Extraction Recovery Research Articles

Simultaneous Electrochemical Determination of Sildenafil Citrate and Tadalafil Using a Multi Walled Carbon Nanotubes Modified Glassy Carbon Electrode by Adsorptive Stripping Linear Sweep Voltammetry

AbstractAn adsorptive stripping linear sweep voltammetric method was developed for the simultaneous determination of sildenafil citrate and tadalafil. The voltammetric working electrode was a glassy carbon electrode modified with carboxylic multi‐walled carbon nanotubes. The sensitivity of the developed voltammetric method was significantly increased by this modification. Both analytes spontaneously adsorbed on the modified electrode surface due to their adsorption affinities. The irreversible oxidation signals of both analytes were used as the analytical signals. The electrochemical behaviour of sildenafil citrate and tadalafil was assessed using cyclic voltammetry. The developed voltammetric method was linear in the range of 0.01–0.50 μM with a correlation coefficient of 0.9997 and 0.9985 for sildenafil citrate and tadalafil, respectively. The LOQs of the method for both analytes were 0.010 μM. The intra‐ and inter‐day reproducibility of the method was less than 10% RSD in all cases. The extraction recoveries for both analytes ranged between 83 and 94%. The applicability of the developed voltammetric method were investigated by determining the analyte in two different spiked samples (an energy drink and a traditional herbal product). Furthermore, the described method would represent the first electrochemical approach for the simultaneous detection of sildenafil citrate and tadalafil, providing an available alternative to current chromatographic techniques.

Polarity Gradient Solvent Confinement Membrane Cartridge to Broaden Metabolite Coverage of Plasma Untargeted Analysis.

Various polarity chemicals exist in complex samples, such as plasma; nontargeted comprehensive analysis naturally requires multiple polar-extracted solvents; consequently, the polarity of the solvent plays a crucial role in the extraction efficiency of analytes from complex samples. In the present study, based on the diffusion behavior and nanoconfinement effect of solvents in the nanoconfined space, the polarity gradient solvent confinement liquid-phase nanoextraction (PGSC-NLPNE) protocol aimed to perform a one-step nontargeted analysis of a wide range of metabolites in plasma was established. The continuously wide range of extracted solvent polarities on carbon nanofibers/carbon fiber (CNFs/CF) membranes was achieved using a mixture of hexane, dichloromethane, methanol, and water as nanoconfined solvents. The polarities (Log P) of gradient solvents ranged from -1.38 to 3.94. Correlational analyses indicated that metabolites with Log P values ranging from -1.90 to 3.84 were closely related according to similarity-intermiscibility theory. Coupled with a homemade modified guard column device, CNFs/CF membrane cartridge (CCMC), a PGSC-NLPNE-UHPLC-MS online protocol was established and applied in plasma untargeted analysis. By comparing metabolome coverage, reproducibility, and extraction recovery with protein precipitation and two-step liquid-liquid extraction commonly used in untargeted analysis, the PGSC-NLPNE-CCMC protocol demonstrated higher reproducibility and recovery. This protocol has shown great potential for ultrafast analysis of plasma untargeted metabolomics with broader metabolome coverage. It could be a potential tool to rapidly screen out valuable biomarkers related to diseases in the clinic.

Preparation and characterization of aptamer-based sorbent for the selective extraction of zearalenone and its derivatives from human urine.

The aim of this work is the development of a biomimetic strategy involving a molecular recognition mechanism using aptamers immobilized on a solid support for the analysis of the mycotoxin zearalenone (ZEA) and two of its derivatives in human urine: alpha-zearelenol (α-ZEL) and beta-zearelenol (β-ZEL). Three oligonucleotide sequences reported in theliterature as beingspecific to ZEA were thus covalently grafted onto activated sepharose, and a thorough study of the percolation and washing conditions was performed to promote the selective retention of the three targeted compounds. With the optimized extraction procedure, a strong and selective retention was obtained for ZEA and to a lesser extent α-ZEL and β-ZEL, with extraction recoveries of 88±9%, 77±15%, and 45±12% respectively, in standard solutions. Application of this procedure to spiked human urine strongly highlighted the efficiency of the clean-up effect resulting from the use of this selective sorbent. Limits of quantification of the whole analytical procedure including extraction on oligosorbent andLC-MS analysis were 0.18 and 0.24ngmL-1, for ZEA and α-ZEL, respectively, thus demonstrating clearly the potential of the developed method for monitoring human dietary exposure to these compounds.

Characterization of Chemical Exposome in A Paired Human Preconception Pilot Study.

Parental preconception exposure to synthetic chemicals may have critical influences on fertility and reproduction. Here, we present a robust LC-MS/MS method covering up to 95 diverse xenobiotics in human urine, serum, seminal and follicular fluids to support exposome-wide assessment in reproductive health outcomes. Extraction recoveries of validated analytes ranged from 62% to 137% and limits of quantification from 0.01 to 6.0 ng/mL in all biofluids. We applied the validated method to a preconception cohort of Australian couples (n = 30) receiving fertility treatment. In total, 36 and 38 xenobiotics were detected across the paired biofluids of males and females, respectively, including PFAS, parabens, organic UV-filters, plastic additives, antimicrobials, and other industrial chemicals. Results showed 39% of analytes in males and 37% in females were equally detected in paired serum, urine, and reproductive fluids. The first detection of the sunscreen ingredient avobenzone and the industrial chemical 4-nitrophenol in follicular and seminal fluids suggests it can cross both blood-follicle/testis barriers, indicating potential risks for fertility. Further, the blood-follicle transfer of perfluorobutanoic acid, PFOA, PFHxS, PFOS, and oxybenzone corroborate that serum concentrations can be reliable proxies for assessing exposure within the ovarian microenvironment. In conclusion, we observed significant preconception exposure to multiple endocrine disruptors in couples and identified potential xenobiotics relevant to male and female fertility impairments.

OPTIMIZATION OF LC-MS/MS METHOD FOR THE SIMULTANEOUS DETERMINATION OF METFORMIN AND ROSIGLITAZONE IN HUMAN PLASMA WITH BOX-BEHNKEN DESIGN

Objective: The objective of this study was to develop a robust Liquid Chromatography – Tandem Mass Spectrometry (LC-MS/MS) methodology for the precise quantification of metformin and rosiglitazone in human plasma. Methods: A Design of Experiments (DOE) framework was utilized, specifically employing a Box-Behnken experimental design, to optimize critical parameters such as Capillary voltage, Cone voltage, Desolvation temperature, and Collision energy. Sample preparation involved protein precipitation using acetonitrile, simplifying the procedure. Chromatography was performed with a mobile phase of 0.1% formic acid and acetonitrile (60:40 V/V) to enhance sensitivity and reproducibility. Quantification was achieved through Multiple Reaction Monitoring (MRM) of the transition’s m/z 130.1 → m/z 60.1 for metformin, m/z 358.2 → m/z 134.9 for rosiglitazone, and m/z 206.3 → m/z 59.9 for phenformin. The methodology was validated according to regulatory guidelines. Results: The developed methodology demonstrated selectivity, linearity, accuracy, precision, recovery, and stability. The calibration curve showed linearity over the concentration range of 5 ng/ml to 1000 ng/ml for metformin and 1.5 ng/ml to 300 ng/ml for rosiglitazone. Accuracy and precision were within acceptable limits across calibration and quality control standards. Assessments of extraction recovery and matrix effects confirmed the robustness of the extraction procedure, with negligible interference from plasma components. Stability studies indicated that the method maintained acceptable limits for metformin and rosiglitazone concentrations under various storage and handling conditions. Conclusion: The validated Liquid Chromatography – Tandem Mass Spectrometry (LC-MS/MS) methodology provides a reliable and accurate platform for the quantification of metformin and rosiglitazone in human plasma. This method shows potential applications in pharmacokinetic studies and clinical research, ensuring consistent performance in routine analysis.

Preparation of ortho-hydroxyl/carboxyl dual-functionalized hypercrosslinked polymers for highly efficient enrichment of nitrosamines with broad polarity prior to gas chromatography-mass spectrometry analysis

N-nitrosamines (NAs) are highly carcinogenic substances commonly detected in food. They demonstrate a broad spectrum of polarity, posing a challenge in finding a suitable adsorbent capable of simultaneously adsorbing and enriching both polar and nonpolar NAs with high extraction recoveries. The present study involves the synthesis of a series of carboxyl functionalized hypercrosslinked polymers, followed by a comparative evaluation of their adsorption performance towards NAs. The results demonstrated that the ortho-hydroxyl/carboxyl dual-functionalized hypercrosslinked polymer (SA-FDA-HCP), synthesized using salicylic acid as the monomer and formaldehyde dimethyl acetal as the crosslinking agent, exhibited significantly enhanced adsorption performance on NAs. The maximum adsorption capacities of SA-FDA-HCP for N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosopyrrolidine, and N-nitrosodiphenylamine were determined to be 1.40, 4.18, 2.84, and 52.4 mg g−1, respectively. These values surpass those reported in the literature for other adsorbents. Furthermore, the polymer exhibited extraction recoveries exceeding 80 % for all four NAs, and it exhibits exceptional selectivity towards NAs. The high adsorption performance can be attributed to the synergistic effects of multiple interactions, including electrostatic, hydrogen bonding and hydrophobic interactions. Based on the synthesized hypercrosslinked polymers, a method for analyzing these NAs was developed using dispersed solid-phase extraction combined with gas chromatography-mass spectrometry. The method demonstrates good accuracy and precision within the linear range of 1 - 80 ng mL−1, while providing relative recoveries for the four NAs range from 91.1 % to 111.5 %. The intra-day and inter-day relative standard deviations are between 4.4 % and 9.8 %, as well as 5.6 % and 10.9 %, respectively. Moreover, the limits of detection fall within a range of 0.11 to 0.73 ng mL−1. These results indicate that the developed material holds great potential for the separation, enrichment and analysis of N-nitrosamines across diverse applications.

Method Development and Comprehensive Study of Matrix Effects for the Determination of Trace Organic Contaminants in Lake Sediments

The presence of trace organic contaminants (TrOCs), such as pharmaceuticals, personal care products, additives, and polar pesticides in sediments of rivers and lakes highly impacted by anthropogenic activities makes sediments a secondary source of contamination for aquatic ecosystems. Considering this, a method for analyzing 44 TrOCs of diverse nature (including five transformation products, 13 pharmaceuticals, five personal care products, 14 pesticides, and seven additives) was developed and validated. It is based on extraction by pressurized liquid extraction (PLE), followed by purification and pre-concentration by solid phase extraction (SPE) and quantification by liquid chromatography coupled to a triple quadrupole mass spectrometer (LC-QqQMS). The method was optimized according to dispersant type, temperature, and extraction solvent. The influence of organic matter in sediments on quantitative analysis was also investigated in detail. Matrix effects were highly and significantly correlated (r=-0.9146, p < 0.0001) with retention time. Using internal standards showed the best results for effectively correcting matrix effects without affecting method sensitivity. The method was then validated according to key figures of merit: linearity (R2 > 0.990), extraction recoveries (> 60% for 34 compounds), trueness (bias % < 15%), precision (relative standard deviation < 20%) and matrix effects (between -13.3% and 17.8%). This method can be applied for routine analysis of TrOCs in different sediment matrices. The method was applied to ten lake sediment samples collected in Québec, Canada. Results demonstrated the presence of 17 compounds in at least one lake at concentrations between 0.07 to 1531 ng g-1. The reported concentrations provide a first picture of the occurrence of chemical stressors in sediments of small lake highly anthropized ecosystems in Eastern Canada.

Eco-friendly synthesized zeolitic imidazolate framework-8 enables one-step cerium recovery from water

The rapid pace of technology advancement has quickly depleted valuable rare earth elements (REEs), which are critical for the function and performance of electric and electronic components, and there is thus a need for REE extraction from secondary sources rather than from virgin mines. This study presents an approach involving the ball-milling-induced construction of zeolitic imidazolate framework-8 (ZIF-8) that integrates REE extraction and recovery processes. ZIF-8 demonstrates remarkable extraction capacities for various REEs, and notably promotes nanoscaled CeO2 formation. Ball-milling-prepared ZIF-8 (ZIF-8-BM) effectively concentrates cerium (III) ions (CeIII), and a purity of 99.34% is achieved by controlling the processing parameters, offering a comprehensive solution for efficient Ce retrieval from wastewater. The superior Ce extraction performance is attributed to the greater numbers of structural defects and surface hydroxyl (–OH) groups and the enhanced phase transformation efficiency. Moreover Ce extraction by ZIF-8-BM is found to be efficient in both low and high Ce concentration ranges. ZIF-8-BM nanoparticles spontaneously oxidize CeIII in solution to insoluble CeO2, thereby facilitating the efficient extraction and subsequent recovery of cerium from complex matrices. The findings of this study provide an environmentally benign approach for the safe and efficient recovery of REEs from waste streams, supported by a scientifically sound and economically feasible processing strategy.

Effective magnetic nanoadsorbent based on natural carboxymethyl cellulose/polyaniline nanotube/graphene oxide for aflatoxin B1 and B2 adsorption in rice utilizing a novel synthesis method

A magnetic nanoadsorbent was prepared via a novel one-pot magnetization method by employing natural carboxymethyl cellulose (CMC), polyaniline (PANI) nanotube, and graphene oxide (GO) for the effective adsorption of aflatoxins B1 (AFB1) and B2 (AFB2) from rice samples. This synthesized adsorbent combines the multifunction of CMC, PANI, and GO and shows improved extraction performance. FT-IR, XRD, FE-SEM, VSM, and TGA analyses were used to investigate the successful synthesis of the nanocomposite. The adsorption mechanism was ascribed to π-π interactions, hydrogen bonding, and hydrophobic interactions. Under optimized conditions, the method achieved extraction recoveries ranging from 78 % to 89 %. Low limits of detection (LODs) and quantification (LOQs) were obtained in the ranges of 0.07 and 0.01 ng g−1, and 0.20 and 0.04 ng g−1 for AFB1 and B2, respectively. This method showed an acceptable precision with intra- and inter-day relative standard deviations (RSDs) of less than 15 %. Comparative studies with other adsorbents used in extraction methods such as solid phase extraction (SPE), magnetic dispersive solid phase extraction (MDSPE), and matrix solid-phase dispersion (MSPD) demonstrated that the proposed method outperforms the existing procedures; it is promising in efficient AFs monitoring in rice.

Determination of endogenous GHB in ante-mortem whole blood, urine, and oral fluid by LC–MS/MS: The effect of different additives and storage conditions on the stability of GHB in blood

Two challenges in detecting γ-hydroxybutyric acid (GHB) intake are its endogenous presence and in vitro production after sampling. This study developed an LC–MS/MS method for selective GHB determination in human antemortem blood, urine, and oral fluid at endogenous concentrations. Furthermore, the stability of GHB in blood samples and its endogenous concentrations in samples taken under controlled circumstances were investigated. Samples were extracted in methanol/acetonitrile and processed by anion exchange solid-phase extraction. GHB was separated from structural isomers using a reversed–phase LC column with anion properties. The validated limit of quantification was 0.005 µg/mL in blood and 0.010 µg/mL in urine and oral fluid, at which the relative reproducibility standard deviation and bias were <15 %. The mean extraction recovery was ≥90 %. The average GHB concentration increased by 1.2 µg/mL in fluoride/citrate- preserved blood after 28 days of storage at 4°C; however, in fluoride/oxalate (FX)-preserved blood, the mean concentration increased by only 0.055 µg/mL. No change was observed at −20°C. In 105 randomly selected samples of FX-preserved blood collected for forensic antemortem toxicological analysis, all concentrations were <0.066 µg/mL, even after long-term storage at −20°C. In blood, urine, and oral fluid samples from a clinical study of GHB intake, endogenous baseline levels from 30 participants ranged from 0.0069–0.050, 0.024–0.38, and 0.034–0.93 µg/mL, respectively. These results demonstrate that the current cut-off level of 5 µg/mL for discriminating between endogenous and exogenous GHB in antemortem blood could be considerably lower for FX-preserved blood stored at −20°C.

Development of “water-lean” solvent-based air-assisted liquid–liquid microextraction; application in the extraction of some phenolic compounds from water and wastewater samples prior to GC-FID analysis

In the present study, an efficient, robust, and reliable air–assisted liquid–liquid microextraction procedure was introduced based on a “water-lean” solvents for the extraction and preconcentration of phenolic compounds from spring water and petrochemical, Songun mine, and municipal wastewater samples. For this purpose, various hydrophobic water-lean solvents composed of organic solvents consisting of carbon tetrachloride, dichloromethane, 1,1,2-trichloro-1,2,2-trifluoroethane, and chloroform with amines including n-butylamine, di-n-butylamine, iso-propylamine, n-hexylamine, diethylamine, pyridine, aniline, toluidine, and benzylamine) were prepared and they were used as the new extraction media. The selected compounds (phenol, 1-naphthol, 2-naphthol, 4- chlorophenol, o-cresol, 2-nitrophenol, and 2-nitroso-1-naphthol) were extracted from sample solution containing sodium chloride (5 %, w/v) using 200 µL of a water-lean solvent composed of dichloromethane: butylamine (1:1) by performing the sucking/injection cycles for four times. The effect of several parameters on the extraction efficiency of the method, consisting of type and volume of water-lean solvent, extraction numbers, pH, and ionic strength, were examined and optimized by “one-variable-at-one-time” strategy. High enrichment factors (315–420), respectable extraction recoveries (63–84 %), low limits of detection (0.23–0.56 ng mL−1) and quantification (0.77–1.86 ng mL−1), and broad linearity of the calibration curve (1.86–500 ng mL−1) demonstrated satisfactory performance of the present approach. The relative standard deviation for the extraction of 50 and 100 ng mL−1 of each phenol (n = 6) were ≤ 6.3 % for intra- and inter-day precisions. Eventually, the proposed method was efficaciously performed for extraction and determination of the selected analytes in various water and wastewater samples and phenol and 4-chlorophenol were found in the samples at ng mL−1 level.

Rapid and eco-friendly microextraction procedure based on green hydrophobic deep eutectic solvent for simultaneous determination of five sex hormones from cosmetic samples

Hormones, which are among the endocrine disruptors, are used in many fields and their use in cosmetic products has recently attracted considerable attention. Despite the negative health consequences, there is no detailed guidance that limits the use of these endocrine disruptors. This study aimed to develop a green hydrophobic deep eutectic solvent (HDES)-based microextraction method for the detection and quantification of sex hormones (progesterone, β-estradiol, estrone, ethinylestradiol, and testosterone) in different cosmetic products. The best value for extraction recovery was obtained by using DL-menthol and dodecanoic acid as green HDES in a 4:1 mole ratio. Optimization parameters such as HDES volume, pH, sample volume, centrifugation time, mixing type, and mixing time were investigated for cosmetic samples to be used as real samples. Furthermore, the extraction recovery values ranged from 85.7 % to 101.3 % and the detection limit was between 2.33–3.30 ng mL−1. Additionally, three different greenness methods, namely ComplexGAPI, AGREEprep, and BAGI, were used to evaluate how green the proposed method is in this study. The microextraction procedure developed in this study was successfully applied to five different cosmetic samples that will be used as real samples to detect and determine sex hormones.

Modular Point-of-Need Tropane Alkaloid Detection at Regulatory Levels: Combining Solid-Liquid Extraction from Buckwheat with a Paper-Immobilized Liquid-Phase Microextraction and Immuno-Detection in Interconnectable 3D-Printed Devices.

Contamination with tropane alkaloids in cereals is expected to increase globally. However, current identification tools (e.g., liquid chromatography-mass spectrometry) for tropane alkaloids are time-consuming and expensive. Furthermore, their miniaturized alternatives lack sensitivity and robustness. Therefore, there is a pressing need for inexpensive and effective screening methods. Here, an on-site applicable modular workflow for tropane alkaloid detection in buckwheat is presented. The modular workflow combines paper microfluidics and interconnectable 3D-printed sample preparation tools and was evaluated for different tropane alkaloids, including atropine and scopolamine. Furthermore, integration with an indirect competitive lateral flow immunoassay (icLFIA) for atropine detection at relevant levels was demonstrated. In the modular workflow, to minimize matrix coextraction, tropane alkaloids were extracted from the milled buckwheat cereals by a mixture of alkaline aqueous and immiscible organic solvents (extraction recoveries: 66-79%). The tropane alkaloids were subsequently concentrated with a newly developed paper-immobilized liquid-phase microextraction (PI-LPME, extraction recoveries: 34-60%, concentration factor to immobilized solution in paper: 60-108×). After the PI-LPME, with an integrated 3D-printed setup, the tropane alkaloids were directly eluted (elution recoveries: 83-93%) and detected with the icLFIA. Digital read-out of the icLFIA, by employing a hand-held reader, enabled semiquantification of atropine (IC50 = 0.56 ng mL-1 in standard solutions). The modular workflow was validated by analyzing 24 blank and spiked buckwheat cereal samples with 5 and 10 μg kg-1 atropine. A cutoff value was established with an estimated false negative rate of 1% and estimated false positive rate of 0.68%. Therefore, the modular workflow can aid in fast, inexpensive, and on-site atropine detection by nonexperts, and when integrated with a scopolamine-specific icLFIA expanded toward scopolamine detection. Moreover, the developed sample extraction and concentration method (PI-LPME) is suitable for the analysis of many other compounds with pH-dependent polarity.

Application of magnetic AlFu MOF nanocomposite for the extraction and preconcentration of some pesticides from different distillates

This research used a magnetic AlFu nano-metal-organic framework as an adsorbent for the first time. This approach extracts and preconcentrates eight pesticides from various distillates through a two-step process: magnetic dispersive micro solid phase extraction and dispersive liquid-liquid microextraction. Initially, the nanocomposite is dispersed into a sample solution containing the pesticides and Na2SO4. The target pesticides are then adsorbed onto the nanocomposite, which is subsequently isolated from the aqueous phase using an external magnetic field. Acetonitrile is used to elute the adsorbed analytes pesticides from the nanocomposite surface. The resulting acetonitrile extract, containing the concentrated pesticides, is then mixed with a tiny amount of another solvent and injected into a NaCl solution. Centrifugation allows the organic phase, enriched with the pesticides, to settle down. An aliquot of this organic layer is then analyzed using a gas chromatography-flame ionization detector. Optimization of the procedure led to favorable performance, including good extraction recovery of the pesticides (68–98 %), significant enrichment (enrichment factors of 340–489), a wide range of detectable concentrations (2.90–1400 µg L−1), and low detection (0.15–0.88 µg L−1) and quantification limits. (0.49–2.90 µg L−1)

A New Validated Method for Rapid Determination of OLEU Concentration in Dietary Supplements: Comparison with Total Phenol Content and Antioxidant Activity

The market for olive leaf dietary supplements is expanding rapidly and is valued at $437.15 million today. However, information on the control of these products is sketchy and the origin and variety of olives are rarely stated. The aim of this research was to validate a simple and rapid screening method for oleuropein determination in olive leaf dietary supplements. A matrix blank was prepared by removal of oleuropein from a mixture of dietary supplements and the matrix was then spiked with known concentrations to create a spiked matrix calibration curve in the range 5 - 40% oleuropein. Five replicate extractions and analyses of the matrix standards were carried out over 10 days. Precision was less than 6% RSD and linearity was demonstrated by the Fischer test. Extraction recovery was > 90% and there was a strong linear relationship between authentic and matrix standards. All tested products conformed to the label claim which was strongly correlated with total polyphenols measured by the Folin-Ciocalteau method. Antioxidant activity was measured by the DPPH assay and was found to be strongly correlated with total phenol content and oleuropein concentration.

Development of a UHPLC-MS/MS Method for the Determination of Moxidectin in Rat Plasma and Its Application in Pharmacokinetics.

The aim of the present study was to establish a simple and reliable ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method and apply it for the determination of pharmacokinetics of moxidectin-loaded microspheres (MOX-MS) in rats. Plasma samples were processed using a simplified liquid-liquid extraction method and were separated using an Agilent Zorbax Eclipse Plus C18 column (50 mm × 2.1 mm, 1.8 μm) with a mobile phase consisting of a 10 mM ammonium formate solution with 0.1% formic acid (A) and acetonitrile (B) at a flow rate of 0.4 mL/min for 5 min. Avermectin B1a was used as an internal standard (IS). The sample was injected at a volume of 10 μL with a column temperature of 35 °C and detected in a positive ion mode. A good linear response across the concentration range of 1.00-200 ng/mL (r2 > 0.99) and a lower limit of quantification (LLOQ) of 1.00 ng/mL were achieved. The extraction recovery of moxidectin exceeded 94.1%, the matrix effect was between 91.2% and 96.2%, the accuracy ranged from 100.1 to 103.6%, and the relative standard deviation (RSD) did not exceed 15% for the intra- and inter-day accuracy and precision. The pharmacokinetic results showed that MOX-MS significantly decreased Cmax, prolonged T1/2, and improved bioavailability. The developed method significantly reduced the assay volume, shortened detection time, simplified sample processing methods and saved assay costs, which may contribute to the development of the new antiparasitic drug.

Simultaneous estimation of nebivolol hydrochloride and amlodipine besylate in human plasma employing an innovative HPLC chromatographic method

Abstract Background This study developed and validated a simple, robust, and cost-effective RP-HPLC bioanalytical method for the determination of nebivolol hydrochloride (NBH) and amlodipine besylate (AMB) in human plasma. Briefly, NBH and AMB were extracted from plasma through protein precipitation using 5% formic acid and acetonitrile. Chromatographic separation was achieved using an Inertsil ODS-3 V column (150 mm × 4.6 mm, 5 μm) with a mobile phase composed of acetonitrile and buffer (40:60, v/v). The analysis was conducted using UV detection at 215 nm. Results The bioanalytical method demonstrated linearity for NBH (4.50–180.12 μg/mL) and AMB (3.50–140.06 μg/mL). It exhibited good selectivity and sensitivity, with LLOQ responses within ≤ 20% of the analyte signal. Accuracy and precision were within acceptable limits. The extraction recovery from human plasma showed a CV (%) of 1.15% for NBH and 1.35% for AMB, indicating consistent recovery rates. Stability studies on drug-spiked human plasma at LQC and HQC levels confirmed the stability of the drugs under various conditions. Conclusion The present bioanalytical method successfully quantified NBH and AMB simultaneously in plasma samples. It demonstrated suitability, supported by high recovery rates and low relative standard deviations. With its proven linearity, accuracy, and precision, this technique is well suited for drug identification in plasma samples.

Dispersive solid phase extraction of chloramphenicol and florfenicol in honey sample performed in narrow bore tube with the aid of magnetic ionic liquids prior to HPLC-DAD analysis

The precedence of high levels of antibiotics in animal-derived foods such as honey poses a significant food safety risk. Therefore, the development of an accurate, and reliable method for determining these residues is crucial. In this study, a new extraction method was proposed for the simultaneous determination of chloramphenicol and florfenicol residues in honey samples prior to high performance liquid chromatography analysis. The method involved using amino-functionalized UiO-66 metal–organic framework (NH2-UiO-66) as a sorbent in a narrow bore tube. To begin, the solution was placed into a narrow bore tube and the pH was adjusted to 6. Then, 100 mg of the sorbent was added to the solution. The particles were slowly passed through the solution and collected in the tube bottom. After removing the supernatant phase, 55 µL of 1-butyl-3-methylimidazolium tetrachloroferrate (III) magnetic ionic liquid was used as the elution solvent under sonication for 3 min. The optimized method exhibited low limits of detection (0.19 and 0.44 ng g−1) and quantification (0.63 and 1.4 ng g−1), good extraction recovery (81 and 74 %), and good linearity of the calibration curve (r2 ≥ 0.996) over the ranges of 1.2–500 and 2.4–500 ng g−1 for florfenicol and chloramphenicol, respectively. Precision was satisfactory, with relative standard deviations ≤8.1 % for both intra- and inter-day precisions. The developed method was done on ten honey samples and chloramphenicol was found in five samples.

Medium/Long Chain Hydrophobic Deep Eutectic Solvent-Based Liquid Phase Microextraction for the Determination of Rhein, Emodin, and Chrysophanol with Detection by High-Performance Liquid Chromatography (HPLC)

Medium/long-chain fatty acids/alcohols as hydrogen bond donors coupled with methyltrioctylammonium chloride were used to prepare hydrophobic deep eutectic solvents (DESs) that were employed for the extraction of the anthraquinones (rhein, emodin, and chrysophanol) from fetal bovine serum. Hydrophobic DES-based liquid-phase microextraction and high-performance liquid chromatography were developed. The most suitable combination was optimized for liquid-phase microextraction. Spiked fetal bovine serum was analyzed with satisfactory extraction recoveries.

B-182 Development and validation of an LC-MS/MS assay for simultaneous measurement of serum androstenedione and 17-hydroxyprogesterone in serum

Abstract Background Androstenedione and 17-hydroxyprogesterone are measured via immunoassays or high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) in clinical laboratories. Immunoassays have limited sensitivity and specificity for certain steroid hormones testing. We aimed to develop and validate a sensitive, accurate, and specific in-house LC-MS/MS assay to simultaneously measure both 17-hydroxyprogesterone and androstenedione in serum. Methods 13C-labeled androstenedione and 17-hydroxyprogesterone internal standards were added to calibrator, control, and patient samples. A hexane/ethyl acetate solution was used in a liquid-liquid extraction procedure. The organic layer was then removed and dried followed by reconstituting the extracts in 2.5 mM ammonium formate in 50% methanol. The HPLC mobile phase gradient began with 47%, 2.5 mM ammonium formate in water and 53%, 2.5 mM ammonium formate in methanol. This progressed to 56% of the methanol phase over three minutes. The mixtures were separated though an Agilent 1260 Infinity HPLC system with a Poroshell 120 EC-C18 analytical column (2.1 × 50 mm × 2.7 µm). The separated HPLC eluents then entered an Agilent 6460C QQQ mass spectrometer in positive ion mode through an electrospray ionization source where protonated androstenedione (m/z = 287.2) with the protonated androstenedione-[2, 3, 4-13C3] internal standard (m/z = 290.2) and protonated 17-hydroxyprogesterone (m/z = 331.2) with the protonated 17-hydroxyprogesterone-[2, 3, 4-13C3] (m/z = 334.2) were mass-selected for collision-induced dissociation. For androstenedione, respective quantifier and qualifier m/z values of 287.2 &amp;gt; 97.1 and 287.2 &amp;gt; 109.1 were used while respective quantifier and qualifier m/z values of 331.2 &amp;gt; 97.1 and 331.2 &amp;gt; 109.1 were used for 17-hydroxyprogesterone. Validation studies were performed including imprecision, lower limit of quantitation (LLOQ), analytical measurement range (AMR), interference, specificity, carryover, extraction recovery, matrix effect, and comparison with a reference laboratory LC-MS/MS method. The total allowable error limits used in this study were 23.5% for androstenedione and 30.2% for 17-hydroxyprogesterone. Results Total imprecision results across three concentrations yielded a maximum CV of 4.6 % for androstenedione and 6.5% for 17-hydroxyprogesteron. The AMRs of androstenedione and 17-hydroxyprogesterone were 0.2 to 13.4 and 0.1 to 22.0 ng/mL without significant carryovers. No significant interferences were observed from 11-deoxycorticosterone (700 ng/dL), testosterone (2500 ng/dL), DHEA (1000 ng/mL), bilirubin (30.1 mg/dL), hemoglobin (1032 mg/dL), or triglycerides (1858 mg/dL). The extraction recoveries of androstenedione and 17-hydroxyprogesterone were 98% and 81%, respectively. No significant matrix effects were identified. In comparison to the reference lab LC-MS/MS method, the in-house LC-MS/MS assay demonstrated a 0.523% bias for androstenedione and a -3.77% bias for 17-hydroxyprogesterone with both exhibiting excellent correlations with the reference lab measurements. More specifically, our results (as a function of values obtained from the reference lab) followed the relationship of y = 1.039x - 0.092 (R = 0.9951) for androstenedione and y = 0.957x + 0.01 (R = 0.9974) for 17-hydroxyprogesterone. Conclusions An LC-MS/MS assay is developed for simultaneous detection of serum androstenedione and 17-hydroxyprogesterone. The assay demonstrates acceptable imprecision, AMR, and accuracy. No significant carryover and interference from other structurally similar steroid hormones and other common interferents are identified.