Inmaculada De La Calle

• PhD
• PostDoc Position at University of Vigo

Since its discovery in 1995 by Dasgupta et al., and further implementation by Jeannot et al. in 1996, single-drop microextraction (SDME) has undergone a dramatic increase, as demonstrated by the significant number of developments and the plethora of applications that have extended this technique to almost every area, being nowadays one of the most...

The growing interest in the development of cost-effective, straightforward, and rapid analytical systems has found cellulose-based materials, including cellulose derivatives, cellulose-based gels, nanocellulosic materials, and the corresponding (nano)cellulose-based composites, to be valuable platforms for sensor development. The present work prese...

Preconcentration of Cd and Pb at ultratrace level in waters following filtration through silver nanoparticles-cellulose composites used for thin-film microextraction was performed. The new procedure was based on the formation of pyrrolidine dithiocarbamate (APDC) derivatives, which showed a large affinity toward the AgNPs. For this purpose, cellulo...

In this work, a novel preconcentration method was developed for As, Sb and Bi following trapping of their volatile hydride derivatives onto cellulose-based platforms modified with Ag nanoparticles for ultrasensitive determination by inductively-coupled plasma mass spectrometry (ICP-MS). A continuous flow hydride generation system was coupled to a g...

Lab-on-paper technologies, also known as paper-based analytical devices (PADs), have received increasing attention in the last years, and nowadays, their use has spread to virtually every application area, i.e., medical diagnostic, food safety, environmental monitoring, etc. Advantages inherent to on-field detection, which include avoiding sampling...

Since its discovery in 2004, substantial efforts have been devoted to the use of graphene and graphene oxide (GO) in areas such as catalysis, clean energy devices, electronics, biomedicine and, particularly, as sorbents in sample preparation for both trace organic and inorganic analysis. In a step forward, in the last few years, a number of applica...

The development of disposable sensors that can be easily adapted to every analytical problem is currently a hot topic that is revolutionizing many areas of science and technology. The need for decentralized analytical measurements at real time is increasing for solving problems in areas such as environment pollution, medical diagnostic, food qualit...

Total Reflection X-Ray Fluorescence spectrometry (TXRF) provides many advantages for metal and metalloid analysis. In general, the sample should be prepared as a thin film. To that end, for the analysis of liquid, suspensions or solids previously digested, a small aliquot of the sample is dropped on the sample carrier (e.g. quartz reflector). Howev...

In this work, a new approach for ultrasensitive detection of Hg(II) in waters following preconcentration by filtration through paper modified with nanoparticles (NPs) is described. Reduction of Hg(II) to Hg(0) without chemical reagents followed by amalgamation of Hg⁰ was performed using cellulose substrates containing AgNPs synthetized in situ. Enr...

Poly(vinylpyrrolidone)-supported copper nanoclusters (CuNCs) are employed in the present work as luminescent probes for iodide determination in water samples. The method involves the combination of two miniaturized analytical systems, namely nanoparticle-enhanced liquid-phase microextraction and microvolume fluorospectrometry. The proposed method i...

Cephalopod ink is a complex mixture of bioactive substances with technical properties of interest in many fields (e.g., biophysics, ecology, environment, biomedicine, food technology, cosmetics, or fine arts). It was previously reported that organic nanoparticles may naturally appear in this mixture. Thus, the particle size determination of these b...

Ultrasound-assisted co-precipitation was applied to construct a magnetic nanocomposite following a ‘one-pot’ synthetic strategy for Hg(II) enrichment. The presence of a noble metal such as Ag(I), Au(III), Pd(II) in the synthesis medium proved to be essential in order to attain an efficient co-precipitation of Hg with the magnetic nanoparticles. Fol...

This work reports on the development of a direct immersion thin-film microextraction procedure for the simultaneous preconcentration of different metal ions present in water samples using graphene membranes as novel sorptive platforms. The method relies on the sorption of metal ions as pyrrolidine dithicarbamate (APDC) chelates prior to determinati...

Se presenta el desarrollo de un seminario pensado para captar la atención de los alumnos de Química Analítica. Para ello se seleccionó como tema los envenenamientos por arsénico y la determinación de este elemento. Se plantearon tres cuestiones básicas: el arsénico como veneno, la historia del método de Marsh y la evolución de dicho método. Los alu...

In this work, a novel one–step ‘bottom–up’ synthetic approach is described for obtaining highly fluorescent nitrogen (N) and sulphur (S) co–doped carbon dots (CDs) following photochemical oxidation of carbohydrates naturally occurring in vegetables. N and S co–doping allows more active sites in the CDs surface resulting in an enhancement of their l...

In this work, the potential of several techniques commonly used in research studies for TiO2 nanoparticles' (NPs) characterization was evaluated for the implementation in routine analysis. Namely, Dynamic Light Scattering (DLS), single-particle mode Inductively Coupled Plasma Mass Spectrometry (spICP-MS) and Asymmetrical Flow Field-Flow Fractionati...

A variety of food and drink samples (n = 21) were analyzed to evaluate the presence of (nano-) particles in their composition. After assessment of the sample pre-treatment step, a fast screening analysis was performed for drinks by Dynamic Light Scattering showing particles from 10 to 300 nm that could correspond to organic or metallic NPs. Metalli...

Fungi are responsible for a great number of diseases in plants and cause crop loss. The spread of fungal diseases can be controlled by crop management, rotation systems, the use of resistant cultivars and the application of fungicides. Fungicides are often employed by farmers due to their simplicity and efficiency. However, fungicides are expensive...

In this chapter, we provide a simplified introduction to the book, including some definitions, fungicide classifications and a complete description of their modes of action, appearance and ways of application on agricultural crops. A detailed overview describing the past and the current European legislation regarding the fungicides’ use on agricult...

Microwave energy enhances and shortens the extraction of metallic and organic compounds from environmental, food, and biological samples in research laboratories, and also pilot plants and industry. Solvent-free approaches and green solvents (e.g., water, ionic liquids, supramolecular, and deep eutectic solvents) are increasingly used in combinatio...

Cosmetics are part of the daily life of most of the people. Thus, a complete characterization of the products we applied in our skin is necessary. In this work, an analytical investigation of a wide variety of cosmetics from the point of view of total element content and metallic nanoparticles (NPs) has been performed. Firstly, we analyzed the tota...

Some evidence shows that Cu-based fungicides used on vines increase the levels of copper in soil and sediments. The rainfall induced foliar wash-off is the most complex pathway of contaminants in the environment. Since the Cu wash-off occurs during rain episodes, Cu can be transported in streams along considerable distances as particulate forms. Th...

Due to the increasing use of nanoparticles (NPs) in consumer products, it becomes necessary to develop different strategies for their detection, identification, characterization and quantification in a wide variety of samples. Since the analysis of NPs in consumer products and environmental samples is particularly troublesome, a detailed descriptio...

The continuous use of copper against fungal diseases and off-target effects causes major environmental and agronomic problems. However, the rain-induced removal of Cu-based residues is known only for a limited number of crops. We present the results of rain-induced removal of fungicides from two monitored vineyard plots which were sprayed with two...

RÉSUMÉ Aujourd’hui, l’évaluation de la présence de nanoparticules (N.P.) dans les denrées alimentaires représente un important challenge analytique dans le cadre du contrôle de la qualité des produits. L’intention de cette étude est de développer une méthodologie de routine pour caractériser les N.P. dans ce type de produit en utilisant des procédu...

An overview of the combination of liquid-phase microextraction (LPME) techniques with graphite furnace atomic absorption spectrometry (GFAAS) is reported herein. The high sensitivity of GFAAS is significantly enhanced by its association with a variety of miniaturized solvent extraction approaches. LPME-GFAAS thus represents a powerful combination f...

In the last years, nanoparticles (NPs) were found in different consumer products. For example, TiO2 (E171) and SiO2 (E551) are used as food additives to provide them specific properties. Sizes of the added primary particles of TiO2 and SiO2 are lower than 100 nm, but generally, these compounds tend to aggregate to large particles of 1000 nm. Europe...

Nanoparticles (NPs) can be present in consumer food products, as anticaking agent or as white pigment, for example. Regulations of the European Union currently establish that the word “nano” should be included in the label of the product if NPs are present at 50 % or more in the size range from 1 nm to 100 nm. For the moment, for presence of calciu...

We describe a method for ultrasensitive detection of mercury (Hg) by total reflection X-ray fluorescence following photogeneration of Hg vapor and trapping onto quartz substrates coated with nanostructured palladium. The nanostructured coating was characterized by transmission electron microscopy. Hg vapor was generated by online photo-UV reduction...

Total reflection X-ray fluorescence is an emerging technique that allows performing mutielement determinations at trace level using microsamples deposited onto a smooth surface. Evaluation of metal mobility and bioavailability from soils has been extensively addressed using a variety of operational approaches. In this work, a portable TXRF spectrom...

A method has been developed for the specific and sensitive determination of Cr(VI) in foods. First, the interactions between Cr(VI) and the matrices were investigated by size-exclusion HPLC-ICP-MS (SEC-ICP-MS). Evidence was found for the complexation of Cr(VI) potentially present with the ligands. For quantification of Cr(VI), the method was based...

In this work, a new method based on headspace-single drop microextraction for the determination of residual acetone in cosmetics by microfluorospectrometry is proposed. Acetone causes fluorescence changes in a 2.5µL-ethanolic drop (40% v/v) containing 3.10(-4)molL(-1) 7-hydroxy-4-methylcoumarin ('turn off') or 6.10(-6)molL(-1) 7-diethylamino-4-meth...

Total reflection X-ray fluorescence spectrometry (TXRF) was used to determine residual metal content in metallurgical slag after sulfuric acid extraction. A slag sample provided by a copper smelter industry and submitted to a recycling process with the aim of extracting valuable metals was analyzed. Slurry sampling was evaluated as a simple sample...

The controversial and widespread use of parabens in cosmetics makes this group of compounds particularly interesting from an analytical point of view. This article provides an overview on analytical methodology for the determination of parabens in cosmetic products, placing special emphasis on sample preparation. First, we consider simple approache...

In the last years, there has been a revival of total reflection X-ray fluorescence spectrometry (TXRF), which was firstly applied for analytical purposes in the late 80s. The aim of this work is to discuss and compare the current approaches for sample pretreatment including in situ microdigestion, slurry preparation, acid digestion, extraction, etc...

In this work, ultrasound-assisted extraction (UAE) was employed for acceleration of metal extraction from soil samples. After extraction, multielemental analysis (Cr, Mn, Fe, Ni, Cu, Zn and Pb) of EDTA and acetic acid extracts was performed by total reflection X-ray fluorescence spectrometry (TXRF). High-intensity ultrasonic processors, i.e. the ul...

The aim of this review is to discuss and compare the current trends in liquid–liquid and solid–liquid extraction procedures applied to the analysis of cosmetics. Although classical sample preparation procedures are mostly used in labs, the new trends in sample preparation that provide more effective analyte extractions from these complex matrices a...

A green assay based on the development of an enzymatic reaction in drop format under headspace single-drop microextraction conditions is described for the first time. An aqueous drop containing the enzyme alcohol dehydrogenase and the cofactor β-Nicotinamide adenine dinucleotide has been used as fluorescence probe for determining ethanol in alcohol...

A headspace single drop microextraction procedure is proposed for terpene screening in fragrance-free cosmetics. The drop is composed by an aqueous solution of a fluorescence probe formed by bovine serum albumin and fluorescein. Extracted volatile terpenes produce a fluorescence quenching that can be monitored by microvolume-fluorospectrometry. Thi...

Sample preparation has witnessed transformation in recent years, with the main efforts focused on acceleration, simplification, miniaturization and automation of the operations involved. Ultrasound is a clean, efficient energy that has dramatically improved many sample-preparation protocols. The unique conditions provided by acoustic cavitation hav...

In this work, two ultrasound-based procedures are developed for sample preparation prior to determination of P, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, As, Se and Sr in biological tissues by total reflection X-ray fluorescence spec-trometry. Ultrasound-assisted extraction by means of a cup-horn sonoreactor and ultrasonic-probe slurry sampling were compared...

A simple, fast and reliable method is described for the quantitative extraction of Sb and Co from inorganic environmental matrices containing variable amounts of silicates prior to their determination by electrothermal-atomic absorption spectrometry. The method is based on the ultrasound-assisted extraction of both elements using the mixture 20% v/...

Two ultrasound-assisted emulsification–microextraction procedures based on the use of a micellar ionic liquid as extractant are proposed for triclosan determination in troublesome matrices such as cosmetics and wastewaters. Microvolume UV–vis spectrophotometry was used in order to quantify the yellow azoderivative formed. This compound is polar and...

A miniaturized methodology for the determination of phosphate in waters has been developed by combining directly suspended droplet microextraction (DSDME) with microvolume spectrophotometry. The method is based on the extraction of the ion pair formed between 12-molybdophosphate and malachite green onto a microdrop of methyl isobutyl ketone and sub...

Ultrasound-assisted extraction combined with electrothermal-atomic absorption spectrometry has been applied to the determination of silver and gold at μg g−1 levels in different environmental samples such as soil, sediment, fly ash and industrial sludge. Two different extraction systems have been tried, i.e. acid mixtures (HCl, HF, and HNO3) and th...

A new methodology was developed for the determination of ultratrace levels of gold in water samples, soils and river sediments. Dispersive liquid-liquid microextraction was used to preconcentrate the ion pair formed between AuCl(4)(-) and [CH(3)(CH(2))(3)](4)N(+) in a microliter-range volume of chlorobenzene using acetone as disperser solvent. When...

A simple and miniaturized approach based on ultrasound-assisted emulsification-derivatization is proposed for the determination of nitrite in cosmetic samples by UV-vis micro-spectrophotometry. Oil/water emulsions were formed using 15 mg of cosmetic sample and 1 mL of an aqueous medium containing 0.5% w/v SDS and 1% v/v acetic acid. When powerful s...

Photo-chemical vapour generation has been applied in a flow-injection system under stopped-flow conditions for determination of Hg by atomic absorption spectrometry. The system allows mercury vapour generation without the need for conventional reduction reactions based on sodium/potassium tetrahydroborate (III) or tin chloride in acid medium. The p...

In this work, the determination of rare earth elements (REEs), i.e. Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu in marine biological tissues by inductively coupled-mass spectrometry (ICP-MS) after a sample preparation method based on ultrasound-assisted extraction (UAE) is described. The suitability of the extracts for ICP-MS measu...

In this work, ultrasound-assisted emulsification microextraction in combination with fibre optics-based cuvetteless UV-vis micro-spectrophotometry has been proposed as a novel method for the determination of formaldehyde in water-based cosmetics such as shampoo, conditioner and shower gel. The use of a powerful cup-horn sonoreactor allows simultane...

Photo-chemical vapour generation has been applied in a flow-injection system under stopped-flow conditions for determination of Hg by atomic absorption spectrometry. The system allows mercury vapour generation without the need for conventional reduction reactions based on sodium/potassium tetrahydroborate (III) or tin chloride in acid medium. The p...

In this work, ultrasound-assisted emulsification with a probe system is proposed as a rapid and simple sample treatment for atomic spectrometric determinations (Electrothermal Atomic Absorption Spectrometry, Inductively Coupled Plasma Optical Emission Spectrometry, Flame Atomic Absorption Spectrometry and Cold Vapour Atomic Absorption Spectrometry)...

In this work, a sample preparation method based on ultrasound-assisted extraction of trace metals from a variety of biological and environmental matrices using a cup-horn sonoreactor is described. Diluted acids (HNO3, HCl and HF) and oxidants (H2O2) were tried for extraction, the extracts being directly analyzed by electrothermal-atomic absorption...