Determination of xanthates as Cu(II) complexes by high-performance liquid chromatography - Inductively coupled plasma tandem mass spectrometry.

The present study provides a novel, selective analysis method for the determination of low xanthate concentrations. The rising concern over the environmental effects of xanthates demands the development of analysis methods which this study answers. Complex formation in aqueous solution between xanthates and an excess of Co(II), Ni(II), Pb(II), Cd(II), Cu(II), and Zn(II) ions was utilized to selectively determine xanthates by high-performance liquid chromatography-inductively coupled plasma tandem mass spectrometry for the first time. The complexes that were formed were extracted to ethyl acetate using liquid-liquid extraction and separated by high-performance liquid chromatography technique before the quantitative determination of metal ions and sulfur in the xanthate complexes. Good separation and high measurement sensitivity were achieved using Cu(II) as the complex metal ion. The analysis method was optimized for the determination of sodium isopropyl xanthate and sodium isobutyl xanthate with detection limits of 24.7 and 13.3 µg/L, respectively. With a linear calibration range of 0.1-15 mg/L and a total analysis time of 4-5 min, the present method is a fast and sensitive option for selective xanthate determination.

Response of wheat and barley seedlings on soil contamination with bromides.

Environmental pollution is becoming one of the most important global problems. Understanding the main factors affecting accumulation of toxic trace elements in consumed crops is of particular value. Unfortunately, possible toxicity of many trace elements is still poorly studied. The development of measures on identification of new potentially toxic trace elements is critical for high quality and safety of food. In the research, we performed greenhouse pot experiments with two major crops, wheat and barley, that were grown in the soil contaminated with bromides of ammonium and neodymium. The concentrations of elements in the plants and soil were determined by ICP-MS/ICP-OES after leaching the samples with tetramethyl ammonium hydroxide. Additionally, variations in the biomasses and concentrations of pigments in the plant leaves were studied. Although wheat and barley are botanically similar and were grown under the same conditions, concentrations of several elements in the plants were rather different. Both wheat and barley were capable of accumulating high concentrations of bromine (Br) when the plants grow in the soil contaminated with this trace element, but demonstrated different response on the soil contamination. The Br concentrations were always higher in barley, while the concentrations of pigments in barley leaves were lower than in leaves of wheat. During first days, biomass of the plants grown in the soil contaminated with bromides was slightly lower than biomass of the wheat and barley grown in uncontaminated soil. However, with time the bromides exhibited positive effect on the plant biomass.

Bioavailability and toxicity of bromine and neodymium for plants grown in soil and water.

Information about biological significance and possible phytotoxicity of many trace elements is still scarce. Bromine and neodymium are among the poorly investigated trace elements. In the research, greenhouse experiment was conducted to study the effects of bromide of neodymium on wheat seedlings grown in soil and water. The wheat seedlings were capable of accumulating large amounts of both Br and Nd. Compared to the soil-grown plants, the water-grown plants accumulated higher concentrations of the trace elements. The bioaccumulation of Br and Nd resulted in statistically significant variations in the concentrations of several elements. The concentrations of P, Cl, and Ca in roots and Cl in leaves of the plants grown in the contaminated water and the concentration of I in roots of the soil-grown plants decreased. In the water-grown seedlings, the concentrations of Na and P were higher and concentrations of Mg and K were lower than those in the seedlings grown in soil. In leaves of the plants grown in water, the concentration of Cl was lower than that in leaves of the soil-grown plants. In roots of the water-grown plants, the concentration of Zn was higher, and in leaves, it was lower compared with Zn content in roots and leaves of the plants grown in soil. The K/Na ratios were 4 (leaves) and 20 (roots) times higher in the soil-grown plants, while the Ca/Mg ratios were 8 - 19 times higher in the water-grown plants. Marked distinctions were also observed in relationships between different elements in the soil-grown and water-grown plants.

Potential of wheat (Triticum aestivum L.) and pea (Pisum sativum) for remediation of soils contaminated with bromides and PAHs.

The aim of the research was to study a removal of polycyclic aromatic hydrocarbons (PAHs) and phytoextraction of bromine (Br) from contaminated soils. The experiments using pea and wheat seedlings as potential candidates for soil remediation were performed. The soil for the experiments was collected from a site slightly contaminated by some PAHs. Before planting, the soil was exposed to 20 mg of Br/kg of soil. In the soil taken from rhizosphere of pea and wheat, the concentrations of many PAHs decreased up to 7 times compared to the concentrations of the compounds in the initial soil. Pea was capable of more effectively influencing the soil PAHs than wheat. The growth of pea and wheat in the soil spiked with Br resulted in a significant increase of Br concentration in a plant. Concentration of Br in roots of pea and wheat increased 21 and 3 times, respectively. Bromine content in leaves of wheat and pea increased 10 and 4.5 times. This accumulation of Br in the plants led to a decrease of its concentration in the rhizosphere soil. The experimental results demonstrated a good ability of the plants to cleanup the soils contaminated with organic and inorganic compounds.

Impacts of forest harvesting on mobilization of Hg and MeHg in drained peatland forests on black schist or felsic bedrock.

Forest harvesting, especially when intensified harvesting method as whole-tree harvesting with stump lifting (WTHs) are used, may increase mercury (Hg) and methylmercury (MeHg) leaching to recipient water courses. The effect can be enhanced if the underlying bedrock and overburden soil contain Hg. The impact of stem-only harvesting (SOH) and WTHs on the concentrations of Hg and MeHg as well as several other variables in the ditch water was studied using a paired catchment approach in eight drained peatland-dominated catchments in Finland (2008-2012). Four of the catchments were on felsic bedrock and four on black schist bedrock containing heavy metals. Although both Hg and MeHg concentrations increased after harvesting in all treated sites according to the randomized intervention analyses (RIAs), there was only a weak indication of a harvest-induced mobilization of Hg and MeHg into the ditches. Furthermore, no clear differences between WTHs and SOH were found, although MeHg showed a nearly significant difference (p = 0.06) between the harvesting regimes. However, there was a clear bedrock effect, since the MeHg concentrations in the ditch water were higher at catchments on black schist than at those on felsic bedrock. The pH, suspended solid matter (SSM), dissolved organic carbon (DOC), and iron (Fe) concentrations increased after harvest while the sulfate (SO4-S) concentration decreased. The highest abundances of sulfate-reducing bacteria (SRB) were found on the sites with high MeHg concentrations. The biggest changes in ditch water concentrations occurred first 2 years after harvesting.

The effect of experimental conditions on the formation of dixanthogen by triiodide oxidation in the determination of ethyl xanthate by HPLC-ICP-MS/MS.

The rising concern over the environmental impact of xanthates, especially in the arctic region, has increased the need to study these traditional flotation reagents in greater detail. The environmental concern relates mostly to the formation of carbon disulfide (CS2) and the heavy metal complexes of xanthates. Due to the unstable nature and multiple reaction mechanisms of xanthates, their reliable determination at low concentration levels is difficult. In this study, a xanthate pretreatment method was optimized and applied for the determination of ethyl xanthate (EX-) by high performance liquid chromatography-inductively coupled plasma tandem mass spectrometry (HPLC-ICP-MS/MS). Ethyl xanthate was oxidized to diethyl dixanthogen ((EX)2) by triiodide (I3-) in aqueous solution and the formed (EX)2 was extracted into n-hexane. Important experimental parameters, including pH, I3- amount, and oxidation time, were optimized and the detection limit of 0.29 mg L-1 for potassium ethyl xanthate was obtained. During the optimization experiments, it was found that the oxidation reaction resulted in multiple products, decreasing the efficiency of (EX)2 formation and, therefore, the sensitivity of the method. The proposed method was applied to wastewater samples with recoveries of 105-106%. This study provides a selective method for the determination of ethyl xanthate and introduces novel information on the parameters affecting the oxidation of xanthates.

Short-term Variability of Macro- and Trace Elements in Elymus Repens L. and Urtica Dioica L.

BACKGROUND: The main aim of the research was to study short-term changes in the concentrations of elements in two widely distributed plant species, couch grass and nettle and in the rhizosphere soil of the plants. METHODS: The sampling of plants and soil was carried out on three dates: 3, 10, and 25 May 2021. On each day of sampling, the plants and soil were collected three times: at 9:00, 14:00, and 19:00. The ICP-OES and ICP-MS analytical techniques were used for determination of elements in the plant and soil samples. The Raman spectroscopy was applied to study variations in the organic compounds. RESULTS: The concentrations of both macro-nutrients and trace elements in plants varied greatly over daytime on all dates of sampling. The differences between concentrations of many elements in the plants collected at different times during a day were statistically significant. There were also statistically significant differences between concentrations of some elements (Na, Mg, P, K, Fe, Ba) in the plants collected on different dates. The relative intensity of diffuse luminescence of the rhizosphere soil of couch grass and nettle was different during daytime and also differed between the soils taken from roots of the two plant species, especially in the beginning of May. CONCLUSIONS: The experimental data indicates that the daily variations of the element concentrations in plants might be a result of multiple effects of various factors. The differences in the daily element variations in the couch grass and nettle growing in the same site and collected simultaneously might be due to the fact that these plants belong to different clades. The diurnal fluctuations (that also include regular changes in the element concentrations in plants) can be different for monocotyledons (couch grass) and dicotyledons (nettle). New experimental findings on short-term variations in the concentrations of macro-nutrients and trace elements can help to gain a new insight into accumulation of the elements in different plant species and also be useful in agricultural practice.

Comparison between Fluorescence Imaging and Elemental Analysis to Determine Biodistribution of Inorganic Nanoparticles with Strong Light Absorption.

Black porous silicon nanoparticles (BPSi NPs) are known as highly efficient infrared light absorbers that are well-suitable for photothermal therapy (PTT) and photoacoustic imaging (PAI). PTT and PAI require a sufficient number of effectively light-absorbing NPs to be accumulated in tumor after intravenous administration. Herein, biodistribution of PEGylated BPSi NPs with different sizes (i.e., 140, 200, and 300 nm in diameter) is investigated after intravenous administration in mice. BPSi NPs were conjugated with fluorescent dyes Cy5.5 and Cy7.5 to track them in vitro and in vivo, respectively. Optical imaging with an in vivo imaging system (IVIS) was found to be an inadequate technique to assess the biodistribution of the dye-labeled BPSi NPs in vivo because the intrinsic strong absorbance of the BPSi NPs interfered fluorescence detection. This challenge was resolved via the use of inductively coupled plasma optical emission spectrometry to analyze ex vivo the silicon content in different tissues and tumors. The results indicated that most of the polyethylene glycol-coated BPSi NPs were found to accumulate in the liver and spleen after intravenous injection. The smallest 140 nm particles accumulated the most in tumors at an amount of 9.5 ± 3.4% of the injected dose (concentration of 0.18 ± 0.08 mg/mL), the amount known to produce sufficient heat for cancer PTT. Furthermore, the findings from the present study also suggest that techniques other than optical imaging should be considered to study the organ biodistribution of NPs with strong light absorbance properties.

Evaluating the impact of extraction and cleanup parameters on the yield of total petroleum hydrocarbons in soil.

Interlaboratory comparisons for the analysis of mineral oil in polluted soil using the GC-FID method indicate that extraction and cleanup conditions have significant effects on the analytical results. In this investigation a ruggedness test was performed on the extraction and cleanup method for the determination of total petroleum hydrocarbons in soil. A two-level Plackett-Burman design was utilized to study the effect of 11 different method parameters on the extraction recovery of total petroleum hydrocarbons (TPH) in soil. Both qualitative and quantitative factors were investigated. The results indicate that total petroleum hydrocarbons can be relatively reliably monitored through strict implementation of the ISO and CEN draft standards. However, variation in certain method parameters readily affects the validity of the results. The most critical factors affecting TPH recovery were the solvent and co-solvent used for extraction, the extraction time, adsorbent and its weight and sample TPH concentration. Because adaptation of the draft standards especially with respect to these factors easily leads to TPH recoveries higher than 200% or lower than 70%, the validity of the adapted method should always be verified. A proper estimate of the expanded uncertainty should also be appended to TPH results, because only then can the reliability of the results be guaranteed and further justification is gained to support the end-use of the data. This also supports the credibility of the analytical services and prevents the data end-users from drawing misleading conclusions concerning the environmental risks and potential remediation requirements.

Extractability of trace elements in precipitated calcium carbonate (PCC) waste from an integrated pulp and paper mill complex.

From the utilization point of view, it is notable that the total element concentrations in the precipitated calcium carbonate (PCC) waste were significantly lower than the maximal allowable heavy metal concentrations for fertilizers used in agriculture and in forestry, set on the basis of the EU and Finnish legislation. The easily soluble Ca concentration of 168.5g kg(-1) (d.w.) in PCC waste was 105 times higher than the typical value of 1.6g kg(-1) (d.w.) in the coarse mineral soil in Finland indicates that the PCC waste is a potential agent for soil remediation and for improving soil fertility if it is used as fertilizer. According to a five-stage sequential extraction procedure, the highest concentrations of most of the elements occurred either in HF+HNO3+HCl or H2O2+CH3COONH4 fraction. This means that the major part of the elements retained in the PCC waste are not easy to extract (leach) under conditions normally found in nature. This is beneficial since, if inorganic materials and by-products are utilized in earth construction, the content of harmful compounds must be low and the harmful components must be tightly bound to the matrix.

The use of a sequential leaching procedure for assessing the heavy metal leachability in lime waste from the lime kiln at a caustizicing process of a pulp mill.

A five-stage sequential leaching procedure was used to fractionate 13 heavy metals (Cd, Cu, Pb, Cr, Zn, Fe, Mn, Al, Ni, Co, As, V, Ba) and sulphur (S) in lime waste from the lime kiln at the causticizing plant of Stora Enso Oyj Veitsiluoto Pulp Mills at Kemi, Northern Finland, into the following fractions: (1) water-soluble fraction (H(2)O), (2) exchangeable fraction (CH(3)COOH), (3) easily reduced fraction (HONH(3)Cl), (4) oxidizable fraction (H(2)O(2)+CH(3)COONH(4)), and (5) residual fraction (HF+HNO(3)+HCl). Although metals were leachable in all fractions, the highest concentrations for most of the metals were observed in the residual fraction (stage 5). It was also notable that the total heavy metal concentrations in lime waste did not exceed the maximal allowable heavy metal concentrations for soil conditioner agents set by the ministry of the Agricultural and Forestry in Finland. The heavy metals concentrations in lime waste were also lower than the maximal allowable heavy metals concentrations of the European Union Directive 86/278/EEC on the protection of environment, and in particular of the soil, when sewage sludge is used in agriculture. The Ca concentration (420 g kg(-1); d.w.) was about 262 times higher than the typical value of 1.6 g kg(-1) (d.w.) in arable land in Central Finland. However, the concentration Mg (0.2 g kg(-1); d.w.) in lime waste was equal to the Mg concentration in arable land in the Central Finland. The lime waste has strongly alkaline pH ( approximately 12.8) and a neutralizing value (i.e. liming effect) of 47.9% expressed as Ca equivalents (d.w.). This indicates lime waste to be a potential soil conditioner and improvement as well as a pH buffer.

Active biomonitoring of palladium, platinum, and rhodium emissions from road traffic using transplanted moss.

The use of transplanted moss (Pleurozium schreberi) in active biomonitoring of traffic-related emissions of Pd, Pt, and Rh was studied. Moss mats were transplanted to three locations along highway E75 (in Oulu, Finland) at three different distances from the highway. Five samples were collected from a background site after the same exposure period. Mass fractions of Pd, Pt, and Rh as well as mass fractions of 18 other elements were determined in these samples. The results indicated that P. schreberi is well suited for active biomonitoring of Pd, Pt, and Rh. Mass fractions above the background values were observed in the samples exposed to traffic-related emissions. When the results were compared with those of the other elements, high correlations of Pd, Pt, and Rh with commonly traffic-related elements (e.g., Cu, Ni, Sb, Zn, etc.) were found. It was also found that the amounts of Pd, Pt, and Rh in moss samples decreased when the distance to the highway increased. This trend gives evidence for the suitability of P. schreberi for active biomonitoring of Pd, Pt, and Rh. Furthermore, it can be concluded that the mass fractions determined in this study provide valuable evidence about the current state of Pd, Pt, and Rh emissions in Oulu, Finland.

The use of a sequential leaching procedure for heavy metal fractionation in green liquor dregs from a causticizing process at a pulp mill.

A five-stage sequential leaching procedure was used to fractionate heavy metals (Cd, Cu, Pb, Cr, Zn, Fe, Mn, Ni, Co, As, V, Ba and Ti) in green liquor dregs into the following fractions: (1) water-soluble fraction (H2O), (2) exchangeable fraction (CH3COOH), (3) easily reduced fraction (HONH3Cl), (4) oxidizable fraction (H2O2 + CH3COONH4), and (5) residual fraction (HF + HNO3 + HCl). The green liquor dregs were derived from a causticizing process at a pulp mill at Kemi, Northern Finland. According to the leaching studies, the leachability of heavy metals in the water-soluble fraction varied between 0.5 and 2 mg kg(-1) expressed on a dry weight (d.w.) basis, indicating relatively low bioavailability of the metals. However, the concentration of Mn (2065 mg kg(-1); d.w.) showed a strong and of Zn (17.6 mg kg(-1); d.w.), Ni (39.7 mg kg(-1); d.w.) and Ba (32.0 mg kg(-1); d.w.) slightly tendency to be extracted in the exchangeable fraction. In addition, Zn, Mn, Ni, Co, V and Ba showed clear leachability in the easily reduced fraction, as well as Cd, Cu, Cr, Zn, Mn, As and Ba in the oxidizable fraction. For Cd, Cu, Cr, Zn, Mn, Ni, Co, Ba and Ti, the sum of leachable heavy metal concentrations in fractions 1-5 agreed relatively well with the "total" heavy metal concentrations. Recoveries of the sum of fractions 1-5 were 84-56% of those obtained by the US EPA method 3052 (i.e. concentrations obtained after microwave oven digestion with a mixture of HF and HNO3).

Determination of wear metals in lubrication oils: a comparison study of ICP-OES and FAAS.

Certain wear metals (Fe, Cr, Ni, Cu and Zn) of various lubrication oils were determined by means of ICP-OES and FAAS. The kerosene dilution method, which is used widely together with ICP-OES, was applied with both methods here. Calibration standards were made from a commercial organo-metallic standard. Our aim was to clarify the possibility of using the quick kerosene dilution method together with FAAS for a rapid check for certain indicator metals. Metal determinations with FAAS were accurate enough for quantitative work in machine condition diagnostics and waste oil characterization, when compared with those with ICP-OES.

Response of wheat and pea seedlings on increase of bromine concentration in the growth medium.

Biogeochemical cycles of bromine (Br) and its quantitative requirements for different plant species are still studied poorly. There is a need to examine Br pathways in plants and evaluate the factors important for Br accumulation in a plant. In the present work, the effects of different Br compounds on an uptake of Br by two plant species (wheat and pea) that tolerate Br differently (pea is more sensitive to Br compared with wheat) have been studied. The growth medium was spiked with either KBr or NaBr at concentrations 0, 10, 50 and 100 mg/L. Elemental analysis of the plants was performed using inductively coupled plasma optical emission spectrometry (ICP-OES) and ICP-MS analytical techniques after leaching of the samples with tetramethyl ammonium hydroxide at mild temperature (60 °C). The experimental results have shown that wheat and pea seedlings can accumulate rather large amounts of Br. An increase of Br concentration in a plant was not always directly proportional to the variations in the Br concentration in the growth medium. In wheat, the greater part of Br was accumulated during first 7 days. In pea, the uptake of Br lasted until the end of the experiment. Certain differences in the ability of plants to accumulate Br were observed when the plants were grown in a medium spiked with different Br compounds. In most cases, Br accumulation was higher in the leaves of the plants grown in the medium spiked with KBr. The same tendency was observed for another halogen, chlorine (Cl).

Determination of low methylmercury concentrations in peat soil samples by isotope dilution GC-ICP-MS using distillation and solvent extraction methods.

Most often, only total mercury concentrations in soil samples are determined in environmental studies. However, the determination of extremely toxic methylmercury (MeHg) in addition to the total mercury is critical to understand the biogeochemistry of mercury in the environment. In this study, N2-assisted distillation and acidic KBr/CuSO4 solvent extraction methods were applied to isolate MeHg from wet peat soil samples collected from boreal forest catchments. Determination of MeHg was performed using a purge and trap GC-ICP-MS technique with a species-specific isotope dilution quantification. Distillation is known to be more prone to artificial MeHg formation compared to solvent extraction which may result in the erroneous MeHg results, especially with samples containing high amounts of inorganic mercury. However, methylation of inorganic mercury during the distillation step had no effect on the reliability of the final MeHg results when natural peat soil samples were distilled. MeHg concentrations determined in peat soil samples after distillation were compared to those determined after the solvent extraction method. MeHg concentrations in peat soil samples varied from 0.8 to 18 µg kg(-1) (dry weight) and the results obtained with the two different methods did not differ significantly (p=0.05). The distillation method with an isotope dilution GC-ICP-MS was shown to be a reliable method for the determination of low MeHg concentrations in unpolluted soil samples. Furthermore, the distillation method is solvent-free and less time-consuming and labor-intensive when compared to the solvent extraction method.

Development of analytical methods for the determination of sub-ppm concentrations of palladium and iron in methotrexate.

Analytical methods for limit test (1 microgg(-1)) determination of iron and palladium in the drug substance methotrexate (MTX) were developed. The methods developed were based on microwave-assisted, vapor-phase digestion using quartz inserts inside the digestion vessels, followed by instrumental determination. Iron was determined by graphite furnace atomic absorption spectrometry (GFAAS) and palladium by direct current plasma optical emission spectrometry (DCP-OES). Detection limits of 0.20 microgg(-1) for iron by GFAAS and 0.30 microgg(-1) for palladium by DCP-OES in MTX were obtained. The validity of the methods was studied by spike recovery tests and by analyzing certified reference material (NIST 8433 corn bran, Fe determination) and an organometallic compound ([(C(6)H(5))(3)P](2)PdCl(2), Pd determination). In addition, the specificity of the GFAAS technique for iron determination was confirmed by comparing the results obtained by GFAAS with those obtained by hexapole collision cell, inductively coupled plasma mass spectrometry (ICP-MS).

Determination of trace impurities in germanium dioxide by ICP-OES, ICP-MS and ETAAS after matrix volatilization: a long-run performance of the method.

High-purity germanium compounds (e.g. germanium dioxide) are used these days in several applications (e.g. germanium-based detectors, semiconductors, fiber-optic systems). Thus, reliable methods for the routine determination of trace element impurities from germanium compounds must be developed. In this study, inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectrometry and/or electrothermal atomic-absorption spectrometry was used for the determination of fifteen impurity elements in germanium dioxide. Possible interference effects due to a germanium matrix were eliminated/minimized by a simple open-vessel volatilization of germanium tetra chloride before the determinations. The results, based on the data gathered over a period of one year, showed that the long-run performance of the method is good, and it can be used for routine analysis of impurity elements in high-purity germanium dioxide.

Comparison of digestion methods for the determination of ruthenium in catalyst materials.

A fusion method, an acid digestion method with a high pressure asher (HPA) and two microwave (MW)-assisted acid digestion methods were compared to investigate their suitability for the determination of Ru in catalyst materials. Ru contents in the digested samples were determined with inductively coupled plasma optical emission spectrometry (ICP-OES). Ru powder and three Ru compounds (RuO2 · xH2O, anhydrous RuO2 and RuCl3), possibly present in Ru catalysts, were digested and analyzed to compare the digestion efficiencies of the methods. Significant differences among the digestion efficiencies of the methods were observed; the fusion method having the best digestion efficiency for the compounds studied. The methods were applied for the determination of Ru in alumina- and carbon-supported catalysts. No differences among the methods were observed for these samples.