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The preparation of stable cysteine-capped silver nanoparticles (AgNPs), via the reduction of silver ions with sodium borohydride and modification of formed nanoparticles by l-cysteine, was developed. The micrographs from transmission electron microscopy (TEM) revealed that the spherical AgNPs exhibited an average size equal to 22±4nm. Surface enhanced Raman spectroscopy (SERS) and inductively coupled plasma optical emission spectrometry (ICP-OES) confirmed a chemisorption of cysteine molecules on the AgNPs. Additionally, dynamic light scattering (DLS) measurements showed that the AgNPs were stable for ionic strength lower than 5×10-3molL-1 and at 6.8

In the paper an application of solid phase extraction technique for speciation analysis of manganese in water samples with the use of flame atomic absorption spectrometry is presented. Two types of sorbents, activated silica gel and Dowex 1 × 4, were used respectively for simultaneously Mn 2 + and MnO 4 2 − retention and preconcentration. The whole procedure was realized in multicomutation flow system. Different conditions like: type and concentration of eluent, sample pH and loading time were tested during the study. Under appropriate conditions, it was possible to obtained enrichment factors of 20 and 16 for Mn(II) and Mn(VII), respectively. Precision of the procedure was close to 4% (measured as relative standard deviation), whereas the detection limit (3σ) was 1.4 μg·L − 1 for Mn(II) and 4.8 μg·L − 1 for Mn(VII).

The speciation of Mn(II) and Mn(VII) is reported by ion pair chromatography. To optimize the separation, sample pH, ion pair reagent, Mn(II) complexing agent, and composition of mobile phase were c...

Selenium was determined in serum, hair, and tobacco by inductively coupled plasma-mass spectrometry using 77Se, 78Se, and 82Se. The set of standards method (SSM) and the standard addition method (SAM) were applied to calibration with and without the use of internal standards (72Ge and 103Rh). In addition, the usefulness of the dynamic reaction cell (DRC) with methane as the reaction gas was characterized. The results obtained in different conditions were evaluated in terms of precision and accuracy. It was demonstrated theoretically and experimentally that an internal standard is a potential source of systematic errors as it can be influenced multiplicatively and additively by its own interferents (independently of selenium). Furthermore, it was shown that—against common opinion—an internal standard can fail in elimination of chemical interference effects influencing selenium and in increasing of precision of selenium determinations. The DRC was shown to be effective in the elimination of additive...

Background Biofortification with selenium (Se) elevates its concentration in feed and fodder plants and helps to prevent health problems in animals and humans. The aim of this study was to describe Se-induced modifications in the accumulation of elements important for the proper functioning of wheat, one of the most popular cereals. The presence of Se correlated with carbohydrate synthesis and electron paramagnetic resonance (EPR). This explained the mechanisms of Se's antioxidant activity. Results Selenium accumulation in vegetative and generative leaves, and in the grains of three wheat genotypes (cv. Parabola, cv. Raweta and cv. Manu), differing in their stress tolerance and grown hydroponically in the presence of 10 or 20 μM Na2 SeO4, , was proportional to its content in the medium. Stronger Se accumulation was typical of a stress-sensitive genotype. Selenium generally promoted the uptake of macronutrients and micronutrients but their distribution depended on tissue and genotype. Changes in the Se-induced EPR signals of paramagnetic metals and organic radicals corresponded with stress tolerance of the tested genotypes. Conclusions Se application increased the accumulation of nutrients and carbohydrates that are vital for proper plant growth and development. Accelerated uptake of molybdenum (Mo), an element improving dietary properties of grains, may be an additional advantage of Se fertilization. The mechanisms of Se-induced changes in removing Mn and iron (Fe) ions from macromolecules may be one of the factors that differentiate plant tolerance to oxidative stress. © 2019 Society of Chemical Industry.

The growing popularity of nanomaterials requires a systematic study of their effects on the human body. Silver nanoparticles (AgNPs), due to their antiseptic properties, are used in almost every area of life. The purpose of the study was to examine whether the precursor used for the synthesis of nanoparticles affects their bio-influence and modifies their impact on cells of the human immune system. To compare the effects of precursor silver salts (AgNO3, CH3COOAg and AgClO4) and corresponding nanoparticles (TAN TAA and TAC) cytotoxicity study was conducted on two cell lines U-937 and HL-60. For both cell lines, silver salts are more toxic than the corresponding nanoparticles. Cell viability after treatment with the two forms of silver (salt/particle) is dependent on silver dose and degree of cells differentiation. Addition of the silver salt of doses greater than 5 mg/L results in decreased cell viability by over 60%, whereas nanoparticles' addition reduces cell viability on average by 30%. On the basis of the determined LD50 values it can be stated that for the tested cells the most toxic are AgClO4 and TAC. Production of nitric oxide, which is a mediator of inflammation, is the greatest after treatment of the cells by TAC. Different interactions of studied nanoparticles with albumin has been found and it was shown that addition of albumin to the cells treated by nanoparticles reduces their toxic effects. Obtained by us highly purified, mono-disperse AgNPs exhibit diverse effects relative to the biological systems, depending on the precursor salt used.

Teeth retain different elements at particular stages of life. Hence, the exposure over a selected time span may be characterized by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). A Nd:YAG laser with emission at 266 nm was coupled to a quadrupole ICP-MS for the quantitative study of historical human teeth for Sr and Ba, elements of anthropological significance. A calibration approach incorporating the experimentally derived k coefficient is reported. The coefficients were established based on the mean concentrations of the analytes determined by pneumatic nebulization ICP-MS using acid-digested calcium phosphate standards and the intensities recorded during laser ablation of corresponding standards as pellets. The k values were 0.54 ± 0.05 (µg g−1)−1 and 4.49 ± 1.09 (µg g−1)−1 for Sr and Ba, respectively. This calibration approach provided local quantitative data and demonstrated statistically significant differences in Sr concentrations in enamel and dentine.

A general model of an oxidative dissolution of silver particle suspensions was developed that rigorously considers the bulk and surface solute transport. A two-step surface reaction scheme was proposed that comprises the formation of the silver oxide phase by direct oxidation and the acidic dissolution of this phase leading to silver ion release. By considering this, a complete set of equations is formulated describing oxygen and silver ion transport to and from particles' surfaces. These equations are solved in some limiting cases of nanoparticle dissolution in dilute suspensions. The obtained kinetic equations were used for the interpretation of experimental data pertinent to the dissolution kinetics of citrate-stabilized silver nanoparticles. In these kinetic measurements the role of pH and bulk suspension concentration was quantitatively evaluated by using the atomic absorption spectrometry (AAS). It was shown that the theoretical model adequately reflects the main features of the experimental results, especially the significant increase in the dissolution rate for lower pH. Also the presence of two kinetic regimes was quantitatively explained in terms of the decrease in the coverage of the fast dissolving oxide layer. The overall silver dissolution rate constants characterizing these two regimes were determined.

Recently, many studies have investigated the relationship between the level of metals in the body and various diseases. The objective of this study was to examine any possible influence of periodontal disease upon the concentration of metals in oral fluid and blood and to explore the usability of applying cluster analysis coupled with the analysis of selected elements in oral fluid, calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), zinc (Zn), cadmium (Cd) and lead (Pb), for effectively distinguishing people affected by periodontitis from healthy individuals. The quantification of eight metals in oral fluid and blood samples was performed by two inductively coupled plasma techniques–inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES). Most of the examined elements were detected at elevated concentration in the oral fluid of periodontal patients. However, the differences were statistically significant in the case of three metals: Cu, Mg and Mn (p

Infrared spectroscopic studies have been carried out to address the question of the Cu+ cation migration from hexagonal prisms (SI) and cubooctahedra (SI′) to supercages upon adsorption of ethene and ethyne in CuNaY and CuNaX zeolites. The quantitative assessment of Cu+ content in supercages before ethene and ethyne adsorption was evaluated on the basis of carbon monoxide adsorption experiments and molar absorptivities of Cu+(CO) bands. The same procedure was adapted to estimate the concentration of Cu+ inside supercages in the presence of ethene and ethyne, where the appropriate molar absorptivities of Cdouble bond; length as m-dashC and Ctriple bond; length of mdashC bands was applied. This method seems to be complementary to XRD studies. Since it is insufficient to know the distribution of the cations between Sn positions, the actual number of the cationic sites engaged into the interaction with the reagents under the working conditions of the material was found with the use of IR spectroscopy.

For solid sample quantitative analyses by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), the main analytical problem is the calibration step: evaluation of the function (equation) that correlates the signal with the concentration of analytes in the sample. Except for basic standards preparation, problems result from non-stoichiometric effects during vaporization, transport of ablated aerosols, atomization, and ionization in the plasma. These effects, called elemental fractionation, are mainly sample matrix dependent and thus suggest that standards used for calibration should accurately match the sample matrix. Preparation of such standards is a difficult and time-consuming process, so since the beginning of LA-ICP-MS applications for quantification of solid sample composition, different approaches have been developed to solve the problem, primarily complete matrix matching. Because the calibration of LA-ICP-MS is a key factor for its quantification capabilities, this review summarizes recent calibration approaches and related standards preparation techniques for the analysis of various solid materials by LA-ICP-MS. Selected papers concern the application of reference glasses, solution based standards, synthetic standards based on the main sample matrix component or powdered matrix certified reference materials, matrix-matched standards based on spiked sample materials, and non-matrix-matched standards, for calibration. Isotope dilution methods and signal normalization protocols used in order to improve precision are also considered.

Environmental stresses are forcing breeders to produce new plant genotypes with higher resistance to stressors. Biochemical markers of stress tolerance would assist in the selection of tolerant cultivars on the early stages of plant development. The aim of these studies was to examine whether the concentration of micro and macroelements of embryos and/or endosperm could specify the wheat grains in terms of their tolerance to stress conditions. Two sensitive to drought (Radunia and Raweta), two tolerant (Nawra and Parabola) and one with intermediate tolerance (Manu) were chosen. After dividing embryos and endosperm, the microelements content (Mn, Fe, Cu, Zn and Mo) was analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and macroelements (K, Ca, Mg, P and S) by inductively coupled plasma optical emission spectrometry (ICP-OES). Independent of genotype, the concentration of all elements was higher in embryos than in endosperm. In both embryos and endosperm of tolerant plants, higher content of microelements (except for Cu in embryos) was detected. The accumulation of macroelements was lower in embryos of tolerant plants (except for K), however, in the case of endosperm, higher amounts of these elements, were registered. In embryos of Manu genotype, the content of microelements was more alike to sensitive and macroelements to tolerant plants but in endosperm, the level of both micro- and macroelements was more similar to tolerant ones. It was concluded that mineral composition of wheat grains, especially those in embryos, could inform about possible resistance of genotypes to stress conditions.

This paper describes a simple and sensitive method for the determination of manganese in human urine by graphite furnace atomic absorption spectroscopy (GFAAS), which includes sample preparation by microwave digestion. Matrix modifier combinations, the digestion power, pyrolysis, and atomization temperatures were optimized. A mixture of 5.0 µg Pd(NO3)2 and 3.2 µg Mg(NO3)2 modifier presented the best performance. The optimal temperatures for pyrolysis and atomization were 1500°C and 1950°C, respectively. The GFAAS method was compared to inductively coupled plasma–mass spectrometry (ICP–MS) for the determination of manganese in urine. Analytical figures of merit for GFAAS and ICP–MS were: accuracy (3.46%, 2.19%), precision (3.61%, 5.84%), LOD (0.109 µg · L−1, 0.015 µg · L−1), LOQ (0.327 µg · L−1, 0.045 µg · L−1), and recovery (80–100%, 74–89%). Both methods were employed for the determination of Mn in urine and the results were compared statistically.

Selenium (Se) is essential for health of humans, animals, and plants. Especially wheat is a major source of Se in the terrestrial food chain. In this study, an element analysis was optimized and the content of Ca, Mg, K, S, P, Fe, Se, Mn, Cu, Zn, and Mo in leaves, roots, and seeds were measured during growth of wheat (Triticum aestivum L. cv. Manu) in Hoagland nutrient solution with 5 and 15 μM Na2SeO4. Se was transported to all investigated tissues and accumulated in the seeds in proportion to used amounts. The supplementation of Se, independently of concentration, weakly modified the micro- and macro-elements content in the seedlings. In the flag-leaf stage, an increase of the Mo and S content in the shoots and the S and Cu content in the roots was found. Moreover, in the generative phase, a decrease in Ca and Fe in the roots was registered. Increased Se in the nutrient solution strongly stimulated the Se accumulation in the seeds.

Transition metal ions and radicals in flours of various botanical origins with different content of starch have been studied by EPR before and after thermal treatment. The amounts of metal ions, have been determined by ICP OES. Simulations of EPR spectra have revealed the presence of several types of radicals (carbon-centred, tyrosyl and semiquinone) localized in starch and protein fractions of flours. Thermal treatment of flours significantly increased the amount of radicals with a simultaneous decrease of the signal intensity of transition metal ions. The proposed mechanism of thermal generation of stable organic radicals was associated with the redox processes involving transition metal ions, which facilitated the formation of radicals. The dependence between the way starch is treated and the mechanism of radical formation was also shown.

A calibration procedure consists of several steps, each of which has a significant impact on the final result of the analysis. The preparation of standard samples for analytical calibration is a far more important step in the analytical procedure than it might seem. In this paper, we have discussed a new, innovatory calibration procedure, which is itself a development of one previously published by us concerning a calibration strategy in the determination of trace elements in rat brain tissues by the laser ablation inductively coupled plasma time of flight mass spectrometry (LA-ICP-TOF-MS) method. Moreover, the article has described an important step in the preparation of standard samples, which is both an innovation and exclusive to this work. The linearity of calibration function analysis is fully acceptable (for zinc R = 0.944 and for magnesium R = 0.989), and the applied calibration method, the conventional extrapolative method (CEM), known more generally as the “standard addition method”, makes it possible to avoid interferents from the sample matrix. The results show the usefulness of the procedure developed in the presented analytical problem related to the analysis of solid biological samples. The developed research methodology enabled the preparation of distribution maps of zinc and magnesium in the rat's hippocampus, which is a frontier providing unique research in the pathophysiology of a rat brain.

Here a new flow injection system is reported for the preconcentration of technetium by solid phase extraction. The system provides analyte preconcentration, reduces interferences from polyatomic ions, and prevents interaction of concentrated nitric acid with the inductively coupled plasma mass spectrometer. The volume of eluate was significantly reduced by collecting the eluate of the highest analyte concentration in an injection loop followed by transport to the spectrometer with dilute nitric acid. Due to the absence of a suitable standard reference material, the determination of technetium in peat was compared with liquid scintillation spectrometry.

Manganese as an essential element is required by organisms from simple bacteria to plants, animals and human beings. The identification and determination of organic or inorganic manganese forms are important from many viewpoints, such as their bioavailability or bioactivity. A review of the use of different analytical methods, which allow manganese speciation and fractionation in various types of matrices, such as soils, sediments, air, aerosols, water, plants, animals and polluted environmental samples, is presented in this study. The presented approaches assume mainly the use of indirect techniques from simple ones, such as extraction, through multistep procedures to more complex ones, such as hyphenated techniques. Direct analysis of manganese species is also possible, but unfortunately only in some cases and for selected samples. Significance of manganese speciation and fractionation in different areas of life and difficulties in performing such analysis pose a challenge.

The paper presents application of multiwall carbon nanotubes (MWCNTs) modified with 5-dodecylsalicylaldoxime to copper(II) flow-injection on-line preconcentration and flame atomic absorption spectrometric (FAAS) determination. Two new sorbents were obtained by impregnation of MWCNTs with Cu(II)-LIX 622® complex, however in the first case modification was preceded by carbon wall activation via oxidization (Cu-LIX-CNT-A sorbent), and in the second one no surface activation was performed (Cu-LIX-CNT sorbent). It was found that effective leaching of initially introduced copper and Cu(II) retained in preconcentration process could be realized with the use 7% and 5% (v/v) nitric acid, for particular sorbents. Testing the influence of loading solution pH and rate of loading on sorption it was found out that optimal range of loading solution pH was about 4.5–6.3 for activated and 6.15–6.25 for non-activated CNT. Investigation of sorption kinetics showed that the process can be described by pseudo-second order reaction model. Sorption equilibrium conditions (90% sorption) for LIX-CNT-A and LIX-CNT were obtained after 8–15 min, respectively and maximum sorption capacity for the new sorbents amounted to 18.1 mg g−1 and 31.6 mg g−1, respectively. For the examined sorbents enrichment factors increased with extension of loading time up to 180 s: linearly for activated and non-linearly for non-activated MWCNTs. Influence of potential interferents such as Cd(II), Zn(II), Fe(III), Mg(II) and Ca(II) ions on copper(II) sorption on the new CNT materials was examined individually and with the use of 25–2 factorial design. The study revealed significant interference from iron, magnesium and calcium ions at relatively high concentrations. Applicability of the proposed sorbents was tested for Cu(II) determination in various kinds of water samples and the results were compared with those obtained with the use of ICP MS as a reference technique. Copper(II) determination in two certified reference materials: waste water (EU-H-3) and ground (ES-H-2) water was performed in order to assess trueness of the evaluated preconcentration procedures. Satisfactory values of relative errors were obtained for both procedures.

A series of nanometric materials based on copper-doped cerium (IV) oxide was synthesized using a reverse (w/o) microemulsion method. The obtained powder precursors were tested by the thermal analysis methods coupled with evolved gas analysis (EGA-TGA/DTG/SDTA). Morphology and structure of the samples were characterized by XRD and BET analysis. The content of copper ions was determined using a ICP-OES spectrometer. The electronic structure of the catalysts was characterized by high-temperature electrical conductivity measurements at different pO 2. The obtained materials were tested in catalytic incineration of the selected VOCs (methanol and ethylene). The correlation between the activity of the catalysts and copper content as well as electrical properties has been confirmed.

The selenium effect on the uptake of micro- and macro-elements and the physiological properties of rape and Finnish and Polish wheat seedlings were studied. Selenium was added (in the form of sodium selenate) at two levels (100 and 200 μM) to in vitro culture media supplied with optimal doses of nutrients. The uptake and distribution (between upper parts and roots) of Se and the elements under study: P, S, K, Ca, Mg (macroelements), and B, Mn, Fe and Zn (microelements) were determined and related to the following parameters: plasmalemma fatty acid composition, membrane permeability and fluidity, and lipid peroxidation factor. Noticeable changes in the concentrations of the studied elements in Se treated plants were registered mostly in the case of rape seedlings. The changes caused by Se addition were stronger when the applied dose was higher. The determined parameters indicated that a 200 μM selenium dose added to the growth media of controlled composition represented the level at which stressogenic effects appeared in plants.

Two zeolites of different topology: ZSM-5 and ZSM-12 were subjected to desilication in the NaOH solutions of increasing concentrations. Changes in the properties of modified zeolites were investigated by several methods ( 29 Si and 27 Al MAS NMR, FTIR, SEM, XRD, and sorption techniques). It was shown that desilication led to the formation of mesopores, and indicated that the process started at the faulting sites called “silanol nests” for ZSM-5 while this mechanism for ZSM-12 was different. Acidic properties of parent and desilicated zeolites were investigated by the adsorption of pyridine and CO followed by IR spectroscopy. For both zeolitic series the number of Bronsted acid centres was virtually independent of the desilication progress (differences below 20%), while the number of Lewis centres increased by more than 100% in some cases. Pyridine thermodesorption experiment revealed the presence of the second type of Bronsted sites in desilicated zeolites, their acidic properties may be compared to the hydroxyls existing in mesoporous materials of M41S family.

The paper reports preparation and analytical features of a new Cu(II)-imprinted polymer, based on salen-OMe ligand 2,2′-[ethane-1,2-diylbis(nitrilo( E )methylylidene)]bis(6-allyl-4-methoxyphenol) and styrene–divinylbenzene matrix, as well as its application to on-line preconcentration and flame atomic absorption determination of copper. Sorbent beads (average diameter of 60–80 µm) were obtained using suspension polymerization technique and employed as a column filling. Copper sorption was the most effective at pH 6.8, whereas the highest elution effectiveness was observed when 0.5% HNO 3 was applied. The sorbent exhibited good long-term stability and acid resistance. Enrichment factor (EF) of 12 was found for 60 s loading time and loading flow rate of 4 mL min − 1 . EF value may be further increased by expanding the loading time and/or flow rate. Batch sorbent capacity in optimal pH conditions was found to be 0.16 mmol g − 1 (9.55 mg g − 1 ) of a dry polymer. Calcium(II) turned out to be the only significant interferent. Cadmium(II), silver(I), nickel(II), zinc(II) in concentrations lower than about 1 mg L − 1 did not disturb copper(II) preconcentration. Different calibration methods such as: set of standards method (SSM), standard addition method (SAM) and combinatory calibration method (CCM) were employed for copper(II) determination in tap water, spring mineral water and certified reference material. Analysis of EU-H-3 reference material confirmed good accuracy of the proposed method. Relative standard deviation (RSD) was 3.2 for standard addition method and 2.8% for set of standard calibration method. Detection limit for sample consumption 16 mL was 1.03 and 1.07 µgL –1 respectively.

The properties of Co 2+ in zeolites CoX and CoY and their interaction with CO, NO, and propene were followed. The IR experiments of CO and NO informed on the electron acceptor properties of Co 2+ sites and the influence of framework composition and of geometry of Co 2+ environment on the properties of Co 2+ . It has been found, that the activation of CO and NO is realized mostly by π back donation, on the other hand, the activation of C C double bond in propene is realized by π donation. The strength of molecules to Co 2+ bonding was followed in desorption experiments. It has been found, that σ donation in the case of CO and π donation has more important impact to the strength of molecule to Co 2+ bonding.

The aim of this study was to examine changes in activities of cytochrome c oxidase (CCO), glucose-6-phosphate dehydrogenase (G6PDH), Cu-Zn superoxide dismutase (Cu-Zn SOD), glutathione peroxidase (GSH-Px), glutathione (GSH) levels and copper (Cu), zinc (Zn) and selenium (Se) concentrations, and to assess the possible differences between preterm placentas, placentas from term pregnancies complicated by intrauterine growth restriction (IUGR) and full-term control placentas. The enzyme activities and the level of GSH decreased in IUGR and preterm placentas in comparison with the control group. CCO activity and GSH level in preterm placentas were markedly lower compared with the IUGR (P0.01; P0.05) and control (P0.01; P0.05) placentas, respectively. In IUGR placentas the level of Cu was reduced by 23% (P0.05) and Zn by 37%. In preterm placentas the level of Cu was reduced by 19% and Zn by 42%. Se level in IUGR and preterm placentas was higher (P0.05) by 28% and 32% than in control group, respectively. The strong relation was observed between birth weight and CCO activity, birth weight and Cu-Zn SOD activity, and a low level of Zn and Cu influenced the birth weight especially in IUGR cases. Moreover, the strong inverse correlation between Se level and birth weight, Se level and placental weight and Se level and CCO activity are new findings.

A new Cu(II)-imprinted polymer (Cu-IIP) for preconcentration of copper by liquid–solid extraction via flow injection technique has been proposed. Cu-IIP was obtained by copolymerization of salen–Cu(II) complex with styrene and divinylbenzene using suspension polymerization technique. Granules fraction of 60–80 μm in diameter was used as a microcolumn packing. Cu(II) sorption was proved to be the most effective from solutions of pH 7, whereas similar elution effectiveness was observed when applying as eluents hydrochloric or nitric acid in the concentration range of 0.5–10% (v/v). The system exhibited good long-term stability and acid resistance. Batch sorbent capacity was found to be 0.11 mmol g −1 of a dry polymer. Enrichment factor (EF) for 30 s loading time was 16. Preconcentration of Cu(II) and potentially interfering metal ions is strongly pH dependent. Examination of Cu(II) sorption in the presence of Pb(II), Cd(II), Zn(II) and Ag(I) showed significant influence of cadmium and zinc ions only and that was for the interferent concentrations above 0.5 mg L −1 (Cu-IIP mass of ca. 35 mg). The interference effect was reduced with the sorbent mass increase. Fe(III) and Mn(II) ions, present in treated tap water in relatively high concentrations, did not interfere. Effective pH adjusting of the loaded solution in on-line mode, when applying diluted Clark–Lubs buffering solution, allowed accurate copper determination in tap water (compared to graphite furnace atomic absorption spectrometry, GFAAS) using standard addition or combination calibration method.

Head and neck cancers are one of the most frequent cancers worldwide. This paper attempts to evaluate disturbances of homeostasis of the necessary elements (calcium, magnesium, zinc, copper, iron, manganese) and changes in the levels of toxic metals (lead, cadmium, cobalt, chromium VI) in hair of patients with head and neck cancers, as well as people without a diagnosed neoplastic disease. In order to quantify the necessary elements and toxic metals, a method using ICP-MS and ICP-OES techniques had been developed and validated. The studies have shown that patients with head and neck cancer used to drink alcohol and smoked much more frequently than healthy individuals, both in the past and presently. Statistically significant differences in concentrations of average metal content in the group of patients with head and neck cancers compared to the control group were confirmed. Significant differences in metal content between the group of patients with head and neck cancers and healthy individuals were found which enabled distinguishing between the study groups. To this end, a more advanced statistical tool, i.e. chemometrics, was used. The conducted research analyses and the use of advanced statistical techniques confirm the benefits of using alternative material to distinguish the patients with head and neck cancers from the healthy individuals.

Trace elements have an impact on numerous physiological processes. The monitoring of their levels in the organism allows you to detect not only their deficiencies, but also several illnesses. The aim of this study was to compare the levels of essential elements (calcium, magnesium, zinc, copper, iron, manganese) in hair, nails and serum of both patients with laryngeal cancer and healthy people. The determination of six metals was performed by an inductively coupled plasma mass spectrometry (ICP-MS) and an inductively coupled plasma optical emission spectrometry (ICP-OES). The concentration of essential elements in hair and nails of the control group was statistically significantly higher than in the group of patients with laryngeal cancer. In the case of serum, differences were found between the patients and controls in respect of the level of three metals. The results of principal component analysis (PCA) revealed the strong and similar clustering behavior of essential elements in hair and nails. The metals did not correlate between two alternative materials. The present study indicated that, using the level of essential elements in hair and nails as a basis, it is possible to distinguish cancer patients from healthy people. The alternative materials are independent of homeostasis and therefore seem to be more useful in the detection of diseases and mineral deficiencies in human than the classical biological materials, such as blood.

The Li1+δMn2−δO4 samples (0.00≤δ≤0.20) were obtained by a sol–gel method and characterized using: chemical analyses, XRD, SEM, TGA, DSC, electric conductivity and thermoelectric power. The obtained results were discussed in relation to the calcination temperature, and to the results obtained on commercial LiMn2O4. The samples calcined at 300 °C (S-samples) consisting small excess of Li (δ≤0.04) showed no phase transition at 285 K and no disturbance in electric conductivity and thermoelectric power, as observed for the related samples calcined at 800 °C (H-samples). Partial thermal decomposition of the S-samples or oxygen uptake by the H-samples were observed during TGA experiments above 350 °C. The beginning of the thermal decomposition of the H-samples started at higher temperatures, depending on Li-contents. At about 920 °C, the rapid acceleration took place independently on type of the samples. The thermal decomposition up to 800 °C seems to be reversible, owing to the samples reoxidation.

This work was aimed to provide a well-established approach for the quantification of silver sites in zeolites. The experimental procedure based on carbon monoxide sorption in silver exchanged zeolites ZSM-5, Y, and X was monitored by IR spectroscopy. With regard to the Lambert-Beer law the values of the absorption coefficients of the IR bands of CO interacting with exchangeable cations $(Ag^{+})$ and metallic species $(Ag^{0})$ were attained. Subsequently, the concentrations of silver species of different kinds were calculated. The values of the absorption coefficients are valid for zeolites of FAU and MFI topologies; thus, they are argued to be used for zeolites of other structures.

Silica gel was modified via silanization with 3-chloropropyltrimethoxysilane and subsequently Cu(II)-5- dodecylsalicylaldoxime was grafted. Obtained sorbent was applied to on-line copper(II) preconcentration and its FAAS determination. Effective copper(II) elution was observed for 2% v/v nitric acid. The new sorbent exhibits optimal sorption efficiency within pH 5.6 and 7.5. A portion of the sorbent may be used repeatedly for not less than 100 sorptiondesorption cycles. The sorbent indicates high sorption and elution effectiveness of ca. 96 and 99%, respectively. Introduction of a preconcentration step before flame atomic absorption spectrometry (FAAS) copper determination with 60 s loading time resulted in 12-fold increase in the measured absorbance. This could be further raised by extending the loading time. Metals, like Zn(II), Mn(II) and Pb(II) caused negative interference effect while presence of Ca(II) and Mg(II) caused increase in the obtained signals. Copper(II) in samples such as: well water, mineral water, river and tap water was determined via the standard addition method. Detection limit for the proposed procedure was estimated at 1.5 µg L-1 (3σ). Accuracy of the method was assessed via comparison of the results obtained for copper determination in ground water and waste water certificate reference materials with those obtained with the use of a reference method (ICP MS).

For many years, copper has found fundamental application in metallurgy and electrical industry due to its ductility and excellent electrical conductivity. Nowadays, biostatic properties of this element are ex- ploited in fungicides and wood preservatives, and components of water-treatment agents have attracted growing interest, resulting in its spread in various areas of human life. The need for copper determina- tion at lower and lower concentration levels requires the involvement of dedicated analytical tools. Atomic spectrometric methods are still the most frequently used, but, in some applications, both enhancement of selectivity and increase in sensitivity are required and are realized by introducing solid-phase extrac- tion (SPE) with sorbents selective towards copper. We present the most frequently applied sorbents dedicated to copper preconcentration, new trends in the methods for modifying them and the aspect of copper speciation using sorbents. We pay special attention to construction of on-line and off-line SPE set-ups.

The determination of cadmium and lead in plant samples by flame atomic absorption spectrometry with analyte preconcentration in a flow injection system was studied. Preconcentration of Cd and Pb from solution after wet digestion was performed by the use of C18 column, as sorbent, ammonium diethyldithiophosphate (DDPA) at pH = 1 as complexing agent, and methanol as eluent. A strong column clogging effect of the iron and copper was successfully eliminated by the use of masking agents. Oxalic acid 0,4 M and thiourea 0,06 M are sufficient for masking of iron and cooper in solutions obtained after digestion of various plant samples. The enrichment factors obtained at 30 s loading time were 42 for cadmium and 38 for lead. Detection limits (3[sgrave]) were 0,5 μg/l and 4,4 μg/l respectively, for cadmium and lead.

Cigarette smoking and excessive alcohol drinking result in the rise of numbers of patients suffering from the head and neck cancer. Addiction to any of these stimulants carry a risk of developing a cancerogenesis process. Using them simultaniously lead not to a summary of each of those risks but multiplies them. Scientific research also indicates the important difference in the incidence of cancer in people who have never smoked cigarettes or drunk alcohol in comparison to those, whose exposure to these stimulatns was longterm - in such case, the former group had a lower percentage of developing the disease. Human body burdened with the ongoing cancer shows disturbances on various levels of the system. One of such disturbances is change of the concetration levels of physiological metals, such as calcium, magnesium, iron, copper, zinc or mangenese. They play key roles in maintaing the hormonal and ionic stability, they act as cofactors in many enzymes in metabolic processes. Diagnostic research of any deviations in levels of those essential elements enables a full estimation of a patient condition. The aim of this study was physiological metal levels evaluation in different kinds of biological material in patients with tumors of larynx, salivary glands and oral cavity and tongue. Hair and nail samples were used as examples of alternative material, beside the serum samples, which is a standard material and often used. Subjects were patients of Otolaryngology and Laryngological Oncology Clinic of Poznan University of Medical Sciences (Samodzielny Publiczny Szpital Kliniczny nr 2 im. Heliodora Swiecickiego Uniwersytetu Medycznego im. Karola Marcinkowskiego w Poznaniu) and The Head and Neck Surgery Ward of The Greater Poland Cancer Centre in Poznan. Subjects were 41 men and 18 women with tumors of larynx, salivary glands and oral cavity and tongue. The control group consisted of patients from the Otolaryngology and Laryngological Oncology Clinic of Poznan University of Medical Sciences (Samodzielny Publiczny Szpital Kliniczny nr 2 im. Heliodora Swiecickiego Uniwersytetu Medycznego im. Karola Marcinkowskiego w Poznaniu), The Head and Neck Surgery Ward of The Greater Poland Cancer Centre in Poznan and patients of Department of Endocrinology, Metabolism and Internal Medicine of Poznan University of Medical Sciences (Samodzielny Publiczny Szpital Kliniczny nr 2 im. Heliodora Swiecickiego Uniwersytetu Medycznego im. Karola Marcinkowskiego w Poznaniu) and Department of Conservative Dentistry and Periodontology Poznań University of Medical Sciences. They gave answers to the questionnaire concerning smoking habits, alcohol consumption and dietary habits, Then the samples of their serum, hair and nails were collected. After careful preparations the biological material has underwent the process of digestion, and then calcium, magnesium, iron, copper, zinc, mangenese were determined quantitatively using the method of ICP-MS. Profile of the patients who took part in the research displayed a strong correlation between tobacco smoking with alcohol drinking and appearance of larynx, salivary gland and oral cavity and tongue cancer as well as between exclusively tobacco smoking and appearance of these types of cancer. There is a higher incidence of larynx, salivary gland and oral cavity and tongue cancer when there is a deficiency of grain products or fibre in everyday diet. A higher level of calcium, magnesium, iron and manganese was found in patients' hair and nails who suffered from salivary gland cancer. According to applied Chemometric Analysis of Principal Component 1 - concentrations of iron, copper and manganese with magnesium and zinc in patients' nail samples showed strong correlation between measured variables. In patiens' hair samples measured correlation between variables was decreased - concentrations of calcium and magnesium as well as of iron and manganese were highlighted as two groups of variables which showed some correlation in this type of biological material. Further research is required to indicate which of alternative biological materials - hair or nail samples - in relation to serum, would provide a better evaluation of physiological metal levels.

A calibration step in an analytical procedure is often not adequately treated, although it is a very important step in the analysis. Also, the approach to the nomenclature seems to be disrespectful. In order to resolve this problem we chose a new classification based on both how the calibration dependence is reconstructed, and how the measurement data is then transformed. In this paper we discussed the steps of a developed calibration procedure in the determination of trace elements in rat brain tissues by the Laser Ablation Inductively Coupled Plasma Time of Flight Mass Spectrometry (LA ICP-TOF-MS) method. The developed calibration procedure uses the long established calibration method - the method of standard addition - although the standard samples are in this case the rat brain tissue samples. The results show the usefulness of the procedure developed in the presented analytical problem related to the analysis of solid samples, which is where the work is original.

The procedure of restorative proctocolectomy is associated with a complete removal of the colon and slight reduction of ileum length, which together can lead to systemic shortages of trace elements. Inflammatory changes in the pouch mucosa may also have some impact. However, there is no data on trace elements in pouchitis. Therefore, in the present study we aimed to assess the effect of acute pouchitis on the status of selected trace elements in rats. Restorative proctocolectomy with the construction of intestinal J-pouch was performed in twenty-four Wistar rats. Three weeks after the surgery, pouchitis was induced. Eight untreated rats created the control group. Liver concentrations of selected micronutrients (Zn, Cu, Co, Mn, Se) were measured in both groups six weeks later, using inductively coupled plasma mass spectrometry. Liver concentrations of trace elements did not differ between the study and the control groups. However, copper, cobalt and selenium concentrations [μg/g] were statistically lower (p

The aim of the present work is to study the remains of seven individuals with typical symptoms of tertiary syphilis in terms of mercury content in bones, thereby verifying whether they were subjected to treatment and, if they were, how long their organisms were exposed to toxic mercury fumes. Mercury was used, mainly in the Middle Ages and in the early modern period, as a preventive measure in case of individuals suffering from syphilis, a venereal disease, and also leprosy. Syphilitic patients treated this way should demonstrate increased concentration of mercury in their bones. The skeletons studied in the present work originate from various archaeological sites in southern and north-central Poland. The analyses concerned individuals with diagnosed syphilis as well as healthy individuals who constituted the control group. The analyses were performed by the LA-ICP-MS technique, with the use of laser Nd: YAG, Macro, 266 nm, New Wave, USA, coupled with Spectrometer Elan DRC-e Perkin Elmer, USA. The content analysis of the studied bone material revealed with high probability that the contact method of mercurial treatment was used only in the case of two women from north-central Poland, deceased at the turn of the 15th century at the earliest.

The aim of this study was to find correlations between several studied elements and analyzed materials as well as the application and validation of an analytical method to determine trace elements in hair, fingernails and toenails of healthy volunteers (normal concentration). The method developed covers washing, mineralization and ICP-MS determination of 10 elements (Ca, Cd, Co, Cr, Cu, Fe, Mg, Ni, Pb and Zn) in hair and nails. Concentrations of the selected elements in hair, fingernails and toenails were measured for 24 women and 18 men. Furthermore, a chemometric approach (Principal Component Analysis, PCA) was employed to evaluate the correlations between concentrations of the elements in hair and nails and between these materials. Until now PCA has not been frequently applied in handling and interpretation of the results of analysis of biological materials. However, the results of the present investigation show the high potential of PCA in extraction of valuable information from analytical measurements. Additionally, PCA has become a useful tool for visualization of the obtained results. Moreover, the cluster analysis (CA) was used to group the samples according to gender, taking into account two different groups of elements: essential and toxic.

The paper presents application of a new resin dedicated to copper(II) flow-injection on-line preconcentration prior its flame atomic absorption spectrometric (FAAS) determination. The new sorbent, obtained by suspension polymerization technique, was styrene-divinylbenzene copolymer modified with 5-dodecylsalicylaldoxime-copper(II) complex. In flow mode leaching of initially imprinted Cu(II) ions from polymer beads was effective with 1% (v/v) nitric acid, however for elution of ions retained on the sorbent during the loading process sufficient efficiency was obtained for 0.5% (v/v) nitric acid. The most effective copper(II) sorption was observed within sample pH ca. 6.3 at flow rate 7.5 mL min −1 . Furthermore, preconcentration studies of Cu(II) ions realized in the presence of popular foreign ions like Cd(II), Pb(II), Zn(II), Ni(II), Mn(II), Co(II) did not reveal significant interference. The expected effect of Cu(II)-imprinting was confirmed by higher tolerance level for interferents ions concentration for the new sorbent than for the control polymer. It was found that alkaline metals ions and humic acid had the most relevant influence on copper(II) uptake. Accuracy of the evaluated method was assessed for analysis of water samples (tap and mineral water, river water, artesian water) and certified water reference materials compare them to results obtained by inductively plasma mass spectrometry. The satisfactory relative error values obtained with use of standard addition calibration method, confirms the feasibility of this method for Cu(II) determination in water samples. Application of 120 s sorption time enabled to obtain 74-fold enrichment factor and limit of detection (3 σ ) equal to 0.4 μg L −1 .

A new sorbent – salen impregnated silica gel – was prepared and characterised for application as a minicolumn packing for flow-injection on-line preconcentration of cadmium(II). The system was coupled with flame atomic absorption spectrometer (FI-FAAS). The optimal pH for Cd(II) sorption was in the range of 7.4–8.8 and nitric acid (1%, v/v) was efficient as eluent. Sorption was most effective within the sample flow rate up to 7 mL min−1. Sorption capacity of the sorbent found in a batch procedure was 26.3 µmol g−1 (2.95 mg g−1). Enrichment factor (EF) and limit of detection (LOD) obtained for 120-second loading time were 113 and 0.26 µg L−1, respectively. The sorbent stability in the working conditions was proved for at least 100 preconcentration cycles. The evaluated method was applied to Cd(II) determination in various water samples.

The purpose of this work was to determine trace element levels in urine and evaluate possible associations between urinary iodine concentration (UIC), other trace elements (Cr, Cu, Fe, Mn, Na, Se, Zn), toxic elements (Cd, Pb), anthropometrical measures (body weight and height), glycemic indices (serum insulin and glucose), and several parameters related to thyroid function (thyroid stimulating hormone, free thyroxine, antithyroid peroxidase antibodies, thyroid volume, and thyroid echogenicity) in pregnant women. One hundred sixty-nine participants were recruited. The whole study group, originating from Krakow region, comprised three subgroups belonging to three trimesters: I trimester (n = 28), II trimester (n = 83), and III trimester (n = 58). Trace elements were determined using inductively coupled plasma mass/(atomic emission) spectrometry. Partial least square model was used to reveal correlation structure between parameters investigated, as well as a possible causal relationship between dependent parameters and potentially explanatory parameters. Results obtained for trace and toxic elements in urine were comparable with results of other authors, although the study group was not homogenous. We confirmed (1) low iodine excretion in pregnant women, (2) the existence of statistically significant correlation between UIC and urinary selenium, and (3) lack of correlation between latter parameter and typical indices of thyroid function. Urinary selenium correlated with other urinary trace elements, but physiological significance of this finding remains uncertain. The fact that a large number of pregnant women fail to meet dietary recommendations for iodine is the major reason for concern.

Cadmium (Cd) exerts a detrimental effect on the metabolism of plants, whereas selenium (Se) may protect them against various stressors through its antioxidative activity. In this in vitro study we investigated the impact of Se (2 µM Na2SeO4) on the growth, nutrient (P, S, K, Ca, Mg, B, Mn, Fe and Zn) concentrations and cell integrity of rape (Brassica napus oleifera) and two wheat (Triticum aestivum) genotypes subjected to Cd stress (600 µM CdCl2). Rape accumulated both Cd and Se more than did wheat. In all plants, Cd markedly reduced the biomass, enhanced lipid peroxidation and diminished plasmalemma fluidity. A drop in the K uptake and the reduced plasmalemma permeability diminished the K efflux from the leaf cells. In contrast, Cd elevated S concomitantly with Zn, indicating an activity of detoxifying SH groups and SOD isoenzymes. When added alone, Se promoted the growth of all plants, it enhanced the accumulation of S, but the impact on other nutrients remained minor. In Cd-stressed plants, Se tended to counterbalance the Cd-induced changes in nutrients, it also reduced the lipid peroxidation and exerted positive effects on the cell membrane stability. The Cd stress and the protective role of Se were most evident in rape. The Finnish wheat genotype was less tolerant to Cd than the Polish one.

This study was performed to investigate selenoenzyme activities and trace element concentrations in thyroid tissues, with reference to other parameters routinely used to characterize thyroid function. This was to reveal relevant parameters as possible additional markers of tumor grade, clinical course, and prognosis of thyroid disorders. The tissue samples were obtained during surgical treatment (total or near total thyroidectomy) of 122 patients with different types of thyroid tumor. For most of the investigated parameters in different groups of patients, we did not find statistically significant differences. In the majority of cases, thyroid benign or malignant tumors were not accompanied by significant derangement of the gland selenoenzymes and of either intrathyroidal or plasma concentration of selenium. Nevertheless, types I and II iodothyronine deiodinases were the most promising (among selenoenzymes) targets for diagnoses and possibly therapy of thyroid tumors. Higher activities of both enzymes in cases with Graves’ disease, as compared with other thyroid lesions, suggest their involvement in the pathogenesis of this condition. Patients with struna nodosa had higher levels of thyroid Zn, Cu, and Pb as compared with papillary carcinoma subjects and also a higher level of Cu than follicular carcinoma cases. The above diagnostics may play a similar role to some of the general thyroid function indices, TSH, anti-TG, anti-TPO, and calcitonin, which can partially distinguish between various thyroid tumors. In conclusion, some of selenium status markers, when accompanied with general parameters, and trace elements can serve as factors with pathophysiologic relevance and be helpful in the identification of malignant disease. Multivariate statistical methods should be employed to tackle a broad array of thyroid tumor diagnostic data in a short time. Partial least squares model and other pattern recognition methods seem to be the most appropriate methods for that task. The miniaturization of all the steps of complex analytical procedure should be developed in a way to allow its completion as sensitive, robust, and efficient for use of the small quantity of material provided by fine-needle biopsy.

A new cadmium(II)-imprinted polymer based on cadmium(II) 2,2 - { ethane-1,2- diylbis[nitrilo( E )methylylidene] } diphenolate-4-vinylpyridine complex was obtained via suspension polymerization. The beads were used as a minicolumn packing for flow-injection-flame atomic absorp- tion spectrometry (FI-FAAS) determination of cadmium(II) in water samples. Sorption effectiveness was optimal within pH range of 6.6–7.7. Nitric acid, 0.5% (v/v) was used as eluent. Fast cadmium(II) sorption by the proposed material enabled to apply sample flow rates up to 10mLmin − 1 without loss in sorption effectiveness. Enrichment factor (EF), concentration efficiency (CE) and limit of detection (LOD, 3 ) found for 120-s sorption time were 117, 39.1min − 1 and 0.11 gL − 1 , respectively. Sorbent stability was proved for at least 100 preconcentration cycles (RSD=2.9%). When compared to non-imprinted polymer the new Cd(II)-imprinted polymer exhibited improved selectivity towards cadmium(II) against other heavy metal ions, especially Cu(II) and Pb(II), as well as light metal ions. Accuracy of the method was tested for ground water and waste water certified reference materials and fortified water. The method was applied to Cd(II) determination in natural water samples.

Copper participates in the redox mechanisms and is a cofactor of enzymes responsible for appropriate structure of elastic fibres. The aim of the study was to assess the relationship between plasma copper as well as ceruloplasmin concentrations and carotid-femoral pulse wave velocity (cfPWV). The study group, recruited from the population-based family study, included 138 parents (age 61.5±7.9 years, 57M/81F, 80.4% hypertensives) and 165 offspring (mean age 34.8±8.4 years, 79M/86F, 32.7% hypertensives). Information about each participant’s clinical data were collected with the use of standardized questionnaires. The cfPWV was measured by Micro-Tip pressure transducer (Model SPT-301, Millar Instruments, Houston, Texas, USA) and the SphygmoCor system (ver. 6.31 AtCor Medical Pty., Ltd., Australia). The plasma copper concentration was determined by ICP-MS (Inductively Coupled Plasma Mass Spectrometry) and plasma ceruloplasmin concentration by ELISA test. Database management and multivariate analyses were performed with SAS software (SAS Institute, Cary, NC, version 9.3). The average values of plasma levels were: copper (male 620.4±229.7μg/l, female 740.9±339.3μg/l); ceruloplasmin (male 612.6±221.6μg/ml, female 766.7±337.0μg/ml). With adjustments applied for age, sex, cholesterol level, fasting glucose, body height, use of antihypertensive drugs, smoking and alcohol intake, we observed a positive correlation between the cfPWV and plasma copper concentration (0.00074±0.0003, p=0.011) as well as plasma ceruloplasmin concentration (0.0007±0.0003; p=0.0095). In our study group, higher plasma copper and ceruloplasmin concentrations were related to higher cfPWV. The excess body copper might contribute to the lower antioxidant status and arterial stiffening.

We investigated the relations between selenium status (SeS) parameters, indexes of nutrition, erythropoiesis, and uremic toxemia, serum electrolytes, and other biochemical markers in end-stage renal disease (ESRD) patients, as no multivariate statistical analysis concerning all of these parameters was performed so far. SeS was evaluated by plasma Se concentration (plSe) and glutathione peroxidase (plGSHPx) activity in 69 uremic patients treated with hemodialysis (HD) and 40 healthy controls. The hierarchical multivariate partial least squares model (PLS2) was employed to establish data structure and correlations between parameters investigated. plSe and plGSHPx activity were significantly lower in patients when compared with controls (p=0.000). plSe was positively associated with indexes of erythropoiesis and nutritional status, as well as serum electrolytes and parameters of uremic toxemia. plGSHPx was inversely dependent on the pair of parameters: intact parathyroid hormone (iPTH) and aluminum plasma concentration (Al). We conclude that (1) ESRD strongly decreases selenium status and (2) the PLS2 approach revealed the existence of significant interactions among plSe, plGSHPx, and selected biochemical parameters or groups of such parameters; some of these associations need further studies to be clarified.

Microwave closed-system wet digestion procedures for plant samples were examined. Each procedure was tested with samples of tobacco and cabbage, and included digestion by the use of different acids composition, almost complete evaporation of the digest, and then dissolution of the residue in 1% nitric acid. Three microwave digestion programs that varied power, duration, and temperature were used. Closed-vessel reactions followed open-vessel reaction-delay time. Using flame atomic absorption spectrometry on the digests, four or five elements were determined to evaluate effectiveness, precision and accuracy of analytes extraction into solution. After a preliminary study of tobacco digests, the four most effective procedures were chosen, and detailed investigations were carried out on both tobacco and cabbage reference materials. Although all four of the final procedures were accurate, the most precise procedure, with the lowest errors of determination, was using reverse ‘aqua regia’ for tobacco and ‘aqua re...

The matrix effects in the determination of the main components of dolomite by flame emission (Na, K) and atomic absorption spectrometry (Ca, Mg, Fe, Mn) have been examined according to the methodology based on the theory of design of experiments. The influence of some auxiliary compounds added to a sample solution has been investigated. The determination of Fe and Mn proved to be specific. The matrix effect has been eliminated in the determination of K by adding a mixture of NaCl and H3PO4, in the determination of Na by KCl spectral buffer, in the determination of Mg by NaCl buffer and in the case of Ca by SrCl2 as a spectral buffer.