Quality assessment of environmental water by a simple and fast non-ionic hydrophobic natural deep eutectic solvent-based extraction procedure combined with liquid chromatography tandem mass spectrometry for the determination of plastic migrants.

A non-ionic hydrophobic natural deep eutectic solvent (HNADES) based on thymol and menthol was proposed for the liquid-liquid microextraction of fourteen phthalates and one adipate from environmental water samples. Separation, identification, and quantification were achieved by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. The main factors affecting the extraction efficiency were thoroughly studied. Sample pH of 8 and 100 µL of thymol:menthol at molar ratio 2:1 were selected as the best conditions, while ionic strength and type of dispersant solvent were not relevant for the extraction of the target compounds. The whole methodology was validated for treated wastewater, runoff, and pond water matrices, using di-n-butyl phthalate-3,4,5,6-d4 and dihexyl phthalate-3,4,5,6-d4 as surrogates. Recovery ranged from 70 to 127% with relative standard deviation values lower than 14%. Limits of quantification of the method were in the range 0.042-0.425 µg/L for treated wastewater, 0.015-0.386 µg/L for runoff, and 0.013-0.376 µg/L for pond water. The methodology was applied for the analysis of real treated wastewater, runoff, and pond water samples from different places of Tenerife and Gran Canaria (Canary Islands) finding the presence of diethyl phthalate, diallyl phthalate, dipropyl phthalate, benzylbutyl phthalate, di-n-butyl phthalate, bis-(2-n-butoxyethyl) phthalate, di-n-pentyl phthalate, dicyclohexyl phthalate, and bis-(2-ethylhexyl) phthalate at concentrations between 105.2 and 3414 ng/L.

Application of a Liquid-Liquid Microextraction Method Based on a Natural Hydrophobic Deep Eutectic Solvent for the Extraction of Plastic Migrants from Kombuchas.

A vortex-assisted liquid-liquid microextraction, based on a natural hydrophobic deep eutectic solvent made from the monoterpene thymol and octanoic fatty acid, was employed for the analysis of 11 phthalate esters and one adipate in kombucha (a tea-based fermented beverage). Separation and determination were performed using an ultra-high performance liquid chromatography (UHPLC) system coupled to a single quadrupole mass spectrometer. Confirmatory analyses were carried out through UHPLC tandem mass spectrometry. The full method was validated in terms of matrix effect, matrix-matched calibration, sensitivity, recovery, limits of detection and quantification and repeatability. Satisfactory determination coefficients for quadratic calibration curves (≥0.9938), recovery values (67-120%) and limits of detection (0.07-5.45 µg/L) were obtained. Analysis of 26 kombucha samples reported concentrations for dibutyl phthalate and dimethyl phthalate in the range between the limit of quantification (LOQ) and 16.18 ± 1.14 µg/L, although these phthalates were also detected under the LOQ in some of the analyzed samples. Only one of the samples bottled in plastic containers (7) did not present residues while only five of the 19 samples in glass bottles contained any plasticizer. However, the highest concentration was found in a kombucha bottled in food-grade glass. This work represents the first application in which phthalates and adipates are analyzed in kombuchas.

Nano-liquid chromatography combined with a sustainable microextraction based on natural deep eutectic solvents for analysis of phthalate esters.

The separation of 11 phthalic acid ester (PAEs) was carried out by nano-liquid chromatography coupled to ultraviolet and MS detection. Preliminary experiments were achieved in order to select suitable stationary phases and chromatographic conditions. The baseline separation was obtained, for all compounds, with an XBridgeTM C18 column in less than 15 min, working in step gradient mode. The sensitivity of the method was improved by on-column focusing. PAEs were extracted from alcoholic and nonalcoholic beverages using vortex-assisted emulsification dispersive liquid-liquid microextration and natural deep eutectic solvents. The whole method was validated in terms of linearity, sensitivity, precision, recovery, and repeatability. Combination of both off-line sample preparation preconcentration and large injection volume led to obtain LOQs in the range 5-47 ng/mL. The developed nano-LC-UV method was extended to MS detection to confirm the presence of PAEs in some beverages commercialized in different types of packaging.

A simple, fast and easy methodology for the monitoring of plastic migrants in alcoholic and non-alcoholic beverages using the QuEChERS method prior to gas chromatography tandem mass spectrometry.

In this work, the development of a simple, fast and reliable method for the evaluation of a group of twelve plastic migrants in alcoholic and non-alcoholic beverages widely consumed by the population has been carried out. For that, a modified QuEChERS method for the extraction and preconcentration of the target compounds has been used prior to their separation and quantification by gas chromatography coupled to triple quadrupole tandem mass spectrometry. The whole methodology was validated for beer, cider and grape juice matrices, using dibutyl phthalate-3,4,5,6-d4 as surrogate. Recovery ranged from 75 to 120% for all matrices with relative standard deviation values lower than 20%, and the limits of quantification of the method were achieved in the range 0.034-1.415 µg/L. Finally, the analysis of different beer, cider and grape juice samples commercialised in different supermarkets of Tenerife was carried out, finding the presence of four of the evaluated phthalates in the range 0.14-1.1 µg/L in some of the evaluated beers, six of them in several cider samples, in the range 0.3-2.1 µg/L, and one in the range 1.2-1.5 µg/L in three of the analysed grape juices.

Quantum Information Remote Carnot Engines and Voltage Transformers.

A physical system out of thermal equilibrium is a resource for obtaining useful work when a heat bath at some temperature is available. Information Heat Engines are the devices which generalize the Szilard cylinders and make use of the celebrated Maxwell demons to this end. In this paper, we consider a thermo-chemical reservoir of electrons which can be exchanged for entropy and work. Qubits are used as messengers between electron reservoirs to implement long-range voltage transformers with neither electrical nor magnetic interactions between the primary and secondary circuits. When they are at different temperatures, the transformers work according to Carnot cycles. A generalization is carried out to consider an electrical network where quantum techniques can furnish additional security.

Twins Percolation for Qubit Losses in Topological Color Codes.

In this Letter, we establish and explore a new connection between quantum information theory and classical statistical mechanics by studying the problem of qubit losses in 2D topological color codes. We introduce a protocol to cope with qubit losses, which is based on the identification and removal of a twin qubit from the code, and which guarantees the recovery of a valid three-colorable and trivalent reconstructed color code. Moreover, we show that determining the corresponding qubit loss error threshold is equivalent to a new generalized classical percolation problem. We numerically compute the associated qubit loss thresholds for two families of 2D color code and find that with p=0.461±0.005 these are close to satisfying the fundamental limit of 50% as imposed by the no-cloning theorem. Our findings reveal a new connection between topological color codes and percolation theory, show high robustness of color codes against qubit loss, and are directly relevant for implementations of topological quantum error correction in various physical platforms.

Chiral Topological Superconductors Enhanced by Long-Range Interactions.

We study the phase diagram and edge states of a two-dimensional p-wave superconductor with long-range hopping and pairing amplitudes. New topological phases and quasiparticles different from the usual short-range model are obtained. When both hopping and pairing terms decay with the same exponent, one of the topological chiral phases with propagating Majorana edge states gets significantly enhanced by long-range couplings. On the other hand, when the long-range pairing amplitude decays more slowly than the hopping, we discover new topological phases where propagating Majorana fermions at each edge pair nonlocally and become gapped even in the thermodynamic limit. Remarkably, these nonlocal edge states are still robust, remain separated from the bulk, and are localized at both edges at the same time. The inclusion of long-range effects is potentially applicable to recent experiments with magnetic impurities and islands in 2D superconductors.

Multiresidue analysis of oestrogenic compounds in cow, goat, sheep and human milk using core-shell polydopamine coated magnetic nanoparticles as extraction sorbent in micro-dispersive solid-phase extraction followed by ultra-high-performance liquid chromatography tandem mass spectrometry.

In this work, the suitability of Fe3O4 nanoparticles coated with polydopamine was evaluated as sorbent for the extraction of a group of 21 compounds with oestrogenic activity including seven phytoestrogens, six mycotoxins as well as four synthetic and four natural oestrogens from different types of milk, including sheep milk, in which the evaluation of oestrogenic compounds have never been developed before. Extraction was carried out using magnetic micro-dispersive solid-phase extraction after a previous deproteinisation step. Separation, determination and quantification of the target analytes were achieved by ultra-high-performance liquid chromatography coupled to triple quadrupole-tandem mass spectrometry. The methodology was validated for five milk samples using 17ß-estradiol-2,4,16,16,17-d5 as internal standard for natural and synthetic oestrogens, ß-zearalanol-10,10,11,12,12-d5 for mycotoxins and prunetin for phytoestrogens. Recovery values ranged from 70 to 120% for the five types of matrices with relative standard deviation values lower than 18%. Limits of quantification of the method were in the range 0.55-11.8 µg L-1 for all samples. Graphical abstract General scheme of the multiresidue analysis of oestrogenic compounds in milk using core-shell polydopamine coated magnetic nanoparticles as extraction sorbent in µ-dSPE.

Determination of phthalates in beverages using multiwalled carbon nanotubes dispersive solid-phase extraction before HPLC-MS.

A microdispersive solid-phase extraction method has been developed using multiwalled carbon nanotubes of 110-170 nm diameter and 5-9 µm length for the extraction of a group of nine phthalic acid esters (i.e., bis(2-methoxyethyl) phthalate, bis-2-ethoxyethyl phthalate, dipropyl phthalate, butylbenzyl phthalate, bis-2-n-butoxyethyl phthalate, bis-isopentyl phthalate, bis-n-pentyl phthalate, dicyclohexyl phthalate, and di-n-octyl phthalate) from tap water as well as from different beverages commercialized in plastic bottles (mineral water, lemon- and apple-flavored mineral water, and an isotonic drink). Determination was carried out by high-performance liquid chromatography coupled to mass spectrometry. The extraction procedure was optimized following a step-by-step approach, being the optimum extraction conditions: 50 mL of each sample at pH 6.0, 80 mg of sorbent, and 25 mL of acetonitrile as elution solvent. To validate the methodology, matrix-matched calibration and a recovery study were developed, obtaining determination coefficients >0.9906 and absolute recovery values between 70 and 117% (with relative standard deviations < 17%) in all cases. The limits of quantification of the method were between 0.173 and 1.45 µg/L. After the evaluation of the matrix effects, real samples were also analyzed, finding butylbenzyl phthalate in all samples (except in apple-flavored mineral water), though at concentrations below its limit of quantification of the method.

A PUF- and Biometric-Based Lightweight Hardware Solution to Increase Security at Sensor Nodes.

Security is essential in sensor nodes which acquire and transmit sensitive data. However, the constraints of processing, memory and power consumption are very high in these nodes. Cryptographic algorithms based on symmetric key are very suitable for them. The drawback is that secure storage of secret keys is required. In this work, a low-cost solution is presented to obfuscate secret keys with Physically Unclonable Functions (PUFs), which exploit the hardware identity of the node. In addition, a lightweight fingerprint recognition solution is proposed, which can be implemented in low-cost sensor nodes. Since biometric data of individuals are sensitive, they are also obfuscated with PUFs. Both solutions allow authenticating the origin of the sensed data with a proposed dual-factor authentication protocol. One factor is the unique physical identity of the trusted sensor node that measures them. The other factor is the physical presence of the legitimate individual in charge of authorizing their transmission. Experimental results are included to prove how the proposed PUF-based solution can be implemented with the SRAMs of commercial Bluetooth Low Energy (BLE) chips which belong to the communication module of the sensor node. Implementation results show how the proposed fingerprint recognition based on the novel texture-based feature named QFingerMap16 (QFM) can be implemented fully inside a low-cost sensor node. Robustness, security and privacy issues at the proposed sensor nodes are discussed and analyzed with experimental results from PUFs and fingerprints taken from public and standard databases.

Multiclass analytical method for the determination of natural/synthetic steroid hormones, phytoestrogens, and mycoestrogens in milk and yogurt.

Within this study, a new method enabling monitoring of various estrogenic substances potentially occurring in milk and dairy products was proposed. Groups of compounds fairly differing in physico-chemical properties and biological activity were analyzed: four natural estrogens, four synthetic estrogens, five mycoestrogens, and nine phytoestrogens. Since they may pass into milk mainly in glucuronated and sulfated forms, an enzymatic hydrolysis was involved prior to the extraction based on the QuEChERS methodology. For the purification of the organic extract, a dispersive solid-phase extraction (d-SPE) with sorbent C18 was applied. The final analysis was performed by ultra-high-performance liquid chromatography (UHPLC) coupled with triple quadrupole tandem mass spectrometry (MS/MS). Method recovery ranged from 70 to 120% with a relative standard deviation (RSD) value lower than 20% and limits of quantification (LOQs) in the range of 0.02-0.60 µg/L (0.2-6.0 µg/kg dry weight) and 0.02-0.90 µg/kg (0.2-6.0 µg/kg dry weight) for milk and yogurt, respectively. The new procedure was applied for the investigation of estrogenic compounds in 11 milk samples and 13 yogurt samples from a Czech retail market. Mainly phytoestrogens were found in the studied samples. The most abundant compounds were equol and enterolactone representing 40-90% of all estrogens. The total content of phytoestrogens (free and bound) was in the range of 149-3870 µg/kg dry weight. This amount is approximately 20 times higher compared to non-bound estrogens.

Application of multiwalled carbon nanotubes as sorbents for the extraction of mycotoxins in water samples and infant milk formula prior to high performance liquid chromatography mass spectrometry analysis.

In this work, a simple and environmental friendly methodology has been developed for the analysis of a group of six mycotoxins with estrogenic activity produced by Fusarium species (i.e. zearalanone, zearalenone, α-zearalanol, ß-zearalanol, α-zearalenol, and ß-zearalenol), using microdispersive SPE the symbol micro should de before dSPE with multiwalled carbon nanotubes as sorbent. Separation, determination, and quantification were achieved by HPLC coupled to ion trap MS with an ESI interface. Parameters affecting the extraction efficiency of µ-dSPE such as pH of the sample, amount of multiwalled carbon nanotubes, and type and volume of elution solvent, were studied and optimized. The methodology was validated for mineral, pond, and wastewater as well as for powdered infant milk using 17ß-estradiol-2,4,16,16,17-d5 (17ß-E2 -D5 ) as internal standard, obtaining recoveries ranging from 85 to 120% for the three types of water samples and from 77 to 115% for powdered infant milk. RSD values were lower than 10%. The LOQs achieved were in the range 0.05-2.90 µg/L for water samples and 2.02-31.9 µg/L for powdered infant milk samples.

Capillary electrochromatography and nano-liquid chromatography coupled to nano-electrospray ionization interface for the separation and identification of estrogenic compounds.

Nano-LC and CEC were coupled to MS through a nanospray or a pressurized liquid-junction interface for the simultaneous separation and determination of 11 estrogenic compounds. Different stationary phases, that is, phenyl, C18, and C18 bidentate silica hydrate, were studied. For both techniques, the phenyl stationary phase was the best option, considering separation efficiency, selectivity, and resolution. Under the optimized conditions, the baseline separation of the target compounds (including estradiol and zearalanol epimers) was achieved in less than 20 min in nano-LC-MS and less than 13 min in CEC-MS. Molecular imprinted polymer SPE was used for extracting the target compounds from mineral water samples with the analysis of nano-LC-MS. The whole molecular imprinted polymer SPE nano-LC-MS method was validated through a recovery study at two levels of concentration. Sensitivity was improved by on-column focusing technique obtaining LODs in the range 1.4-55.4 ng/L.

Determination of estrogenic compounds in milk and yogurt samples by hollow-fibre liquid-phase microextraction-gas chromatography-triple quadrupole mass spectrometry.

An environmentally friendly method based on hollow-fibre liquid-phase microextraction (HF-LPME) was developed for the extraction of selected estrogenic compounds (i.e. four natural sexual hormones: estrone, 17ß-estradiol, 17α-estradiol and estriol; two exoestrogens: 17α-ethynylestradiol and 2-methoxyestradiol; two synthetic stilbenes: dienestrol and hexestrol; and five resorcylic acid lactones: zearalenone, α-zearalanol, ß-zearalanol, α-zearalenol and ß-zearalenol), from whole cow and semi-skimmed goat milk and whole natural yogurt. After the optimization of the sample preparation procedure, spiked extracts were derivatized to their trimethylsilyl products using N,O-bis(trimethylsilyl)trifluoroacetamide reagent and then analyzed by gas chromatography-tandem mass spectrometry (GC-MS/MS). Once optimum extraction conditions were established (protein precipitation with acetonitrile, extraction and the back-extraction in acetonitrile following the HF-LPME procedure), the method was validated and the calibration range, precision and accuracy were studied. The RSD values for the intra- and inter-day precision of the peak areas were in the range 0.65-9.69 and 1.00-11.47 %, respectively. The determination coefficients were higher than 0.991 for method calibration curves while LOD and LOQ values were between 0.06-2.55 and 0.16-6.11 µg/L for whole cow milk, 0.04-1.70 and 0.11-4.86 µg/L for semi-skimmed goat milk and 0.07-3.73 and 0.23-9.81 µg/L for natural yogurt, respectively. Finally, the accuracy and precision of the method were evaluated, obtaining a value in the range 84 81-119 % and RSD values lower than 20 % in all cases.

Speciation, behaviour, and fate of mercury under oxy-fuel combustion conditions.

The work presented here reports the first study in which the speciation, behaviour and fate of mercury (Hg) have been evaluated under oxy-fuel combustion at the largest oxy-Pulverised Coal Combustion (oxy-PCC) demonstration plant to date during routine operating conditions and partial exhaust flue gas re-circulation to the boiler. The effect of the CO2-rich flue gas re-circulation on Hg has also been evaluated. Results reveal that oxy-PCC operational conditions play a significant role on Hg partitioning and fate because of the continuous CO2-rich flue gas re-circulations to the boiler. Mercury escapes from the cyclone in a gaseous form as Hg(2+) (68%) and it is the prevalent form in the CO2-rich exhaust flue gas (99%) with lower proportions of Hg(0) (1.3%). The overall retention rate for gaseous Hg is around 12%; Hg(0) is more prone to be retained (95%) while Hg(2+) shows a negative efficiency capture for the whole installation. The negative Hg(2+) capture efficiencies are due to the continuous CO2-rich exhaust flue gas recirculation to the boiler with enhanced Hg contents. Calculations revealed that 44mg of Hg were re-circulated to the boiler as a result of 2183 re-circulations of CO2-rich flue gas. Especial attention must be paid to the role of the CO2-rich exhaust flue gas re-circulation to the boiler on the Hg enrichment in Fly Ashes (FAs).

Evaluation of the combination of a dispersive liquid-liquid microextraction method with micellar electrokinetic chromatography coupled to mass spectrometry for the determination of estrogenic compounds in milk and yogurt.

In this work, the suitability of a methodology based on dispersive liquid-liquid microextraction (DLLME) has been evaluated for the extraction of four endoestrogens (estriol, 17α-estradiol, 17ß-estradiol, and estrone), an exoestrogen (17α-etynylestradiol), and a mycotoxin (zearalenone), together with some of their major metabolites (2-methoxyestradiol, α-zearalanol, ß-zearalanol, α-zearalenol, and ß-zearalenol) from different types of milk (whole and skimmed cow milk and semiskimmed goat milk) and whole natural yogurt. The methodology includes a previous protein precipitation with acidified ACN and a defatting step with n-hexane. Separation of the analytes, determination, and quantification were developed by MEKC coupled to ESI-MS using a BGE containing an aqueous solution of ammonium perfluorooctanoate as MS friendly surfactant. Calibration, precision, and accuracy studies of the described DLLME-MEKC-MS/MS method were evaluated obtaining a good linearity and LODs in the low micrograms per liter range.

Evaluation of two molecularly imprinted polymers for the solid-phase extraction of natural, synthetic and mycoestrogens from environmental water samples before liquid chromatography with mass spectrometry.

In this work, we have compared the selectivity of two commercial molecularly imprinted polymers (AFFINIMIP®SPE Estrogens and AFFINIMIP®SPE Zearalenone) for the extraction of 12 estrogenic compounds of interest (i.e. 17α-estradiol, 17ß-estradiol, estrone, hexestrol, 17α-ethynylestradiol, diethylstibestrol, dienestrol, zearalenone, α-zearalanol, ß-zearalanol, α-zearalenol and ß-zearalenol) from different water samples. High-performance liquid chromatography coupled with ion trap mass spectrometry with electrospray ionization was used for their determination. Results showed that although both molecularly imprinted polymeric cartridges were specifically designed for different groups of analytes (natural estrogens like estradiol in the first case and zearalenone derivatives in the second) they nearly have the same extraction performance (with recovery values in the range 65-101%) for the same analytes in Milli-Q water because of the cross-reactivity of the polymer. However, when more complex water samples were analyzed, it was clear that the behavior was different and that the AFFINIMIP®SPE Estrogens showed less cross-reactivity than the other cartridge. Validation of the proposed methodology with both cartridges revealed that the extraction was reproducible and that the final limits of detection of the proposed method were in the low ng/L range.

Determination of estrogens in environmental water samples using 1,3-dipentylimidazolium hexafluorophosphate ionic liquid as extraction solvent in dispersive liquid-liquid microextraction.

In this work, the potential of a symmetric dialkyl-substituted ionic liquid (IL), 1,3-dipenthylimidazolium hexafluorophosphate ([PPIm][PF6 ]), as extraction solvent in dispersive liquid-liquid microextraction (DLLME) has been studied for the analysis of a group of three natural (estriol, 17ß-estradiol, and 17α-estradiol) and four synthetic (17α-ethynylestradiol, diethylstibestrol, dienestrol, and hexestrol) estrogenic compounds as well as one mycotoxin with estrogenic activity (zearalenone) in different types of water samples (Milli-Q, mineral, and wastewater). Separation, determination, and quantification were developed by HPLC-DAD and a fluorescence detector (FD) connected in series. Factors influencing the IL-DLLME procedure (sample pH, amount of IL, type and volume of disperser solvent, ionic strength, and assistance of vortex agitation) were investigated and optimized by means of a step-by-step approach. Once the optimum extraction conditions were established (10 mL of water at pH 8, 60 mg of [PPIm][PF6 ], 500 µL of ACN as disperser solvent and vortex agitation for 1 min), the calibration curves of the whole method (IL-DLLME-HPLC-DAD/FD) were obtained and precision and accuracy were evaluated. It was demonstrated that the developed methodology was repeatable, accurate, and selective with limits of detection in the 0.30-0.57 µg/L and 13.8-37.1 µg/L range for FD and DAD, respectively. Relative recovery values were higher than 85% for the different types of water samples and the Student's t test demonstrated that there were not significant differences between the added and the found concentration.

Analysis of pesticides residues in environmental water samples using multiwalled carbon nanotubes dispersive solid-phase extraction.

In this manuscript, a dispersive SPE method based on the use of multiwalled carbon nanotubes has been developed for the determination of 15 organophosphorus pesticides residues including some of their metabolites (disulfoton sulfoxide, ethoprophos, cadusafos, dimethoate, terbufos, disulfoton, chlorpyrifos-methyl, malaoxon, fenitrothion, pirimiphos-methyl, malathion, chlorpyrifos, terbufos sulfone, disulfoton sulfone, and fensulfothion) from real environmental waters (run-off, mineral and tap water) by GC with nitrogen phosphorus detection. Factors that affect the enrichment efficiency such as sample volume, multiwalled carbon nanotubes amount, and volume of eluent were studied. The optimized method was validated in terms of matrix-matched calibration, recovery, precision, and accuracy for the three analyzed samples. In this last case, the developed Student's t test demonstrated that there were no significant differences between real and spiked concentrations. Optimum dispersive SPE conditions (extraction of 200 mL of water, pH 6.0, with 130 mg of multiwalled carbon nanotubes, elution with 25 mL of dichloromethane for run-off and tap water and 30 mL for mineral water) allowed the quantitative extraction of analytes at levels lower than the maximum residues limits legislated by the European Union, with LODs between 1.16 and 93.6 ng/L. Absolute recovery values achieved were in the range of 67-107% (RSD values <10.1%).

Assessment of pesticide residues contamination in cereals and pseudo-cereals marketed in the Canary Islands.

In this work, the development of an analytical method for the evaluation of a wide variety of pesticide residues in cereals and pseudo-cereals widely consumed has been carried out. A QuEChERS method was used as extraction and clean-up procedure prior to separation and quantification of the target analytes by ultra-high performance liquid chromatography coupled to mass spectrometry using a single quadrupole-time-of-flight analyser. The methodology was validated for oat, rye, spelt, barley and quinoa matrices, following the European Commission guidelines (SANTE/11312/2021), achieving good absolute recovery values in the range 60-124% with relative standard deviation values lower than 20% and providing limits of quantification of the method in the low mg/kg range, in accordance with the maximum residue limits established by European policies. Finally, considering the importance of cereals in general population diet, the analysis of 60 samples was carried out in order to assure their safe consumption.