Selective Solid-phase Extraction Research Articles

Selective solid phase extraction of phototoxic furanocoumarins using molecularly imprinted polymers

Furanocoumarins are secondary plant metabolites found in citrus plants. Essential oils from these plants are widely used in cosmetic products. They have attracted attention for their phototoxicity, which can even lead to skin burns. Therefore, the furanocoumarin concentration is controlled by the European Union according to Regulation (EC) No. 1223/2009, where a limit of 1 mg kg−1 is specified in sun protection and bronzing agents. This study describes the synthesis of two molecularly imprinted polymers (methacrylamide and methacrylic acid as monomers) as novel materials for solid phase extraction. After optimisation of the extraction protocol, both polymers gave satisfying recovery results for a furanocoumarin standard mixture containing the six markers proposed by the International Fragrance Association (IFRA). Furthermore, spiked sun oil samples were extracted using an adapted extraction protocol. Since the studies showed promising results including 75–149 % recovery and 100 % loading efficiency for the methacrylic acid polymer, a validation of the analytical method was performed. Analysis was performed using HPLC-MS/MS in high specificity multi-reaction monitoring mode. The validation showed acceptable results for most parameters. In addition, a comparison with commercially available Strata-X cartridges was completed, revealing superior recovery performance of the molecularly imprinted polymer. In conclusion, molecularly imprinted polymers represent a novel and efficient method for selective solid-phase extraction of phototoxic furanocoumarins.

SYNTHESIS OF TETRACYCLINE IMPRINTED POLYMERS WITH METHACRYLIC ACID AS FUNCTIONAL MONOMER IN METHANOL-CHLOROFORM MIXTURE USING BULK AND PRECIPITATION POLYMERIZATION METHOD

The content of tetracycline residues in poultry meat products can cause antibiotic resistance in humans who consume these products, so it is necessary to develop sensitive analytical techniques to determine the levels of tetracycline residues to assess the safety of these products for consumption. The molecular imprinting technique is a method to produce sorbents with molecular recognition capability of target compounds that can be used to increase the selectivity of solid phase extraction to extract tetracycline residues for further analysis. This study aimed to obtain a sorbent synthesized by molecular imprinting technique to analyze tetracycline in poultry meat products. The stages of the research began with the study of the interaction of functional monomers with template molecules, determining the association constants of functional monomers with template molecules, synthesis of imprinted polymer molecules using bulk and precipitation methods, evaluating the ability and adsorption capacity of the synthesized polymers, assess the selectivity of polymers for analog structures and physical characteristics with FTIR. The research showed that methacrylic acid was the best functional monomer with a binding energy value of -27.3776 kcal/mol. The higher adsorption capacity was achieved by Molecularly Imprinted Polymer (MIP) that was synthesized by precipitation method (MIP2) than the other MIP synthesized by bulk polymerization (MIP1) with a value of 0.8748 mg/g and 0.4077 mg/g, respectively. The analogous compounds' imprinting factor values for each MIP were 1.197 and 1.1272. The polymer synthesized by molecular imprinting technique is selective for extracting and analyzing tetracycline from poultry meat matrix.

ПРИМЕНЕНИЕ СОРБЕНТА ДЛЯ ТВЕРДОФАЗНОЙ ЭКСТРАКЦИИ НА ОСНОВЕ ГИПРОМЕЛЛОЗЫ ДЛЯ КОЛИЧЕСТВЕННОГО ОПРЕДЕЛЕНИЯ КИСЛОТЫ САЛИЦИЛОВОЙ В КОМБИНИРОВАННЫХ ЛЕКАРСТВЕННЫХ ПРЕПАРАТАХ

Introduction. In quality control of pharmaceutical formulations, there are methodological approaches based on the preliminary separation of sample components and approaches without preliminary separation. The use of solid-phase extraction (SPE) allows to separate analytes during sample preparation, with the separation selectivity determining the analysis selectivity as a whole. Currently, sorbents that provide selectivity in interaction with the analyte are of interest. Various derivatives of cellulose are used to obtain selective sorbents: ethylcellulose, hydroxypropylmethylcellulose (hypromellose), carboxymethylcellulose, etc. On the pharmaceutical market of the Russian Federation, there are pharmaceutical formulations with the active pharmaceutical substance salicylic acid. The use of selective SPE for analysis is a promising direction of research in drug quality control. Aim. Evaluation of the metrological characteristics of benzocaine quantitation by UV-spectrophotometry in certain pharmaceutical formulations using hypromellose sorbent for solid-phase extraction. Material and methods. The sorbent using a method developed by us was obtained. Salicylic acid (FS.2.1.0634, Russia State Pharmacopoeia XV ed.) to form active binding sites in sorbent structure was applied. The sorbent structure is polycyanoacrylate matrix with hypromellose fragments, the surface area is 255.50 m2/g, pore volume is 0.1433 cm3, pore diameter is 5.32 nm. The sorption capacity of hypromellose sorbent for benzocaine was 12.2 ± 0.8 μg/g. The SPE technique is proposed. SPE includes the stages: conditioning, sample addition and step-by-step elution with purified water and sodium hydroxide solution 0.1 mol/L. The spectrophotometer SF-56 was used to measure the absorbance at an analytical wavelength of 286 nm. To evaluate the selectivity (specificity) of sample preparation during chromatographic (SPE) separation of pharmaceutical formulations, absorption spectra of eluates in the wavelength range of 200-400 nm were scanned. The salicylic acid identification in the eluate was carried out based on absorption peaks at 228 and 298 nm.The salicylic acid calibration curve in the range of 1-20 μg/ml. To determination the metrological characteristics of salicylic acid quantitation method, 16 parallel determinations of samples of each pharmaceutical formulation were made. Statistical processing of the experimental results and determination of the metrological characteristics evaluation of analytical technique were carried out in accordance with general pharmacopoeial monograph (OFS.1.1.0013 "Statistical processing of results of physical, physicochemical, and chemical tests"). Results. When realizing the salicylic acid quantitation technique for measuring absorbance, it is advisable to use only the first portions of eluate (a solution of sodium hydroxide) in a volume of 5-10 ml were obtained. The relative error in determining the average content of salicylic acid in the analyzed preparations ranged from 1.18 to 1.44% for methods with solid-phase extraction (SPE) and 1.86-2.62% in its absence. It has been shown that there is a statistically significant difference in reproducibility for all preparations, as indicated by F-criteria values ranging from 7.81 to 13.5, exceeding their tabulated values. For the method without solid-phase extraction (SPE), there was an overestimation of the salicylic acid content in all cases, increasing the systematic error on average by 87.5%. Conclusion. The possibility of using a selective hypromellose sorbent for sample preparation for salicylic acid quantitation determination in pharmaceutical formulations has been showed. The use of sorbent for analysis provides to systematic error decrement of salicylic acid quantitation by an average of 87.5%.

Silica Grafted Imprinted Mesoporous Polymer for the Development of SPE Coupled FAAS Method of Nickel Determination, Removal, and Spent Polymer for Reduction of Permanganate: Multivariate Optimization

AbstractA novel silica fabricated allyloxy ethanol based imprinted polymer is synthesised with surface area of 333 m2 g−1 and average pore size of 6.5 nm by an environment friendly one pot surface imprinting process. It was employed for the selective solid‐phase extraction (SPE) of trace Ni(II) in real samples prior to FAAS determination. The factor settings produced via central composite design in response surface methodology (RSM) (pH: 3.6; initial concentration; 800 mg L−1 and time; 15 minute) provide adsorption capacity of 176 mg g−1. Artificial neural network model employed on the RSM data, provided better predictability. Sips isotherm model and BSf kinetic model describes best the sorption phenomena of the homogenous binding terrain. The developed SPE‐coupled FAAS method demonstrate a detection limit of 1.62 μg L−1, quantification limit of 4.17 μg L−1, and Linear dynamic range of 20–8000 μg L−1. It was successfully applied to determine nickel in food (Spinach, Radish, Green tea infusion, Black tea infusion, Coffee, Soya milk, Chocolate Soya milk, Tobacco) and wastewater samples (>99 % removal). For five replicate determinations, the method‘s relative standard deviation was 2.3 %. The method was validated by analysing two certified reference materials, and the outcomes were well‐congruent with standard values. For the synthesised polymer Ni(II) exhibits higher distribution ratio than other competing ions (Cu(II), Pb(II), Cd(II), and Zn(II)) with the imprinting factor; β values of 5.73, 4.98, 6.80, and 5.04 respectively. The reusability experiments revealed that APS@Ni‐IIP retains a strong adsorption efficacy even after 15 cycles and after its exhaustion it was employed as catalyst for reducing permanganate ions, further reducing pollution. The rigid structure of mesoporous silica contributes to its acid resilience and reusability, which can lead to a relative increase in polymer performance in absorption rate and selectivity. Apart from the novelty in the synthesis, thorough examination of the method and material selectivity (in binary, ternary and multielement system), multi fold applications of determination, removal of Ni(II) and reduction of permanganate ions, makes APS@Ni‐IIP a promising candidate for environmental remediation.

Mycotoxins-Imprinted Polymers: A State-of-the-Art Review.

Mycotoxins are toxic metabolites of molds which can contaminate food and beverages. Because of their acute and chronic toxicity, they can have harmful effects when ingested or inhaled, posing severe risks to human health. Contemporary analytical methods have the sensitivity required for contamination detection and quantification, but the direct application of these methods on real samples is not straightforward because of matrix complexity, and clean-up and preconcentration steps are needed, more and more requiring the application of highly selective solid-phase extraction materials. Molecularly imprinted polymers (MIPs) are artificial receptors mimicking the natural antibodies that are increasingly being used as a solid phase in extraction methods where selectivity towards target analytes is mandatory. In this review, the state-of-the-art about molecularly imprinted polymers as solid-phase extraction materials in mycotoxin contamination analysis will be discussed, with particular attention paid to the use of mimic molecules in the synthesis of mycotoxin-imprinted materials, to the application of these materials to food real samples, and to the development of advanced extraction methods involving molecular imprinting technology.

Molecularly imprinted polymers with ionic liquid as the functional monomer for selective solid-phase extraction of gastrodin

Gastrodia elata is a well-known Asian traditional herb with gastrodin (GAS; p-hydroxymethylbenzene-β-d-glucopyranoside) as its active ingredient. It is a challenging task to efficiently separate the active ingredient gastrodin from Gastrodia elata by simple procedure. The results of computer molecular simulation & UV-vis spectroscopy showed that water-soluble 1-vinyl-3-tetradecylimidazole bromide([C14VIM+] [Br-]) was selected as the best ionic liquid functional monomer compared with methacrylic acid(MAA), acrylic acid(AA), 3-(2-carboxyethyl)-1-vinylimidazolium bromide ionic liquid (imidazole propionate, [COOHpvimBr]), and dehydroabietic acid [2-(acryloyloxy)ethyl] ester (DAAEE). The force between [C14VIM+] [Br-] and GAS (with multiple hydroxyl groups) is stronger than other monomers with more polar groups. The molecular imprinted polymers (MIPs) and non- molecular imprinted polymers (NIPs) with high selectivity to gastrodin were synthesized utilizing ([C14VIM+] [Br-]) as a novel functional monomer. The polymer was characterized by infrared spectrum, scanning electron microscope, specific surface area tester and thermosgravimetric analyser(TGA). The adsorption performance of the polymer was investigated by adsorption kinetics experiment and static adsorption experiment. Among different eluents, the content of gastrodin in eluent (70% ethanol) significantly increased compared with it in plant extract by the MIPs-solid phase extraction (SPE)-HPLC. The recoveries of the spiked samples for the GAS were 97.75–103.43%, with relative standard deviation values lower than 2.88%. This novel [C14VIM+] [Br-]-based MIP was a potential separation material for gastrodin. The graphical abstract was shown below.

Molecularly imprinted polymers by reflux precipitation polymerization for selective solid-phase extraction of quinolone antibiotics from urine

Molecularly imprinted polymers (MIPs) possess high specific cavities towards the template molecules, thus solid-phase extraction (SPE) based on MIPs using the target as the template has been widely used for selective extraction. However, the performance of SPE depends strongly on the shape and the distribution of the MIP sorbents, and rapid synthesis of MIPs with uniform particles remains a challenge. Our previous studies have shown that reflux precipitation polymerization (RPP) was a simple and rapid method for the synthesis of uniform MIPs. However, synthesis of MIPs by RPP for a group of targets using only one of the targets as the template has rarely been reported. In this work, MIPs with specific recognition capability for a group of quinolone antibiotics were synthesized for the first time via RPP with only ofloxacin as the template. The synthesized MIPs displayed good adsorption performance and selectivity (IF > 3.5) towards five quinolones, and subsequently were used as SPE adsorbents. Based on this MIPs-SPE, after systematic optimization of the SPE operation parameters during loading, washing and elution, an efficient and sensitive enough SPE method for separation and enrichment of the five quinolones in urine was developed and evaluated in combination with LC-MS/MS. The results showed that MIPs-SPE-LC-MS/MS has a good correlation (R2 ≥ 0.9961) in the linear range of 1–500 μg L−1. The limit of detection (LOD) and limit of quantification (LOQ) for the five quinolones were 0.10–0.14 μg L−1 and 0.32–0.48 μg L−1, respectively. In addition, the proposed method demonstrated good reproducibility (≤ 13 %) and high accuracy (92 %–113 %). We are confident that this method holds significant promise for the analysis of quinolones within the contexts of forensic medicine, epidemiology, and environmental chemistry.

Dummy molecularly imprinted polymer-based solid-phase extraction method for the determination of some phthalate monoesters in urine by gas chromatography–mass spectrometry analysis

A dummy molecularly imprinted polymer-based solid-phase extraction (SPE) sorbent was used for the selective extraction of some phthalate monoesters, monoethyl phthalate (MEP), monobutyl phthalate (MnBP) and mono-(2-ethylhexyl) phthalate (MEHP) in urine prior to gas-chromatography-mass spectrometry (GC-MS) analysis. Diethyl phthalate (DEP), a phthalate ester, was successfully used as a dummy template to prepare selective sorbent for MEP, MnBP, and MEHP extraction. DEP-imprinted poly(ethylene glycol dimethacrylate N-methacryloyl-l-tryptophan methyl ester) (DPEMT) microbeads were synthesized by suspension polymerization and characterized by Fourier Transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Brunauer Emmet Teller (BET) analysis. The critical parameters (i.e., pH, sorbent amount, ionic strength, sample volume, elution solvent) affecting the extraction performance of the DPEMT-SPE sorbent were optimized. Under optimum conditions, good linearities were obtained in the concentration range of 4 to 60 ng/mL with determination coefficients (R2) of greater than 0.9959. The developed SPE method provided low limits of detection (LOD) of 0.05–1.20 ng/mL and limits of quantification (LOQ) of 0.18–4.01 ng/mL with relative standard deviations (RSDs) of less than 8.95 % for intra- and inter-day analyses. The proposed SPE method was used to analyze phthalate monoesters in spiked urine samples, and recoveries of 97.45–109.26 % were obtained. DPEMT-SPE sorbent was reused for 15 times without any losses of performance. Consequently, a highly selective and sensitive SPE method based on a dummy molecularly imprinted polymer combined with GC-MS was successfully developed to monitor human phthalate exposure via urine samples.

Assessment of Molecularly Imprinted Polymers as Selective Solid-Phase Extraction Sorbents for the Detection of Cloxacillin in Drinking and River Water.

This paper describes a new methodology for carrying out quantitative extraction of cloxacillin from drinking and river water samples using a molecularly imprinted polymer (MIP) as a selective sorbent for solid-phase extraction (MISPE). Several polymers were synthesized via thermal polymerization using cloxacillin as a template, methacrylic acid (MAA) as a functional monomer, ethyleneglycoldimethacrylate (EGDMA) as a cross-linker and different solvents as porogens. Binding characteristics of the adequate molecularly imprinted and non-imprinted (NIP) polymers were evaluated via batch adsorption assays following the Langmuir and Freundlich isotherms and Scatchard assays. The parameters related to the extraction approach were studied to select the most appropriate polymer for cloxacillin determination. Using the optimized MIP as the SPE sorbent, a simple sample treatment methodology was combined with high-performance liquid chromatography (HPLC) to analyze cloxacillin residues in drinking and river water. Under the optimum experimental conditions, the MISPE methodology was validated using spiked samples. The linearity for cloxacillin was assessed within the limits of 0.05-1.5 µg L-1 and the recovery percentage was higher than 98% (RSD < 4%). The limits of detection and limits of quantification were 0.29 and 0.37 µg L-1 and 0.8 and 0.98 µg L-1 for drinking and river water, respectively. The selectivity of MIP against other ß-lactam antibiotics with similar structures (oxacillin, cefazoline, amoxicillin and penicillin V) was studied, obtaining a good recovery higher than 85% for all except cefazoline. The proposed MISPE-HPLC methodology was successfully applied for the detection of cloxacillin in drinking water from Canal de Isabel II (Madrid) and river water from the Manzanares River (Madrid).

Miniaturized point discharge optical emission spectrometry coupling with solid phase extraction: A robust approach for sensitive quantification of total mercury in mung bean sprout growth.

In this work, a portable chemical vapor generation point discharge optical emission spectrometry (CVG-PD-OES) system was designed for trace Hg2+ monitoring in mung bean sprout samples. The system incorporated selective solid phase extraction (SPE) to enhance the detection sensitivity. Gold nanoparticles (AuNPs) were prepared and utilized to extract trace amounts of Hg2+ by forming gold amalgam. Subsequently, the amalgam was desorbed using 5% HCl and introduced into a low-power PD-OES system analysis via CVG. A low limit of detection (LOD) of 0.16ngmL-1 was obtained with a linear range of 0.5-6ngmL-1. The well-designed system was successfully utilized for monitoring trace Hg2+ in the growth of mung beans. The results indicated that the Hg2+ in mung bean sprouts was continuously decreased during growth based on the metabolism. Furthermore, the risk assessment conducted implied a negligible hazard quotient, suggesting that the observed levels of exposure posed minimal risk.

Synthesis and characterization of pH-sensitive thin-layer molecularly imprinted membranes for selective solid-phase extraction of celecoxib from biological fluids followed by high-performance liquid chromatography with UV detection

In this work, the synthesis of thin-layer, pH-sensitive molecularly imprinted membrane using methacrylic acid and maleic acid as functional monomers, ethylene glycol dimethacrylate as cross-linker, 2,2′-azobisisobutyronitrile as initiator, poly (vinylidene fluoride) as porous membrane, and celecoxib as a target molecule have been reported. Different technique analyses characterized the membrane product. A novel molecularly imprinted membrane-solid phase extraction method was used for the extraction of celecoxib and concentrating it prior to be analyzed in the human plasma and urine matrix. High-performance liquid chromatography with ultraviolet detection was used and validated for the analysis of celecoxib which was extracted from biological fluids. The molecularly imprinted membrane showed selective performance for the template, and extraction recoveries of the drug by the membrane from human plasma and urine samples were between 96.2 and 97.3%. The obtained results showed that the detection and quantification limits of the drug were 0.12 and 0.40 ng mL−1, respectively. The adsorption capacity of 4.95 mg g−1 was obtained from the fitting by the Langmuir model. The molecularly imprinted membrane can be easily regenerated eight times with sustained efficiency. Therefore, the developed method can be a good candidate for the separation and detection of celecoxib in biological samples.

A molecularly imprinted polymer monolithic column with dual template and bifunctional monomers for selective extraction and simultaneous determination of eight phenolics from polycarbonate cups

A molecularly imprinted polymer (MIP) monolithic column was prepared in situ in a pipette tip using phenol and bisphenol A as dual templates, 4-vinyl pyridine and β-cyclodextrin as bifunctional monomers. It was used for the selective and simultaneous solid phase extraction of eight phenolics, including phenol, m-cresol, p-tert-butylphenol, bisphenol A, bisphenol B, bisphenol E, bisphenol Z, and bisphenol AP. The MIP monolithic column was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and nitrogen adsorption experiment. The results of selective adsorption experiments showed that the MIP monolithic column can selective recognize the phenolics and have excellent adsorption property. The imprinting factor for bisphenol A can be as high as 4.31, and the maximum adsorption capacity for bisphenol Z can reach 201.66 mg g−1. Under the optimal extraction conditions, a selective and simultaneous extraction and determination method for eight phenolics was established based on the MIP monolithic column and high-performance liquid chromatography with ultraviolet detection. The linear ranges (LRs) of the eight phenolics were 0.5–200 μg L−1, the limits of quantification (LOQs) and detection (LODs) were 0.5–2.0 μg L−1 and 0.15–0.67 μg L−1. The method was applied to detect the migration quantity of the eight phenolics from polycarbonate cups and had satisfactory recovery. The method has the advantages of simple synthesis, short extraction time, as well as good repeatability and reproducibility, which provides a sensitive and reliable strategy for extracting and detecting phenolics from food contact material.

Experimental strategy for acid-free plutonium recovery from assorted matrices: Non-aqueous leaching followed by selective solid phase extraction

Experimental strategy for acid-free plutonium recovery from assorted matrices: Non-aqueous leaching followed by selective solid phase extraction

Synthesis and Characterization of a New Molecularly Imprinted Polymer for Selective Extraction of Mandelic Acid Metabolite from Human Urine as a Biomarker of Environmental and Occupational Exposures to Styrene.

4-Vinylpyridine molecularly imprinted polymer (4-VPMIP) microparticles for mandelic acid (MA) metabolite as a major biomarker of exposure to styrene (S) were synthesized by bulk polymerization with a noncovalent approach. A common mole ratio of 1:4:20 (i.e., metabolite template: functional monomer: cross-linking agent, respectively) was applied to allow the selective solid-phase extraction of MA in a urine sample followed by high-performance liquid chromatography-diode array detection (HPLC-DAD). In this research, the 4-VPMIP components were carefully selected: MA was used as a template (T), 4-Vinylpyridine (4-VP) as a functional monomer (FM), ethylene glycol dimethacrylate (EGDMA) as a cross-linker (XL), and azobisisobutyronitrile (AIBN) as an initiator (I) and acetonitrile (ACN) as a porogenic solvent. Non-imprinted polymer (NIP) which serves as a "control" was also synthesized simultaneously under the same condition without the addition of MA molecules. Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) were used to characterize the imprinted and nonimprinted polymer to explain the structural and morphological characteristics of the 4-VPMIP and surface NIP. The results obtained from SEM depicted that the polymers were irregularly shaped microparticles. Moreover, MIPs surfaces had cavities and were rougher than NIP. In addition, all particle sizes were less than 40 µm in diameter. The IR spectra of 4-VPMIPs before washing MA were a little different from NIP, while 4-VPMIP after elution had a spectrum that was almost identical to the NIP spectrum. The adsorption kinetics, isotherms, competitive adsorption, and reusability of 4-VPMIP were investigated. 4-VPMIP showed good recognition selectivity as well as enrichment and separation abilities for MA in the extract of human urine with satisfactory recoveries. The results obtained in this research imply that 4-VPMIP might be used as a sorbent for MA solid-phase extraction (MISPE), for the exclusive extraction of MA in human urine.

Novel Ion-imprinted Polymer as a Tool for Selective Determination of SbIII in Natural Waters

A novel SbIII-imprinted polymer was synthesized via radical copolymerization of methacrylic acid and trimethylolpropane trimethacrylate in the presence of 2-mercapto-N-(2-naphthyl)acetamide as a chelating ligand forming the functionality of specific binding sites. The extent of ligand incorporation in the active centres was evaluated by elemental analysis and found to be 73.6%. The IIP was utilized as a sorbent material for selective solid-phase extraction of SbIII in drinking waters after optimization of sorption and desorption processes in a batch mode. Excellent separation of SbIII and SbV was accomplished at pH 8 followed by elution of SbIII with 0.5 M thiocarbamide. Analytical procedure for non-chromatographic speciation and determination of SbIII was developed demonstrating very good precision (RSD 7–11%) and recoveries between 97–105%. This procedure enabled up to 25-fold reconcentration and completely met the requirements of EU legislation for the quality of water intended for human consumption.

How Conventional Approaches to the Use of Polymer-Containing Composites in Molecular Diagnostics Are Changing

Known approaches to the isolation of biopolymers, in particular nucleic acids (NAs), from biological samples are based on the binding of molecules to a sorbent (“positive selection”) with their subsequent elution using a suitable eluent. The review article discusses the physicochemical processes underlying the development of methods for isolating of NAs from biological samples. It has been shown that methods including the selective solid-phase extraction (i.e., reversible sorption) provide the possibility of miniaturization and automation of the corresponding processes. The review discusses the advantages of an alternative approach to NAs isolation based on the use of special sorbents that bind proteins and other components of biological samples, while these sorbents exhibit sorption inertness with respect to NAs (“negative selection”). Approaches providing the creation of such composite polymer-containing sorbents, which are designed for the sample preparation during molecular diagnostics, as well as the methods of their effective use are considered. It has been demonstrated that due to an interdisciplinary approach using a complex of synthetic and analytical methods, it is possible to combine as a single object of study the composite materials that are very different in structure and properties. Such nanostructured composites (based on porous silica, synthetic membranes, glass multicapillaries) contain fluoropolymers and polyanilines. The results of the use of such composites for selective isolation of NAs and/or proteins from biological samples are discussed. Alternative applications of such composites in molecular diagnostics, in particular, in mass spectrometry, are considered. Directions for expanding of the field of application of polymer-containing composites due to simultaneous use of the sorption properties of the obtained composites surface and the properties of sorbate molecules are outlined. It has been shown that both polymeric and low molecular weight modifiers of the same chemical nature are suitable for the technological preparation of such composites.

Accurate quantitative determination of the total amounts of Strecker aldehydes contained in wine. Assessment of their presence in table wines

Strecker aldehydes (SAs) are key determinants of wine shelf-life and can be present in unoxidized wines in odorless forms, such as hydroxyalkylsulfonates, imines or acetals. A robust and accurate method for the determination of total forms of SAs, based on the classical derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) and in the selective solid phase extraction of derivatives has been optimized and validated. Matrix effects have been solved by the use of adequate internal standards and by large-enough equilibration times under anoxic conditions. Method figures of merit are highly satisfactory in terms of detection limits (<0.1 μg/L), linearity (R2 > 0.997), reproducibility (5–13%) and recoveries (RSDs, between 2 and 10%, for 3-methylbutanal, 14%). The analysis of total SAs in 108 Spanish wines revealed that between 52% and 70% of unoxidized red wines and likely a similar fraction of white wines, contain levels of SAs high enough to cause oxidative aromas if bound forms of SAs cleave.

Selective and efficient solid phase extraction of cadmium (II) in sub-trace limits based on alizarin red-S cross-linked-2-mercapto-N-(3-(triethoxysilyl) propyl) acetamide bi-functionalized graphene oxide nanocomposite from different environmental water samples

A novel bi-functionalized nanocomposite based on graphene oxide-alizarin red-S cross-linked-2-mercapto-N-(3-(triethoxysilyl) propyl) acetamide (ARS-MTPS@GO) was developed for the sequestration of cadmium Cd(II) ions from water. The nanocomposite fabrication was characterized through different physicochemical techniques (FTIR, XRD, SEM, TEM, Raman, and TGA). In addition to its hydrophilicity, high surface area, and ability to interact with the functionalized moieties, the ARS-MTPS@GO nanocomposite has improved Cd(II) adsorption. An optimization study was carried out on various analytical parameters that affect cadmium extraction, including the pH, contact time, and nanocomposite mass dosage. The maximum sorption capacity and percentage removal efficiency of Cd(II) ions reached 222.7 mg g−1 and 99.4 ± 3.7%, respectively, at pH = 6 within 30 minutes and the pseudo-second-order kinetic model best fits the sorption rate. Validation of the proposed method was evaluated for nine replicate measurements for recovery of Cd(II), showed favorable analysis precision, and the estimated detection limit was 0.18 ± 0.02 ng mL−1. Additionally, the reusability and stability of the nanocomposite and the effects of interfering cations and anions were investigated. Finally, the developed method was successfully applied for the selective extraction of Cd(II) from environmental water samples of different matrices, and the Cd(II) recoveries were 96.2–99.2%±2.3%. This study’s findings prove the potential applicability of the novel nanocomposite for removing cadmium ions from different environmental waters.

Preparation of Molecularly Imprinted Polymer Microspheres for Selective Solid-Phase Extraction of Capecitabine in Urine Samples.

Molecularly imprinted solid-phase extraction to treat biological samples has attracted considerable attention. Herein, molecularly imprinted polymer (MIP) microspheres with porous structures were prepared by a combined suspension-iniferter polymerization method using capecitabine (CAP) as a template molecule. This material was subsequently used as a solid-phase extraction agent to separate and enrich drug molecules in urine samples. UV analysis revealed that methacrylate (MAA) was an ideal functional monomer, and 1H Nuclear Magnetic Resonance (1H NMR), Ultraviolet (UV), and Fourier transform-infrared (FT-IR) spectroscopic analyses were used to study the interaction forces between MAA and CAP, demonstrating that hydrogen bonding was the primary interaction force. MIPs with outstanding selectivity were successfully prepared, and the analysis of their surface morphology and chemical structure revealed a spherical morphology with small holes distributed across a rough surface. This surface morphology significantly reduced the mass transfer resistance of template molecules, providing an ideal template recognition effect. Using the molecularly imprinted solid-phase extraction method, CAP and the structural analog cytidine (CYT) were pretreated in urine samples and quantified by HPLC. The results showed that CAP and CYT recoveries reached 97.2% and 39.8%, respectively, with a limit of detection of 10.0–50.0 µg·mL−1. This study provides a novel approach to drug molecule pretreatment that can be applied in drug separation and functional materials science fields.

Novel approach for strontium preconcentration from seawater and rapid determination of 89,90Sr in emergency situations

A novel approach for rapid 89,90Sr determination in seawater samples is developed. For the first time in the radioanalytical application, the features of the synthetic zeolite Z4A and a highly selective material for Sr separation were synergically employed. Seawater composition significantly reduces Sr yield on highly selective solid-phase extraction materials, making the preconcentration step essentially important but laborious and time-consuming. To address this issue, the ability of zeolite 4A to concentrate the Sr from the seawater matrix was employed. With the proposed method, two important goals were achieved: (i) simple preconcentration of Sr that can be conducted directly at the sampling site, enabling a rapid procedure for 89,90Sr determination in emergencies, and (ii) high and stable Sr recoveries (89 ± 4%) necessary for lowering detection limits. Strontium is effectively separated from 1 L of seawater in less than 1.5 h, which is especially important in emergency situations, such as the Fukushima Daiichi Nuclear Power Plant accident. Minimum detectable activities achieved for 89Sr:90Sr activity ratio ∼10:1 were 0.74 Bq/L for 89Sr, and 1.47 Bq/L for 90Sr, detected by Cherenkov counting, 36–38 h after separation, and 30 min counting time.