Solid-phase Extraction Research Articles

Evaluation of Jacalin lectin sorbents for the extraction of the human chorionic gonadotropin glycoforms prior to analysis by nano liquid chromatography-high resolution mass spectrometry

Human chorionic gonadotropin (hCG) is a dimeric, highly glycosylated hormone with a total of 4 N- and 4 O-glycosylation sites in its two subunits, hCGα and hCGβ. Recently, we developed a novel nano liquid chromatography coupled to high resolution mass spectrometry (nanoLC-HRMS) method for the analysis and thus the detection of the intact glycoforms of hCG. Here, a sorbent functionalized with the Jacalin lectin was evaluated in solid-phase extraction (SPE) for its potential to fractionate the hCG glycoforms prior to their nanoLC-HRMS analysis at the intact level, which may facilitate the detection of low-abundance glycoforms and may lead to a more detailed characterization of the hormone glycosylation. A commercial sorbent based on Jacalin immobilized on Sepharose and having a lectin density of 4.5mg per ml of gel was selected to carry out SPE and its capacity was estimated to be of some tens of μg of hCG per ml of lectin sorbent. Next, the SPE protocol was modified to improve the extraction recoveries. Especially, it was noticed that an extensive pre-conditioning procedure prior to the first use of a cartridge was necessary to remove the residual non-grafted lectins. Indeed, if on-grafted lectins are not eliminated, they may bind a part of hCG glycoformes preventing they retention by the sorbent, leading to low extraction recoveries (around 10%). With the extensive pre-conditioning procedure, the average extraction recoveries for both hCGα and hCGβ glycoforms were about 50%, with either recombinant or urinary hCG. Qualitatively, the fractionation of hCG glycoforms between the washing and elution fractions was achieved with the urinary hCG sample by determining the number of glycoforms detected in each fraction. It appears that 12 hCGα glycoforms have a low affinity (detected only in the washing fraction), 1 a low-medium affinity (detected in washing and elution 1 fractions), 16 a medium affinity (detected in washing, elution 1 and 2 fractions), and 12 a high affinity (detected only in elution 1 and 2 fractions). For the hCGβ glycoforms, similarly, 3 have a low affinity and 12 a low-medium affinity. Additionally, the 3 hCGβ glycoforms were detected better. A different behavior was observed with the recombinant hCG sample, which indicates glycosylation differences between the two hCG samples. This shows the potential of lectin-based affinity fractionation before nanoLC-HRMS analysis to better characterize the glycosylation state of hCG at the intact level.

Application of a laccase-catalyzed oxidative coupling for the removal and detoxification of typical flotation reagent salicylhydroxamic acid

Residual organic flotation reagents in mineral processing wastewater (MPW) can pose environmental hazards and hinder the sustainable development of the mining industry. Laccase as a versatile biocatalyst can eliminate various recalcitrant contaminants from the environment, but its potential applications for the removal and detoxification of organic flotation reagents have until now been overlooked. Herein, the influence of superparamagnetic immobilized laccase (SPM-IMLac) on the enzymatic removal of salicylhydroxamic acid (SHA), a typical mineral flotation reagent, as well as the mechanism of this process have been explored for the first time. The results indicated that SPM-IMLac can effectively remove SHA over a broad pH range and this process follows the pseudo-first-order reaction kinetics. A methodology which combined high resolution mass spectrometry (HRMS) and a solid phase extraction (SPE) technique revealed that SPM-IMLac could catalyze a single-electron oxidation of SHA to generate self/cross-oligomers via radical-driven C-C and/or C-O-C covalent coupling pathways. The Vibrio fischeri bioluminescence inhibition assay and a total organic carbon (TOC) analysis corroborated that the SHA transformation was accompanied by detoxification and by a reduction in TOC of the reaction solution, the extent of which correlated with the extent of the oxidative coupling. Moreover, SPM-IMLac could be easily recovered and reused, while keeping its high removal efficiency of SHA in the actual MPW matrices. This study not only provides fascinating insights into the transformation mechanisms and environmental fate of SHA mediated by SPM-IMLac, but it also exploits a viable and sustainable approach for the remediation of organic flotation reagents-contaminated MPW.

Extraction and Analysis of Mycotoxins from Whole Wheat Flour - A Methods Efficiency Comparison

Abstract Wheat is considered as staple food source for 40% of the population worldwide. Yet, the yield and quality can be compromised by fungal diseases, which are also responsible for mycotoxins presence at wheat seeds and originating foodstuff. In this context, the tackling of this problem by developing regulatory limits and standards have induced the development of various methods for sampling, extraction, identification and quantification of mycotoxins in food samples. This review addresses the comparison of the technical and cost efficiency of methods for the extraction and qualitative- quantitative analysis of mycotoxins from whole wheat flour. Methods of extraction such as the Solvent Extraction method, the Liquid Liquid Extraction, the Solid Liquid Extraction, the Solid Phase Extraction, the Immuno-Affinity Columns, the QuEChERS, and the use of absorbent nanomaterials such as graphene oxide and multi-walled carbon nanotubes in extraction procedures, are described in principle, technical details are presented, and examples of reported use are given. Methods of mycotoxin analysis such as Immunological Assays (LFIA, ELISA, FPIA), the Sensor-based (Surface Plasmon Resonance Sensor, Piezoelectric Sensors, Electrochemical Sensors, Colorimetric Sensors), and Chromatographic Techniques (TLC, GC, HPLC, HPLC-FLD, LC-MS/MS, UPLC-MS/MS, UHPLC-MS/MS, UFLC-MS/MS) are reviewed. To compare their efficiency, main advantages and disadvantages, the ongoing improvements, as well as the validation parameters (linearity, recovery range, RSDr range, RSDR %, LOQ range, and cut off) are summarized, and pairing of extraction to analysis methods for specific mycotoxins is provided. It was evidenced that none of methods already in use is capable of analyzing all mycotoxin categories at once, because of their chemical characteristics (volatile/non-volatile, co-elution, UV absorption, fluorescence) versus methods restrictions (matrix interferences, cross-reactivity of antibodies, selectivity and reproducibility of data, need for derivatization, etc). Also, depending on the purpose of the analysis (research or screening as part of legal requirements), to date the immunological methods are only suitable for validated matrices, biosensors can be used for routine screening, and that GC-MS and HPLC-based methods fulfill the legal requirements. In conclusion, while the selectivity and accuracy of methods for mycotoxin detection is being improved rapidly (those sensor-based thanks to the use of nanoparticles, nanomaterials, aptasensors, etc., and the chromatographic techniques coupled with mass spectrometry offer a higher selectivity and sensitivity, low detection limits, maintained resolution performance), and the duration of the analysis, the cost, and the need for highly-skilled staff go in favor of rapid methods (immunological and sensors-based), it is the capacity to fulfill legal requirements, which will determine the trend and their future success in the market.

Determination of Macrolides in Water Using Solid-Phase Extraction and Supercritical Fluid Chromatography-Tandem Mass Spectrometry.

Macrolides are a group of compounds used to treat bacterial infections in humans and animals. Their widespread use results in the contamination of the water environment, which, on the one hand, has a detrimental effect on aquatic organisms and, on the other hand, can lead to the emergence of resistant strains of microorganisms. All of the above determines the need for monitoring of these compounds in the environment, particularly, in water objects. Usually, the high-performance liquid chromatography combined with tandem mass spectrometry method is used to solve this problem, however, this work shows the possibility of using the supercritical fluid chromatography-tandem mass spectrometry method. An approach for the determination of four common macrolides, namely erythromycin, clarithromycin, midecamycin, and josamycin, was developed. The use of solid-phase extraction allowed to achieve limits of quantification at 0.57-6.8ng/L. The presented approach was validated and tested on a real object-a sample of municipal wastewater.

Per- and polyfluoroalkyl substances in food and beverages: determination by LC-HRMS and occurrence in products from the Belgian market

Per- and polyfluoroalkyl substances (PFAS) are industrial chemicals encompassing thousands of compounds. Due to their persistent, bioaccumulative and toxic character, PFAS have become environmental contaminants, and exposure to these chemicals may lead to adverse health effects. This study aimed to provide a sensitive analytical method for the quantification of 25 PFAS in food including food for the young population and beverages, and to gather the missing occurrence data for the dietary exposure evaluation for the Belgian population. More than a decade ago, such assessment was performed only for PFOS and PFOA and is currently outdated. For the determination of PFAS in foodstuffs, an extraction based on a “quick, easy, cheap, effective, rugged, and safe” (QuEChERS) protocol and combined with a two-step purification using solid-phase extraction (SPE) was optimised. The quantitative analysis was performed by liquid chromatography high-resolution mass spectrometry (LC-HRMS). The method was validated, and the achieved limits of quantification (LOQs) ranged from 0.002 to 0.3 μg/kg, with the exception of HFPO-DA (1 μg/kg). The LC-HRMS analysis of 268 food products from the Belgian market demonstrated that 43% of samples contained at least one PFAS with a maximum of eleven PFAS measured in a stew of wild pork. PFOS was the most detected compound found in 19% of samples, followed by PFBA (18%) and PFOA (15%), while PFTeDA, PFPeS, PFHpS, PFDS, PFUnDS, PFDoDS, PFTrDS, Minor F53B and HFPO-DA were not detected. The concentrations of the different PFAS in commercial food varied from <LOQ to 2.85 μg/kg, with only one crab sample exceeding the maximum level for PFOA set by the Commission Regulation (EU) 2023/915.

In vitro human oral bioaccessibility assessment of hazardous chemicals, including N, N′-substituted-p-phenylenediamines, coming from recycled tire crumb rubber

Tires, apart from being formed by rubber and filling materials, contain organic compounds added to make them resistant and durable. The widely use of recycled tire crumb rubber (RTCR), main product of the shredding process of end-of-life tires, can cause human exposure to these chemicals due to its use in synthetic football fields and kid's playgrounds. In 2023, the European Commission banned the use of recycled tire crumb rubber in synthetic fields, giving eight years to replace the used material. This study intends to assess the oral bioaccessibility of antiozonants, crosslinking and vulcanizer agents present in RTCR. With this purpose, the Unified Bioaccessibility Method (BARGE) was used to simulate the material ingestion. RTCR is put into contact with the four simulated biological fluids including saliva, gastric and duodenal juice and bile, attempting to simulate human digestion. Afterwards, the organic compounds present in the fluid need to be extracted and Solid-phase extraction (SPE) was the technique selected after being optimized to obtain the best extraction conditions. Ultrasound assisted extraction was performed to evaluate the total concentration of the target compounds in the crumb rubber matrixes. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was employed to identify and quantify the target compounds. The results showed the bioaccessibility of all the studied analytes, with values ranging from 0.1 % up to 70 %. Benzothiazole was the compound with the highest bioaccessibility with a mean value of 40 % and concentrations reaching 32000 ng g−1 in the bioaccessible fraction. N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine and its transformation product ((4-Methylpentan-2-yl)amino)-5-(phenylamino)cyclohexa-2,5-diene-1,4-dione) showed an average bioaccessibility of 0.1 % and 1.8 %, respectively, the latter being present in all the analysed samples.

Liquid chromatography-tandem mass spectrometry analysis of nitrogen mustard degradation products after derivatization with benzoylimidazole

Nitrogen mustards are highly toxic compounds and strictly controlled by the Chemical Weapons Convention. When those agents are used, exposure must be confirmed by analyzing biological samples from victims to allow prompt medication and reduction of secondary damage. In this study, a derivatization-liquid chromatography (LC)-tandem mass spectrometry (MS/MS) method to analyze nitrogen mustard degradation products (ethanolamines; EAs) in human urine was developed. Benzoylimidazole (BzI) was used as a derivatization reagent, and two highly hydrophilic EAs (methyldiethanolamine and ethyldiethanolamine) were analyzed by using a reversed-phase column with sufficient retention. For urine samples, after solid-phase extraction with cation exchange cartridge and derivatization, EAs were analyzed at low limits of detection (5 ng/mL). The calibration curves had a wide linear range (50–1000 ng/mL), and the quantitation results were sufficient for screening. Compared with our previous derivatization-LC-MS/MS method using pentafluorobenzoyl chloride as a derivatization reagent and hydrophilic interaction liquid chromatography (HILIC)-MS/MS method, not only the limits of detection but also the operability and throughput were improved. The performance of the newly developed derivatization reagent was also evaluated using density functional theory (DFT) calculations.

Evaluating the reliability of solid phase extraction techniques for hydrocarbon analysis by GC–MS

Saturate and aromatic compounds are essential in the petroleum industry for assessing the thermal maturity of source rocks and oils, which is critical for basin modeling and sweet-spot mapping. These compounds also play a role in environmental applications, such as oil spill fingerprinting and biogeochemistry. However, the analysis of these compounds by gas chromatography-mass spectrometry (GC–MS) requires meticulous and time-consuming separation processes. Traditional methods like normal-phase liquid column chromatography (LCC) involve large volumes of harmful solvents. This study evaluates the effectiveness of five different sorbents using solid-phase extraction (SPE) techniques—neutral Si, SiOH, Ag-ion, neutral Al, and Ag-ion mixed with activated silica—compared to LCC. The goal was to discern differences in peak resolution, concentration, and isomer ratios of saturate and aromatic compounds for thermal maturity and source rock assessments. The results show that SiOH, neutral Si, and neutral Al do not fully separate aromatic compounds from the saturate fraction, sometimes leaving 40–100% of aromatics within the saturate fraction. Ag-ion mixed with activated silica provided the best separation, resulting in up to 23 times higher aromatic concentration than SiOH. This method is more reliable for quantifying both saturate and aromatic compounds, increases the efficiency of hydrocarbon evaluations, and reduces solvent consumption by 63%, offering a more sustainable approach to hydrocarbon analysis.

Functionalization of Ti3C2 MXene with Diethylenetriamine for a Column-Based Solid-Phase Extraction of Heavy Metals.

Transition metal carbides, nitrides, and carbonitrides, known as MXenes, are attracting attention for their potential application in trace detection of heavy metals. This study presents diethylenetriamine-functionalized Ti3C2 MXene for trace detection of cadmium and lead ions. Functionalization of Ti3C2 significantly improves the adsorption properties of MXenes by replacing native functional groups with silane moieties that contain three amine groups, offering higher affinity for heavy metals. We demonstrate the efficacy of this material as a solid-phase extractor in column-based solid-phase extraction for heavy metal analysis in various food samples. Diethylenetriamine-functionalized Ti3C2 coupled with the flame atomic absorption spectrometer exhibits exceptional analytical performance. While maintaining a robust stability for 15 adsorption-desorption cycles, the proposed method shows detection limits of 0.09 ng mL-1 for cadmium and 1.7 ng mL-1 for lead, with a linear dynamic range of 0.3-50 ng mL-1 for cadmium and 5-90 ng mL-1 for lead, and relative recoveries of 97.50-101.05 and 98.65-100.80% for cadmium and lead ions, respectively. Additionally, relative standard deviations and enrichment factors were calculated as 0.60-4.70% and 42.3 for cadmium ions and 0.65-1.24% and 44.2 for lead ions.

Accurate determination of three new antihypertensive drugs illegally added to food using ultra-high performance liquid chromatography-tandem mass spectrometry

Effective strategies are required to address food safety issues related to the illegal addition of antihypertensive drugs to food and claims of antihypertensive function. In this study, a novel ultra-high performance liquid chromatography-triple-quadrupole mass spectrometry (UHPLC-MS/MS) method was developed for the simultaneous determination of three antihypertensive drugs (azilsartan, candesartan cilexetil, and lacidipine) in 12 food matrices (pressed candies, solid beverages, alternative teas, tea drinks, biscuits, jellies, mixed liquors, oral liquids, medicinal teas, tablets, hard capsules, and soft capsules). Initially, mass spectrometry parameters, such as the collision energies of the three antihypertensive drugs, were optimized. Subsequently, the response intensities and chromatographic separation conditions of the three drugs in different mobile phases were compared. In addition, to enhance the recoveries, various extraction solvents and purification methods, including solid-phase extraction (SPE) columns and the QuEChERS technique, were investigated. In the developed method, sample determination involved three steps. First, the sample was extracted using 0.2% (v/v) formic acid in acetonitrile and then filtered using high-speed centrifugation, in addition, the extracted solution of alternative tea and medicinal tea was purified using the QuEChERS technique. Second, the supernatant was diluted with water, and filtered through a 0.22 μm polytetrafluoroethylene (PTFE) membrane. Finally, the analytes were separated on an Agilent Eclipse Plus RRHD C18 column (50 mm×2.1 mm, 1.8 μm) using a 5 mmol/L ammonium formate aqueous solution and acetonitrile as the mobile phases under gradient elution conditions and then detected using UHPLC-MS/MS with positive electrospray ionization (ESI) in the multiple reaction monitoring (MRM) mode. Quantitative analysis was performed using a matrix-matched external standard method. Methodological validation showed good linear relationships for all three antihypertensive drugs in the investigated concentration ranges, with correlation coefficients (r2) greater than 0.996. The limit of detection (LOD) and limit of quantification (LOQ) of lacidipine were 0.02 mg/kg and 0.04 mg/kg, respectively, whereas those of the other two drugs were 0.01 mg/kg and 0.02 mg/kg, respectively. In the 12 food matrices, the average recoveries of the drugs ranged from 86.6% to 107.5% with relative standard deviations (RSDs) of 1.1%-10.9% (n=6) at low, medium, and high spiked levels. Furthermore, this method was successfully applied to the analysis of real food samples. Overall, the newly developed method is simple, rapid, sensitive, accurate, and suitable for the qualitative and quantitative determination of antihypertensive drugs in different food matrices. This work could provide technical support for food safety agencies in implementing measures against the illegal addition of antihypertensive drugs to food.

Application of osmotic pump coupled solid phase extraction samplers for the on-site sampling and enrichment of pharmaceuticals and personal care products in wastewater treatment plants

Application of osmotic pump coupled solid phase extraction samplers for the on-site sampling and enrichment of pharmaceuticals and personal care products in wastewater treatment plants

Synthesis of 1,2,4-triazole-based deep eutectic solvents modified nickel ferrite nanoparticles and their application in dispersive solid phase extraction of triazole pesticides prior to LC-MS/MS analysis

A dispersive solid phase extraction method using new magnetic nanoparticles based on nickel ferrite was introduced for the extraction of six triazole pesticides (penconazole, hexaconazole, tebuconazole, diniconazole, triadimefon, and difenoconazole) from water samples before liquid chromatography-tandem mass spectrometry analyses. Initially, a new deep eutectic solvent was synthesized with 1,2,4-triazole and n-octanol for surface modification of the nanoparticles easily achieved through microwave radiation. The nanoparticles morphology, magnetic properties, adsorption capacity, isotherms, and crystalline patterns of the sorbent were examined. The capability of the sorbent was evaluated by extracting the target pesticides from water samples showing significant differences in adsorption capacity and efficiency between the modified and non-modified nanoparticles. High extraction recoveries (68-86%) were achieved for the analytes using small amounts of the sorbent with low limits of detection (0.03-0.08 ng mL-1) and quantification (0.13-0.29 ng mL-1), a wide linear range (0.29-250 ng mL-1), and acceptable precision (relative standard deviations ≤6.9%).

Preparation of novel semi-covalent molecularly imprinted polymer for highly improved adsorption performance of tetracycline in aqueous medium

In the present study, a novel tetracycline-imprinted polymer for tetracycline (TC) adsorption in an aqueous medium was synthesized using a semi-covalent imprinting method for the first time. In this approach, the template-monomer complex was synthesized by the reaction of 3-isopropenyl-α,α-dimethylbenzyl isocyanate (IPDMBI) as the functional monomer and TC as a template, forming a thermally reversible urethane bond (covalent bond). The polymer was characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), nitrogen adsorption/desorption measurements, and determination of point zero charge (PCZ). The equilibrium time of TC onto MIP was reached in 15 min, which was described by the non-linear pseud second-order kinetic model. Adsorption isotherm was described as a dual-site Langmuir-Freundlich model and the maximum adsorption capacity, determined at pH 5.0, was found to be 76.74 mg g−1 for MIP, exhibiting higher adsorption capacity when compared with other adsorbent materials previously reported in the literature for TC. Based on the increment relative selectivity coefficient the MIP showed higher selectivity towards TC and some structurally similar compounds belonging to the tetracyclines family (oxytetracycline and chlorotetracycline), when compared with NIP (non-imprinted polymer). The obtained outcomes in terms of selectivity, maximum adsorption capacity, and fast kinetic make this imprinted polymer an outstanding material for future application in molecularly imprinted solid phase extraction for analytical purposes.

Production of 67Cu at a biomedical cyclotron via 70Zn(p,α)67Cu reaction and its evaluation in a preclinical study using small animal SPECT/CT

Clinical advancements in nuclear medicine theranostics has excited a research interest in exploring novel radionuclides for medical use. The duo of the β- emitter 67Cu and the positron emitter 64Cu, has advantages over the well-established clinical pair 68Ga and 177Lu in terms of capability for high-precision therapy. Low availability has hindered the use of 67Cu whereas 64Cu has become established at a limited number of sites through production in low-to-medium energy biomedical cyclotrons. Via the reaction 70Zn(p,α)67Cu, 67Cu can also be cyclotron produced, although data on the cross sections of this reaction are sparse. Our aim in this study was three-fold: 1) to establish cross sections for relevant beam energies (14-16 MeV) of the 70Zn(p,α)67Cu reaction; 2) determine experimentally the thick target yield for 16.5 MeV proton beam; 3) establish a routine production of 67Cu for radiochemical and preclinical research. Additionally, our work aims to explore the feasibility of using biomedical cyclotrons for developing of novel therapeutic radionuclides.Thin layers of enriched 70Zn were electrodeposited onto silver foils to employ the stacked foils technique for assessing the cross section at six energies. The thick target yield was measured experimentally using a pressed [70Zn]ZnO target. Methods were developed for solid phase extraction separation of 67Cu from the target material, as well as quality control of the product with regards to radionuclidic and radiochemical purity. Radiolabelling of PSMA-617 precursor was performed and the end product injected in a healthy mouse for a kinetic study. As a proof of concept for preclinical applications The animal was then SPECT imaged using the 185 keV gamma emission line.Summarizing, our data confirm that biomedical cyclotrons can contribute in developing novel radionuclides, even of low cross section, for preclinical research.

Experiment on selective dynamic extraction of germanium by ultrasonic enhanced N235 extraction resin under complex system

Germanium plays an irreplaceable role in the field of modern high-tech materials and is an important strategic metal resource. N235 extraction resin was used to selectively extract [Ge(C4O6H4)3]2-. Under the condition of ultrasonic power at 120 W in a water bath, the extraction rate of germanium was 97.32%. The extraction rate of zinc was 2.37% under the conditions of a three-stage solid phase extraction column in series (single-stage filling N235 extraction resin 0.8 g), reaction temperature 25 °C, tartaric acid concentration of 2.0 g/L, and the dwell time is 4.1min. The saturated adsorption capacity of the resin is 51.90 mg/g. The extraction rate of germanium increased by 14.4% under ultrasonic-assisted strengthening conditions. The [Ge(C4O6H4)3]2- can be separated from the resin by NaOH solution. The desorption rate of germanium was 94.12% under the condition of water bath ultrasonic power of 120W, 30 ml concentration of 3.5 mol/L NaOH solution, and the dwell time is 5.2min. Under the optimum conditions, the extraction rate of N235 extraction resin was 85.23% after repeated regeneration five times. The results demonstrate that the extraction resin exhibits high selectivity and reproducibility in complex systems, presenting a new method for extracting germanium under complex conditions.

A Method to Estimate the Dietary α-Linolenic Acid Requirement Using Nonesterified DHA and Arachidonic Acid Oxylipins and Fatty Acids

BackgroundThe dietary requirement for α-linolenic acid (ALA) remains unclear, as evidenced by the absence of an RDA for this essential fatty acid (FA). In previous studies, we observed that the amount of dietary ALA required to maximize nonesterified (NE) DHA oxylipins appears to be higher than the amount required to maximize tissue esterified DHA levels, which have classically been used to estimate the ALA requirement. Further, we observed that dietary ALA reduces esterified arachidonic acid (ARA) and its NE oxylipins. ObjectivesSince NE oxylipins and FA mediate the biological activities of FA, we examined whether these DHA and ARA pools could be used to determine the dietary ALA requirement. MethodsNine groups of 4-wk-old male Sprague-Dawley rats (n = 5) and 10 groups of male and female CD1 mice (n = 6) were provided 0.1–2.5 g ALA and 2 g of linoleic acid per 100 g of AIN93G-based diets. NE DHA and ARA and their oxylipins in serum, liver, kidney, and brain homogenates underwent solid phase extraction and were quantified by HPLC-MS/MS. Breakpoint analysis of transitions from increase to plateau was conducted using piecewise regression. ResultsIn response to increasing dietary ALA, NE DHA oxylipins, and DHA in serum, liver, and kidney (but not the brain) initially increased rapidly and then plateaued whereas ARA oxylipins and ARA tended to decrease and plateau. Thus, breakpoints were calculated for the ratios of DHA/ARA and hydroxy-DHA/hydroxy-ARA (DHAOH/ARAOH), which consisted of oxylipins synthesized via pathways common to both FA. In serum, liver, and kidney, the highest estimated breakpoint indicated an ALA requirement of ∼0.7 g/100 g diet (1.7% energy), approximately twice that of previous estimations. ConclusionsThis study supports the use of NE DHAOH/ARAOH or DHA/ARA as biochemical indicators of the ALA requirement. Applying this method in rats and mice indicates that the requirement is higher than previously estimated using esterified DHA alone.

Rapid on-site detection of illicit drugs in urine using C18 pipette-tip based solid-phase extraction coupled with a miniaturized mass spectrometer

Drug abuse is a social issue worldwide, and there is an increasing demand for on-site rapid detection of illicit drugs. In this study, a rapid and simple analytical method for the detection of 6-monoacetylmorphine (6-MAM), methamphetamine (MA), methylenedioxymethamphetamine (MDMA), ketamine (K), norketamine (NK), and cocaine (COC) in urine was developed. The developed method combines C18 pipette-tip based solid-phase extraction (C18 PT-SPE) with a miniaturized mass spectrometer (miniMS), exhibiting remarkable simplicity, high sensitivity, and strong reliability, compared with the conventional method. The optimal extraction and elution conditions for C18 PT-SPE were considered as 9 and 3 aspirating-dispensing cycles, respectively. The miniMS parameters including spray voltage, isolation potential, and collision-induced dissociation energy for the detection of these six illicit drugs were optimized using a nano-electrospray ionization method. The limit of detection (LOD), limit of quantification (LOQ), linear range, and linearity for the analysis of six illicit drugs in urine with the proposed C18 PT-SPE-miniMS method were determined. Except for the LOD of K and COC was determined as 0.5 and 0.25 ng mL−1 respectively, and the LOD of 6-MAM MA, MDMA, and NK was determined as 1 ng mL−1. This method enables rapid on-site detection, providing easier operation, lower cost, and better portability compared to conventional methods, making it a potential tool in drug crime investigation and forensic science.

Starch-modified nickel ferrite nanoparticles as a magnetic nano-bio adsorbent for the extraction and determination of lead in water and Moringa oleifera samples

In this work, nickel ferrite magnetic nanoparticles were synthesized using a facile hydrothermal method. The surface modification of the prepared nanoparticles was carried out using cross-linked starch as a good stabilizer and biopolymer. The as-prepared nickel ferrite-starch nano-bio composite was characterized using numerous techniques, and introduced as a novel adsorbent. The initial experimental results indicated that the adsorbent has a good capability to extract lead ions (Pb(II)) from aqueous solutions. Hence, the adsorbent was applied for dispersive magnetic solid-phase extraction of Pb(II) before flame atomic absorption spectrometric detection. Some variables affecting the extraction efficiency such as sample volume (250.0mL), pH (6.5), type and eluent concentration (0.3molL1 nitric acid), amount of the adsorbent (200mg), extraction time (15min), and desorption time (15min) were investigated and optimized. Moreover, the adsorption capacity (35.50mgg1), stability and reusability (80 extraction/desorption cycles), and selectivity of the adsorbent towards the analyte were studied. In the optimized conditions, the linear dynamic range of the constructed calibration graph is between 0.5 and 140.0ngmL1. The limit of detection and limit of quantification of the method are 0.12 and 0.40ngmL1, respectively. The average intra-day and inter-day relative standard deviations (for n=6 and 5.0, 50.0 and 100.0ngmL1 Pb(II) concentration) are 2.02% and 3.72%, respectively. To validate the method, the certified reference material NIST SRM 1643e was analyzed, and the method was used for the pre-concentration and determination of lead ions in different sections of Moringa oleifera medicinal plant and several water samples. The acceptable relative recovery values between 98.0 and 102.7% were attained for the spiked samples, approving the ignorable matrix effect of the method.

Multi-attribute method analysis of therapeutic monoclonal antibodies using an automated sample preparation system

The multi-attribute method (MAM) has attracted increased attention as an alternative strategy for evaluating structural heterogeneity using conventional separation techniques such as ion-exchange chromatography and capillary electrophoresis of therapeutic monoclonal antibodies (mAbs). One of the remaining challenges for the practical use of the MAM is reliable and robust continuous monitoring. In this study, we successfully established an automated sample preparation system as a solution to this issue. Through method optimization, we confirmed that the peptide purification step using a solid-phase extraction column, which is usually performed after the digestion step, was not mandatory and that the addition of methionine as an oxidation inhibitor was able to significantly reduce artificial oxidation. Importantly, the use of our system enabled high-precision analysis for targeted peptide monitoring without relying on the operator’s knowledge and experience with peptide mapping using liquid chromatography/mass spectrometry (LC/MS). Our system could also be useful as a platform approach for targeted peptide monitoring in MAM workflow of traditional IgG-type mAbs. Furthermore, using common samples that were prepared using the automated system, we assessed the compatibility of LC/MS system in the targeted peptide monitoring via a collaborative study with MS vendors. The results showed that there was no significant difference in the mass accuracy, repeatability of the peak retention time and variations of intermediate precision of the measurement values among the four LC/MS systems, suggesting sufficient compatibility among the LC/MS systems. MAM system using our automated sample preparation method, which had high intermediate precision, will be useful for release and stability testing as well as characterization and manufacturing process development.

Determination of three dechloranes in environmental water by magnetic solid-phase extraction-gas chromatography-negative chemical ionization mass spectrometry based on the covalent organic framework material

Dechloranes are additive-type chlorine flame retardants that are widely used in processing industrial products, such as electronic equipment and textiles. Dechloranes, which can enter the human body through various routes, pose significant health risks because of their toxicity, persistence, and bioaccumulation. In 2023, dechlorane plus was listed in the Stockholm Convention on Persistent Organic Pollutants. In the same year, China recognized this compound as a priority-controlled substance. Dechloranes are commonly found at trace levels in water, which is extremely harmful to the environment and human health. Therefore, the development of detection methods for dechloranes is crucial. Magnetic solid-phase extraction (MSPE) has attracted considerable attention because of its low organic solvent consumption, simplicity of adsorbent separation, and ease of operation. In general, the selectivity and efficiency of MSPE depend on the characteristics of the adsorbent. Covalent organic frameworks (COFs) have regular porosity, structural predictability and stability, high specific surface areas, and adjustable pore sizes, which are advantageous for a wide range of separation and analysis applications. In this study, Fe3O4 magnetic nanoparticles and a COF material (TpBD) were combined to prepare Fe3O4@TpBD as an adsorbent for dechloranes. Subsequently, an effective method for analyzing dechlorane in environmental water was established by coupling MSPE with gas chromatography-negative chemical ionization mass spectrometry (GC-NCI/MS). The successful synthesis of Fe3O4@TpBD was confirmed using transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and vibrating sample magnetometry. A single-factor method was used to optimize the extraction conditions, including the Fe3O4@TpBD dosage, pH of water sample, elution solvent type and volume, extraction time, elution time, and ionic strength. The target analytes were separated on a TG-5SILMS column (30 m×0.25 mm×0.25 μm) and quantified using the external standard method in the selected-ion monitoring (SIM) mode. Under the optimal extraction conditions, the method validation results showed a linear range of 2-1000 ng/L. The limits of detection (LODs) and quantification (LOQs) were 0.18-0.27 ng/L and 0.60-0.92 ng/L, respectively, for the three analytes. The intra-day and inter-day precisions at three spiked levels were 4.2%-16.2% and 6.9%-15.7%, respectively. This method was successfully applied to the determination of dechloranes in environmental water samples (laboratory tap water, reservoir water, wastewater treatment plant effluent, and landfill leachate treatment effluent). The recoveries of the three dechloranes at different spiked levels ranged from 77.8% to 113.3% with relative standard deviations (RSDs) of 2.5%-16.3% (n=3). With the advantages of operational simplicity, high sensitivity, and good reproducibility, the proposed method is suitable for the qualitative and quantitative determination of dechloranes in environmental water.