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A simple method to determine hazardous silver nanoparticles (AgNPs) based on ionic liquid (IL) dispersive liquid-liquid microextraction and back-extraction is described. This approach involves AgNP stabilization using a cationic surfactant followed by extraction from the sample matrix by means of an IL as an extraction phase. Certain ILs have high affinity for metals, and preliminary experiments showed that those ILs consisting of imidazolium cation efficiently extracted AgNPs in the presence of a cationic surfactant and a chelating agent. Afterward, histamine was used as a dispersing agent to promote phase transfer of differently coated AgNPs from the IL in aqueous solution to be subsequently analyzed by UV-visible spectrometry. The analytical procedure allows AgNPs to be recovered from the sample matrix in an aqueous medium, the enrichment factor being up to 4, preserving both AgNP size and AgNP shape as demonstrated by transmission electron microscopy images and the localized surface plasmon resonance band characteristic of each AgNP. The present method exhibited a linear response for AgNPs in the range from 3 to 20 μg/mL, the limit of detection being 0.15 μg/mL. Method efficiency was assessed in spiked orange juice and face cream, yielding recoveries ranging from 75.7% to 96.6%. The method was evaluated in the presence of other nanointerferents (namely, gold nanoparticles). On the basis of diverse electrophoretic mobilities and surface plasmon resonance bands for metal nanoparticles, capillary electrophoresis was used to prove the lack of interaction of the target AgNPs with gold nanoparticles during the whole protocol; thus, interferents do not affect AgNP determination. As a consequence, the analytical approach described has great potential for the analysis of engineered nanosilver in consumer products. Graphical abstract Simple protocol for the determination of silver nanoparticles (AgNPs) based on dispersive liquid-liquid extraction with a specific short alkyl side chain ionic liquid and their quantitative detection with a UV-visible spectrometer. HMIM•PF

There is an urgent need to assure the quality of the results provided by rapid, simple and direct analytical processes, ordinary not involving sample preparation steps. These analytical systems, sometimes called “tests methods”, which are of increasing importance in the production of data, information and knowledge, are outlined here. To support this goal, an analytical property named “reliability”, non-systematically used, is fully defined here by emphasizing its summative character of the other analytical properties, as well as by exploiting the fact that its meaning is well understood by the society. After describing the principal bottle-necks of analytical chemistry, the relationships between clients and analysts, as well as the types of analytical results are discussed. In the second part, the basic definition allows to show the variety of meanings of it. Then, analytical reliability is fully described by showing the application the adjective reliable in this context, as well as the way that it can express almost homogeneous reliability of test methods providing different analytical results. These aspects are proposed and discussed in this review.

Embargado hasta 30/11/2023 The term “innovation” is core to modern science and society with respect to novelty, creation and added value, yet it is also a source of misunderstandings. We aim herein at the clarification of the different approaches to innovation by establishing three general types: background, basic and applied innovations. The relation between the three concepts is also established. The exclusive relationship between innovation and market is put into question. The contradictory conceptions of innovation are also accompanied by complementary connotations that can enrich one to other. Finally, a transversal proposal to deal with “innovation” in different environments is presented.

Resumen: Después de una contextualización en los marcos genéricos de la nanotecnología y la nanomedicina, se exponen las 2 connotaciones nanotecnológicas de la Nefrología. La potencial faceta negativa de la nanonefrología es el aclaramiento renal de las nanopartículas usadas con fines nanomédicos o ingeridas en los nanoalimentos, cada vez más abundantes. El impacto positivo de la nanotecnología en la Nefrología se centra en el desarrollo de nanodiagnósticos renales para estudios básicos de la función renal, diagnóstico precoz del fallo renal agudo, seguimiento fiable y simple de la enfermedad renal crónica o la mejora de las imágenes de resonancia magnética nuclear. Las nanoterapias renales con fármacos es un tema de importancia que tiene 2 connotaciones: la protección de fármacos y agentes nefrotóxicos (ej. antibióticos, retrovirales, medios de contraste, etc.) y el desarrollo de nuevos medicamentos para enfermedades renales. La nanoteragnosis renal es una línea prometedora poco desarrollada. Se explicita también el impacto de los soportes nanoestructurados en la regeneración tisular renal. El artículo finaliza con un breve análisis de las perspectivas de la nanonefrología. Abstract: After contextualising the generic frameworks of nanotechnology and nanomedicine, the 2 disciplines are discussed in the field of Nephrology. The potential downside to nanonephrology is the renal clearance of nanoparticles, the use of which is ever-increasing both for nanomedicinal purposes and in nanofoods. The positive impact of nanotechnology in Nephrology is centred on the development of renal nanodiagnostics for basic renal function studies, the early diagnosis of acute kidney injury, reliable and simple follow-up of chronic kidney disease and the improvement of magnetic resonance imaging. Renal drug nanotherapies comprise an important and dual-faceted area: The protection of drugs and nephrotoxic agents (e.g. antibiotics, antiretrovirals, contrast media, etc.) on the one hand, and the development of new kidney disease medications on the other. Renal ‘nanotheranostics’ is a promising but little-studied area. The impact of nanostructured supports on renal tissue regeneration is also discussed. The article concludes with a brief analysis of the various nanonephrology perspectives. Palabras clave: Nanotecnología, Nanomedicina, Nefrología, Aclaramiento renal, Nanodiagnósticos renales, Nanofármacos renales, Nanotecnologías de reemplazo renal, Nanorregeneración de tejido renal, Keywords: Nanotechnology, Nanomedicine, Nephrology, Renal clearance, Renal nanodiagnostics, Renal nanodrugs, Renal replacement nanotechnologies, Renal tissue nanoregeneration

Scientific Research (SciRes) can and should be a platform for mankind?s progress by tackling previously unsolved problems and new ones arising each day. However, for SciRes to succeed in this role, it must be properly aimed. This paper presents a systematic analysis of the diverging crossroads SciRes has reached, discusses the right way to go at each in order to pursue quality and examines the implications of taking the wrong way in each case. The most critical crossroads or dilemmas for SciRes at present demand choosing between true or only apparent innovation; publication or usefulness; opacity or transparency; isolation or interdisciplinarity; social responsibility or no social commitment and proper or spurious assessment of research. The paper ends with a summative discussion of the right and wrong ways that can be taken at SciRes crossroads now and in the future.

Increasing number of engineering nanoparticles (NPs) in consumer products is unstoppable even after the toxic effect of metallic-based nanomaterials stated more than a decade ago; thus, selective methods for detecting metallic NPs are highly demanded and of great importance. A simple and rapid approach for detecting gold NPs (AuNPs) using ecofriendly sulfonated nanocellulose (s-NC) as sorbent material is described. The interaction between s-NC and AuNP is based on the affinity of sulfur atoms towards metals. We found that the use of cationic surfactant substantially benefitted the extraction and preconcentration of AuNPs by virtue of the NP stabilization. Good linear correlations were found in a concentration range spanned from 7 to 20 μg/mL with a detection limit of 0.26 μg/mL. Furthermore, the proposed method was successfully applied to detect AuNPs in presence of other nanowastes, opening new opportunities of creating functional materials to collect and store nanoobjects for further uses. Further experiments are directed for reaching a generalized method towards the analysis of a bigger variety of NPs covering the trending topic third facet of the analytical nanoscience and nanotechnology.

The main aim of this paper is to offer an objective and critical overview of the situation and trends in Analytical Nanoscience and Nanotechnology (AN&N), which is an important break point in the evolution of Analytical Chemistry in the XXI century as they were computers and instruments in the second half of XX century. The first part of this overview is devoted to provide a general approach to AN&N by describing the state of the art of this recent topic, being the importance of it also emphasized. Secondly, particular but very relevant trends in this topic are outlined: the analysis of the nanoworld, the so "third way" in AN&N, the growing importance of bioanalysis, the evaluation of both nanosensors and nanosorbents, the impact of AN&N in bioimaging and in nanotoxicological studies, as well as the crucial importance of reliability of the nanotechnological processes and results for solving real analytical problems in the frame of Social Responsibility (SR) of science and technology. Several reflections are included at the end of this overview written as a bird's eye view, which is not an easy task for experts in AN&N.

A novel low-cost fluorimetric platform based on sulfur, nitrogen-codoped graphene quantum dots immersed into nanocellulosic hydrogels is designed and applied in detecting the laccase enzyme. Although most of methods for detecting laccase are based on their catalytic activity, which is strongly dependent on environmental parameters, we report a sensitive and selective method based on the fluorescence response of hydrogels containing graphene quantum dots (GQDs) acting as luminophore towards laccase. The easily-prepared gel matrix not only improves the fluorescence signal of GQDs by avoiding their self-quenching but also stabilizes their fluorescence signal and improves their sensitivity towards laccase. Noncovalent interactions between the sensor and the analyte are believed to be causing this significant quenching without peak-shifts of GQD fluorescence via energy transfer. The selective extraction of laccase was proved in different shampoos as complex matrices achieving a detection limit of 0.048 U mL−1 and recoveries of 86.2–94.1%. As the unusual properties of nanocellulose and GQDs, the fluorescent sensor is simple, eco-friendly and cost-efficient. This straightforward strategy is able to detect and stabilize laccase, being an added-value for storage and recycling enzymes.

This article presents a novel unit that integrates for the first time air sampling and preconcentration based on the use of fabric phase sorptive extraction principles. The determination of Tuta absoluta sexual pheromone traces in environmental air has been selected as analytical problem. For this aim, a novel laboratory-built unit made up of commercial brass elements as holder of the sol-gel coated fabric extracting phase has been designed and optimized. The performance of the integrated unit was evaluated analyzing environmental air sampled in tomato crops. The unit can work under sampling and analysis mode which eliminates any need for sorptive phase manipulation prior to instrumental analysis. In the sampling mode, the unit can be connected to a sampling pump to pass the air through the sorptive phase at a controlled flow-rate. In the analysis mode, it is placed in the gas chromatograph autosampler without any instrumental modification. It also diminishes the risk of cross contamination between sampling and analysis. The performance of the new unit has been evaluated using the main components of the sexual pheromone of Tuta absoluta [(3E,8Z,11Z)-tetradecatrien-1-yl acetate and (3E,8Z)-tetradecadien-1-yl acetate] as model analytes. The limits of detection for both compounds resulted to be 1.6 μg and 0.8 μg, respectively, while the precision (expressed as relative standard deviation) was better than 3.7%. Finally, the unit has been deployed in the field to analyze a number of real life samples, some of them were found positive.

In this paper, we report a simple, rapid and reproducible sensing approach for determination of fenoxycarb pesticide in river water based on the combined use of nitrogen-doped graphene quantum dots (N-GQDs) and acetylcholinesterase (AChE) enzyme as biorecognition element. Nanoparticles were used as fluorescent probes, while AChE was employed for inhibitor screening. The enzyme-generated products quenched the native fluorescence of N-GQDs. When fenoxycarb was introduced into the assay solution, the activity of AChE to convert substrate into products resulted to be reduced and consequently, N-GQD fluorescence was recovered gradually in an inhibitor concentration-dependent manner. Preliminary studies showed that nanoparticles were not directly sensitive to fenoxycarb, however, the inclusion of an enzymatic system in solution allowed for successful determination of pesticide in aqueous samples. Under optimized conditions, fenoxycarb concentrations ranging from 6 to 70 μM exhibited an excellent linear relationship with the inhibition efficiency percentage (R2 = 0.9941). The proposed biosensor has a limit of detection (LOD) of 3.15 μM, and excellent reproducibility values (RSD

The paper reports on a method for the detection of nanocellulose (NC) in consumer products by making use of a combination of (a) liquid-liquid extraction with an ionic liquid, and (b) size characterization by asymmetric flow field-flow fractionation (AF4) coupled to multi-angle light scattering (MALS) and refractive index (RI) detection. Both AF4 and MALS are viable tools for characterizing the size of the nanofibers. Sample preparation is easy, and the extraction efficiency of the method is 80.9 ± 1.8% (n = 5). It was applied to the detection of NC in toothpaste and coconut foodstuff to verify the practicability of the method.

In the run-up to Nanoscience and Nanotechnology (N&N), researchers have investigated and applied a wide variety of nanomaterials (e.g. from carbon nanotubes to graphene) with spectacular properties that overwhelmed the conventional materials. Far from most of nanoparticles (NPs) studied since the last decade like graphene, nanocellulose (NC) has been recently considered as one of the renewable materials that will revolutionize the future, as virtue of its powerful properties, biocompatibility, low toxicity and low production costs from natural resources. The main purpose of this paper is to compile the recent achievements of NC in analytical chemistry and other areas such as medicine. NC can play different roles in analytical processes. On the one hand, a first approximation consists of the consideration of NC as target analyte in real samples where it is added to improve some properties. On the other hand, a variety of methods in which NC acted as an efficient tool to improve the analytical processes is summarized, taking into account their use as sorbent, as separation media or as sensor. Within this thematic, some examples of great relevance related to sorbents and sensing platforms based on NC for the determination of other nanoobjects are thoroughly outlined, which belong to the new trending topic known as the Third way of Analytical Nanoscience and Nanotechnology (AN&N). Along this overview, emerging advances based on NC are further outlined for opening new research lines for such atypical eco-friendly functional nanoparticle.

Comprehensive research on toxicological effects of nanoparticles is of vital importance owing to their increasing manufacturing and use. This review outlines critical aspects in nanotoxicity assessment, from the primordial characterization of physicochemical properties of nanoparticles, to the most important analytical strategies/techniques for elucidating their biological behaviour at cellular and organismal levels.

A novel hybrid micro and meso porous silica monolith with embedded carbon nanoparticles (Si-CNPs monolith) was prepared inside a fused silica capillary (3cm in length) and used as a sorbent for solid-phase microextraction. The hybrid monolithic capillary was synthetized by hydrolysis and polycondensation of a mixture of tetraethoxysilane (TEOS), ethanol, and three different carbon nanoparticles such as carboxylated single-walled carbon nanotubes (c-SWCNTs), carboxylated multi-walled carbon nanotubes (c-MWCNTs), and oxidized single-walled carbon nanohorns (o-SWNHs) via a two-step catalytic sol-gel process. Compared with silica monolith without carbon nanoparticles, the developed monolithic capillary column exhibited a higher extraction efficiency towards the analytes which can be ascribed to the presence of the carbon nanoparticles. In this regard, the best performance was achieved for silica monolith with embedded c-MWCNTs. The resulted monolithic capillaries were also characterized by scanning electron microscopy (SEM), elemental analysis and nitrogen intrusion porosimetry. Variables affecting to the preparation of the sorbent phase including three different carbon nanoparticles and extraction parameters were studied in depth using polycyclic aromatic hydrocarbons (PAHs) as target analytes. Gas chromatography-mass spectrometry was selected as instrumental technique. Detection limits range from 0.1 to 0.3μgL-1, and the inter-extraction units precision (expressed as relative standard deviation) is between 5.9 and 14.4%.

The subject matter of this article is the use of nanomaterials as tools (i.e. sorbents in microextraction techniques, optical sensors, vibrational spectroscopies, etc.) for the characterization and/or determination of nanoanalytes (analysis of the nanoworld). The so-called Third Way is the combination of the two classical approaches of analytical nanoscience and nanotechnology (AN&N), namely, the use of nanotools and determination of nanoanalytes, looking for synergies between the two nanoparticles involved in the same analytical process. After an overview of AN&N, the definition, the objectives, and the types of Third Way processes in AN&N are outlined. Moreover, examples of analytical methodologies involving the use of nanotools (i.e. sorbents in (micro)extraction techniques) for the determination of nanomaterials involving different analytical techniques (i.e. optical sensors and vibrational spectroscopies) are systematically presented. Last but not least, a critical approach to the future of these analytical nanotechnological mixed processes is discussed. Keywords: analytical chemistry; nanoscience; nanotechnology; nanotool; nanoanalyte; Third Way

Bactrocera oleae Gmelin, also known as olive fruit fly, is the main olive tree pest. It produces a severe effect not only on the productivity but also on the quality of the olive-related products. In fact, the oil obtained from infected olives has a lower antioxidant power. In addition, an increase of the oil acidity, peroxide index and UV-absorbance can also be observed. 1,7-dioxaspiro-[5,5]-undecane (DSU), is the main component of the sexual pheromone of this pest and may be used as marker of the pest incidence. In this context, the development of new methods able to detect the pheromones in several samples, including agri-food or environmental ones, is interesting. In this work, we synthesized a molecularly imprinted polymer (MIPS) layer over magnetic nanoparticles (Fe3O4@SiO2@MIP) for the selective recognition of DSU. They were prepared using DSU as template and 3-aminopropyltriethoxysilane (APTES) to associate the target analyte on the surface of the magnetic substrate and the later polymerization of ethylene glycol dimethacrylate (EGDMA) in presence of 2,2-azobisisobutyonnitrile (AIBN). The resulting Fe3O4@SiO2@MIP composite was characterized by different techniques. The maximum adsorption capacity of DSU on Fe3O4@SiO2@MIP in hexane was 32mg/g (5.3 times than that obtained for the non-imprinted composite). In addition, Fe3O4@SiO2@MIP showed a short equilibrium time (45min) and potential reusability. The combination of dispersive magnetic microsolid phase extraction and gas chromatography with mass spectrometric detection allows the determination of DSU in real samples at concentrations as low as 10μg/L with precision better than 7.5% (expressed as relative standard deviation). The relative recoveries are in the range between 95 and 99%, which indicates the potential of the methodology. Finally, it has been applied to real olive oil samples being the presence of the pest detected is some of them.

Novel highly luminescent gels based on carboxylated nanocellulose as gelator and Ru(bpy)2(a-bpy)](PF6)2 as the luminophore and sensitizer is reported. The resulting gel exhibits a significant enhancement of its photoluminescence (PL) as well as a strong sensing response towards silver nanoparticles (AgNPs). The electrostatically interaction of the cationic amine groups of the luminophore and the carboxylic anions of the gelator can greatly amplify the sensing signal and specificity towards AgNPs. A simple procedure to determine AgNPs in a wide variety of matrices is developed, with a broad response range of 1.85 × 10−5 to 1.48 × 10−4 mol l−1 and detection limit (LOD) of 1.11 × 10−5 mol l−1. The proposed analytical method was successfully applied in deodorant and socks with antimicrobial activity. It is worthy to mention that the proposed methodology belongs to the “Third Way” of Analytical Nanoscience and Nanotechnology (AN&N).

The paper reports for the first time the direct determination of silver ion (Ag(+)) using luminescent Carbon Quantum Dot hydrogels (CQDGs). Carbon Quantum Dots (CQDs) with different superficial moieties (passivate-CQDs with carboxylic groups, thiol-CQDs and amine-CQDs) were used to prepare hybrid gels using a low molecular weight hydrogelator (LMWG). The use of the gels results in considerable fluorescence enhancement and also markedly influences selectivity. The most selective CQDG system for Ag(+) ion detection proved to be those containing carboxylic groups onto their surface. The selectivity towards Ag(+) ions is possibly due to its flexible coordination sphere compared with other metal ions. This fluorescent sensing platform is based on the strong Ag-O interaction which can quench the photoluminescence of passivate-CQDs (p-CQDs) through charge transfer. The limit of detection (LOD) and quantification (LOQ) of the proposed method were 0.55 and 1.83µgmL(-1), respectively, being applied in river water samples.

Photoluminescent nitrogen-doped carbon nanodots (N-doped CNDs) soluble in organic media are synthesized in a one-step synthesis from a single-source precursor (an amphiphilic polymer), which exhibits a very high quantum yield (QY = 78%), excitation wavelength-dependent emission, and upconversion emission properties. The evolution of N-doped CND formation is studied via ultraviolet-visible and photoluminescence spectroscopy. Their analytical application as an effective sensor for the direct determination of nitroaromatic explosives and byproducts is shown based on their selective response via a fluorescence quenching mechanism. The proposed method is validated in soil samples by directly using the sensor in organic media without any further treatment or additional functionalization, which is an interesting aspect for practical applications.

Fluorescent nanodots have become increasingly prevalent in a wide variety of applications with special interest in analytical and biomedical fields. The present overview focuses on three main aspects: (i) a systematic description and reasonable classification of the most relevant types of fluorescent nanodots according to their nature, quantum confinement and crystalline structure is provided, starting with a clear distinction between semiconductor and carbon-based dots (graphene quantum dots, carbon quantum dots and carbon nanodots). A new set of abbreviations and definitions for them to avoid contradictions found in literature is also proposed; (ii) a rational classification allows the establishment of clear-cut differences and similarities among them. From a basic point of view, the origins of the photoluminescence of the different nanodots are also established, which is a relevant contribution of this overview. Additionally, the most outstanding similarities and differences in a great variety of criteria (i.e. year of discovery, synthesis, the physico-chemical characteristics like structure, nature, shape, size, quantum confinement, toxicity and solubility, the optical characteristics including the quantum yield and lifetime, limitations, applications as well as the evolution of publications) are thoroughly outlined; and (iii) finally, the promising future of fluorescent nanodots in both analytical and biomedical fields is discussed using selected examples of relevant applications.

This paper reports a simple approach to Analytical Nanoscience and Nanotechnology (AN&N) that integrates the nanotool, sulfonated nanocellulose (s-NC), and nanoanalyte, silver nanoparticles (AgNPs), in the same analytical process by using an efficient, environmentally friendly dispersive micro solid-phase extraction (D-μSPE) capillary electrophoresis (CE) method with s-NC as sorbent material. Introducing negatively charged sulfate groups onto the surface of cellulose enhances its surface chemistry and enables the extraction and preconcentration of AgNPs of variable diameter (10, 20 and 60 nm) and shell composition (citrate and polyvinylpyrrolidone coatings) from complex matrices into a cationic surfactant. In this way, AgNPs of diverse nature were successfully extracted onto the s-NC sorbent and then desorbed into an aqueous solution containing thiotic acid (TA) prior to CE without the need for any labor-intensive cleanup. The ensuing eco-friendly D-μSPE method exhibited a linear response to AgNPs with a limit of detection (LOD) of 20 μg/L. Its ability to specifically recognize AgNPs of different sizes was checked in orange juice and mussels, which afforded recoveries of 70.9–108.4%. The repeatability of the method at the limit of quantitation (LOQ) level was 5.6%. Based on the results, sulfonated nanocellulose provides an efficient, cost-effective analytical nanotool for the extraction of AgNPs from food products.

Herein, a new method for the determination of bisphenol A (BPA) in milk samples is presented. This method comprises a precipitation process, bearing in mind that the analyte has a high tendency to interact with the fatty compounds of the milk, and a magnetic micro-solid phase extraction prior to the determination by high-performance liquid chromatography with UV detection. The presented precipitation process combines EDTA-McIlvaine buffer (the common precipitation agent) with acetonitrile to facilitate the transference of the analyte to the supernatant (only the 30% is transferred in the absence of acetonitrile). The employed sorbent, a magnetic nanoparticles-nylon 6 composite, was synthesized in a quick and one-step method, and was also characterized by several instrumental techniques (SEM, TEM, FT-IR, and SQUID). The developed methodology provides a limit of detection of 3.05 μg/L, which is in accordance with the specific migration limit (SML) established by the European Union. The repeatability of the method, in terms of relative standard deviation, was better than 9.1% (at 100 μg/L) and 16.8% (at 25 μg/L). The recovery study provided values in the range from 86 ± 7 to 99 ± 5%.

Ion mobility spectrometry (IMS) provides quick and reliable responses when applied in the environmental field. However, when headspace (HS) is used as the sample introduction system, in some cases there may be a need to preconcentrate analyte if it is presented at low concentrations due to the low efficiency of HS. Herein, we discuss the parameters that affect the HS and the potential of combining solid phase extraction (SPE) and HS-IMS to improve the sensitivity of the method. The determination of phenol when it is presented in water or soil samples was selected as a case study and a limit of detection of 0.94 μg mL−1 and 0.14 μg mL−1 was obtained when direct analysis by HS-IMS was used. This methodology, which was developed based on SPE prior to HS-IMS analysis, was suitable for the detection of phenol at 0.05 μg mL−1 when 15 mL of water sample was passed through an HLB 60 mg SPE cartridge and eluted with 1 mL of dichloromethane. The HS-IMS analysis of the eluent in which phenol was present was carried out without any interference from the solvent.

A selective photoluminescence method based on Carbon Quantum Dots (CQDs) functionalized with carboxymethyl-β-cyclodextrin for the direct determination of water-soluble C60 fullerene has been developed. CQDs were synthesized using a top-down methodology from multiwall carbon nanotubes (MWCNTs) and further functionalized with N-Boc-ethylenediamine to confer monoprotected amine groups onto their surface. Once amine-functionalized CQDs were obtained after deprotection, an amidation reaction with carboxymethyl-β-cyclodextrin cavitands was achieved and the obtained fluorescent β-cyclodextrin functionalized Carbon Quantum Dots (cd-CQDs) were investigated for the inclusion complexation of water-soluble C60. Quenching of their fluorescence was observed owing to the non-covalent self-assembly of cd-CQDs and C60, making possible the quantification of C60. A method to determine water-soluble C60 is then proposed with detection and quantification limits of 0.525 and 1.751 μg mL(-1), respectively. The method was validated by determining soluble C60 fullerene in spiked river water. One added value of the paper is the fact that it can be ascribed to the "Third Way in Analytical Nanoscience and Nanotechnology".

The article describes a method for the determination of titanium oxide nanoparticles (TiO2NPs) in sunscreens using N-doped graphene quantum dots (N-GQDs). The TiO2-NPs are first extracted from the highly lipophilic sunscreen via liquid-liquid extraction. Subsequent fluorimetric analysis of the extracts is based on the quenching effect exerted by TiO2NPs on the fluorescence of N-GQDs. The effect is assumed to be due to an electrostatic interaction and/or hydrogen bonding between the particles. The limit of detection for TiO2NPs is 1.4 μg⋅g‾1. The precision at a 5 μg⋅g‾1 concentration of TiO2NPs is 6.95 %. The optimized procedure was successively applied to the determination of TiO2 NPs in sunscreens with different sun protection factors.

This article reports on the enhancement of the capacity of an acrylate-based monolithic solid sorbent by anchoring carboxylated multi-walled carbon nanotubes (c-MWCNTs) in its pores and on its surface. Monolithic poly(butyl acrylate-co-ethyleneglycol dimethacrylate) [poly(BA-co-EGDMA)] was synthetized inside a fused silica capillary via free-radical polymerization, and an ethanolic dispersion of c-MWCNTs was passed through the capillary. The resulting poly(BA-co-EGDMA-c-MWCNTs) monolith was characterized by scanning electron microscopy to confirm the presence of the c-MWCNTs. The effect of using three different kinds of carbon nanoparticles and the microextraction step were studied using triazine herbicides as model compunds. The use of c-MWCNTs resulted in best performance in terms of extraction enhancement (compared to carboxylated single-walled carbon nanotubes and oxidized single-walled carbon nanohorns). The use of these carbon nanoparticles improved the extraction of triazines in any case when compared to using a bare poly(BA-co-EGDMA) monolith. The triazines were then quantified by gas chromatography with mass spectrometric detection. Detection limits ranged from 0.03 to 0.1 μg·L−1 (except for simazine; 0.6 μg·L−1), and the precision (relative standard deviation) varied between 3.0 and 11.4 %. The reproducibility between units is

Background: In this article, carbon coated titanium dioxide nanotubes (TiO2-NT@C) are employed for the determination of 5-hydroxyindole-3-acetic acid in urine by LC–MS/MS. Results: All the variables involved in the extraction have been studied and optimized in depth. The method has been analytically characterized on the basis of its linearity, accuracy, sensitivity and precision. The LOD is 155.8 μg/l while the repeatability and the reproducibility, expressed as RSD, are better than 5.42 and 5.25%, respectively. The obtained relative recovery is 115%. Conclusion: TiO2-NT@C permit the efficient extraction of 5-hydroxyindole-3-acetic acid from complex biological samples such as urine allowing its sensitive determination by LC–MS/MS.

The quantitative determination of some compounds such as benzene and phenol in a complex matrix by ion mobility spectrometry (IMS) can be a difficult task, due to the influence of other components present in the matrix and the chemical properties of both compounds, such as their high volatility and low proton affinity. Monitoring of these compounds in a heat transfer fluid (HTF) is essential to check the correct working of a thermosolar plant and for safety and environmental reasons. Benzene and phenol, among other compounds, are produced when HTF is exposed to high temperatures in continuous cycles and their presence can decrease the efficiency of HTF. For the first time, a headspace module coupled to a gas chromatography column in combination with an IMS (with a tritium ionization source) has been optimized and fully validated to simultaneously quantify benzene and phenol in HTF. The limit of detection (LOD) and limit of quantification (LOQ) achieved with the method proposed were 0.011 and 0.038 g L(-1) and 0.004 and 0.014 g L(-1) for benzene and phenol respectively. The precision of the method was evaluated in terms of repeatability and reproducibility with all values lower than 9.2% and 13.3%, respectively. Results demonstrated that benzene and phenol were generated in the HTF heating process, and its concentration increased with heating time (approximately 483 h). The average concentration values for benzene and phenol in degraded HTF samples were not significantly different to values obtained using a gas chromatography-flame ionization detector instrument. Therefore, IMS is a promising technique for in-field quality control of HTF in a thermosolar plant due to its speed, versatility, sensitivity and selectivity to quantify these degradation compounds.

This work presents a simple, fast and sensitive method for the preconcentration and quantification of graphene quantum dots (GQDs) in aqueous samples. GQDs are considered an object of analysis (analyte) not an analytical tool which is the most frequent situation in Analytical Nanoscience and Nanotechnology. This approach is based on the preconcentration of graphene quantum dots on an anion exchange sorbent by solid phase extraction and their subsequent elution prior fluorimetric analysis of the solution containing graphene quantum dots. Parameters of the extraction procedure such as sample volume, type of solvent, sample pH, sample flow rate and elution conditions were investigated in order to achieve extraction efficiency. The limits of detection and quantification were 7.5 μg L(-1) and 25 μg L(-1), respectively. The precision for 200 μg L(-1), expressed as %RSD, was 2.8%. Recoveries percentages between 86.9 and 103.9% were obtained for two different concentration levels. Interferences from other nanoparticles were studied and no significant changes were observed at the concentration levels tested. Consequently, the optimized procedure has great potential to be applied to the determination of graphene quantum dots at trace levels in drinking and environmental waters.

Graphene quantum dots (GQDs) are small fluorescent nanoparticles with unique properties that make them attractive tools for research in various fields. We review their state of the art in analytical chemistry and summarize their analytical applications. Also, we deal with GQDs as target analytes, a scarcely explored aspect in analytical nanoscience and nanotechnology, and suggest potential future directions for GQD-based analytical research.

In this work we present the results from the use of ionic liquids (ILs) for the sample preparation of carbon nanotubes prior to their characterization by scanning electron microscopy (SEM). Their use implies some advantages such as no damage of the surface of CNTs, the aggregation of the nanoparticles decreases while the number of CNTs individually dispersed increases, therefore, the sample is more representive. The use of ILs avoids the gold sputtering of the sample prior to analysis owing to the conductivity of the ionic liquid medium while increasing the contrast and brightness of the image. A comparative study of the feasibility of three different solvents — namely methanol, surfactant Triton X-100 solution, and imidazolium-based ionic liquid – for the dispersion of MWNTs prior to SEM analysis was carried out. Complementarily, Raman spectroscopy was employed to follow the solubilization of carbon nanotubes within the ionic liquid medium, demonstrating the excellent features of ILs for their use as solvent of CNTs.

Heat transfer fluid (HTF) is commonly used in heat transfer industrial processes such as those performed in thermosolar plants. Although HTF is thermally stable, the high temperatures used in such plants (around 400 °C) and overheating in continuous cycles can alter its composition. The potential changes in its initial composition (biphenyl and diphenyl ether), and the likely production of new compounds, such as benzene and phenol, require using fast-response portable instruments for on-site quality control at thermosolar plants. In this work, the degradation profile of HTF heated for a variable time was for the first time characterized by using two different ion mobility spectrometry (IMS) instruments. The simple one used a UV lamp as ionization source (UV-IMS), whereas the other included a chromatographic column coupled to a tritium source (GC-3H-IMS). Other analytical techniques such as Fourier transform-mid infrared spectroscopy (FT-MIR) and gas chromatography–mass spectrometry (GC-MS) were also used for the same purpose. Based on the results, both IMS instruments can be useful for online quality control of HTF in a thermosolar plant. Thus, the UV-IMS instrument can be used for screening purposes and the GC-3H-IMS instrument for selective detection of benzene and phenol as degradation products.

In this paper, a simple, quick and reproducible SERS substrate combining the properties of multilayer graphene (≈ 4 layers) and gold nanoparticles has been developed. The Raman signal of metronidazole is enhanced at a factor of 124 when deposited on the hybrid substrate enabling its determination at low concentrations. The five most relevant added values of the paper as regards other similar proposed procedures are: i) better sensibility, ii) good reproducibility, iii) rapidity, iv) reusability and v) instrumental simplicity. The procedure presented is capable of detecting and quantifying small quantities of metronidazole without implying any preconcentration step, just using an affordable and portable Raman spectrometer. The LOD and LOQ achieved with this hybrid substrate were 1.1 and 3.68 mg L− 1 of the analyte. The use of graphene provides high reproducibility to the SERS active hybrid substrate. The RSD was 7.76% within a substrate and 10.92% between substrates. The developed SERS active hybrid substrate can be reused without loss in sensitivity.

An experimental study was conducted to assess the stability of a single-variety (Arbequina) extra virgin olive oil (EVOO) as a function of container type and storage conditions over a period of 11 months. EVOO quality was assessed by using ion mobility spectrometry (IMS), which provides increased simplicity, expeditiousness, and relative economy. The results were compared with the ones obtained by using the official method based on classical physico-chemical analysis. Bag-in-box, metal, dark glass, clear glass, and polyethylene terephthalate containers holding EVOO were opened on a periodic basis for sampling to simulate domestic use; in parallel, other containers were kept closed until analysis to simulate the storage conditions on market shelves. The results of the physico-chemical and instrumental analyses led to similar conclusions. Thus, samples packaged in bag-in-box containers preserved oil quality for 11 months, better than other container types. The HS-GC-IMS results confirm that 2-heptenal and 1-penten-3-one are two accurate markers of EVOO quality.

A simple, rapid and efficient luminescent method based on carbon dots (CDs) as nanosensor of carboxylated multiwalled carbon nanotubes (c-MWCNTs) has been developed for the first time. Luminescent CDs were successfully synthesized by making use of bottom-up methodology without the need of further surface passivation, obtaining the highest quantum yield (QY: 19%) for cellulose microcrystalline as precursor. This simple and economic preparation of luminescent CDs was accompanied by an evaluation of their ability for detecting c-MWCNTs in water owing to the formation of hydrogen bond interactions. The limits of detection (LOD) and quantification (LOQ) for c-MWCNTs were 0.37 and 1.25 μg mL −1 , respectively. The proposed sensing method was validated in spiked river water, demonstrating its potential in environment water samples.

The manuscript reports on the preparation of β-cyclodextrin-modified nanodiamonds (βCD-ND) for the extraction and preconcentration of the fluorescent anticancer drug doxorubicin (DOX) from biological samples. The inclusion of DOX into the cavities of β- and γ-cyclodextrin (CD) confirms their utility for selective extraction and elution of the drug based on its good fit to the cyclodextrin cavity. Although both larger cyclodextrins (βCD and γCD) accommodate DOX, DOX clearly prefers the bigger γCD cavities. Dispersive micro solid-phase extraction using βCD-ND as sorbent enables the inclusion complexation of DOX. The elution of DOX from βCD-ND cavities occurs with a basic solution of γCD containing 10% acetonitrile owing to the preferential affinity (i.e. optimal fit) of DOX into the larger γCD cavity. DOX is quantified by monitoring its intrinsic fluorescence (exc/em = 475/595 nm). The method can determine DOX in urine with a limit of detection of 18 ng·mL−1. Recoveries (93.2% and 94.0%) and precision (RSDs of 5.9% and 4.7%) at 100 and 400 ng·mL−1 DOX levels in urine are satisfactory. The matrix effect is negligible even when working with undiluted urine samples.

An innovative and versatile strategy of Solid Phase Microextraction (SPME) is shown by using a new type of β-cyclodextrin-modified nanocellulose (CD-NC) as a sorbent material. β-cyclodextrin (used as an inclusion-type selector) was covalently bonded to amine-modified nanocellulose by an amidation reaction. Such novel nanocavities were successfully applied to the selective recognition of danofloxacin (DAN), an antibiotic used to treat animal diseases, via supramolecular host-guest interactions. The SPME methodology, using a platform based on β-cyclodextrin-"decorated" nanocellulose as a sorbent material, showed a wide linear fluorimetric response against DAN from 8 to 800 μg L(-1) and a detection limit of 2.5 μg L(-1). The specific recognition of DAN has been proven to be highly selective and efficient against this metabolite and other fluoroquinolones. The reusability and the high efficiency in the extraction and preconcentration of DAN in milk samples allow recoveries of 94%.

In this article, a new homogeneous liquid-liquid microextraction alternative, based on the use of switchable hydrophilicity solvents (SHS), is presented for the first time. The extraction technique makes use of a water-immiscible solvent (N,N-Dimethylcyclohexylamine) that can be solubilised in 1:1 ratio using CO2 as reagent. After the extraction, phases' separation is induced by the addition of sodium hydroxide, which produces a change on the ionisation state of the amine, centrifugation not being necessary. The extraction technique has been optimised and characterised using the determination of benz[a]anthracene by fluorimetric measurements in water samples as model analytical problem. Although the native fluorescence of the compound is quenched in the organic phase, this attenuation is reduced by diluting the extractant (1:1) in acetic acid. The fluorescence intensity is 35% higher in the SHS-acetic acid mixture than that obtained in pure methanol. The proposed method allows the determination of the target analyte with limit of detection of 0.08 μg/L and good precision (relative standard deviation of 6.7% at the limit of quantification level). The recoveries were in the range of 72-100% fulfilling the Environmental Protection Agency criterion. Finally, the potential use of this microextraction technique in combination with gas chromatography is shown for several polycyclic aromatic hydrocarbons.

Bactrocera oleae Gmelin, the olive fruit fly, is considered a serious pest in the cultivation of olive trees since the larvae feed on the fruit damaging the productivity and quality of the final products (olive fruit and olive oil). An extensive application of pesticides is usually employed to fight this pest producing secondary side-effects of environmental and safety concern. In this context, the development of green analytical methods focused on the detection of the pest may reduce these secondary problems. In this article, the combination of headspace and gas chromatography with mass spectrometric detection is proposed for the identification of the olive fruit fly pest using one of its sexual pheromone components (1,7-dioxaspiro-[5,5]-undecane) as a marker. The developed method is characterized by its simplicity, automation and robustness and follows the principles of green analytical chemistry. It provides, working under its optimal operation conditions, a limit of detection of 26.55 μ kg−1 and precision, expressed as a relative standard deviation, better than 4.7% (calculated at 100 μg kg−1). The relative recovery values (calculated at 100 μg kg−1 and 500 μg kg−1) ranged between 93% and 98% for different olive cultivars which testifies to the applicability of the proposed method.