Using a Simple Magnetic Adsorbent for the Preconcentration and Determination of Ga(III) and In(III) by Electrothermal Atomic Absorption Spectrometry.

A solid-phase dispersive microextraction procedure has been developed using ferrite (Fe3O4), an inexpensive magnetic material, as an adsorbent for the separation and subsequent determination of Ga(III) and In(III). The ions were removed from an aqueous solution by adsorption on Fe3O4, which was next easily collected from the medium by the action of a magnet. The analytes were then desorbed using 50 µL of 2 M NaOH or 50 µL of a 4:1 mixture of 0.1 M EDTA and 2 M HNO3 for the determination of Ga(III) or In(III), respectively. The level of the elements in the desorption phase was measured by electrothermal atomic absorption spectrometry (ETAAS) by injecting 10 µL of this phase into the atomizer. The enrichment factor was 163, and detection limits of 0.02 and 0.01 µg L-1 were achieved for Ga(III) and In(III), respectively. The reliability of the procedure has been verified by means of standard reference materials and by means of standard additions. Results are given for waters, soils and samples obtained from various electronic devices. It is of note that the procedure could be the basis for a useful way of recovering these valuable elements from different matrices for reuse.

Dispersive magnetic solid-phase extraction for capsaicinoid compounds in human serum using LC-HRMS: targeted and non-targeted approaches.

A new analytical method based on the use of dispersive magnetic solid-phase extraction (DMSPE) is described for the preconcentration of capsaicin (CAP), dihydrocapsaicin (DCAP), and N-vanillylnonanamide (PCAP) from human serum samples. The influence of several experimental factors affecting the adsorption (nature and amount of magnetic material, adsorption time, and pH) and desorption (nature of solvent, its volume and desorption time) steps was studied. Among seven different nanomaterials studied, the best results were obtained using magnetic multiwalled carbon nanotubes, which were characterized by means of spectrometry- and microscopy-based techniques. Analyses were performed by ultra-high-performance liquid chromatography with quadrupole-time-of-flight mass spectrometry using electrospray ionization in positive mode (UHPLC-ESI-Q-TOF-MS). The developed method was validated by obtaining several parameters, including linearity (0.3-300 µg L-1 range), and limits of detection which were 0.1, 0.15, and 0.17 µg L-1 for CAP, DCAP, and PCAP, respectively. The repeatability of the method, expressed as relative standard deviation (RSD, n = 7), varied from 3.4 to 11%. The serum samples were also studied through a non-targeted approach in a search for capsaicinoid metabolites and related compounds. With this objective, the fragmentation pathway of this family of compounds was initially studied and a strategy was established for the identification of novel or less studied capsaicinoid-derived compounds.

Improvement in the Chromium(VI)-Diphenylcarbazide Determination Using Cloud Point Microextraction; Speciation of Chromium at Low Levels in Water Samples.

A reliable, rapid, and low-cost procedure for determining very low concentrations of hexavalent chromium (Cr) in water is discussed. The procedure is based in the classical reaction of Cr6+ with diphenylcarbazide. Once this reaction has taken place, sodium dodecylsulfate is added to obtain an ion-pair, and Triton X-114 is incorporated. Next, the heating of the mixture allows two phases that can be separated by centrifugation to be obtained in a cloud point microextraction (CPE) process. The coacervate contains all the Cr6+ originally present in the water sample, so that the measurement by molecular absorption spectrophotometry allows the concentration of the metal to be calculated. No harmful organic solvents are required. The discrimination of hexavalent and trivalent forms is achieved by including an oxidation stage with Ce4+. To take full advantage of the pre-concentration effect inherent to the coacervation process, as well as to minimize reagent consumption and waste generation, a portable mini-spectrophotometer which is compatible with microvolumes of liquid samples is used. The preconcentration factor is 415 and a chromium concentration as low as 0.02 µg L-1 can be detected. The procedure shows a good reproducibility (relative standard deviation close to 3%).

Free and glycosylated aroma compounds in grapes monitored by solid-liquid extraction and dispersive liquid-liquid microextraction combined with gas chromatography-mass spectrometry.

Fifteen aroma compounds have been determined in their free and glycosylated forms in grapes using dispersive liquid-liquid microextraction with gas chromatography-mass spectrometry. The sample treatment includes a previous solid-liquid extraction stage and subsequent parallel microextraction approaches to preconcentrate total aroma content and the free fraction. Thus, the extraction of the total content of analytes requires previous enzymatic hydrolysis of the bound forms. For preconcentration, chloroform (250 µl) and acetonitrile (1.5 ml) were added to 10 ml of the sample extract in the presence of 0.5 g sodium chloride. The absence of matrix effect in the samples allowed quantification against aqueous external standards. Limits of detection ranged between 5 and 30 ng/g, depending on the compound. Method accuracy was studied through recovery assays, with recoveries in the 82-115% range being obtained. Relative standard deviations for repeatability studies were lower than 12%. Four different samples of grapes were analyzed, being quantified linalool in its free form at concentrations in the 359-470 ng/g range, and benzyl alcohol, 2-phenylethanol, and linalool oxide I and II in their bound forms between 52 and 464 ng/g.

Determination of Hg(II) and Methylmercury by Electrothermal Atomic Absorption Spectrometry after Dispersive Solid-Phase Microextraction with a Graphene Oxide Magnetic Material.

The toxicity of all species of mercury makes it necessary to implement analytical procedures capable of quantifying the different forms this element presents in the environment, even at very low concentrations. In addition, due to the assorted environmental and health consequences caused by each mercury species, it is desirable that the procedures are able to distinguish these forms. In nature, mercury is mainly found as Hg0, Hg2+ and methylmercury (MeHg), with the latter being rapidly assimilated by living organisms in the aquatic environment and biomagnified through the food chain. In this work, a dispersive solid-phase microextraction of Hg2+ and MeHg is proposed using as the adsorbent a magnetic hybrid material formed by graphene oxide and ferrite (Fe3O4@GO), along with a subsequent determination by electrothermal atomic absorption spectrometry (ETAAS). On the one hand, when dithizone at a pH = 5 is used as an auxiliary agent, both Hg(II) and MeHg are retained on the adsorbent. Next, for the determination of both species, the solid collected by the means of a magnet is suspended in a mixture of 50 µL of HNO3 (8% v/v) and 50 µL of H2O2 at 30% v/v by heating for 10 min in an ultrasound thermostatic bath at 80 °C. On the other hand, when the sample is set at a pH = 9, Hg(II) and MeHg are also retained, but if the solid collected is washed with N-acetyl-L-cysteine only, then the Hg(II) remains on the adsorbent, and can be determined as indicated above. The proposed procedure exhibits an enrichment factor of 49 and the determination presents a linear range between 0.1 and 10 µg L-1 of mercury. The procedure has been applied to the determination of mercury in water samples from different sources.

Ultrasound Assisted Extraction Approach to Test the Effect of Elastic Rubber Nettings on the N-Nitrosamines Content of Ham Meat Samples.

Nitrosamines (NAs), which are catalogued as carcinogenic compounds, may be present in meat products due to the conversion of nitrites and as result of migration from elastic rubber nettings used. A method based on ultrasonic assisted extraction coupled with dispersive liquid-liquid microextraction as sample treatment and gas chromatography-mass spectrometry as separation and detection technique was proposed for the determination of twelve NAs in cooked ham samples. The method was validated by evaluating linearity (0.5-1000 ng g-1), matrix effect, sensitivity (detection limits were between 0.15 and 1.4 ng g-1) and precision, which was below 12%. Five NAs were found in the samples with levels ranging from not quantifiable to 40 ng g-1. The effect of the elastic rubber nettings on the nitrosamine content of meat was evaluated by comparing the levels found in products made with several plastics or thread in the presence of additives.

Portable Raman Spectrometer as a Screening Tool for Characterization of Iberian Dry-Cured Ham.

Dry-cured Iberian ham is officially classified into different commercial categories according to the pig's breed and feeding regime. These reach very different prices, thus promoting labelling fraud and causing great damage to the food sector. In this work, a method based on Raman spectroscopy was explored as a rapid in situ screening tool for Iberian ham samples. A total of 110 samples were analyzed to assess the potential of this technique to differentiate purebred, crossbred, acorn-fed and feed-fed dry-cured Iberian ham. A continuous signal probably due to sample fluorescence was obtained, which hid the Raman scattering signal. Therefore, chemometric treatment was applied in order to extract non-apparent information. High validated classification rates were obtained for feeding regime (83.3%) and breed (86.7%). In addition, an interlaboratory study was carried out to confirm the applicability of the method with 52 samples, obtaining a validated rate above 80%.

Dispersive micro-solid phase extraction with a magnetic nanocomposite followed by electrothermal atomic absorption measurement for the speciation of thallium.

A magnetic dispersive micro-solid phase extraction procedure for the determination of the thallium content in waters is presented. The incorporation in the sample (10 mL) of a small amount of graphene-Fe3O4 composite (3.6 mg) in the presence of 10-4 mol L-1 Aliquat 336 at pH 2 results in the complete retention of both thallium(I) and thallium(III). After separation with a magnet, the micro-solid phase recovered is treated with 0.05 mL of a 0.1 mol L-1 sodium ethylenediaminetetracetate solution at pH 9, and the supernatant obtained after application of the magnet is introduced in the electrothermal atomizer of an atomic absorption spectrometer to obtain the signal corresponding to the total thallium content. For speciation, the trivalent form in a second sample aliquot is separated by means of a liquid-liquid extraction stage with chloroform and methyl trioctyl ammonium in the presence of bromide, and the signal corresponding to the monovalent form is obtained, the concentration of thallium(III) being obtained by difference. The enrichment factor is 185, which permits a detection limit as low as 0.01 µg L-1 of the analyte to be achieved. The relative standard deviation for five measurements at the 0.1 µg L-1 thallium level is below 5%. The reliability of the procedure is verified by analysing five certified reference samples for which speciation data are also given.

Toward Nitrite-Free Curing: Evaluation of a New Approach to Distinguish Real Uncured Meat from Cured Meat Made with Nitrite.

After the International Agency for Research on Cancer (IARC) classified ingested nitrites and nitrates as "probably carcinogenic to humans" under conditions favoring endogenous nitrosation, several meat products labeled as "made without nitrite" were launched. In order to distinguish uncured products truly made without nitrite from cured products made with any nitrite source (vegetal or mineral), this article presents an approach to detect and quantify nitrite from different origins added to meat. The method consists on the determination of nitrous oxide as a target compound using headspace gas chromatography-mass spectrometry (HS-GC-MS). Nitrous oxide (N2O) is formed after two reduction steps: from nitrite to nitric oxide (NO) and then to N2O. The NO is bound to myoglobin (Mb) or metmyoglobin (Met-Mb), forming a complex, which is subsequently released using sulfuric acid, which also favors the reduction to N2O. The HS-GC-MS conditions were split ratio 1:10; injection temperature at 70 °C; incubation temperature at 30 °C and time 45 min; and injection volume 1 mL. As a result, a relationship was established between the concentration of nitrite in cooked ham samples and the area of the N2O peak generated, meaning that this method allows the quantification of added nitrite within a concentration range of 10 to 100 mg kg-1.

Monitoring Lipophilic Toxins in Seawater Using Dispersive Liquid-Liquid Microextraction and Liquid Chromatography with Triple Quadrupole Mass Spectrometry.

The use of dispersive liquid-liquid microextraction (DLLME) is proposed for the preconcentration of thirteen lipophilic marine toxins in seawater samples. For this purpose, 0.5 mL of methanol and 440 µL of chloroform were injected into 12 mL of sample. The enriched organic phase, once evaporated and reconstituted in methanol, was analyzed by reversed-phase liquid chromatography with triple-quadrupole tandem mass spectrometry. A central composite design multivariate method was used to optimize the interrelated parameters affecting DLLME efficiency. The absence of any matrix effect in the samples allowed them to be quantified against aqueous standards. The optimized procedure was validated by recovery studies, which provided values in the 82-123% range. The detection limits varied between 0.2 and 5.7 ng L-1, depending on the analyte, and the intraday precision values were in the 0.1-7.5% range in terms of relative standard deviation. Ten water samples taken from different points of the Mar Menor lagoon were analyzed and were found to be free of the studied toxins.

Occurrence of Organochlorine Pesticides in Human Tissues Assessed Using a Microextraction Procedure and Gas Chromatography-Mass Spectrometry.

This work focuses on the development, validation and application of an analytical method for the determination of twenty organochlorine pesticides (OCPs) in human tissues using salting-out liquid-liquid extraction and dispersive liquid-liquid microextraction for sample preparation and gas chromatography-mass spectrometry to analyze the obtained extracts. Measurement of the concentration levels of these toxics in tissues can be used to assess the risk of the population to exposure. The linearity of the proposed method was verified in the 10-1,000 ng/g range. The sensitivity was evaluated calculating the limits of detection (LODs) for 20 OCPs (α-, ß-, γ- and δ-hexachlorocyclohexane (HCH), α- and ß-endosulfan, endosulfan sulfate, aldrin, dieldrin, endrin, endrin ketone, endrin aldehyde, α- and γ-chlordane, 4,4'-dichlorodiphenyltrichloroethane, 4,4'-dichlorodiphenyldichloroethylene (DDE), 4,4'-dichlorodiphenyldichloroethane, heptachlor, heptachlor epoxide and methoxychlor), most of them being found between 1.0 and 16 ng/g. The intra- and interday precisions were <12% for relative standard deviation values. The accuracy of the method was evaluated by recovery studies, which gave recovery percentages in the 85-109% range. Seven different tissues (liver, kidney, heart, spleen, lung, brain and abdominal fat) from eight autopsies were analyzed, and only three cases were seen to have ß-HCH and 4,4'-DDE in abdominal fat, while 4,4'-DDE was also detected in the heart of one case. The rest of the samples were free of the studied OCPs at least above the corresponding LODs.

Development of a new methodology for the determination of N-nitrosamines impurities in ranitidine pharmaceuticals using microextraction and gas chromatography-mass spectrometry.

Ranitidine drug products were recently recalled because they contained carcinogenic nitrosamines (NAs), such as N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA). This episode emphasises the importance of developing analytical methods to determine NAs in this type of product. This study describes the development and validation of an analytical method for the determination of nine NAs (NDMA, N-nitrosomethylethylamine (NEMA), NDEA, N-nitrosopyrrolidine (NPYR), N-nitrosomorpholine (NMOR) N-nitrosodi-n-propylamine (NDPA) N-nitrosopiperidine (NPIP), N-nitrosodi-n-butylamine (NDBA) and N-nitrosodiphenylamine (NDPhA)) in ranitidine drug samples using a combination of microextraction and gas chromatography-mass spectrometry. The procedure involved the dissolution of 1 g of sample in 10 mL of water. For the dispersive liquid-liquid microextraction, 0.5 g of NaCl was added to this aqueous solution, followed by a mixture containing 0.5 mL methanol as dispersant and 150 µL chloroform as extractant solvent. The recovered organic phase was injected into the GC-MS system and a 20 min oven programme was applied. Quantification limits were in the 0.21-21 ng g-1 range, corresponding the lower limit to NDPhA and the higher to NDMA. Relative standard deviations lower than 12% were achieved in all cases, which indicates the adequate precision of the method. Seven pharmaceutical products containing two different amounts of ranitidine (150 and 300 mg) were analysed. None of the samples contained NEMA, NDEA, NPYR, NMOR, NDPA or NPIP, while NDMA, NDBA and NDPhA were found in three products.

A rapid dispersive liquid-liquid microextraction of antimicrobial onion organosulfur compounds in animal feed coupled to gas chromatography-mass spectrometry.

A rapid analytical procedure is proposed for determining two antimicrobial onion organosulfur compounds, propyl disulfide (PDS) and propyl propane thiosulfonate (PTSO), in animal feed. The use of PTSO as a natural ingredient in animal feed is allowed due to its antimicrobial activity against pathogenic organisms. Two analytical methodologies using gas chromatography coupled to mass spectrometry (GC-MS) are compared. After the extraction of the compounds from animal feed with acetonitrile, dispersive solid phase extraction (DSPE) as a cleaning stage with C18, or dispersive liquid-liquid microextraction (DLLME), using 100 µL of CHCl3, was tried. Both the methods were validated using a pig feed sample and the best results were achieved by DLLME. This technique provided cleaner extracts, five-times greater linear ranges and lower detection limits than simple cleaning due to the enrichment factor achieved. The relative standard deviation decreased from 22% with DSPE to 13% with DLLME. The usefulness of the DLLME-GC-MS methodology was tested by analysing 10 different samples of chicken, calf, hen, cow and fish feed. The concentrations of PDS were in the 0.1-1.7 µg g-1 range and those of PTSO were between 0.09 and 2.1 µg g-1.

Headspace Gas Chromatography Coupled to Mass Spectrometry and Ion Mobility Spectrometry: Classification of Virgin Olive Oils as a Study Case.

Due to its multiple advantages, ion mobility spectrometry (IMS) is being considered as a complementary technique to mass spectrometry (MS). The goal of this work is to investigate and compare the capacity of IMS and MS in the classification of olive oil according to its quality. For this purpose, two analytical methods based on headspace gas chromatography (HS-GC) coupled with MS or with IMS have been optimized and characterized for the determination of volatile organic compounds from olive oil samples. Both detectors were compared in terms of sensitivity and selectivity, demonstrating that complementary data were obtained and both detectors have proven to be complementary. MS and IMS showed similar selectivity (10 out of 38 compounds were detected by HS-GC-IMS, whereas twelve compounds were detected by HS-GC-MS). However, IMS presented slightly better sensitivity (Limits of quantification (LOQ) ranged between 0.08 and 0.8 µg g-1 for HS-GC-IMS, and between 0.2 and 2.1 µg g-1 for HS-GC-MS). Finally, the potential of both detectors coupled with HS-GC for classification of olive oil samples depending on its quality was investigated. In this case, similar results were obtained when using both HS-GC-MS and HS-GC-IMS equipment (85.71 % of samples of the external validation set were classified correctly (validation rate)) and, although both techniques were shown to be complementary, data fusion did not improve validation results (80.95% validation rate).

Determination of cadmium in used engine oil, gasoline and diesel by electrothermal atomic absorption spectrometry using magnetic ionic liquid-based dispersive liquid-liquid microextraction.

In this study, a sensitive and matrix-effect free analytical method for Cd determination in engine oils and fuel samples by dispersive liquid-liquid microextraction with electrothermal atomic absorption spectrometry has been successfully developed. The extractant solvent used for the microextraction procedure was a magnetic ionic liquid (MIL) (i.e., bis(1-ethyl-3-methylimidazolium) tetrathiocyanatocobaltate (II) [Emim]2[Co(SCN)4]), which presents a paramagnetic property, and allows an easy phase separation using a magnet. In order to eliminate the well-known drawbacks of direct introduction of MIL in the graphite furnace, a back-extraction procedure was performed to transfer the analyte into an aqueous phase. The main experimental factors affecting the extraction of Cd (i.e., amount of sample and MIL, extraction and back-extraction time and concentration and amount of nitric acid) were optimized using a multivariate analysis consisting in two steps: a Plackett-Burman design followed by a circumscribed central composite design. Under optimum conditions (i.e., amount of sample: 6.2 g; amount of MIL: 119 mg; extraction time: 1 min; amount of nitric acid: 200 mg; nitric acid concentration: 1 mol L-1 and back-extraction time: 1 min), the proposed analytical method was validated and successfully used to analyze three real-world samples (i.e., used engine oil, gasoline and diesel). The three samples were spiked at two levels (i.e., 10 and 20 µg kg-1 of Cd for used engine oil and 1 and 3 µg kg-1 of Cd for gasoline and diesel). RSD and recovery values were within the range of 6-11% and 95-110%, respectively.

Ion mobility spectrometry and mass spectrometry coupled to gas chromatography for analysis of microbial contaminated cosmetic creams.

The most commonly used technique for monitoring microbial contamination in cosmetic products is plate counting. In this contribution, headspace - gas chromatography (HS-GC) coupled to mass spectrometry (MS) or ion mobility spectrometry (IMS) is proposed as a technique to evaluate rapidly and accurately the state of microbial colonies in cosmetic creams using the volatile organic compounds produced by microorganisms (MVOC). The work focuses on monitoring two of the microorganisms that most frequently occur in such creams, Candida albicans and Staphylococcus aureus. In addition, two different types of ingredient with antimicrobial properties (a chemical preservative and a natural preservative) were added to study the behaviour of these microorganisms under different conditions. The facial creams were elaborated and inoculated with the two above microorganisms, and then sampled weekly for 4 weeks, analysing the evolution of the MVOCs by HS-GC-MS and HS-GC-IMS. In addition, microbial contamination was determined by the classical plate counting method. The pH, colour, viscosity and water activity parameters were also measured. The use of chemometric tools is essential because of the large amount of data generated, and different models based on discriminant analysis with an orthogonal projection on latent structures (OPLS-DA) were constructed. The optimal models obtained by both analytical techniques allowed differentiation between contaminated and non-contaminated creams, with a validation success rate of 94.4%. In addition, MVOC monitoring also allowed assessment of the microbial concentration.

Determination of amphenicol antibiotics and their glucuronide metabolites in urine samples using liquid chromatography with quadrupole time-of-flight mass spectrometry.

A rapid procedure for the determination of amphenicol antibiotics in human urine by liquid chromatography with quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) is proposed. The presence of thiamphenicol (TAP), florfenicol (FF) and chloramphenicol (CAP) in the human body can be attributed to their administration to treat certain diseases or by eating food of animal origin. The TAP, FF and CAP excreted in urine is mainly in the form of glucuronide conjugates, although their free forms may also be excreted to a lesser extent. In the procedure described, the enzymatic hydrolysis of amphenicol glucuronide forms in urine was carried out using ß-glucuronidase and sulfatase at pH 5 (37 °C, overnight) in order to discriminate the free and conjugated forms. Then, amphenicol antibiotics were submitted to dispersive liquid-liquid microextraction (DLLME) for preconcentration. All the parameters affecting DLLME efficiency were optimized, and the following conditions were selected: 0.9 g NaCl in 10 mL of urine, to which 1.2 mL methanol (as dispersant solvent) and 1 mL of 4-methyl-2-pentanone (as extractant solvent) were added. The absence of a matrix effect allowed quantification of the samples against aqueous standards. Detection limits were 29, 6 and 3 pg mL-1 for TAP, FF and CAP, respectively. Relative standard deviations were calculated to evaluate the intra- and inter-day precision and values lower than 10% were obtained in all cases. The trueness of the method was tested through recovery studies, obtaining satisfactory values (83-104%). Ten urine samples obtained from volunteers were analysed and all of them were free of the studied antibiotics.

Speciation of chromium in waters using dispersive micro-solid phase extraction with magnetic ferrite and graphite furnace atomic absorption spectrometry.

The combination of a solid-phase microextraction process with graphite furnace atomic absorption spectrometry provides a very sensitive determination method for determining chromium in waters. Freshly prepared ferrite particles are used to retain the chromium species, and then separated by a magnet without the need for a centrifugation step. The solid phase is suspended in water and directly introduced into the graphite furnace to obtain the analytical signal. The complexation of Cr(III) with ethylenediaminetetraacetate allows the selective retention of Cr(VI), and thus the speciation of the metal. The procedure is sensitive (0.01 µg L-1 detection limit when using a 10 mL sample aliquot) and reproducible (5% relative standard deviation for five consecutive experiments at the 0.3 µg L-1 level). The reliability of the procedure is verified by analysing five certified water samples.

Dual stir bar sorptive extraction coupled to thermal desorption-gas chromatography-mass spectrometry for the determination of endocrine disruptors in human tissues.

The validation of a procedure for the determination of six alkylphenols (APs), 4-tert-butylphenol, 4-pentylphenol, 4-tert-octylphenol, 4-hexylphenol, 4-octylphenol and 4-nonylphenol, and three bisphenols (BPs), bisphenol A, bisphenol F and bisphenol Z, in seven human organs and tissues (kidney, liver, heart, lung, spleen, brain and abdominal fat) obtained from eight autopsies is presented. Previously ground samples were treated by salt-assisted liquid-liquid extraction (SALLE) for isolation of the analytes and then pre-concentrated using dual stir bar sorptive extraction (SBSE), allowing two different extraction conditions for the same sample. Finally, thermal desorption was used as the injector system in combination with gas chromatography coupled to mass spectrometry (GC-MS). To determine BPs, derivatization using acetic anhydride was required, although this step was not necessary for the APs. Two parallel extractions of the contaminants with the stir bars were performed, followed by thermal desorption and chromatographic analysis. The procedure provided quantification limits between 0.050 and 4.0 ng g-1 for APs and from 0.26 to 2.6 ng g-1 for BPs. Repeatability and reproducibility values were lower than 15% in all cases. The accuracy of the procedure was established by a recovery study, which provided values in the 85.8-115% range for APs and 83.6-120% for BPs. Samples were analyzed with the proposed methodology and data were processed by ANOVA tests to study the behaviour and bioaccumulation of these compounds in human tissues or organs. In addition, discriminant analysis detected age- and sex-dependent differences in bioaccumulation.

An overview of microplastics characterization by thermal analysis.

Microplastics may be present in the environment as primary microplastics (manufactured) or secondary microplastics (result of the continuous degradation of larger plastic pieces into smaller fragments due to environmental, physicochemical and biotic factors). To fully understand the dynamics of microplastic particles and their environmental effects, harmonized, automated, cheap, rapid and reliable methodologies for sampling, extraction and characterization of microplastic need to be developed. This review focuses on the potential of thermal analytical techniques for microplastics characterization and highlights some of the new trends in this area.