molecules-logo

Journal Browser

Journal Browser

Special Issue "Chemical Speciation of Organic and Inorganic components of Environmental and Biological Interest in Natural Fluids: Behaviour, Interaction and Sequestration"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Analytical Chemistry".

Deadline for manuscript submissions: closed (15 October 2019).

Special Issue Editors

Prof. Dr. Francesco Crea
E-Mail Website
Guest Editor
Dipartimento di Scienze Chimiche, Università di Messina, Viale Ferdinando Stagno d'Alcontres, 31, I-98166 Messina (Vill. S. Agata), Italy
Interests: speciation of polyelectrolytes; acid-base properties and complexing ability towards different classes of organic and inorganic ligands; modelling in HPLC; modelling of separation of linear and branched polyamines by IC chromatography; speciation of UO22+ in different ionic media; interaction with carboxylic acids at low molecular weight and formation of hydrolytic hetero-metal species; determination of the solubility and activity coefficients of different classes of organic ligands in different ionic media
Prof. Dr. Alberto Pettignano
E-Mail
Guest Editor
Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, I-90128 Palermo, Italy
Interests: speciation of ligands of biological and environmental interest; acid-base properties and complexation ability of natural and synthetic polyelectrolytes; removal/recovery of toxic or precious metals by means of biocompatible materials; electrochemical techniques; spectroscopic techniques; calorimetric techniques

Special Issue Information

Dear Colleagues,

The chemical speciation of elements in natural waters and biological fluids is a key topic, essential for discussing the chemical reactivity of constituents in these systems. It is well understood that it is the chemical form of a metal or metalloids that conditions its reactivity, life time and fate in the environment. The chemical speciation is also important from a geochemical and toxicological point of view, since it gives essential information on the geochemical behavior of chemical species and on the biological availability and toxicity of elements. The knowledge of speciation is critical to understand the transport, accumulation, bioavailability and toxicity of elements within and between the environmental compartments of air, soil, water, sediments and biota.

We invite researchers to contribute with original articles or reviews that can give an update on the knowledge of chemical speciation of the main and trace organic and inorganic components of natural waters and biological fluids. Potential topics include:

  • Papers that lead with chemical speciation or coordination chemistry of organic and inorganic components in aqueous solutions;
  • Study of interactions of metals and ligands in aqueous solution simulating the composition of the natural waters, and determination of the thermodynamic aqueous parameters;
  • Speciation analysis with new hyphenated techniques;
  • Sequestration or removal of pollutants and potential remediation techniques.

 Prof. Dr. Francesco Crea
Prof. Dr. Alberto Pettignano
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • speciation analysis
  • sequestration ability
  • equilibrium constants
  • ligand classes
  • models
  • natural fluids
  • sediments
  • soils

Published Papers (12 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Editorial

Jump to: Research, Review

Open AccessEditorial
Special Issue “Chemical Speciation of Organic and Inorganic Components of Environmental and Biological Interest in Natural Fluids: Behaviour, Interaction and Sequestration”
Molecules 2020, 25(4), 826; https://doi.org/10.3390/molecules25040826 (registering DOI) - 13 Feb 2020
Abstract
Several different definitions were in the past proposed to describe the term chemical speciation, and some of them were accepted from the scientific community [...] Full article

Research

Jump to: Editorial, Review

Open AccessFeature PaperArticle
Understanding the Solution Behavior of Epinephrine in the Presence of Toxic Cations: A Thermodynamic Investigation in Different Experimental Conditions
Molecules 2020, 25(3), 511; https://doi.org/10.3390/molecules25030511 - 24 Jan 2020
Abstract
The interactions of epinephrine ((R)-(−)-3,4-dihydroxy-α-(methylaminomethyl)benzyl alcohol; Eph) with different toxic cations (methylmercury(II): CH3Hg+; dimethyltin(IV): (CH3)2Sn2+; dioxouranium(VI): UO22+) were studied in NaClaq at different ionic strengths [...] Read more.
The interactions of epinephrine ((R)-(−)-3,4-dihydroxy-α-(methylaminomethyl)benzyl alcohol; Eph) with different toxic cations (methylmercury(II): CH3Hg+; dimethyltin(IV): (CH3)2Sn2+; dioxouranium(VI): UO22+) were studied in NaClaq at different ionic strengths and at T = 298.15 K (T = 310.15 K for (CH3)2Sn2+). The enthalpy changes for the protonation of epinephrine and its complex formation with UO22+ were also determined using isoperibolic titration calorimetry: ΔHHL = −39 ± 1 kJ mol−1, ΔHH2L = −67 ± 1 kJ mol−1 (overall reaction), ΔHML = −26 ± 4 kJ mol−1, and ΔHM2L2(OH)2 = 39 ± 2 kJ mol−1. The results were that UO22+ complexation by Eph was an entropy-driven process. The dependence on the ionic strength of protonation and the complex formation constants was modeled using the extended Debye–Hückel, specific ion interaction theory (SIT), and Pitzer approaches. The sequestering ability of adrenaline toward the investigated cations was evaluated using the calculation of pL0.5 parameters. The sequestering ability trend resulted in the following: UO22+ >> (CH3)2Sn2+ > CH3Hg+. For example, at I = 0.15 mol dm−3 and pH = 7.4 (pH = 9.5 for CH3Hg+), pL0.5 = 7.68, 5.64, and 2.40 for UO22+, (CH3)2Sn2+, and CH3Hg+, respectively. Here, the pH is with respect to ionic strength in terms of sequestration. Full article
Show Figures

Graphical abstract

Open AccessArticle
Speciation Studies of Bifunctional 3-Hydroxy-4-Pyridinone Ligands in the Presence of Zn2+ at Different Ionic Strengths and Temperatures
Molecules 2019, 24(22), 4084; https://doi.org/10.3390/molecules24224084 - 12 Nov 2019
Abstract
The acid–base properties of two bifunctional 3-hydroxy-4-pyridinone ligands and their chelating capacity towards Zn2+, an essential bio-metal cation, were investigated in NaCl aqueous solutions by potentiometric, UV-Vis spectrophotometric, and 1H NMR spectroscopic titrations, carried out at 0.15 ≤ I/mol [...] Read more.
The acid–base properties of two bifunctional 3-hydroxy-4-pyridinone ligands and their chelating capacity towards Zn2+, an essential bio-metal cation, were investigated in NaCl aqueous solutions by potentiometric, UV-Vis spectrophotometric, and 1H NMR spectroscopic titrations, carried out at 0.15 ≤ I/mol −1 ≤ 1.00 and 288.15 ≤ T/K ≤ 310.15. A study at I = 0.15 mol L−1 and T = 298.15 K was also performed for other three Zn2+/Lz− systems, with ligands belonging to the same family of compounds. The processing of experimental data allowed the determination of protonation and stability constants, which showed accordance with the data obtained from the different analytical techniques used, and with those reported in the literature for the same class of compounds. ESI-MS spectrometric measurements provided support for the formation of the different Zn2+/ligand species, while computational molecular simulations allowed information to be gained on the metal–ligand coordination. The dependence on ionic strength and the temperature of equilibrium constants were investigated by means of the extended Debye–Hückel model, the classical specific ion interaction theory, and the van’t Hoff equations, respectively. Full article
Show Figures

Figure 1

Open AccessArticle
Trends and Exceptions in the Interaction of Hydroxamic Acid Derivatives of Common Di- and Tripeptides with Some 3d and 4d Metal Ions in Aqueous Solution
Molecules 2019, 24(21), 3941; https://doi.org/10.3390/molecules24213941 - 31 Oct 2019
Abstract
By using various techniques (pH-potentiometry, UV-Visible spectrophotometry, 1H and 17O-NMR, EPR, ESI-MS), first time in the literature, solution equilibrium study has been performed on complexes of dipeptide and tripeptide hydroxamic acids—AlaAlaNHOH, AlaAlaN(Me)OH, AlaGlyGlyNHOH, and AlaGlyGlyN(Me)OH—with 4d metals: the essential Mo(VI) and [...] Read more.
By using various techniques (pH-potentiometry, UV-Visible spectrophotometry, 1H and 17O-NMR, EPR, ESI-MS), first time in the literature, solution equilibrium study has been performed on complexes of dipeptide and tripeptide hydroxamic acids—AlaAlaNHOH, AlaAlaN(Me)OH, AlaGlyGlyNHOH, and AlaGlyGlyN(Me)OH—with 4d metals: the essential Mo(VI) and two half-sandwich type cations, [(η6-p-cym)Ru(H2O)3]2+ as well as [(η5-Cp*)Rh(H2O)3]2+, the latter two having potential importance in cancer therapy. The tripeptide derivatives have also been studied with some biologically important 3d metals, such as Fe(III), Ni(II), Cu(II), and Zn(II), in order to compare these new results with the corresponding previously obtained ones on dipeptide hydroxamic acids. Based on the outcomes, the effects of the type of metal ions, the coordination number, the number and types of donor atoms, and their relative positions to each other on the complexation have been evaluated in the present work. We hope that these collected results might be used when a new peptide-based hydroxamic acid molecule is planned with some purpose, e.g. to develop a potential metalloenzyme inhibitor. Full article
Show Figures

Figure 1

Open AccessArticle
Modeling Solid State Stability for Speciation: A Ten-Year Long Study
Molecules 2019, 24(16), 3013; https://doi.org/10.3390/molecules24163013 - 20 Aug 2019
Abstract
Speciation studies are based on fundamental models that relate the properties of biomimetic coordination compounds to the stability of the complexes. In addition to the classic approach based on solution studies, solid state properties have been recently proposed as supporting tools to understand [...] Read more.
Speciation studies are based on fundamental models that relate the properties of biomimetic coordination compounds to the stability of the complexes. In addition to the classic approach based on solution studies, solid state properties have been recently proposed as supporting tools to understand the bioavailability of the involved metal. A ten-year long systematic study of several different complexes of imidazole substituted ligands with transition metal ions led our group to the definition of a model based on experimental evidences. This model revealed to be a useful tool to predict the stability of such coordination complexes and is based on the induced behavior under thermal stress. Several different solid state complexes were characterized by Thermally Induced Evolved Gas Analysis by Mass Spectrometry (TI-EGA-MS). This hyphenated technique provides fundamental information to determine the solid state properties and to create a model that relates stability to coordination. In this research, the model resulting from our ten-year long systematic study of complexes of transition metal ions with imidazole substituted ligands is described. In view of a systematic addition of information, new complexes of Cu(II), Zn(II), or Cd(II) with 2-propyl-4,5-imidazoledicarboxylic acid were precipitated, characterized, and studied by means of Thermally Induced Evolved Gas Analysis performed by mass spectrometry (TI-EGA-MS). The hyphenated approach was applied to enrich the information related to thermally induced steps, to confirm the supposed decomposition mechanism, and to determine the thermal stability of the studied complexes. Results, again, allowed supporting the theory that only two main characteristic and common thermally induced decomposition behaviors join the imidazole substituted complexes studied by our group. These two behaviors could be considered as typical trends and the model allowed to predict coordination behavior and to provide speciation information. Full article
Show Figures

Figure 1

Open AccessArticle
Associated Effects of Cadmium and Copper Alter the Heavy Metals Uptake by Melissa Officinalis
Molecules 2019, 24(13), 2458; https://doi.org/10.3390/molecules24132458 - 04 Jul 2019
Abstract
Lemon balm (Melissa officinalis) is a popular herb widely used in medicine. It is often cultivated in soils with substantial heavy metal content. Here we investigate the associated effects of cadmium and copper on the plant growth parameters augmented by the [...] Read more.
Lemon balm (Melissa officinalis) is a popular herb widely used in medicine. It is often cultivated in soils with substantial heavy metal content. Here we investigate the associated effects of cadmium and copper on the plant growth parameters augmented by the manganese, zinc, and lead uptake indicators. The concentration of all elements in soil and plants was determined by the HR-CS FAAS with the ContrAA 300 Analytik Jena spectrometer. Bioavailable and total forms calculated for all examined metals were augmented by the soil analyses. The index of chlorophyll content in leaves, the activity of net photosynthesis, stomatal conductance, transpiration rate, and intercellular concentration of CO2 were also investigated. Either Cd or Cu acting alone at high concentrations in soil are toxic to plants as indicated by chlorophyll indices and gas exchange parameters. Surprisingly, this effect was not observed when both metals were administered together. The sole cadmium or copper supplementations hampered the plant’s growth, lowered the leaf area, and altered the plant’s stem elongation. Analysis of variance showed that cadmium and copper treatments of lemon balm significantly influenced manganese, lead, and zinc concentration in roots and above ground parts. Full article
Show Figures

Figure 1

Open AccessArticle
Increased Aluminum Content in Certain Brain Structures is Correlated with Higher Silicon Concentration in Alcoholic Use Disorder
Molecules 2019, 24(9), 1721; https://doi.org/10.3390/molecules24091721 - 03 May 2019
Cited by 3
Abstract
Introduction: Alcohol overuse may be related to increased aluminum (Al) exposure, the brain accumulation of which contributes to dementia. However, some reports indicate that silicon (Si) may have a protective role over Al-induced toxicity. Still, no study has ever explored the brain content [...] Read more.
Introduction: Alcohol overuse may be related to increased aluminum (Al) exposure, the brain accumulation of which contributes to dementia. However, some reports indicate that silicon (Si) may have a protective role over Al-induced toxicity. Still, no study has ever explored the brain content of Al and Si in alcoholic use disorder (AUD). Materials and methods: To fill this gap, the present study employed inductively coupled plasma optical emission spectrometry to investigate levels of Al and Si in 10 brain regions and in the liver of AUD patients (n = 31) and control (n = 32) post-mortem. Results: Al content was detected only in AUD patients at mean ± SD total brain content of 1.59 ± 1.19 mg/kg, with the highest levels in the thalamus (4.05 ± 12.7 mg/kg, FTH), inferior longitudinal fasciculus (3.48 ± 9.67 mg/kg, ILF), insula (2.41 ± 4.10 mg/kg) and superior longitudinal fasciculus (1.08 ± 2.30 mg/kg). Si content displayed no difference between AUD and control, except for FTH. Positive inter-region correlations between the content of both elements were identified in the cingulate cortex, hippocampus, and ILF. Conclusions: The findings of this study suggest that AUD patients may potentially be prone to Al-induced neurodegeneration in their brain—although this hypothesis requires further exploration. Full article
Open AccessArticle
Analysis of Hazardous Elements in Children Toys: Multi-Elemental Determination by Chromatography and Spectrometry Methods
Molecules 2018, 23(11), 3017; https://doi.org/10.3390/molecules23113017 - 19 Nov 2018
Cited by 2
Abstract
This paper presents the results of determination of hazardous metal (Cd, Cu, Cr, Hg, Mn, Ni, Pb, Zn) and metalloid (As, Sb) levels in toys available in the Polish market. Two independent sample preparation methods were used to determine the concentration and content [...] Read more.
This paper presents the results of determination of hazardous metal (Cd, Cu, Cr, Hg, Mn, Ni, Pb, Zn) and metalloid (As, Sb) levels in toys available in the Polish market. Two independent sample preparation methods were used to determine the concentration and content of the metals and metalloids. The first one is defined by the guidelines of the EN-71 standard and undertook extraction in 0.07 mol/L HCl. This method was used to conduct speciation analysis of Cr(III) and Cr(VI), as well as for the determination of selected metals and metalloids. The second method conducted mineralization in a HNO3 and H2O2 mixture using microwave energy to determine the content of metals and metalloids. Determination of chromium forms was made using the high-performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) method, while those of metals and metalloids were made using the ICP-MS technique. Additionally, in order to determine total content of chromium in toys, an energy dispersive X-ray fluorescence spectrometer (EDX) was used. The results of the analyses showed that Cr(VI) was not detected in the toys. In general, the content of heavy metals and metalloids in the studied samples was below the migration limit set by the norm EN-71. Full article
Show Figures

Graphical abstract

Open AccessArticle
Evaluation of Highly Detectable Pesticides Sprayed in Brassica napus L.: Degradation Behavior and Risk Assessment for Honeybees
Molecules 2018, 23(10), 2482; https://doi.org/10.3390/molecules23102482 - 27 Sep 2018
Cited by 2
Abstract
Honeybees are major pollinators of agricultural crops and many other plants in natural ecosystems alike. In recent years, managed honeybee colonies have decreased rapidly. The application of pesticides is hypothesized to be an important route leading to colony loss. Herein, a quick, easy, [...] Read more.
Honeybees are major pollinators of agricultural crops and many other plants in natural ecosystems alike. In recent years, managed honeybee colonies have decreased rapidly. The application of pesticides is hypothesized to be an important route leading to colony loss. Herein, a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was used to determine eight highly detectable pesticides (carbendazim, prochloraz, pyrimethanil, fenpropathrin, chlorpyrifos, imidacloprid, thiamethoxam, and acetamiprid) in rape flowers. A field experiment was conducted at the recommended dose to evaluate the contact exposure risk posed to honeybees for 0–14 days after treatment. The initial residue deposits of neonicotinoids and fungicides among these compounds were 0.4–1.3 mg/kg and 11.7–32.3 mg/kg, respectively, and 6.4 mg/kg for fenpropathrin and 4.2 mg/kg for chlorpyrifos. The risk was quantified using the flower hazard quotient (FHQ) value. According to the data, we considered imidacloprid, thiamethoxam, chlorpyrifos, fenpropathrin, and prochloraz to pose an unacceptable risk to honeybees after spraying in fields, while fungicides (carbendazim and pyrimethanil) and acetamiprid posed moderate or acceptable risks to honeybees. Therefore, acetamiprid can be used instead of imidacloprid and thiamethoxam to protect rape from some insects in agriculture, and the application of prochloraz should be reduced. Full article
Show Figures

Graphical abstract

Review

Jump to: Editorial, Research

Open AccessReview
Zn2+ Interaction with Amyloid-B: Affinity and Speciation
Molecules 2019, 24(15), 2796; https://doi.org/10.3390/molecules24152796 - 31 Jul 2019
Cited by 1
Abstract
Conflicting values, obtained by different techniques and often under different experimental conditions have been reported on the affinity of Zn2+ for amyloid-β, that is recognized as the major interaction responsible for Alzheimer’s disease. Here, we compare the approaches employed so far, i.e., [...] Read more.
Conflicting values, obtained by different techniques and often under different experimental conditions have been reported on the affinity of Zn2+ for amyloid-β, that is recognized as the major interaction responsible for Alzheimer’s disease. Here, we compare the approaches employed so far, i.e., the evaluation of Kd and the determination of the stability constants to quantitatively express the affinity of Zn2+ for the amyloid-β peptide, evidencing the pros and cons of the two approaches. We also comment on the different techniques and conditions employed that may lead to divergent data. Through the analysis of the species distribution obtained for two selected examples, we show the implications that the speciation, based on stoichiometric constants rather than on Kd, may have on data interpretation. The paper also demonstrates that the problem is further complicated by the occurrence of multiple equilibria over a relatively narrow pH range. Full article
Show Figures

Figure 1

Open AccessReview
Serum iron, Magnesium, Copper, and Manganese Levels in Alcoholism: A Systematic Review
Molecules 2019, 24(7), 1361; https://doi.org/10.3390/molecules24071361 - 07 Apr 2019
Cited by 8
Abstract
The aim of this paper was to review recent literature (from 2000 onwards) and summarize the newest findings on fluctuations in the concentration of some essential macro- and microelements in those patients with a history of chronic alcohol abuse. The focus was mainly [...] Read more.
The aim of this paper was to review recent literature (from 2000 onwards) and summarize the newest findings on fluctuations in the concentration of some essential macro- and microelements in those patients with a history of chronic alcohol abuse. The focus was mainly on four elements which the authors found of particular interest: Iron, magnesium, copper, and manganese. After independently reviewing over 50 articles, the results were consistent with regard to iron and magnesium. On the other hand, data were limited, and in some cases contradictory, as far as copper and manganese were concerned. Iron overload and magnesium deficiency are two common results of an excessive and prolonged consumption of alcohol. An increase in the levels of iron can be seen both in the serum and within the cells, hepatocytes in particular. This is due to a number of factors: Increased ferritin levels, lower hepcidin levels, as well as some fluctuations in the concentration of the TfR receptor for transferrin, among others. Hypomagnesemia is universally observed among those suffering from alcoholism. Again, the causes for this are numerous and include malnutrition, drug abuse, respiratory alkalosis, and gastrointestinal problems, apart from the direct influence of excessive alcohol intake. Unfortunately, studies regarding the levels of both copper and manganese in the case of (alcoholic) liver disease are scarce and often contradictory. Still, the authors have attempted to summarize and give a thorough insight into the literature available, bearing in mind the difficulties involved in the studies. Frequent comorbidities and mutual relationships between the elements in question are just some of the complications in the study of this topic. Full article
Open AccessReview
Speciation Analysis of Trace Arsenic, Mercury, Selenium and Antimony in Environmental and Biological Samples Based on Hyphenated Techniques
Molecules 2019, 24(5), 926; https://doi.org/10.3390/molecules24050926 - 07 Mar 2019
Cited by 3
Abstract
In order to obtain a well understanding of the toxicity and ecological effects of trace elements in the environment, it is necessary to determine not only the total amount, but also their existing species. Speciation analysis has become increasingly important in making risk [...] Read more.
In order to obtain a well understanding of the toxicity and ecological effects of trace elements in the environment, it is necessary to determine not only the total amount, but also their existing species. Speciation analysis has become increasingly important in making risk assessments of toxic elements since the toxicity and bioavailability strongly depend on their chemical forms. Effective separation of different species in combination with highly sensitive detectors to quantify these particular species is indispensable to meet this requirement. In this paper, we present the recent progresses on the speciation analysis of trace arsenic, mercury, selenium and antimony in environmental and biological samples with an emphasis on the separation and detection techniques, especially the recent applications of high performance liquid chromatography (HPLC) hyphenated to atomic spectrometry or mass spectrometry. Full article
Show Figures

Figure 1

Back to TopTop