard method and the optode membrane method (α = 0.05). These results confirm that optodes can be used as an alternative method for detecting hexavalent chromium below the regulation of the WHO maximum allowable limit drinking and sanitation water.

Development of a Simple HPLC Method for the Analysis of Ergosterol and UV-Enriched Vitamin D₂ in Mushroom Powders

In this study, a straightforward and cost-effective HPLC-UV method was developed for the rapid determination of vitamin D2 and ergosterol in mushrooms. These bioactive components are known to play a significant role in the nutritional value of mushrooms, particularly in the production of mushroom-based food supplements. The method, designed for routine analysis, involves a simple sample preparation process combining saponification and solid–liquid extraction, followed by HPLC-UV detection. High recovery rates (97–99%) were achieved by the method, with limits of detection (LOD) and quantitation (LOQ) of 0.1 mg/kg dry weight and 0.5 mg/kg dry weight, respectively. The enrichment of vitamin D₂ content in mushroom powders through UV irradiation was also investigated. In Agaricus bisporus, vitamin D₂ levels increased from an initial 1.92 mg/kg to 4.66 mg/kg following heat treatment at 100 °C, and reached a maximum of 28.13 mg/kg when heat treatment was combined with UV irradiation. In contrast, Lentinula edodes exhibited an initial vitamin D₂ content of 7–8.5 mg/kg, with the highest levels achieved through UV treatment alone, which also preserved ergosterol content. These findings highlight species-specific differences in vitamin D₂ conversion and present an effective approach for enhancing the nutritional profile of mushroom-based products, while providing a reliable analytical tool for quality control.

Development of chiral and achiral high performance liquid chromatography methods for the analysis of main flavour compound of hazelnut

Abstract (E)-5-Methylhept-2-en-4-one is a key flavour compound in hazelnuts with practical applications in perfumery, flavour, and food industries due to its unique sensory properties. This study developed an effective and sustainable achiral reverse-phase high-performance liquid chromatography (HPLC) method with diode array detection (DAD) to determine (E)-5-methylhept-2-en-4-one and its reaction intermediates prepared via chiral-pool-based chemoenzymatic synthesis. Given that two reaction intermediates are thermally unstable at the high temperatures used in gas chromatography, HPLC separation at ambient temperatures (avg. 25 °C) was an appropriate approach. Optimised HPLC conditions consisting of C18 type stationary phase, mixture of acetonitrile: water (60:40, v/v) as mobile phase under isocratic conditions and flow rate 0.5 mL.min−1 were used. Chiral normal phase HPLC–DAD method with polysaccharide derivative stationary phase and n-hexane:propan-2-ol (90:10, v/v) as mobile phase was used for separation of enantiomers of (E)-5-methylhept-2-en-4-one. Both achiral and chiral methods were successfully used for monitoring the course of chemoenzymatic synthesis, conversion of reaction intermediates and purity of final product. The achiral HPLC–DAD method showed good linearity (R 2 = 0.9997) in concentration range 0.5–100 μg.mL−1. The limits of detection and quantitation were 0.1 and 0.3 μg.mL−1, respectively. Using developed chiral HPLC–DAD method, sufficient enantioseparation was achieved with resolution of 4.73. Values of LOD and LOQ were 0.2 μg.mL–1 and 0.5 μg.mL–1, respectively. Besides synthesis monitoring and purity product determination, the developed chiral and achiral HPLC methods could find application in the analysis of (S)-(E)-5-methylhept-2-en-4-one in nut-flavoured foods (e.g., pastries, cookies, desserts, beverages) and personal care products, as well as differentiate pure olive oil from those adulterated with hazelnut oil. Graphic Abstract

Determination, Mobility and Risk Assessment of Pesticides in Ginseng Wine Using Dispersive Liquid–Liquid Micro Extraction Combined with GC-MS/MS and LC-MS/MS

The simultaneous determination of 166 pesticides using dispersive liquid–liquid micro extraction combined with gas chromatography–tandem mass spectrometry and ultra-high performance liquid chromatography–tandem mass spectrometry (DLLME–GC-MS/MS+LC-MS/MS) is presented here. In this work, DLLME was extended to complex residues in the ginseng wine matrix. This study first focused on the selection of an appropriate solvent that enabled the dissolution of analytes from ginseng wine. The matrix-matched calibration curves showed good linearity in the range of 2–100 µg L−1 for all pesticides, with coefficients of determination of 0.977–1. The mean recoveries were in the range of 3–124%, with 133 pesticides in the range of 60–130%, and the relative standard deviations (RSDs) were between 0.4% and 31.4%. The limits of detection (LOD) and limits of quantitation (LOQ) were within the ranges of 0.14–140 and 0.5–470 ng L−1, respectively. Therefore, this analytical method contributes to residue analyses of 133 pesticides for the routine laboratory testing of ginseng wine. Research was also carried out by soaking the pesticide-positive samples in ginseng wine to monitor the migration and degradation of pesticides. The results showed that, the migration rates of thifluzamidewaslower than 60%, cyprodinil was 73.7, while azoxystrobin, pyrimethanil, carbendazim, dimethomorph, difenoconazole, pyraclostrobin, propiconazole, quintozene, pentachloroaniline, tebuconazole and phoximwere between 75% and 95%. Quintozene was more easily degraded into pentachloroaniline in the wine.

Functionalized novel carbon dots from bell pepper seeds for sustainable green Edoxaban quantification

Global warming and the developed worldwide awareness have persuaded efforts to minimize the generated hazardous wastes. As a result, “green” chemical procedures are being gradually included in science for sustainable development. This concept has been extended and inspired chemists to fabricate novel green carbon dots (CDs) from natural plants. Herein, we represent novel CDs synthesized by recycling seeds obtained from bell pepper as fluorescent probe for the determination of Edoxaban tosylate hydrate (EDO) a non-fluorescent drug; we exploit the advantage of the inner filter effect between the absorption peak of the drug and the emission peak of the CDs. This overlap resulted in quenching the fluorescence of CDs by increasing the concentration of EDO within the range 0.80–20.00 µg/mL with a limit of detection 0.23 and 0.22 µg/mL and a limit of quantitation 0.69 and 0.72 µg/mL for Microwave CDs and Plate CDs, respectively, at λex/λem 310/409 nm. Two facile preparation techniques for the CDs were used, the microwave-assisted method and the thermal decomposition method, using a single-step approach. The fabricated CDs were characterized using various techniques, including UV-vis, fluorescence and Fourier transform infrared spectroscopies, energy-dispersive X-ray, high-resolution transmission electron microscope, X-ray Diffaction, X-Ray photoelectron spectroscopy and zeta potential. The performance of the synthesized fluorescent probe for the determination of EDO was evaluated according to ICH guidelines. The accomplished results, together with the simplicity, sensitivity, and low cost of the developed probe, recommended its appropriateness for the routine quality control assay of EDO pharmaceutical formulation, as good % recovery was obtained upon the investigation of the marketed tablets with 99.77% and 98.79% recoveries for microwave CDs and plate CDs, respectively. The method’s greenness was evaluated using three integral matrices, the Blue Applicability Grade Index, the Complementary Green Analytical Procedure Index and Analytical Eco-Scale.Graphical abstract

ANALYTICAL METHOD DEVELOPMENT AND VALIDATION OF FLAVOXATE HCL WITH RP-HPLC

Objective: To verify analytical methods, suitability for its intended use is the goal of validation by Reverse Phase-High Performance Liquid Chromatography (RP-HPLC) method. Methods: A validated method for determining flavoxate hydrochloride was created using HPLC, which is a sensitive, exact, and straightforward technique. The inertsilC18 (150 mm×4.6 mm, 5µm) is used in this approach. The buffer, which included 3g of 1-hexane sulphonic acid, 3 ml of Orthophosphoric Acid (OPA) and 3 ml of Triethylamine (TMA), was combined with Acetonitrile (ACN) in a 650:350 ratio to form the mobile phase. At 293 nm, Ultraviolet (UV) detection was done. Results: The Retaining time for flavoxate HCl was found to be 2.43 min. It was discovered that the linearity range of flavoxate HCl was 800-1200 µg/ml, and that the regression equation was y=17118x+80943. R 2 = 0.981 was found to be the linearity regression coefficient value. It was discovered that the RSD for intra-and inter-day precision was less than 2 %. Flavoxate HCl was discovered to have Limit of Detection (LOD)-83.13734 and Limit of Quantitation (LOQ)-251.9313 values of µg/ml and µg/ml, respectively. After statistical analysis, the results are deemed satisfactory. Conclusion: This technique can be used to analyze bulk forms of the antimuscarinic medication flavoxate HCl with success.

Ratio-fluorescence detection of propyl gallate based on MnOOH nanoflakes and β-cyclodextrin modified quantum dots.

Ratio-fluorescence detection of propyl gallate based on MnOOH nanoflakes and β-cyclodextrin modified quantum dots.

Rapid determination of etomidate and its structural analogues in e-liquid by probe electrospray ionization quadrupole time-of-flight mass spectrometry.

Rapid determination of etomidate and its structural analogues in e-liquid by probe electrospray ionization quadrupole time-of-flight mass spectrometry.

Development of a procedure based on dispersive solid phase extraction and LC-MS/MS for the analysis of perfluoroalkyl and polyfluoroalkyl substances in food contact materials.

Development of a procedure based on dispersive solid phase extraction and LC-MS/MS for the analysis of perfluoroalkyl and polyfluoroalkyl substances in food contact materials.

Synthesis of sulfonamide-functionalized magnetic microporous organic network for magnetic solid-phase extraction of polar aromatic amines from tea beverages.

Synthesis of sulfonamide-functionalized magnetic microporous organic network for magnetic solid-phase extraction of polar aromatic amines from tea beverages.

Determination of nitrofuran metabolites in fish samples by boronate affinity extraction coupled to HPLC-MS/MS using cis diol-modified mesoporous polymer (GMA-EGDMA) microspheres as adsorbents.

Determination of nitrofuran metabolites in fish samples by boronate affinity extraction coupled to HPLC-MS/MS using cis diol-modified mesoporous polymer (GMA-EGDMA) microspheres as adsorbents.

HPLC method for novel cannabinoid separation with electrochemical detection on boron-doped diamond electrode.

HPLC method for novel cannabinoid separation with electrochemical detection on boron-doped diamond electrode.

Electrochemical Behavior of Some Cinchona Alkaloids Using Screen-Printed Electrodes.

An effective deposition of a cinchonine layer on a platinum metal surface can be easily achieved through the cathodic reduction of a cinchonine hydrochloride methanolic solution at a controlled potential of -220 mV vs. the silver standard electrode (SSE). A coated screen-printed platinum electrode has proven to be suitable for cinchonine determination in water, urine, and serum at µg L-1 concentration levels using differential pulse voltammetry in a phosphate buffer solution (pH 7.0). The limits of detection (LOD) and quantitation (LOQ) were 0.6 µg L-1 and 1.8 µg L-1, respectively.

Rapid and in-situ detection of iodine and potassium ferrocyanide in table salt using enhanced-Multipass cavity Raman scattering.

Rapid and in-situ detection of iodine and potassium ferrocyanide in table salt using enhanced-Multipass cavity Raman scattering.

MRM-based LC-MS method for accurate C-peptide quantitation.

MRM-based LC-MS method for accurate C-peptide quantitation.

Rapid analysis in small-volume urine: Optimizing LC-MS/MS for free glucocorticoids.

Rapid analysis in small-volume urine: Optimizing LC-MS/MS for free glucocorticoids.