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Well-established label in biomolecules analysis, fluorescein isothiocyanate is commercially available in its two different isomers with equal fluorescence sensitivity, differing in meta- vs. para-isothiocyanate position. It was found in this study that the stability of the isomers depends on the polarity of different solvents and the pyridine (stabiliser) presence. The lowest stability has fluorescein isothiocyanate in water solvent. In acidic solution, their quinoid (acid) form switches to the lactone form. The p-quinoid form has higher tendency to create dimers and trimers and is less soluble in acetone than the lactone form. [GRAPHICS] .

Pyridine-terminated molecular rods and either (i) the cis-(dppp)(I)Pt(C≡C-triptycene-C≡C)Pt(I)(dppp) rod or (ii) the trans-(PEt3)2(I)Pt(C≡C-biphenyl-C≡C)Pt(I)(PEt3)2 rod assemble into macrocycles, ...

A part of the fungicides used in foliar treatment penetrates into the soil. This study describes changes in the bioavailability of (essential) elements in soil, fructification, the amount of green biomass and the production of phenolic compounds related solely to the presence of triazoles (penconazole and cyproconazole) in soil, injected as a single compound or their mixture. The triazoles presence has substantially affected the bioavailability of Fe, Cu and Zn in soil. The amount of green biomass has significantly decreased, whereas the chlorophylls a and b have not been affected. As a potential mark of plant stress, the fruits of the treated variants are significantly bigger. The content of phenolics in tomato peel (e.g. quercetin, quercitrin, hesperidin, naringin, and chlorogenic, salicylic and p-coumaric acid) has been quantified. The biggest changes (increase/decrease) have been observed in the contents of p-coumaric and chlorogenic acid, quercetin and quercitrin.

Triazoles are used as antifungal agents, they mostly inhibit two enzymes: 14α-demethylase and aromatase. These enzymes are utilised also in other species and therefore the affection in non-target species in the environment is expected as well. Besides, triazoles are often being applied in a mixture and they can also interact with other substances present. This study clarifies how three selected representative triazoles (tebuconazole, penconazole and cyproconazole) interact with each other (group effect) and in mixtures (cocktail effect) with copper, essential/toxic for all organisms. Within the experiments on electrospray and collision-induced dissociations (both ESI-MS), it has been found that the fragments correspond to typical triazole metabolites. For their formation, the presence of copper ions is crucial. The inhibitory effect of Cu cocktails on aromatase enzymatic activity has been studied. The presence of Cu ions together with triazole(s) significantly increases the inhibitory effect on aromatase activity. The highest inhibitory effect (more than 60%) on aromatase activity is produced by cocktails containing penconazole and Cu ions, namely by penconazole/Cu and penconazole/tebuconazole/Cu. The reactivity of triazoles in groups is not significantly affected by the interactions among them. Additionally, the role of triazoles in copper Fenton reaction regulation has been observed and described. These changes may be attributed to the formation and stabilization of the complexes with the central Cu ion, with usually one, two or three triazolic ligands, depending on the mixture. The study demonstrates that the interaction of triazoles and Cu ions is a complex process; their impact on metabolism seems to be rather extensive and must be evaluated in the context of biochemical reactions.

RATIONALE For the risk assessment of penconazole in the environment and the evaluation of the possible consequences of its use, it is important to determine how its reactivity and degradation are influenced by metals commonly found in nature, such as copper and zinc. METHODS Changes in the reactivity of penconazole in the presence of zinc/copper ions were studied using electrospray ionisation mass spectrometry and density functional theory calculations. RESULTS Many penconazole complexes with copper and zinc ions were created; a comparison of the elements showed that a few complexes were formed analogously (doubly charged complexes with four penconazole molecules, singly charged complexes with chlorine as a counterion and singly charged complexes with deprotonated penconazole as a counterion). The metal complexes with different structures indicated different reactivity of penconazole with copper and zinc. CONCLUSIONS The experimental and computational approaches have revealed different changes in the structure of penconazole. In the Zn(II) complex, penconazole deprotonated to stabilise the bond to Zn(II). In the Cu(II) complex, it loses one chlorine atom, creates an additional ring between the triazole ring and the phenyl ring, and/or creates a double bond in the short aliphatic chain.

Resveratrol is antioxidant naturally occurring in wine grapes. It is thought to have a preventive biological activity against number of diseases. However, it has been recently shown that in the presence of metal ions, such as Cu2+, resveratrol forms oxidative radicals. Cu2+ is usually present in wine due to former usage of bluestone in vineyards. Fungicide tebuconazole has substituted bluestone and is presently one of the most widely used agrochemicals in wine industry; wine thus may contain traces of tebuconazole. Here, we study the ternary system of resveratrol, Cu2+, and tebuconazole experimentally and theoretically (using mass spectrometry, antioxidant capacity assay and quantum-chemical calculations) to model the redox behaviour of resveratrol in wine. We show that tebuconazole prevents formation of oxidative resveratrol radicals (induced by Cu2+ reaction with resveratrol) via preferential Cu2+ capture and protection of the binding sites of resveratrol. This positive effect of tebuconazole has not been observed before.

Triazole fungicides (TAFs) are frequently used fungicides for various antifungal treatments of crops. Tre treatment is provided foliarly. However, some significant amount of TAFs may remain on/in fruits. We have developed a methodology for the determination of penconazole, tebuconazole and cyproconazole in tomato fruit peel. The extraction of TAFs was provided with chloroform (acidified with 0.1% acetic acid). In the electrokinetic chromatography, the mixed micellar pseudo-stationary phase was composed of anionic detergent sodium dodecyl sulphate (15 mM) and randomly highly sulphated gamma-cyclodextrin (17.5 mg/mL). The background electrolyte consisted of 100 mM phosphoric acid and 100 mM Tris in the mixed hydro-organic solvent water/methanol (80/20 v/v), apparent pH 4.8. Complete separation of penconazole, tebuconazole, and two diastereomers of cyproconazole with resolutions higher than 5.1 were achieved within a relatively short time of less than 17 min in the bare fused silica capillary of 425/500 mm total/effective lengths and 50/375 μm I.D./O.D. at separation voltage -15 kV (cathode at injection capillary end) and at constant capillary cassette temperature of 22°C. The TAFs were detected by a UV-spectrophotometric diode array detector set at 200 nm. The limits of detection and limits of quantification were in the range of 71-92 and 214-278 μg/kg of peel, respectively. Analyses of the peel extracts revealed that even 10 days after the last treatment, TAF concentrations were higher than the recommended maximum residue limits in both application ways, as individual as well as in the TAF binary or ternary mixtures.

Triazolic fungicides are widely applied in crop production to protect plants against fungal pathogens. However, they may influence the biochemical processes in plants and other non-target species. This paper is aimed at the effect of triazoles (namely tebuconazole, cyproconazole, and penconazole) single/mixed applications on the phenolics production in tomato (Solanum lycopersicum L.) fruit peel, amount of chlorophyll a and b in tomato leaves as well as on basic plant growth parameters. For this purpose, cherry tomatoes were planted in the pot experiment and foliarly-treated weekly, with the same total triazoles dose of 3.52 μmol per plant (in mixtures of 1.71 or 1.17 μmol of each in two or three components, respectively). The treatments increased the weight of fruits in the 1 harvest about 43%, however, this effect was not observed in the next harvest. Increased oxidative stress in the triazoles presence was observed, based on the elevated production of antioxidant phenolics in the 1 harvest. Most alarming is the decrease of the weight of thin stems and foliage and the concentration of chlorophyll a (b) in leaves in all triazoles-treated variants. The non-target impacts on plant biochemical processes (related to the phenolics or chlorophylls production and functionality) were confirmed.

RATIONALE Frequently used pesticide cyproconazole (Cyp) interacts with essential elements commonly present in soil and playing important roles in various enzymatic processes. These interactions predetermine Cyp degradation pathways. We suggest a simple experimental and theoretical approach for the prediction of pesticides behavior. METHODS Cu/Cyp complexes are explored because of the typical Cu(II) reduction in complexes. Its level and the stability of Cu-ligand bond depend on the type and the number of the surrounding ligands. Zn/Cyp complexes were compared as it is not expected that Zn(II) will reduce. The complexations were studied by means of electrospray ionization ion trap mass spectrometry and MS/MS collision induced dissociations with comparative and explicative density functional theory calculations. RESULTS Cyp ligand allows both, Cu(II) reduction as well as, in specific cases, it protects the higher Cu oxidation state. The reduction is observed in the complexes with solely neutral Cyp where the ligands number is below 3, higher number protects the Cu(II) state. The metal atom binds to Cyp via 2N of the triazole ring as well as via π–electrons of the benzene ring, additional stabilization brings the interaction with deprotonated OH group. CONCLUSIONS The character of Cyp interactions with doubly charged metals (Cu(II), Zn(II)) clarified the creation of Cyp metabolites. The phenyl and triazole rings are bounded to metal cation and take accessible the isopropyl ring to be cleaved leaving the common metabolite (CAS Number: 58905-19-4).

The azoles (represented by penconazole, cyproconazole, and tebuconazole in this study) are frequently used agrochemicals to protect various crops against mildew and fungi. They are considered as endocrine disruptors, because they block the biosynthesis (on the level of enzymes inhibition) of biochemicals with steroid structure. Besides targeted impacts, they can partly get into the soil with the rainfall or litter fall and influence/block the biosynthesis of sterols of non-target organisms. In this sense, the risk of disruption of rhizosphere plant-microbial symbiosis and dynamic processes in the soil solution by azoles is of high importance to be evaluated. We have developed an analytical methodology for determination of penconazole, cyproconazole, and tebuconazole in soil solution using capillary electrophoresis with a photodiode array detector at UV-214 nm and acidic electrolyte solution (pH 1.48). The results were also compared with mass spectrometric measurements using mu-TOF mass spectrometry. There approx. 90% of present azoles were bound in the soil solution matrix. The detection limit for these azoles is about 10(-7) mol dm(-3). Because of very low pK(a) of azoles, we have to consider deprotonation of azoles and consequently the high affinity to create complexes with cations. The majority of present azoles in soil solution might form neutral adducts with mono-cations, making them invisible in electrospray mass spectra. [GRAPHICS] .

The effect of solvent on the strength of noncovalent interactions and ionic mobility of the dibenzo-18-crown-6 complex with K+ in water/organic solvents was investigated by using affinity capillary electrophoresis. The proportion of organic solvent (methanol, ethanol, propan-2-ol, and acetonitrile) in the mixtures ranged from 0 to 100 vol. %. The stability constant, KKL, and actual ionic mobility of the dibenzo-18-crown-6-K+ complex were determined by the nonlinear regression analysis of the dependence of the effective electrophoretic mobility of dibenzo-18-crown-6 on the concentration of K+ (added as KCl) in the background electrolyte (25 mM lithium acetate, pH 5.5, in the above mixed hydro–organic solvents). Competitive interaction of the dibenzo-18-crown-6 with Li+ was observed and quantified in mixtures containing more than 60 vol.% of the organic solvent. However, the stability constant of the dibenzo-18-crown-6-Li+ complex was in all cases lower than 0.5 % of KKL. The log KKL increased approximately linearly in the range 1.62–4.98 with the increasing molar fraction of organic solvent in the above mixed solvents and with similar slopes for all four organic solvents used in this study. The ionic mobilities of the dibenzo-18-crown-6-K+ complex were in the range (6.1–43.4) × 10−9 m2 V−1 s−1. This article is protected by copyright. All rights reserved

An electrochemical device enabling selection of the working electrode was developed to be hyphenated with a mass spectrometer equipped with an electrospray. The device contains a rotatable block (carousel) with three ports for working electrodes, which can be easily chosen (changed) by a rotation of the carousel. The method takes advantage of the high reactivity of electrochemically generated metallic ions “in statu nascendi”. The device is suitable for ionization of various organic compounds (e.g., lipids, lipoproteins, pesticides, drugs, metabolites, lipids, lipoproteins) in biological and other matrices. The wide range of applications is made possible by the selection from three different solid electrodes placed in the carousel. This technical upgrade allows providing a number of possible chemical adducts and hereby the method can be tailored according to specific demands. The applicability of the electrochemical device is demonstrated by the electrochemical activation of pesticide cyproconazole (Cyp) in a soil solution matrix via formation of its adducts with Ag and Cu cations, generated from the working electrode material. The metal/Cyp adducts are on-line detected using an electrospray ionization mass spectrometer.

Affinity capillary electrophoresis (ACE) is typically used for the determination of stability constant, Kst, of weak to moderately strong complexes. Sensitive detection such as mass spectrometry (MS) is required for extension of ACE methodology for estimation of Kst of stronger complexes. Consequently, an efficient interface for hyphenation of CE with MS detection is necessary. For evaluation of interfaces for electrospray ionization mass spectrometric (ESI/MS) detection in ACE conditions, potassium-crown ether complexation was used as model system. The effective mobilities of the crown ether ligands and the Kst of their potassium complexes were measured/determined by ACE-ESI/MS using two lab-made interfaces: (i) a sheathless porous tip CE-ESI/MS interface and (ii) a nano-sheath liquid flow CE-ESI/MS interface, and, in turn, compared with those obtained by ACE with UV spectrophotometric detection. Apparent stability constant of potassium-crown ether complexes in 60/40 (v/v) methanol/water mixed solvent, pH* 5.5, was about 1300 L/mol for dibenzo-18-crown-6, 1600 L/mol for benzo-18-crown-6 and 5200 L/mol for 18-crown-6 ligands, respectively. It was observed that electrophoretic mobilities from CE-MS experiments differ from reference values determined by UV detection by ∼7% depending on the CE-MS interface used. Good agreement of CE-MS and CE-UV data was achieved for nano-sheath liquid flow interface, in which the spray potential and the CE separation potential can be effectively decoupled. As for sheathless porous tip interface, a correction procedure involving a mobility marker has been proposed. It provides typically only ca. 1% difference of effective mobilities and Kst values obtained from CE-MS data as compared to those received by the reference ACE-UV method.

By employing electrospray ionization mass spectrometry (ESI-MS), it was proven experimentally that the [6]helicene–Ag + complex (i.e., [Ag(C 26 H 16 )] + ) exists in the gas phase. Further, applying quantum mechanical DFT calculations, the most probable structure of this cationic complex [Ag(C 26 H 16 )] + was derived. Finally, in the solid state, the complex [6]helicene–silver perchlorate–monohydrate (i.e., C 26 H 16 –AgClO 4 –H 2 O), crystallizing in the monoclinic system with the centro-symmetric P 2 1 / c space group, was prepared and analyzed by X-ray crystallography.

By using electrospray ionization mass spectrometry (ESI-MS), it was proven that the univalent silver cation (Ag + ) forms with [6]helicene (C 26 H 16 ) the cationic complex species [Ag(C 26 H 16 )] + . Further, by means of the collision-induced dissociation (CID) experiments, the appearance energy ( AE ) of the proven complex was found to be 255.0 kJ mol −1 . Finally, applying quantum mechanical DFT calculations, the most probable structure of the resulting complex was derived.

By employing electrospray ionization mass spectrometry, it was proven experimentally that the [6]helicene–Ag+ complex (i.e., [Ag(C26H16)]+) exists in the gas phase. Further, applying quantum mechanical DFT calculations, the most probable structure of this cationic complex [Ag(C26H16)]+ was derived. Finally, in the solid state, the complex [6]helicene–silver triflate–monohydrate (i.e., C26H16–AgCF3SO3–H2O), crystallizing in the monoclinic system with the centro-symmetric P21/c space group, was prepared and analyzed. The characteristic feature of this complex packing in the solid state is the formation of the separated [6]helicene and silver triflate domains. In both of these binding modes, the investigated [6]helicene ligand functions as a molecular tweezer for the univalent silver cation.

Cu(II) creates complexes with dipalmitoylphosphatidylcholine (lecithin), which are detectable using electrospray ionization mass spectrometry. Lecithin (L) as a relatively big ligand prevents Cu(II) reduction to Cu(I) during the electrospray process. The detected complexes include (1) dications with a general formula: [Cu(L) n ]2+, where n prevails from 2 to 5 (in the m/z range from 50 to 2,000); and (2) monocations originated from the metal salt precursor [CuCl(L) k ]+ (k is 1 or 2). The Cu(II)/lecithin complexes are stable enough (appearance energy higher than 200 kJ mol−1) to utilize Cu(II) for stabilization of an artificial membrane. The impermeability of an artificial phospholipid membrane for oxalic acid and its complexes with copper ions in slightly acidic pH 5 was confirmed voltammetrically. However, adsorption of copper–oxalate complexes on the membrane surface was proved using electrochemical impedance spectroscopy. .

Dimethyl sulfoxide (DMSO) is widely utilized compound in biomedical and technological applications. Predominantly, it is used for biomembranes opening during a drug delivery procedure. The mechanism of DMSO membrane treatment is influenced by DMSO interactions with Ca 2+ as well as with water presence. In this study we investigate Ca 2+ interactions with DMSO in an aqueous environment using electrospray ionization mass spectrometry supported by density functional calculations. The number of DMSO ligands in [Ca(DMSO) x ] 2+ depends on the conditions during the electrospray and ion-transfer process. At capillary temperatures lower than 120 °C the complexes with a high number of DMSO are preferentially transferred to the gas phase (e.g. [Ca(DMSO) 6 ] 2+ ). With increasing temperature the number of DMSO ligands decreases while they are replaced with water molecules. Both the experiment and the calculations show that the bonding energy of DMSO to Ca 2+ is strongly influenced by the presence of water. The calculations also demonstrate that the bonding of DMSO to Ca 2+ is rather strong; the Ca 2+ -DMSO bonding energy was calculated to be two times higher than the Ca-H 2 O bonding energy.

The frequent use of pesticides in crop protection leads to their accumulation in soil as well as to the formation of their complexes with ions present in soil. The formation of such complexes can change the mobility of both the pesticides and the ions as well as their ability to penetrate biological membranes and enter biota. The problem of triazole-fungicide complexation with dications is demonstrated on the case of zinc and cadmium ions (M). Complexation with tebuconazole ( 1 ) has been studied using electrospray ionization mass spectrometry and quantum mechanical DFT-based computations. These experiments have revealed that the deprotonation of 1 leads to the stabilization of the complexes formed, which has been confirmed by our computations. In terms of stability, two types of complexes have been described: (i) a less stable complex (approx. 125 kJ mol −1 ) with neutral 1 [M( 1 ) 2,3,4 ] 2+ and [MCl( 1 ) 1,2 ] + , and (ii) a more stable complex (approx. 220 kJ mol −1 ) with deprotonated 1 [M( 1 ) n ( 1 -H)] + ( n = 0,1). The high stability of the complexes with deprotonated 1 is given by their stabilization via a metal interaction with the oxygen atom or phenyl ring. The structure of [M( 1 -H)] + is very compact when compared to the structure of parent 1 .

Tebuconazole ( 1 ) belongs to a class of widely utilized plant fungicides, mostly in vineyards. Consequently, traces of this compound are present in plant tissues, wine as well as in soil. The aim of this study was in situ generation of Cu cations and creation of very stable Cu complexes with 1 . The proposed method involves a hyphenation of electrochemistry with electrospray ionization mass spectrometry (ESI-MS), based on the high affinity of 1 for dissolved copper cations. We demonstrate that at appropriate potentials (above 500 mV vs. silver reference electrode) Cu cations can be generated in an electrochemical cell, which subsequently form complexes with 1 present in the sample. The resulting complex [Cu( 1 )] + as well as its fragment [Cu( 1 -C 4 H 10 )] + are then detected with online-coupled ESI-MS. This finding is useful for a creation of an analytical method based on the detection of trace amounts of 1 in complex matrices (e.g., soil solution), in which the analyte may be spread among various species.

The complexes formed between copper and thiram and between mercury and thiram have been electrochemically (voltammetrically) investigated in the present work. Their structure was confirmed using electrospray ionization mass spectrometry. Due to formation of the complex between copper (from copper solid amalgam electrode) and thiram, the concentration of this pesticide can be determined. The voltammetric behavior of thiram was investigated at polished (p-CuSAE) and mercury meniscus modified (m-CuSAE) copper solid amalgam electrodes (inner diameter 1.5 mm) by differential pulse voltammetry (DPV) and by direct current voltammetry (DCV). Optimum conditions for DPV determination of thiram were found in Britton–Robinson buffer. The reaction mechanism was investigated using DCV and elimination voltammetry with linear scan. DPV with optimized parameters was applied for determination of thiram in analyzed solutions. The limits of detection were calculated as 16 nmol L−1 (t acc = 100 s) for m-CuSAE and 23 nmol L−1 (t acc = 60 s) for p-CuSAE. The proposed method was successfully applied for thiram determination in real sample solutions.

The effect of solvent on the strength of noncovalent interactions and ionic mobility of the dibenzo-18-crown-6 complex with K

Electrospray ionization was used as a technique for the characterization of the interactions between cadmium(II) ions and malic acid (1) in aqueous solution. Particular attention was paid to the nature of the species formed, which generally correspond to complexes of CdX(+) cations with neutral malic acid, where X either is the counterion of the metal salt used as a precursor (i.e. X=Cl, I) or corresponds to singly deprotonated malic acid. In pure water solutions, also highly coordinated complexes [Cd(1-H)(1)(2)](+) and [CdCl(1)(2)](+) were detected, whereas the most abundant complexes detected in a sample of soil solution were: [Cd(1-H)(1)](+) and [CdCl(1)](+). With respect to possible application in environmental analysis, the effects of (i) metal salts present in solution, (ii) modest mineralization, and (iii) the matrices of real soil solutions were probed. While the presence of other metals leads to additional complexes, the characteristic species containing both cadmium(II) and malic acid can still be detected with good sensitivity.

The formation of complexes between tebuconazole (Teb) and cadmium in simplified model solutions as well as soil solutions was studied using electrospray ionization mass spectrometry. Teb and cadmium form two types of complexes with the general formulas [Cd(Teb)n]2+ (n = 1–4) and [CdI(Teb)m]+ (m = 1–3), where iodine corresponds to the counterion used. The most intense Teb/cadmium complex is [CdI(Teb)2]+, and the most stable one is [Cd(Teb)(Teb − H)]+. Another detected complex, the dication [Cd(Teb)4]2+, was considered as the origin complex for the iodine-free complexes and was found in a sample prepared from forest soil solution naturally contaminated with cadmium ions.

Electrospray ionization mass spectrometry (ESI-MS) is used to probe the complex formation between tebuconazole (1) and copper(II) salts, which both are commonly used fungicides in agriculture. Experiments with model solutions containing 1 and CuCl2 reveal the initial formation of the copper(II) species [(1)CuCl]+ and [(1)2CuCl]+ which undergo reduction to the corresponding copper(I) ions [(1)Cu]+ and [(1)2Cu]+ under more drastic ionization conditions in the ESI source. In additional experiments, copper/tebuconazole complexes were also detected in samples made from soil solutions of various origin and different amount of mineralization. The direct sampling of such solutions via ESI-MS is thus potentially useful for understanding of the interactions between copper(II) salts and tebuconazole in environmental samples. Copyright © 2011 John Wiley & Sons, Ltd.

The stabilization of lecithin layer physically adsorbed on the interface between two immiscible electrolyte solutions (ITIES) using addition of Yb3+ to the aqueous phase was studied using cyclic voltammetry. Stability of this layer was evaluated according to the time of the layer formation; the optimal time amounted to 180 s. The stability of the layer as a function of the potential applied on the system during the layer formation was investigated. The behavior of the monolayer during the layer polarization was studied by the facilitated K+ transport using dibenzo-18-crown-6. The stoichiometry of Yb/anion/lecithin complexes was investigated using electrospray ionization mass spectrometry (ESI-MS).

A young speckled alder ( Alnus incana (L.) Moench) stand was planted on a tract clear-felled due to air pollution and located on a summit plateau of the Jizerske hory Mts. (Central Europe, Czech Republic) at an altitude of 950 m a.s.l. The aim of the experiment was to test the suitability of Alnus incana to form preparatory stands covering the site and thus enabling the reintroduction of more sensitive target species. A potential of Alnus incana to respond to slow-release fertilizing was tested as well. The control treatment showed sufficient growth dynamics, nevertheless, the fertilization significantly promoted the growth (documented by height, height increment and stem-base diameter). If some limitations of alder such as high light requirements are respected, the speckled alder can be recommended as a suitable species for preparatory stands even in the 7 th and 8 th altitudinal (vegetation) zones, especially when fertilized.

The Cd and Pb complexes with oxalic (OA) and citric acid (CA) were detected in model and soil solutions using cyclic and stripping voltammetry. A mixed complex consisting of Cd, Pb, and OA was found; its peak potential varied from −582.0 to −542.5 mV (vs. Ag/AgCl/KCl(3 mol L−1)). For mixed complex formation, the presence of PbOH+ species and Cd2+ in oxalic acid solution was necessary. Only the ‘simple’ complexes of CA with Pb and Cd were found in the model solution. The existence of all investigated metal complexes is confined to neutral pH range. The mixed complex was also found in real soil solutions.

In experiments with willow planted in cadmium- or lead-contaminated Knopp nutrient solutions, the ability of willow and chelex gel in the diffusive gradient in a thin film (DGT) unit to absorb these elements was observed and compared. A method to compare the accumulated amount of metals by the willow and the sorbed amount of metal onto the DGT unit was designed. The accumulatedysorbed amount of metals was recalculated to the same units (m gc m � 2 day � 1 ). The study of Cd(Pb) dynamic uptake by willow showed an exponential decrease of metal content in the exposure solution. The willow planted in the Knopp nutrient solution accumulated Cd(Pb) less than did the DGT unit in the same matrix. The willow planted in the soilywater system accumulated more lead than did the willow in a lead-contaminated aquatic system nor did the DGT unit in the nitrate matrix. The willow further accumulated lead from the soilywater system due to the active co-uptake of nutrients and lead. The DGT technique was considered as very good comparative method to measure heavy metals plant uptake. This technique is suitable for use in water as well as in soil systems.

In the soil solutions obtained in situ with suction cups from soils (Cambisol and Fluvisol) of pot experiment with Salix smithiana Smith, Lolium perenne L. and Thlaspi caerulescens J. & C. Presl heavy metals species (Cd, Pb and Cu) were assayed by differential pulse anodic stripping voltammetry and diffusive gradient in thin films. Prediction of accumulation performed best at free metal ion concentrations in unchanged pH (in 10−3 mol L−1 NaClO4 base electrolyte). The speciation provided by differential pulse anodic stripping voltammetry according to pH can provide a detailed description of the soil solution matrix. The concentration of free metals in unchanged pH represents a small part of the total content and varied from 0.04 to 0.75% with two exceptions found for accumulating plants (the content of Cd2+ in the soil solution from T. caerulescens was about 6% and the content of Cu2+ in the soil solution from S. smithiana was about 30%). The available concentration as determined by diffusive gradient in thin films was not in correlation with the heavy metals concentration in plant biomass.

The changes in the availability of selected elements (Ca, Mg, K, Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) 16 years after amphibolite treatment were studied in the root zone of spruce (40 and 80 cm from the stem base) using the diffusive gradient in thin film (DGT) technique. The effective concentrations of some of the tested elements significantly increased (Ca (34 %), Mg (31 %), K (65 %), Al (143 %), Fe (242 %), and Pb (27 %)) in 80 cm distance from the stem, whereas the total and the water-soluble concentrations of the elements did not differ from the control. The changes in effective concentrations of the elements in soil were related to higher vitality of the trees on amended soil in contrast to the control.

Pressure assisted capillary electrophoresis was applied to determination of acid dissociation constants (pKa) of six widely used triazole fungicides (cyproconazole, epoxiconazole, flusilazole, tebuconazole, penconazole and propiconazole) in aqueous medium. The pKa values were determined from the dependence of effective electrophoretic mobility of the triazole fungicides on p[H(+)] of the background electrolyte (BGE) using non-linear regression analysis. The p[H(+)] was used instead of pH to reflect the increased ionic strength of the strongly acidic BGEs (pH

Concentrations and bioavailability of Al, Fe, Cd, Pb, Cu, Zn, and Mn in mountain forest soil replanted with speckled alder (Alnus incana (L.) Moench) are explored 7 years after soil surface vs. planting hole application of amphibolite and dolomitic limestone mixture. The mechanisms of slow limestone dissolution are explained and discussed from broader systematic view. The aspects of soil pH and oxidable carbon and the cation exchange capacity changes as well as changes of water-soluble, total, and effective concentrations of tested elements in the amended soils are included. The soil amendment invoked the depletion of K (and slightly Zn) effective concentration. The total concentrations of Ca, Mn, Al, and partly Mg in soil were increased owing to the presence of these elements in the amendment; the water-soluble concentrations nor effective concentrations of Al, Mn, Zn, Cu, Cd, and Pb were increased. Moreover, the effective concentration of Al in both amended variants decreased. The usual negative side effects of liming were not observed due to the slow dissolution of the amendment. Further, the surface application of the amendment is cheaper than the planting hole application, but there are some expected losses of the amendment by concurrent uptake by grass and by flushing.

The article summarizes outcomes of a biomass study conducted in a young speckled alder plantation on a cold mountain site. At this location, the previously existing old forest was clear felled because of damage from air pollution, and present-day surface humus is in need of restoration. The intention of this study was to quantify the biomass and nutrients accumulated by alders and their components and assess whether the initial fertilization resulted in increased biomass production and nutrient accumulation in the biomass. Besides the control, two fertilized treatments were installed. In the surface treatment (SUT), the amendment was applied as a base dressing in small circles around trees. In the planting-hole treatment (PHT), the amendment was incorporated into soil inside the planting holes. Five growth seasons after planting and fertilization, six alders from each treatment were harvested including roots. Their biomass was quantified and analyzed for macroelements. The greatest pool of dry mass (DM) was branches in the control and stem wood in the fertilized treatments. The greatest pools of macroelements were leaves and branches. The most pronounced effects of fertilization were recorded in the DM and consequently in the absolute quantities of nutrients. The DM of an average tree in the control, SUT, and PHT was 85, 226, and 231 g, respectively. The absolute contents of nutrients per tree in the fertilized treatments showed the following increases, as compared with the control: (N) 2.5–2.6 times; (P) 1.6–2.4 times; (K) 1.8–2.1 times; and (Mg) 1.8–2.0 times, respectively. Speckled alder responded positively to fertilization.

Electrospray ionization mass spectrometry (ESI-MS) is used to probe the complex formation between tebuconazole (1) and copper(II) salts, which both are commonly used fungicides in agriculture. Experiments with model solutions containing 1 and CuCl(2) reveal the initial formation of the copper(II) species [(1)CuCl](+) and [(1)(2)CuCl](+) which undergo reduction to the corresponding copper(I) ions [(1)Cu](+) and [(1)(2)Cu](+) under more drastic ionization conditions in the ESI source. In additional experiments, copper/tebuconazole complexes were also detected in samples made from soil solutions of various origin and different amount of mineralization. The direct sampling of such solutions via ESI-MS is thus potentially useful for understanding of the interactions between copper(II) salts and tebuconazole in environmental samples.

This study presents a new analytical approach for the determination of heavy metals complexed to low-molecular-weight-organic acids in soil solutions, which combines the sensitivity of differential pulse anodic stripping voltammetry (DPASV) with the molecular insight gained by electrospray ionization mass spectrometry (ESI–MS). The combination of these analytical methods allows the investigation of such complexes in complex matrixes. On the voltammograms of the soil solutions, in addition to the expected complexes of oxalic acid with cadmium and lead, respectively, also peaks belonging to mixed complexes of cadmium, lead, and oxalic acid (OAH 2 ) were observed. In order to verify the possible formation of complexes with OAH 2 , aqueous solutions of OAH 2 with traces of Cd(II) were investigated as model systems. Signals corresponding to several distinct molecular complexes between cadmium and oxalic acid were detected in the model solutions using negative-ion ESI–MS, which follow the general formula [Cd n ( X , Y ) (2 n +1) ] − , where n is the number of cadmium atoms, X = Cl − , and Y = OAH − . Some of these complexes were also identified in the ESI mass spectra taken from the soil solutions.

led alder is a convenient pioneer species that can be cultivated on harsh mountain sites where the climatic extremes need to be alleviated and a layer of surface humus renewed. The initial slow-release fertilization is, nonetheless, highly desirable. As contrasted to the control the surface and planting hole applications of amendment reduced the total seven-year mortality rate by 9.5% and 20.1%, respectively, and the periodic annual height increment (2003-2009) was promoted by 47% and 59%, respectively. Analogous results were obtained when the values of basal stem diameter and crown diameter were compared. As for the method of application, the placement of the slow-release amendment in the planting holes seems to be more efficient mainly in terms of survival promoting. The surface application is, nonetheless, less laborious and also yielded satisfactory results.