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Background: Bisphenols are major industrial chemicals that have raised public concern due to their endocrine disrupting properties and toxicity. Sample preparation is the most critical step for the determination of bisphenols, especially if the analyst has to deal with environmental samples which are complex matrices and the co-extraction and co-elution of other relevant compounds results in the enhancement or suppression of the analyte signal. The need for the precise determination of bisphenols has signaled the development of effective microextraction techniques according to the Green Analytical Chemistry (GAC) guidelines. Objective: The objective of this review is to gather and discuss all the recent advances in the development of microextraction techniques such as solid phase extraction (SPE), solid phase microextraction (SPME), magnetic solid phase microextraction (MSPE), liquid-phase microextraction (LPME), dispersive liquid-liquid microextraction (DLLME), stir bar sorptive extraction (SBSE), and matrix solid-phase dispersion (MSPD), that have been successfully applied in the extraction of bisphenols from environmental matrices. Conclusion: The analytical performance of the proposed techniques is critically discussed, highlighting the potential and the limitations of each method.

Background:: Nuts have been incorporated into guidelines for healthy eating since they contain considerable amounts of antioxidants and their effects are related to health benefits since they contribute to the prevention of nutritional deficiencies. The micronutrient characterization is based mainly on the determination of phenolics, which is the most abundant class of bioactive compounds in nuts. Terpenes constitute another class of bioactive compounds that are present in nuts and show high volatility. The analysis of phenolic compounds and terpenes is a very demanding task that requires optimization of the chromatographic conditions to improve the separation of the components. Moreover, nuts are rich in unsaturated fatty acids and they are therefore considered as cardioprotective. Gas chromatography is the predominant instrumental analytical technique for the determination of derivatized fatty acids and terpenes in food matrices, while high performance liquid chromatography is currently the most popular technique for the determination of phenolic compounds. Objective:: This review summarizes all the recent advances in the optimization of the chromatographic conditions for the determination of phenolic compounds, fatty acids and terpenes in nuts. Conclusion:: The state-of-the art in the technology available is critically discussed, exploring new analytical approaches to reduce the time of analysis and improve the performance of the chromatographic systems in terms of precision, reproducibility, limits of detection and quantification and overall quality of the results.

Monitoring the residual toxicant concentrations in foods is the key step for minimizing potential hazards. The huge interest about food contamination and exposure to endocrine disruptors such as bisphenol A has emerged the development of sensitive analytical methodologies to guarantee the safety and quality of foods. In this work, a green molecularly imprinted solid-phase extraction protocol coupled with high-performance liquid chromatography with UV detection was optimized following the principles of green analytical chemistry. An imprinted sol-gel silica-based hybrid inorganic-organic polymeric sorbent was used to monitor the leaching of bisphenol A from different packaging materials (glass vessels, cans, and polypropylene containers) in walnuts stored within a period of 6 months at 25 and 4°C. Extraction parameters including loading time (5-20 min), solvent type (acetonitrile, ethanol, methanol, acetone, acetonitrile:methanol, 50:50, v/v), and elution flow rate (0.2-1 mL/min) were optimized with one-factor-at-a-time method. The selected extraction optimum parameters incorporated elution with acetonitrile at 0.2 mL/min flow rate, for 10 min sample holding time. The imprinting factor was equal to 4.55 ± 0.26 (n = 3). The optimized method presented high recovery (94.3 ± 4.2%, n = 3), good linearity (>0.999), intra-assay repeatability (90.2-95.6%, n = 3), and interassay precision (86.7-93.1%, n = 3).

Novel materials used in preventive and restorative dentistry contain monomers with endocrine or cytotoxic properties, which can cause minimum or even severe damage to human body, when found in specific concentrations. The degradation of resin composite restorations after aging and/or storage in different solutions is associated with leaching monomers, like bisphenol A- glycidyl methacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), Urethane dimethacrylate (UDMA), Bisphenol A (BPA), which are potentially leading to toxicity and mutagenicity effects or cause allergic reactions. These monomers may cause health issues to patients, therefore their determination both in-vitro and in biological fluids e.g. saliva, blood serum/plasma and urine is significant. Moreover, analytical methods are necessary to investigate the rate of elution, as well as the conditions that mainly affect the mechanism of short-term and long-term release of monomers from dental composites. In this review article we present some of the techniques and methods used to determine the short-term and long-term release of these monomers from modern dental materials and prove that analytical chemistry and especially bioanalysis can be a powerful tool in dentistry

Background: Medicinal plants consist a rich source of natural pharmacologically active compounds. The aim of the current work, was the study and optimization of the extraction conditions of phenolic constituents from important medicinal and aromatic plants, id. Sideritis raeseri, Sideritis scardica and Origanum vulgare, implementing microwave assisted extraction technique. Methods: Optimization was based on various parameters affecting extraction procedure, such as the duration of microwave radiation, the ratio of plant material mass to the solvent, the type and the concentration of the solvent. Results: The results revealed that 10 min of microwave radiation provided the maximum extraction yield of the phenolic constituents. The ratio of the plant material mass and the solvent had minor effect to the extraction efficiency. Conclusion: The examined solvents provided an extraction yield of phenolic constituents following the order: EtOH

Benzoyl urea insecticides are a class of pesticides used in agriculture for the inhibition of chitin synthesis in pests. These compounds are persistent in environmental samples, and thus their monitoring is necessary to avoid detrimental effects to human health and the environment. Magnet integrated fabric phase sorptive extraction (MI-FPSE) is a recently introduced sample preparation technique that combines sample stirring and analyte extraction into one stand-alone device. However, the applicability and the potential benefits of this technique in environmental analysis remain unexplored. In the present study, MI-FPSE was employed for the first time for the extraction and preconcentration of benzoyl urea insecticides (i.e., diflubenzuron, triflumuron, hexaflumuron, lufenuron and chlorfluazuron) from environmental water samples prior to their determination by high performance liquid chromatography-diode array detection (HPLC-DAD). The main factors affecting the performance of the proposed methodology were thoroughly investigated and optimized and the MI-FPSE-HPLC-DAD method was validated. The proposed method enabled the handling of relatively high sample quantity resulting in high preconcentration factors (501 and 731) and good sensitivity. Under optimum conditions, the limits of detection and the limits of quantification for the benzoyl urea insecticides were 0.06 ng mL

The possible presence of contaminants, pesticide residues and mycotoxins, in agricultural commodities is a critical issue for food safety, causing great concern. In this work, a simple and rapid analytical method employing liquid chromatography–tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous determination of pesticide residues and mycotoxins in apples. Microwave-assisted extraction (MAE) was used for sample preparation. The MAE protocol was optimized after evaluating the effects of the following extraction parameters: (a) extraction solvent, (b) acidic environment, (c) temperature, and (d) extraction time. The multiresidue MAE-LC-MS/MS method was validated for linearity, accuracy (bias and precision), limits of detection (LODs), limits of quantification (LOQs), and matrix effect. The validation of the method was carried out according to the SANTE/12682/2019 document. The method demonstrated good linearity with R2 ≥ 0.99, acceptable accuracy in the recovery rate range 70–116%, acceptable interassay precision with RSD% ≤ 20, and low LODs and LOQs in the ranges 0.005–0.015 μg/g and 0.01–0.03 μg/g, respectively. Matrix effects were observed only for the 25% of the analytes. The performance of the MAE-LC-MS/MS method was compared to that of the QuEChERS sample preparation method, and the MAE-LC-MS/MS method proved to be rapid and effective.

Reversed phase-high-pressure liquid chromatographic methodologies equipped with UV detector (RP-HPLC-UV) were developed for the determination of phenolic compounds and tocopherols in almonds. Nineteen samples of Texas almonds originating from USA and Greece were analyzed and 7 phenolic acids, 7 flavonoids, and tocopherols (−α, −β + γ) were determined. The analytical methodologies were validated and presented excellent linearity (r2 &gt, 0.99), high recoveries over the range between 83.1 (syringic acid) to 95.5% (ferulic acid) for within-day assay (n = 6), and between 90.2 (diosmin) to 103.4% (rosmarinic acid) for between-day assay (n = 3 × 3), for phenolic compounds, and between 95.1 and 100.4% for within-day assay (n = 6), and between 93.2–96.2% for between-day assay (n = 3 × 3) for tocopherols. The analytes were further quantified, and the results were analyzed by principal component analysis (PCA), and agglomerative hierarchical clustering (AHC) to investigate potential differences between the bioactive content of almonds and the geographical origin. A decision tree (DT) was developed for the prediction of the geographical origin of almonds proposing a characteristic marker with a concentration threshold, proving to be a promising and reliable tool for the guarantee of the authenticity of the almonds.

Nowadays, the interest in preparing new, cheap and simple adsorbents that are used in sample preparation is on the rise. Graphene oxide (GO) nanomaterials and nanocomposites have become increasingly popular due to the novel methods of syntheses that have been published. Owing to their vast specific surface area and their π-delocalized electron system they possess, they are appropriate for the adsorption of a variety of aromatic organic compounds, being utilized either as adsorbents in analytical methods or as filter materials for the removal of pollutants in water. Pharmaceutical compounds, such as benzodiazepines, end up in surface waters caused by consumption or their disposal through sewage, thus becoming pollutants. In the present study, an analytical method has been developed and validated for the determination of two model-analytes of benzodiazepines by HPLC-DAD and their sample preparation protocol which consists of the Stir bar magnetic solid phase extraction (SB-MSPE) method, evaluating therefore the nanocomposite material as a decent adsorbent. The separation took place with the usage of an analytical column C18 RP-HPLC in 10 min. For the alprazolam (ALP) and the flunitrazepam (FLT), the LODs and LOQs were 3 ng/mL and 10 ng/mL, respectively, while the relative recoveries ranged between 93.6–112.9% and the RSDs were 1.11–9.50%. Finally, the material was examined for its reusability and was found that it can be used for over eight cycles of extraction/elution.

Background: Biopharmaceuticals are biological drugs consisting of a complex compound that can be produced by a living organism or derive from it. Biopharmaceuticals are very complicated compounds from structural point of view and for this reason, they cannot be fully characterized in terms of their structure with current analytical methods as it happens instead of low molecular weight chemicals drugs. Introduction: The regulatory guidelines require the characterization of the primary or higher sequence of these molecules and the characterization of any post-translational modifications. The use of biopharmaceuticals has really grown in the last few years: in 2016, the number of biopharmaceuticals approved by the Food and Drug Administration (FDA) and European Medicines Agency (EMA) for use in humans’ diseases was 1357. From 2013 to 2016, 73 of these compounds were approved for the treatment of cancer, inflammation, immune disorders, infections, anemia and cardiovascular diseases. Aim/Conclusion: The aim of the present review is to provide an overview of recent approaches for the characterization of biopharmaceutical products in HPLC that have been presented in the literature in the last years.

Background:The sample preparation is the most crucial step in the analytical method development. Taking this into account, it is easily understood why the domain of sample preparation prior to detection is rapidly developing. Following the modern trends towards the automation, miniaturization, simplification and minimization of organic solvents and sample volumes, green microextraction techniques witness rapid growth in the field of food quality and safety. In a globalized market, it is essential to face the consumers need and develop analytical methods that guarantee the quality of food products and beverages. The strive for the accurate determination of organic hazards in a famous and appreciated alcoholic beverage like wine has necessitated the development of microextraction techniques.Objective:The objective of this review is to summarize all the recent microextraction methodologies, including solid phase extraction (SPE), solid phase microextraction (SPME), liquid-phase microextraction (LPME), dispersive liquid-liquid microextraction (DLLME), stir bar sorptive extraction (SBSE), matrix solid-phase dispersion (MSPD), single-drop microextraction (SDME) and dispersive solid phase extraction (DSPE) that were developed for the determination of hazardous organic compounds (pesticides, mycotoxins, colorants, biogenic amines, off-flavors) in wine. The analytical performance of the techniques is evaluated and their advantages and limitations are discussed.Conclusion:An extensive investigation of these techniques remains vital through the development of novel strategies and the implication of new materials that could upgrade the selectivity for the extraction of target analytes.

Background:Silk fibroin is the main protein of silk, and it has recently been evaluated for drug delivery applications due to its excellent properties. Specifically, silk fibroin exhibits good biocompatibility, biodegradability and low immunogenicity. Fibroin nanoparticles have attracted attention due to their high binding ability to different drugs as well as their ability for controlled drug release. The improvement of the therapeutic efficiency of drug encapsulation is important and depends on the particle size, the chemical structure and the properties of the silk fibroin nanoparticles.Methods:There is a variety of methods for the preparation of fibroin nanoparticles such as (i) electrospraying and desolvation method, (ii) supercritical fluid technologies, (iii) capillary-microdot technique, (iv) salting out etc. Furthermore, various techniques have been used for the characterization of nanoparticles such as SEM (scanning electron microscopy), TEM (transmission electron microscopy), DLS (dynamic light scattering), Zeta-potential and FTIR (Fourier transform infrared spectroscopy). Different drugs (paclitaxel, curcumin, 5-fluorouracil etc) have been encapsulated in fibroin nanoparticles.Results:Each separated synthesis method has different advantages such as (i) high yield, (ii) avoid use of toxic solvents, (iii) low cost, (iv) controllable particle size, (v) no organic solvent residue, (vi) simplicity of operation, (vii) small particles size, (viii) homeliness of operation, (ix) restrainable particle size, (x) easy and safe to operate, (xi) no use of organic solvent. Moreover, some major drugs studied are Floxuridine, Fluorouracil, Curcumin, Doxorubicin, Metotrexate, Paclitaxel and Doxorubicin, Horseradish peroxidase. All the above combinations (preparation method-drug) are studied in detail.Conclusion:Various drugs have been encapsulated successfully in silk fibroin and all of them exhibit a significant release rate. Finally, the encapsulation efficiency and release rate depend on the molecular weight of the drugs and it can be adjusted by controlling the crystallinity and concentration of silk fibroin.

Among epigenetic mechanisms, DNA methylation has been widely studied with respect to many environmental factors. Smoking is a common factor which affects both global and gene-specific DNA methylation. It is supported that smoking directly affects DNA methylation, and these effects contribute to the development and progression of various diseases, such as cancer, lung and cardiovascular diseases and male infertility. In addition, prenatal smoking influences the normal development of the fetus via DNA methylation changes. The DNA methylation profile and its smoking-induced alterations helps to distinguish current from former smokers and non-smokers and can be used to predict the risk for the development of a disease. This review summarizes the DNA methylation changes induced by smoking, their correlation with smoking behavior and their association with various diseases and fetus development.

An innovative fabric phase sorptive extraction-high performance liquid chromatography-diode array detection (FPSE-HPLC-DAD) method is developed and validated herein for the simultaneous extraction and analysis of five common antidepressants (venlafaxine, paroxetine, fluoxetine, amitriptyline, clomipramine) in human urine samples. Separation was obtained using a reverse phase column LiChroCART-LiChrospher®100 RP-8e (5 μm, 250 × 4 mm) with diode array detection monitoring at 235 nm. Gradient elution was applied at a flow rate of 1.2 mL/min with a mobile phase that consisted of acetonitrile and ammonium acetate (0.05 M). Fabric Phase Sorptive Extraction was evaluated for the first time with regards to the extraction of the examined antidepressants from human urine and proved to be a rapid, simple, environmentally friendly, efficient, and selective sample preparation approach. Sol-gel graphene sorbent, coated on cellulose FPSE media, were the most efficient among other with different polarities. The absolute recovery values were 25.5% for venlafaxine, 33.9% for paroxetine, 67.0% for fluoxetine, 43.0% for amitriptyline and 29.0% for clomipramine, while relative recoveries were higher than 90%. The developed method provides satisfactory limit of detection 0.15 ng/μL.

Modified graphite oxide (ΝGO) was used as a support of a manganese oxide of hausmannite type (Mn3O4) nanocatalyst and applied for the degradation of an endocrine disruptor, bisphenol-A (BPA). The prepared nanocomposite/catalyst (NGO-Mn3O4), as well as pure modified graphite oxide and manganese oxide, were characterized by X-ray diffraction, Scanning Electron Microscopy, nitrogen adsorption, X-ray photoelectron spectroscopy, Fourier Transform Infrared Spectroscopy, and potentiometric titration. The maximum removal activity for all the materials was measured at pH = 3. The NGO-Mn3O4 nanocomposite showed the highest removal efficiency of BPA at an ambient temperature without light irradiation and/or the addition of chemicals, which can be attributed to the synergistic effect of the composite formation. The nanocomposite exhibited a high catalytic activity for the degradation/oxidation of BPA, which was dramatically higher than that of the pristine Mn3O4 phase. Modified graphite oxide showed also an enhanced capability for the BPA removal, which was linked to an increased physical adsorption component.

Capsule phase microextraction is introduced herein for the first time to determine four sulfonamide residues in milk samples (sulfanilamide, sulfadiazine, sulfamethizole, and sulfathiazole). The technique eloquently integrates filtration and stirring mechanism into the extraction device, as such no filtration of the sample is needed prior to introducing the extraction device into the sample, and when placed on a magnetic stirrer, the device spins itself in order to diffuse the sample, resulting in faster extraction equilibrium. Microextraction capsules consist of three main parts; a magnet, a cellulose fiber substrate coated with high performance sol-gel hybrid organic-inorganic sorbent, and a porous membrane. Various encapsulated sol-gel sorbents were tested in standard solutions prepared in deionized water and milk samples under different operational conditions. Analyte extraction time and elution time, type of sol-gel sorbent, elution solvent, as well as the ratio of the sorbent to the elution solvent were among the optimized conditions. The protocols that yielded the best absolute recovery rates were subsequently tested in various milk samples. Method validation was performed in terms of linearity, accuracy and precision, reusability and ruggedness using the Youden test. The examined sulfonamides were subsequently analysed by reversed phase high performance liquid chromatography with diode array detection.

In current paper, a new advanced modification of fabric phase sorptive extraction is introduced for the first time. This advantageous configuration that integrates the stirring and extraction mechanism into a single sample preparation device was originated by equally considering the beneficial role of the increase of extraction kinetics and more specifically of diffusion on the extraction efficiency of the equilibrium based microextraction techniques and the need for integrating and unite processes for better promotion and implementation of the principles of Green Analytical Chemistry. The resulted magnet integrated fabric phase sorptive extraction (MI-FPSE) device was the spearhead to develop a new analytical methodology for the determination of selected very common endocrine disrupting chemicals as model analytes in human urine by high-performance liquid chromatography-photodiode array analysis. More specifically, the sol-gel Carbowax 20 M coated on hydrophilic cellulose fabric substrate, MI-FPSE device was efficiently employed for the establishment of a new extraction protocol before the chromatographic determination. The sample preparation workflow was methodically optimized in terms of the elution solvent mixture, the volume of the sample, the extraction and the elution time, the stirring speed during the extraction, the ionic strength, and the pH of the sample matrix. The chromatographic separation was performed on a Spherisorb C18 column and a gradient elution program within 14 minutes. Mobile phase consisted of 0.05 ammonium acetate aqueous solution and acetonitrile. The method was validated towards linearity, sensitivity, selectivity, precision, accuracy, and stability. LOD and LOQ ranged between 1.05-1.80 and 3.5-6.0 ng/mL, while %RSD values were found lower than 9.0% in all cases. The method was efficiently applied to the bioanalysis of real samples. All the chosen EDCs were measured at high detection levels. The new MI-FPSE device has demonstrated its performance superiority as a magnet integrated stand-alone extraction device and could be considered as a significant improvement in the field of analytical/bioanalytical sample preparation.

The determination of triazine herbicides in water samples is of utmost importance, due to their persistence and excessive use. However, since the concentration of triazine pesticides in real samples is low, an extraction/preconcentration step is typically required. Capsule phase microextraction (CPME) is a recently introduced sample preparation technique in which highly efficient sol-gel sorbents are encapsulated in a tubular polymer membrane. This particular design integrates the filtration and stirring mechanism into one extraction device, enabling the application of CPME for in situ sampling. In this study, CPME coupled to high performance liquid chromatography-diode array detection (HPLC-DAD) was employed for the first time for the determination of six triazine herbicides (i.e., simazine, cyanazine, atrazine, prometryn, terbuthylazine and propazine) in water samples. Microextraction capsules containing a moderately hydrophobic sol‐gel Carbowax 20 M sorbent provided the highest extraction efficiency towards the examined pesticides. The main parameters affecting the adsorption and desorption steps of the CPME procedure were investigated and optimized. Under the selected conditions, limits of detection (signal/noise = 3.3) were 0.15 ng mL−1 for the target analytes. Moreover, the relative standard deviation for the within-day and between-days repeatability were less than 7.2% and 9.9%, respectively. The method was successfully applied to the analysis of mineral water, tap water, rainwater and lake water samples. The reported protocol could overcome the need for sample filtration prior to the sample preparation of the water samples, resulting in simplification of the overall sample handling, improved data quality with minimal loss of analytes and reduced sample preparation cost.

It is challenging to establish a correlation between the agronomical practices and the volatile profile of high-value agricultural products. In this study, the volatile metabolome of walnut oils from conventional and organic farming type was explored by HS-SPME-GC-MS. The SPME protocol was optimized after evaluating the effects of extraction time, extraction temperature, and sample mass. The optimum parameters involved the extraction of 0.500 g walnut oil at 40 °C within 60 min. Twenty Greek walnut oils produced with conventional and organic farming were analyzed and 41 volatile compounds were identified. The determined compounds were semi-quantified, and further processed with chemometrics. Agglomerative hierarchical clustering (AHC) and principal component analysis (PCA) were used. A robust classification model was developed using sparse partial least squares–discriminant analysis (sPLS-DA) for the discrimination of walnut oils into conventional and organic, establishing volatile markers that could be used to guarantee the type of farming.

Thiophenic compounds constitute a class of sulfur compounds derived by thiophene, containing at least one thiophenic ring. Their presence in fuels (crude oil, etc.) is important and can reach 3% m/m. The combustion of fuels leads to the formation of sulfur oxides a severe source of environmental pollution issues, such as acid rain with adverse effects both to humans and to the environment. To reduce such problems, the EU and other regulatory agencies worldwide set increasingly stringent regulations for sulfur content in fuels resulting in the necessity for intense desulphurization processes. However, most of these processes are inefficient in the total removal of sulfur compounds. Therefore, thiophenic compounds such as benzothiophenes and dibenzothiophenes are still present in heavier fractions of petroleum, therefore, their determination is of great importance. Until now, all HPLC methods applied in similar studies use gradient elution programs that may last more than 25 min with no validation results provided. To fill this gap, the aim of the present study was to develop and validate a simple and fast HPLC-UV method in order to be used as a useful monitoring tool in the evaluation studies of novel desulfurization technologies by means of simultaneous determination of dibenzothiophene (DBT) and 4,6-dimethyl-dibenzothiophene and dibenzothiophene sulfone in the desulfurization effluents.