Solid-phase Extraction Cartridges Research Articles

Hydroxylated hierarchical flower-like COF for solid-phase extraction of adrenergic receptor agonists in milk.

A new detection platform based on a hydroxylated covalent organic framework (COF) integrated with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was constructed and used for detecting adrenergic receptor agonists (ARAs) residues in milk. The hydroxylated COF was prepared by polymerization of tris(4-aminophenyl)amine and 1,3,5-tris(4-formyl-3-hydroxyphenyl)benzene and applied to solid-phase extraction (SPE) of ARAs. This hydroxylated COF was featured with hierarchical flower-like morphology, easy preparation, and copious active adsorption sites. The adsorption model fittings and molecular simulation were applied to explore the potential adsorption mechanism. This detection platform was suitable for detecting four α2- and five β2-ARAs residues in milk. The linear ranges of the ARAs were from 0.25 to 50 µg·kg-1; the intra-day and the inter-day repeatability were in the range 2.9-7.9% and 2.0-10.1%, respectively. This work demonstrates this hydroxylated COF has great potential as SPE cartridge packing, and provides a new way to determine ARAs residues in milk.

For the occurrence of PPCPs from source to tap: A novel approach modified in terms of sample preservation and SPE cartridge to monitor PPCPs in our water supply

BackgroundThe ongoing infusion of pharmaceutical and personal care products (PPCPs) into ecosystems sustains a perpetual life cycle and leads to multi-generational exposures. Limited understanding of their environmental impact and their intrinsic ability to induce physiological effect in humans, even at low doses, pose great risks to human health. Few scholarly works have conducted systematic research into the occurrence of PPCPs within potable water systems. Concurrently, the associated monitoring techniques have not been comprehensively examined with regards to the specific nature of drinking water, namely whether the significant presence of disinfectants may influence the detection of PPCPs. ResultsA modified approach in terms of detailed investigation of sample preservation and optimization of an in-lab fabricated solid phase extraction (SPE) cartridge filled with DVB-VP and PS-DVB sorbent was proposed. Favorable methodological parameters were achieved, with correlation coefficients spanning from 0.9866 to 0.9998. The LODs of the PPCPs fluctuated from 0.001 to 2 μg L−1, while the LOQs varied from 0.002 to 5 μg L−1. The analysis of spiked samples disclosed a methodological precision of 2.31–9.86 % and a recovery of 52.4–119 %. We utilized the established method for analyzing 14 water samples of three categories (source water, finished water and tap water) from five centralized water supply plants. A total of 24 categories encompassing 72 PPCPs were detected, with the concentrations of PPCPs manifested a marked decrease from source water to finished water and finally to tap water. SignificanceOur research meticulously examined the enhancement and purification effects of widely used commercial SPE cartridges and suggested the use of in-lab fabricated SPE cartridges packed with DVB-VP and PS-DVB adsorbents. We also conducted a systematic evaluation of the need to incorporate ascorbic acid and sodium thiosulfate as preservatives for PPCP measurement, in consideration of the unique characteristics of drinking water matrices, specifically, the significant concentration levels of disinfectants. Furthermore, the proposed method was effectively employed to study the presence of PPCPs in source water, finished water, and tap water collected from centralized water supply plants.

Optimization of volatile organic compounds sampling from dairy cow exhaled breath using polymer-based solid-phase extraction cartridges for gas chromatographic analysis

We explored appropriate technical setups for the detection of volatile organic compounds (VOCs) from exhaled cow breath by comparing six different polymer-based solid-phase extraction (SPE) cartridges currently on the market for gas chromatography/mass spectrometry (GC-MS) screening. Exhaled breath was sampled at a single timepoint from five lactating dairy cows using six different SPE cartridges (Bond Elut ENV (ENV); Chromabond HRX (HRX); Chromabond HRP (HRP); Chromabond HLB (HLB); Chromabond HR-XCW (XCW) and Chromabond HR-XAW (XAW)). The trapped VOCs were analyzed by dynamic headspace vacuum in-tube extraction GC-MS (DHS-V-ITEX-GC-MS). Depending on the SPE cartridge, we detected 1174–1312 VOCs per cartridge. Most VOCs were alkenes, alkanes, esters, ketones, alcohols, aldehydes, amines, nitriles, ethers, amides, carboxylic acids, alkynes, azoles, terpenes, pyridines, or sulfur-containing compounds. The six SPE cartridges differed in their specificity for the chemical compounds, with the XAW cartridge showing the best specificity for ketones. The greatest differences between the tested SPE cartridges appeared in the detection of specific VOCs. In total, 176 different VOCs were detected with a match factor >80%. The greatest number of specific VOCs was captured by XAW (149), followed by ENV (118), HLB (117), HRP (115), HRX (114), and XCW (114). We conclude that the tested SPE cartridges are suitable for VOC sampling from exhaled cow breath, but the SPE cartridge choice enormously affects the detected chemical groups and the number of detected VOCs. Therefore, an appropriate SPE adsorbent cartridge should be selected according to our proposed inclusion criteria. For targeted metabolomics approaches, the SPE cartridge choice depends on the VOCs or chemical compound groups of interest based on our provided VOC list. For untargeted approaches without information on the animals’ metabolic condition, we suggest using multi-sorbent SPE cartridges or multiple cartridges per animal.

Carbamazepine Adsorption onto Giant Macroporous Silica and Adaptive Neuro-Fuzzy Inference System Modeling

AbstractThere is an imperative need to eliminate pharmaceutical residues from aquatic environments due to their hazardous properties, including toxicity, mutagenicity, and carcinogenicity, particularly when present in water sources. Conventional water treatment methods have proven insufficient in addressing nano-pollutants such as pharmaceutical residues. Consequently, the ongoing quest for economically viable, sustainable, and environmentally friendly removal mechanisms persists. In this particular study, we employed Giant Macroporous Silica (GMS) derived from marine sponges as a promising biosorbent. GMS exhibits commendable characteristics, including a high specific surface area, swift mass transfer capabilities, and non-discriminatory adsorption qualities. The efficacy of GMS in adsorbing carbamazepine (CBZ), a common drug residue, was scrutinized under diverse experimental conditions, including a sorbate/sorbent ratio ranging from 0.005 to 1.500 weight ratio, contact times spanning from 0 to 240 min, and initial pH values ranging from 5 to 9. Remarkably, at a concentration of 1000 µg L−1, GMS demonstrated an attractive adsorption rate (98.88%) of carbamazepine at pH 7.07, within 90 min. To enhance our understanding, we developed an ANFIS model utilizing the experimental parameters as inputs. The developed model exhibited a high correlation coefficient of 0.9944% and a root mean square error (RMSE) of 1.6693, indicating its dependability in accurately predicting the adsorption of CBZ on GMS. The results of our study highlight the efficacy of GMS in adsorbing CBZ, suggesting its considerable potential for adsorbing other pharmaceutical residues and nano-pollutants. Furthermore, we propose the possibility of developing a solid-phase extraction cartridge from GMS.

Determination of antibiotics of the tetracycline group in water by high-performance liquid chromatography on a diode matrix detector with preliminary concentration by solid-phase extraction

Introduction. Antibiotic contamination of the environment is a serious environmental threat that poses a hazard to human health. To monitor the content of tetracycline antibiotics in environmental objects and control technological processes aimed at their disposal, accessible analytical methods are needed. 
 Purpose of the study. Development of a method for determining antibiotics of the tetracycline group in water using a diode array detector with preliminary solid-phase concentration.
 Material and methods. The objects of the study were model solutions of minocycline, tetracycline, oxytetracycline, demeclocycline, metacycline, and doxycycline in deionized, tap, natural, and treated wastewater. For solid-phase extraction, Diapak P and Diapak PG cartridges were used. SPE was performed using a VacMaster-10 manifold (Biotage). Chromatographic separation was carried out on Diasphere C10CN and Kromasil Eternity 250 × 4.6 mm 5 µm columns on an Agilent 1100 liquid chromatograph (Agilent Technology).
 Results. Optimal conditions for the chromatographic separation of minocycline, tetracycline, oxytetracycline, demeclocycline, metacycline, and doxycycline were selected: isocratic mode, wavelength of 350 nm, mobile phase – acetonitrile: aqueous solution of phosphoric acid (pH = 3.0). The analysis time on Diasphere C10CN and Kromasil Eternity columns was 12 and 14 minutes, respectively. The reliability of the linear approximation in both cases was more than 0.99, however, the slopes on the Kromasil Eternity column were 1.35 –1.65 times higher than on Diasphere C10CN. The degree of extraction of tetracyclines from deionized water on Diapak P and Diapak PG cartridges was 90–95%, from tap water 61–89%, from purified waste water: 51–87%.
 Limitations. The method is not suitable for water bodies with tetracycline contents less than 2 µg/dm3.
 Conclusion. An HPLC method has been developed for the determination of minocycline, tetracycline, oxytetracycline, demeclocycline, metacycline, and doxycycline in water with preliminary SPE concentration on Diapak P and Diapak PG cartridges. The lower limit of determination for the sorption of target compounds from 0,1 dm3 of sample was 2 μg/dm3.

Optimization, validation, and application of a liquid chromatography-tandem mass spectrometry method for the determination of 47 banned drug and related chemical residues in livestock urine using graphitized carboxyl multi-walled carbon nanotubes-based QuEChERS extraction

The establishment of an efficient method for the analysis of drug residues in animal urine facilitates the real-time monitoring of drugs used in the production of animal-derived food. A modified QuEChERS extraction–liquid chromatography-tandem mass spectrometry (LC–MS/MS) method was established for the determination of 47 banned drug and related chemical residues in livestock urine. The sample was extracted with acetonitrile by converting the acid-base environment. The sample cleanup effects of seven solid phase extraction cartridges and two EMR-Lipid products were compared, and three materials, including graphitized carboxyl multi-walled carbon nanotubes (MWCNTs), PSA, and C18, were selected as QuEChERS adsorbents from 24 materials. All analytes showed good linearity, with correlation coefficients (R2) greater than 0.9936. Low limits of quantification could be obtained, ranging from 0.2 to 5.5 ng/mL. The average recoveries at low, medium, and high spiked levels were in the range of 70.8–114.9 %, with intra-day precision ranging from 2.4 % to 11.2 % and inter-day precision ranging from 4.5 % to 16.1 %. Swine urine and bovine urine samples collected from different farms were effectively analyzed using the developed method, and metronidazole was detected in three swine urine samples.

Organ-level distribution tandem mass spectrometry analysis of three structural types of brassinosteroids in rapeseed.

Brassinosteroids (BRs) are a class of naturally occurring steroidal phytohormones mediating a wide range of pivotal developmental and physiological functions throughout the plant's life cycle. Therefore, it is of great significance to determine the content and the distribution of BRs in plants.Regretfully, although a large number of quantitative methods for BRs by liquid chromatography-tandem mass spectrometry (LC-MS/MS) have been reported, the in planta distribution of BRs is still unclear because of their lower contents in plant tissues and the lack of effective ionizable groups in their chemical structures. We stablished a novel analytical method of BRs based on C18 cartridge solid-phase extraction (SPE) purification, 4-(dimethylamino)-phenylboronic acid (DMAPBA) derivatization, and online valve-switching system coupled with ultra-high performance liquid chromatography-electro spray ionization-triple quadrupole mass spectrometry (UHPLC-ESI-MS/MS). This method has been used to quantify three structural types of BRs (epibrassinolide, epicastasterone, and 6-deoxo-24-epicastaster one) in different organs of Brassica napus L. (rapeseed). We obtained the contents of three structural types of BRs in various organ tissues of rapeseed. The contents of three BRs in rapeseed flowers were the highest, followed by tender pods. The levels of three BRs all decreased during the maturation of the organs. We outlined the spatial distribution maps of three BRs in rapeseed based on these results, so as to understand the spatial distribution of BRs at the visual level. Our results provided useful information for the precise in situ localization of BRs in plants and the metabolomic research of BRs in future work. The in planta spatial distribution of BRs at the visual level has been studied for the first time.

Determination of lipophilic marine biotoxins (azaspiracids, brevetoxins, and okadaic acid group) and domoic acid in mussels by solid-phase extraction and reversed-phase liquid chromatography with tandem mass spectrometry

An accurate and efficient method was developed for the determination of azaspiracid shellfish toxins (azaspiracids-1, -2, and -3), neurotoxic shellfish toxins (brevetoxins-2 and -3), diarrhetic shellfish toxins (okadaic acid and dinophysistoxins-1 and -2), and the amnesic shellfish toxin (domoic acid) in mussels (Mytilus galloprovincialis). Lipophilic marine biotoxins (azaspiracids, brevetoxins, and okadaic acid group) were extracted with 0.5 % acetic acid in methanol under heating at 60°C to improve the extraction efficiency of okadaic acid group toxins and then cleaned up with a C18 solid-phase extraction cartridge. Domoic acid was extracted with 50 % aqueous methanol and then cleaned up with a graphitized carbon solid-phase extraction cartridge. Lipophilic marine biotoxins and domoic acid were quantified by reversed-phase liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The developed method had insignificant matrix effects for the nine analytes and good recoveries in the range of 79.0 % to 97.6 % at three spiking levels for all analytes except brevetoxin-2 (43.8–49.8 %). The developed method was further validated by analyzing mussel tissue certified reference materials, and good agreement was observed between certified and determined values.

Use of the dummy approach for the synthesis of ion imprinted polymers with Ni(II) or Zn(II) as template ion for the solid-phase extraction of Cu(II).

There is a strong interest in monitoring copper in environmental waters, but its direct analysis suffers from strong matrix interferences. This is why, a sample pretreatment based on solid-phase extraction (SPE) is often used but conventional sorbents usually lack specificity. It is overcome with ion-imprinted polymers (IIPs). This work evaluates for the first time the use of the dummy approach for the synthesis of Cu(II)-targeting IIPs. Two analog ions Ni(II) and Zn(II) were tested as templates and the resulting IIPs were packed in SPE cartridges. The SPE procedure was designed by optimizing a washing step following the sample percolation, to eliminate the interfering ions retained on the IIP by non-specific interactions. To optimize the washing step, solutions at different pH or containing tris(hydroxymethyl)aminomethane as a complexing agent at different concentrations were tested and combined. Zn-IIP appeared more promising than Ni-IIP, showing excellent specificity and a high selectivity. Its retention capacity was determined to be 100µg/g, and different isotherm models were evaluated to fit with the adsorption data. Finally, applications to mineral and sea waters were successfully completed and led to high and repeatable extraction recoveries for Cu(II) (88±1% and 83±3%, respectively).

A Fast and Simple Solid Phase Extraction-Based Method for Glucosinolate Determination: An Alternative to the ISO-9167 Method.

Glucosinolates (GLSs) are a well-studied sulfur-containing compound found in Brassicaceae plants that play critical roles in plant resistance and human health. Correctly identifying and reliably quantifying the total and individual GLS content is of great importance. An improved method as an alternative to the ISO 9167-1 (ISO) method is developed in the present study. An efficient extraction and purification procedure is proposed with a commercially available dimethylaminopropyl (DEA)-based weak anion exchange solid-phase extraction (SPE) cartridge instead of using the self-prepared ion-exchange columns in the ISO method. The GLSs are identified and quantified by ultra high-performance liquid chromatography (UHPLC) high-resolution mass spectrometry (HRMS). The method demonstrates a comparable quantification of total and individual GLSs on certified rapeseeds and other Brassicaceae vegetables when compared to the ISO method. The developed SPE method is simpler and more efficient, thus allowing for applications to a large sample size with reduced analysis time, improved repeatability and accuracy, and possible automation.

Development of antibody-engineered molecularly imprinted polymers for selective capture of aflatoxin B1 from starchy food and medicinal materials

Molecularly imprinted polymers(MIPs) have been widely used as selective recognition materials for analysis and detection of mycotoxins, such as aflatoxin B1(AFB1). However, little attention was given to investigate key factors that affecting selectivity and specificity of MIPs, such as functional monomers and imprinted cavity compatibility. Inspired by the recognition of antibody to antigen, we designed and employed amino acids as functional monomers with multiple interaction sites via hydrogen bonding and aromatic π-π stacking, meanwhile, synthesized structurally matched alternative template, 5,7-dimethoxycyclopentenone [2,3-c]coumarin(DMPC) to prepare MIPs via silica surface grafting. The adsorption of antibody-engineered MIPs was enhanced significantly compared to that of MIPs prepared by conventional functional monomers and dummy templates for selective capture of AFB1. And the specific recognition sites of MIPs left by DMPC conferred the most remarkable selectivity toward AFB1 among aflatoxins. The mechanism and contribution of functional groups and imprinted cavities for selective adsorption of AFB1 were elucidated, providing a different approach to improving functional monomers and templates in MIPs. The solid phase extraction cartridges packed DMPC-ATry-MIPs@SiO2 were used for enrichment of AFB1 in Lotus seeds and Coix seeds. The recoveries were 94.48–112.90 % and 83.32–116.04 % respectively, even after being used five times repeatedly. The cartridges could replace expensive and low-reusability immunoaffinity columns in the analysis and detection of AFB1 in real samples, providing a kind of promising sample pretreatment materials for trace analysis in food and drugs.

Validation of a LC-MS/MS method for establishing reference intervals and assessing diagnostic performance of urinary free cortisol and cortisone

Background24-h urinary free cortisol (UFF) is recommended for screening of Cushing's syndrome (CS), a rare disease characterized by apparent cortisol and cortisone excess. We aimed to validate a simple LC-MS/MS method for accurate measurement of UFF and urinary free cortisone (UFE), establishment of reference ranges, and evaluation of performance for CS diagnosis. MethodsUrine samples were processed using solid-phase extraction cartridges, followed by elution with methanol and acetonitrile. Analysis was performed via tandem mass spectrometry, utilizing multiple reaction monitoring and electrospray ionization source in positive ion mode. ResultsThe assay displayed excellent linearity (r > 0.99) in the range of 0.05–100 ng/mL for cortisol and 0.25–500 ng/mL for cortisone, with lower limits of quantification (LLOQ) at 0.05 ng/mL for cortisol and 0.25 ng/mL for cortisone. The obtained results for intra-day and inter-day imprecision for both analytes were within the acceptable range of less than 10 %. The trueness values for both compounds were also within the acceptable limit of 15 %. No significant matrix effects or carry over observed in our method. The reference intervals of UFF, UFE and UFF:UFE ratio were 7.01–45.66 µg/24-h, 27.97–139.21 µg/24-h and 0.17–0.56, respectively. UFF > 56.75 µg/24-h showed 100 % specificity and 100 % sensitivity for CS diagnosis, which was superior to UFF:UFE ratio. ConclusionsWe developed and validated a sensitive LC-MS/MS method to detect UFF and UFE. Our data indicate that UFF measured by the current LC-MS/MS assay exhibited high diagnostic performance for CS.

Salt-assisted liquid-liquid extraction and on-column concentration for chromatographic determination of phenolic compounds in beer

Salt-assisted liquid-liquid extraction (SALLE) and on-column concentration were evaluated to simplify the chromatographic determination of phenolic compounds in beer. Resveratrol, flavonoids (quercetin and kaempferol), and phenolic acids (caffeic, p-coumaric, and trans-ferulic acids) were used as model compounds based on their concentrations reported in craft beers. SALLE with acetonitrile was effective for sample cleanup, with recoveries ranging from 84 % to 112 %. The on-column concentration was carried out in high performance liquid chromatography by starting the gradient elution with acidified water (sample carrier stream) in a reversed-phase mode. Consequently, the analytes were retained in a narrow band, and highly polar/ionic potentially interfering species were flushed from the column. The effectiveness of the approach was demonstrated by linear correlations between the peak areas and the injected volumes from 10 to 200 µL (r ≥ 0.999), without significant variations in peak width (< 10 %), retention times (< 0.7 %), and peak symmetry (tailing factors within the range of 0.8–1.1). For all analytes, a linear response was achieved from 100 to 1000 µg L−1 (r > 0.999), with limits of detection within the range of 9–82 µg L−1. The approach was also effective for on-column concentrations of resveratrol, quercetin, and kaempferol in sequential injection chromatography (SIC), with injected volumes up to 750 µL and linear responses within 100–1000 µg L−1 (r > 0.997). The proposal reduced consumption of organic solvents (with only 770 µL required per determination in SIC) and avoided solid-phase extraction cartridges for analyte preconcentration.

Determination of 60 Food-Borne Stimulant Drug Residues in Animal-Derived Foods by Solid-Phase Extraction Purification and Ultra-High-Performance Liquid Chromatography-Quadrupole/Orbitrap High-Resolution Mass Spectrometry

A method for the rapid screening and confirmation of 60 food-borne stimulants in animal-derived foods was developed using the ultra-high-performance liquid chromatography-quadrupole/orbitrap high-resolution mass spectrometry (UPLC-Q/Orbitrap HRMS). After enzymatic hydrolysis at 37°C for 16 h, the samples were extracted with acetonitrile solution. The extraction solution was purified by PRiME HLB pass-through solid-phase extraction cartridge and redissolved by nitrogen blowing. The target compounds of reconstitution fluid were separated by Hypersil GOLD™ VANQUISH column (2.1 mm × 100 mm, 1.9 μm). The raw data were collected for the target compounds in Full Scan-ddMS2 mode, and then the Quan Browser module under Xcalibur software can be used to analyze the quantitative results of the samples. The combination of Tracefinder and mzVault software can realize the qualitative screening and confirmation of the samples. The results showed that the relative deviation of the exact mass of the 60 food-borne stimulants was less than 5.0 × 10−6, which had a good linear relationship in the corresponding concentration, and the correlation coefficient (R2) was greater than 0.9966. The detection limit ranged from 0.05 to 0.5 μg/kg. The quantification limit ranged from 0.1 to 1 μg/kg. The method recoveries ranged from 70.2% to 111.9% with relative standard deviations of 0.05% to 9.00% (n = 6). The method is easy to operate, covers a wide range of targets, and has high efficiency and accuracy. It is suitable for rapid screening and confirmation of various food-derived stimulants in animal-derived foods and provides assistance for food safety in the major events.

Capillary electrophoresis tandem mass spectrometry to determine multiclass cyanotoxins in reservoir water and spinach samples

Cyanotoxins constitute a group of toxic secondary metabolites, the presence of which in any water body poses a major health risk. Moreover, advanced organisms such as edible plants exposed to these toxins, are a possible pathway for human exposure. Green analytical chemistry is demanding environmentally friendly analytical techniques. In this sense, we propose the use of capillary electrophoresis coupled to tandem mass spectrometry (CE-MS/MS) to determine a mixture of eight cyanotoxins belonging to three different classes: cyclic peptides (microcystin-LR, microcystin-RR and nodularin), alkaloids (cylindrospermopsin and anatoxin-a) and three isomeric non-protein amino acids (β-methylamino-l-alanine, 2,4-diaminobutyric acid and N-(2-aminoethyl)glycine). Separation was achieved by using an acidic background electrolyte consisting of 2 M formic acid and 20% acetonitrile in water. Parameters affecting MS/MS detection and the sheath-liquid interface were also studied. Finally, a combination of pH-junction, field-amplified sample stacking (FASS) and acid barrage as online preconcentration strategies, was employed to improve sensitivity and efficiency. The online preconcentration applied, in combination with a dual cartridge solid-phase extraction (SPE) system, allows to obtain limits of detection in the very low range of µg·L−1 for these multiclass cyanotoxins in reservoir water samples (from 0.005 to 0.10 µg·L−1). Furthermore, for the first time cyanotoxins are analysed in spinach samples through CE-MS/MS using the same SPE procedure, following lyophilisation and solid-liquid extraction with 6 mL 80 % aqueous MeOH.

A miniaturized stir bar sorptive dispersive microextraction method for the determination of bisphenols in follicular fluid using a magnetic covalent organic framework

BackgroundBisphenols, particularly bisphenol A (BPA), are the primary monomers used as additives in the manufacturing of many consumer products. The exposure to these compounds is related to endocrine-disrupting and reproductive effects, among others. For this reason, the development of analytical methods for their determination in biological matrixes is needed to monitor the population exposure to these compounds. Their quantification at ovarian level (i.e., follicular fluid) is interesting for the assessment of the bisphenol content to draw conclusions about infertility problems. However, the background does not meet all requirements by focusing mainly on BPA. ResultsIn this work, a miniaturized stir bar sorptive dispersive microextraction (mSBSDME) approach has been developed for the determination of BPA and eight analogues in follicular fluid. In the proposed method, the sample is previously cleaned-up using a zirconia-based solid-phase extraction cartridge, removing proteins and phospholipids, and then subjected to the mSBSDME for the preconcentration of the analytes. For this purpose, a magnetic covalent organic framework was used as sorbent. A Plackett-Burman design was applied to select the significant variables affecting the mSBSDME. Afterwards, the only significant variable (i.e., sorbent amount) was optimized. Under the optimized conditions, the proposed method was properly validated, and satisfactory analytical parameters in terms of linearity (up to 50 ng mL−1), enrichment factors (8.5–14.3), limits of detection in the low ng mL−1 range, and precision (relative standard deviations below 11.5 %) were obtained. Finally, the method was successfully applied to five samples, detecting BPA and other two analogues. SignificanceThis method expands the potential applicability of the mSBSDME to other low-availability complex matrixes, which would otherwise be difficult to analyze. Moreover, it offers a valuable tool for monitoring the female population's exposure to bisphenols with the final aim of evaluating if infertility problems of women might be associated to the exposure to these highly endocrine disrupting compounds.

CSF N-Glycomics Using MALDI MS Techniques.

In this chapter, we will present the methodology currently applied in our laboratory for the structural elucidation of the cerebrospinal fluid (CSF) N-glycome. N-glycans are released from denatured carboxymethylated glycoproteins by digestion with peptide-N-glycosidase F (PNGase F) and purified using both C18 Sep-Pak® and porous graphitized carbon (PGC) HyperSep™ Hypercarb™ solid phase extraction (SPE) cartridges. The glycan pool is subsequently permethylated to increase mass spectrometry sensitivity. Molecular assignments are performed through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) analysis considering either the protein N-linked glycosylation pathway or MALDI TOF MS/MS data. Each stage has been optimized to obtain high-quality mass spectra in reflector mode with an optimal signal-to-noise ratio up to m/z 4800. This method has been successfully adopted to associate specific N-glycome profiles to the early and the advanced phases of Alzheimer's disease (AD).

High-Performance enrichment and sensitive analysis of bisphenol and its analogues in water and milk using a novel Ni-Based cationic Metal-Organic framework

A novel cationic metal–organic framework (iMOF-Ni) was designed and synthesized by a solvothermal method. It was fabricated as a solid-phase extraction (SPE) cartridge and exhibited high adsorption performance for Bisphenols (BPs). The theoretical simulation demonstrated that the adsorption mechanism between iMOF-Ni and BPs was attributed to cation-π bonding, π-π interaction, and electrostatic interactions. Under optimized SPE, a method for analyzing BPs was established by combining high-performance liquid chromatography-diode array detection (HPLC-DAD). The developed method has good linearity (R2 ≥ 0.994), low detection limits (0.07–0.16 ng/mL), and good reproducibility (1.72–6.35 %, n = 6). The applicability of the method was further evaluated by analyzing water and milk samples. Recoveries of four BPs in spiked samples were from 72.2 % to 96.6 %.

Solid-Phase Extraction at High pH as a Promising Tool for Targeted Isolation of Biologically Active Fractions of Humic Acids.

A search for novel sources of biologically active compounds is at the top of the agenda for biomedical technologies. Natural humic substances (HSs) contain a large variety of different chemotypes, such as condensed tannins, hydrolyzable tannins, terpenoids, lignins, etc. The goal of this work was to develop an efficient separation technique based on solid-phase extraction (SPE) for the isolation of narrow fractions of HS with higher biological activity compared to the initial material. We used lignite humic acid as the parent humic material, which showed moderate inhibition activity toward beta-lactamase TEM 1 and antioxidant activity. We applied two different SPE techniques: the first one was based on a gradient elution with water/methanol mixtures of the humic material sorbed at pH 2, and the second one implied separation by a difference in the pKa value by the use of sequential sorption of HS at pH from 8 to 3. SPE cartridges Bond Elute PPL (Agilent) were used in the fractionation experiments. The first and second techniques yielded 9 and 7 fractions, respectively. All fractions were characterized using high-resolution mass spectrometry and biological assays, including the determination of beta-lactamase (TEM 1) inhibition activity and antioxidant activity. The acidity-based separation technique demonstrated substantial advantages: it enabled the isolation of components, outcompeting the initial material at the first step of separation (sorption at pH 8). It showed moderate orthogonality in separation with regard to the polarity-based technique. Good perspectives are shown for developing a 2D separation scheme using a combination of polarity and acidity-based approaches to reduce structural heterogeneity of the narrow fractions of HS.

Development of an enhanced analytical method utilizing pepper matrix as an analyte protectant for sensitive GC‒MS/MS detection of dimethipin in animal-based food products.

Herein, an analytical method using gas chromatography-tandem mass spectrometry (GC‒MS/MS) was devised to detect the presence of the troublesome pesticide dimethipin in various animal-based food products, including chicken, pork, beef, eggs, and milk. The injection port was primed with a matrix derived from pepper leaves that acts as an analyte protectant (AP) to safeguard the target compound from thermal degradation during gas chromatography. The presence of AP resulted in a remarkable limit of quantification of 0.005 mg/kg for dimethipin in five matrices. Three different versions (original, EN, and AOAC) of the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method were compared for dimethipin extraction, with a double-layer solid-phase extraction (SPE) cartridge utilized for matrix purification. A seven-point external calibration curve was established for dimethipin in the five matrices, demonstrating excellent linearity with determination coefficients (R2) ≥ 0.998. The developed quantitative method was validated by fortifying each matrix with three different concentrations of standard dimethipin, and the average recovery fell within the acceptable range outlined in the CODEX guidelines (ranging from 88.8% to 110.0%), with a relative standard deviation (RSD) of ≤ 11.97%. This method effectively addresses the challenge of analyzing dimethipin and can therefore be used as a routine monitoring tool for dimethipin across various matrices.