Béla Kovács

A study of plant sample preparation and inductively coupled plasma emission spectrometry parameters

Abstract Adjustable parameters of an inductively coupled plasma emission spectrometer (ICP) are investigated and a digestion method of plant samples is developed which does not require the use of HC104. This HNO3‐H2O2 wet digestion method eliminates the hazards associated with hot, concentrated HClO4. The adjustable parameters of ICP are viewing height, forward power as well as the sample, coolant, auxiliary, and flushing gas flow rates, and the sample uptake flow rate. The digestion parameters examined are the type and amount of the applied acids (HNO3, HCl, and H2SO4), the temperature and duration of predigestion, the amount of H2O2, and the temperature and duration of digestion. Three plant samples (maize seed, wheat straw, and sunflower seed) and three dry weights are analyzed. The optimal parameters of the ICP spectrometer and HNO3‐H2O2 wet digestion for plants are determined. Optimal parameters of HNO3‐H2O2 wet digestion sample preparation: Optimal parameters of the ICP instrument:

Comparison of trace element and stable isotope approaches to the study of migratory connectivity: an example using two hirundine species breeding in Europe and wintering in Africa

Analyses of stable isotopes and trace elements in feathers may provide important information about location and habitat use during molt, thereby enabling the investigation of migratory connectivity and its ecological consequences in bird species that breed and winter in different areas. We have compared the conclusions arrived at based on the use of these two methods on the same samples of feathers from two migratory birds, the Sand Martin Riparia riparia and the Barn Swallow Hirundo rustica. We investigated the effects of location, age and sex on stable isotope (δ13C, δ15N, δD) and trace element profiles (As, Cd, Mg, Mn, Mo, Se, Sr, Co, Fe, Zn, Li, P, Ti, V, Ag, Cr, Ba, Hg, Pb, S, Ni and Cu). The feathers of adults at the breeding grounds were removed, forcing in birds to grow new feathers at the breeding grounds; this enabled a comparison of composition of feathers grown in Europe and Africa by the same individual. Stable isotope and trace element profiles varied geographically, even at micro-geographic scales, and also among age classes. The results of both methods suggest that food composition and/or source differs between adults and nestlings in the breeding area and that food and/or molting location changes with the age of individuals in Africa. In an attempt to determine the usefulness of data obtained from composition of feathers, we performed discriminant function analyses on information obtained on stable isotopes and trace elements in order to assess the correctness of the classification of group membership. When feathers molted in Africa were compared to those molted in Europe, trace element profiles of the 22 elements generally had a much greater resolution than the stable isotope profiles based on three stable isotopes. The proportion of correctly classified samples was also greater for analyses based on trace elements than for those based on stable isotopes.

Studies on soil sample preparation for inductively coupled plasma atomic emission spectrometry analysis

Abstract A wet digestion method of soil samples has been developed for analysis of “total” concentration (acid extraction) of elements by inductively coupled plasma emission spectrometry (ICP‐AES). This HNO3‐H2O2 wet digestion method is a simple, fast and safe sample preparation method with satisfactory accuracy and precision. The first examined condition was the applied digestion acid or acid mixture (HNO3, HNO3‐H2O2, HCl‐H2O2, HNO3‐HClO4, H2SO4‐H2O2), and the volume of concentrated nitric acid (65% HNO3). Temperature and duration of predigestion, volume of concentrated hydrogen‐peroxide (30 % H2O2), temperature and duration of digestion were also investigated. Two different kind of soil samples (a sandy soil with low humus content, calcareous chernozem with relatively high humus content), three different dry weight values and three different values for each parameters were chosen to investigate soil sample digestion in order to select the best parameters. A LABOR MIM Electronic Block Digest Apparatus was applied for sample preparation and numerous elements (e.g. Al, As, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Sr, Zn) have been measured by a LABTAM 8440M Inductively Coupled Plasma Emission Spectrometer. The optimum values of parameters to digest soil sample in an electronic block digest apparatus are: a) 1 g dry weight, b) 5 cm3 HNO3 as digestion acid, c) 30°C‐60°C temperature range for 30–60 minutes predigestion, d) 5 cm3 30% H2O2, e) 120 C temperature for 270 minutes digestion. Two soil samples were digested with four methods (block digestion, Milestone microwave, Prolabo focused microwave and Hungarian standard). Results of the two microwaves and detailed block digestion methods are in well agreement in the two soil samples. Finally three Standard Reference Materials were applied to compare the appropriate results. These results showed well agreement for all elements except for aluminium and iron content. The difference between certified and measured results is dependent on their concentrations in soil.A wet digestion method of soil samples has been developed for analysis of total concentration (acid extraction) of elements by inductively coupled plasma emission spectrometry (ICP-AES). This HNO 3 -H 2 O 2 wet digestion method is a simple, fast and safe sample preparation method with satisfactory accuracy and precision. The first examined condition was the applied digestion acid or acid mixture (HNO 3 , HNO 3 -H 2 O 2 , HCl-H 2 O 2 , HNO 3 -HClO 4 , H 2 SO 4 -H 2 O 2 ), and the volume of concentrated nitric acid (65% HNO 3 ). Temperature and duration of predigestion, volume of concentrated hydrogen-peroxide (30 % H 2 O 2 ), temperature and duration of digestion were also investigated. Two different kind of soil samples (a sandy soil with low humus content, calcareous chernozem with relatively high humus content), three different dry weight values and three different values for each parameters were chosen to investigate soil sample digestion in order to select the best parameters. A LABOR MIM Electronic Block Digest Apparatus was applied for sample preparation and numerous elements (e.g. Al, As, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Sr, Zn) have been measured by a LABTAM 8440M Inductively Coupled Plasma Emission Spectrometer. The optimum values of parameters to digest soil sample in an electronic block digest apparatus are: a) 1 g dry weight, b) 5 cm 3 HNO 3 as digestion acid, c) 30°C-60°C temperature range for 30-60 minutes predigestion, d) 5 cm 3 30% H 2 O 2 , e) 120°C temperature for 270 minutes digestion. Two soil samples were digested with four methods (block digestion, Milestone microwave, Prolabo focused microwave and Hungarian standard). Results of the two microwaves and detailed block digestion methods are in well agreement in the two soil samples. Finally three Standard Reference Materials were applied to compare the appropriate results. These results showed well agreement for all elements except for aluminium and iron content. The difference between certified and measured results is dependent on their concentrations in soil.

Speciation of chromium from industrial wastes and incinerated sludges

Abstract In this study, the Cr(III) and Cr(VI) contents of seven international standards, wastes, incinerated wastes and ash samples were measured with a simply hyphenated system. The Cr(III) and Cr(VI) content was measured using an on-line method, which contained an acid-activated aluminium oxide filled microcolumn that was developed especially for the study and an inductively coupled plasma atomic emission spectrometer. The sample introduction and the steps in on-line measurement were controlled by an autosampling program. For lower chromate concentrations, a similar, but off-line separation method was applied with an aluminium-oxide filled solid-phase extraction column and a graphite furnace atomic absorption spectrometer. Acid-activated aluminium oxide adsorbs the Cr(VI) in the pH 2–7 range, but does not adsorb the Cr(III). The adsorbed Cr(VI) can be eluted with strong acid. The changes in chromium forms were studied in the waste burning process as well. In our incineration studies, we obtained the following results: A portion of the chromium(III) content of wastes can be oxidised to chromium(VI) by the incineration process. It increases the potential risk of air and soil contamination of chromium(VI).

Determination of essential and toxic elements in Hungarian honeys.

The aim of this present study was determination of essential and toxic element concentrations in 34 mono- and multi-floral honey samples from four geographical regions of Hungary, and examination of the connection between the floral origin and the element content. Ten elements (Al, Ca, Cu, Fe, K, Mg, Mn, P, S and Zn) were identified by ICP-OES and six (As, Cd, Cr, Mo, Pb, Se) were analysed by ICP-MS. Potassium, calcium, and phosphorus were the most abundant elements with mean concentrations of 372, 47.9 and 44.3 mg kg(-1), respectively. The essential element content was very low in the analysed samples and generally below literature values. The concentrations of toxic elements were sufficiently low as to pose no risk to human health. The concentrations of aluminium, arsenic, cadmium and lead were low, with mean concentrations of 1028, 15.6, 0.746 and 45.5 μg kg(-1), respectively. Three honey groups (acacia, rape and sunflower) were distinguished by linear discriminant analysis from their element content.

Interfacing ion chromatography with inductively coupled plasma atomic emission spectrometry for the determination of chromium(III) and chromium(VI)

Abstract Cr(III) and Cr(VI) can be separated and detected by ion chromatography (IC) with inductively coupled plasma atomic emission spectrometry (ICP-AES). This combined method gives reliable, reproducible results rather quickly. A measurement requires 3 min and a 50-μl sample. ICP-AES was used as an element-selective detection method for IC. Two IC techniques were compared for separation. In the first case the eluent was 7.5 mM potassium hydrogenphthalate and in the second case eluent changing was used. The first eluent was water; the second was 1 M HNO3. The IC column was a Polispher AN anion exchanger. The Cr(VI) (CrO2−4, Cr2O2−7) is retained in the column while the Cr(III) passes through without any retention. The main advantages of ICP detection are: the first (eluent) peak —which contains the Cr(III)— can be evaluated and the element selectivity and sensitivity provides reliable results. These methods were used for measuring the water-soluble Cr(III) and Cr(VI) contents of contaminated soils. The detection limits of Cr(III) and Cr(VI) are 0.25 and 0.27 μg/g, respectively.

Analytical methods and quality assurance

Abstract A wet digestion method of soil samples has been developed for analysis of “total” concentration (acid extraction) of elements by inductively coupled plasma emission spectrometry (ICP‐AES). This HNO3‐H2O2 wet digestion method is a simple, fast and safe sample preparation method with satisfactory accuracy and precision. The first examined condition was the applied digestion acid or acid mixture (HNO3, HNO3‐H2O2, HCl‐H2O2, HNO3‐HClO4, H2SO4‐H2O2), and the volume of concentrated nitric acid (65% HNO3). Temperature and duration of predigestion, volume of concentrated hydrogen‐peroxide (30 % H2O2), temperature and duration of digestion were also investigated. Two different kind of soil samples (a sandy soil with low humus content, calcareous chernozem with relatively high humus content), three different dry weight values and three different values for each parameters were chosen to investigate soil sample digestion in order to select the best parameters. A LABOR MIM Electronic Block Digest Apparatus was applied for sample preparation and numerous elements (e.g. Al, As, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Sr, Zn) have been measured by a LABTAM 8440M Inductively Coupled Plasma Emission Spectrometer. The optimum values of parameters to digest soil sample in an electronic block digest apparatus are: a) 1 g dry weight, b) 5 cm3 HNO3 as digestion acid, c) 30°C‐60°C temperature range for 30–60 minutes predigestion, d) 5 cm3 30% H2O2, e) 120 C temperature for 270 minutes digestion. Two soil samples were digested with four methods (block digestion, Milestone microwave, Prolabo focused microwave and Hungarian standard). Results of the two microwaves and detailed block digestion methods are in well agreement in the two soil samples. Finally three Standard Reference Materials were applied to compare the appropriate results. These results showed well agreement for all elements except for aluminium and iron content. The difference between certified and measured results is dependent on their concentrations in soil.A wet digestion method of soil samples has been developed for analysis of total concentration (acid extraction) of elements by inductively coupled plasma emission spectrometry (ICP-AES). This HNO 3 -H 2 O 2 wet digestion method is a simple, fast and safe sample preparation method with satisfactory accuracy and precision. The first examined condition was the applied digestion acid or acid mixture (HNO 3 , HNO 3 -H 2 O 2 , HCl-H 2 O 2 , HNO 3 -HClO 4 , H 2 SO 4 -H 2 O 2 ), and the volume of concentrated nitric acid (65% HNO 3 ). Temperature and duration of predigestion, volume of concentrated hydrogen-peroxide (30 % H 2 O 2 ), temperature and duration of digestion were also investigated. Two different kind of soil samples (a sandy soil with low humus content, calcareous chernozem with relatively high humus content), three different dry weight values and three different values for each parameters were chosen to investigate soil sample digestion in order to select the best parameters. A LABOR MIM Electronic Block Digest Apparatus was applied for sample preparation and numerous elements (e.g. Al, As, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Sr, Zn) have been measured by a LABTAM 8440M Inductively Coupled Plasma Emission Spectrometer. The optimum values of parameters to digest soil sample in an electronic block digest apparatus are: a) 1 g dry weight, b) 5 cm 3 HNO 3 as digestion acid, c) 30°C-60°C temperature range for 30-60 minutes predigestion, d) 5 cm 3 30% H 2 O 2 , e) 120°C temperature for 270 minutes digestion. Two soil samples were digested with four methods (block digestion, Milestone microwave, Prolabo focused microwave and Hungarian standard). Results of the two microwaves and detailed block digestion methods are in well agreement in the two soil samples. Finally three Standard Reference Materials were applied to compare the appropriate results. These results showed well agreement for all elements except for aluminium and iron content. The difference between certified and measured results is dependent on their concentrations in soil.

Heavy metal dispersion detected in soils and plants alongside roads in Hungary

ABSTRACTSoil and plant samples from roadside areas contaminated with toxic by-products of vehicular traffic (for example, lead compounds from leaded fuel, metal contaminants derived from spare parts) were analysed in the case of five Hungarian sampling sites. The analyses were carried out with a new analytical method which is based on the use of a high performance sample introduction unit in the conventional ICP spectrometry. By using this system, significantly lower detection limits were obtained related to the conventional ICP—AES method. The analysis results showed a close correlation between the daily mean volume of traffic and metals accumulated in the soil samples. On the other hand, using this method similar heavy metal profiles were gained, i.e. the total and plant-available heavy metal concentrations were the highest in the 0–1 m region from the road, and the further sampling points (0–90 m) showed significantly lower and lower heavy metal contents until at about 90 m distance from the road, wher...

Relationship between Serum Nickel and Homocysteine Concentration in Hemodialysis Patients

Severe hyperhomocysteinemia (HHC) is associated with atherosclerosis. In hemodialysis (HD) patients, one of the main causes of death is cardiovascular disease. In animals, trace elements such as cobalt, copper, iron, and nickel ameliorated vitamin B12 deficiency-induced HHC. However, correlations between plasma total homocysteine (tHcy) and trace elements in HD patients have not been investigated. Therefore, tHcy, folate, vitamin B12, trace elements (cobalt, copper, iron, and nickel), and some laboratory parameters such as serum total protein, albumin, transferrin, ferritin, C-reactive protein (CRP), and interleukin-6 concentrations were determined in 122 hemodialysis patients. When patients were divided into groups according to their tHcy, we found no significant differences in concentrations of cobalt, copper, and total protein, while nickel was higher, and folate, vitamin B12, and iron were lower in patients with lower than higher tHcy. In univariate regression analysis, tHcy negatively correlated with concentrations of folate (r = −0.302, p < 0.006), vitamin B12 (r = −0.347, p < 0.0001), nickel (r = −0.289, p < 0.006), and CRP (r = −0.230, p < 0.02) and positively with serum albumin (r = 0.316, p < 0.0004) and hemoglobin (r = 0.329, p < 0.0001) values. No relationship between tHcy and serum concentrations of cobalt, copper, iron, or other laboratory parameters was found in HD patients. The effect of cobalt and nickel on homocysteine production was assessed in human peripheral mononuclear cells (PBMCs). Nickel but not cobalt at concentrations found in HD patients significantly inhibited homocysteine, cysteine, and S-adenosylhomocysteine production in human PBMCs. These results suggest that nickel might also be involved in the regulation of the methionine–folate cycle in humans, as was demonstrated in animal experiments.

Yttrium normalisation: a new tool for detection of chromium contamination in soil samples.

The measurement of chromium and yttrium concentration could give a chance to detect 5–10 times less chromium contamination in soil by using the yttrium normalisation method. The principle of the method is the following: elements such as chromium and yttrium exist naturally in the soil in a strongly bonded form. Therefore, in a noncontaminated area there should be a close correlation between the yttrium and chromium concentrations. If the measured Cr concentration in a sample is not on the Cr–Y trend line then the distance of plotted point from the line indicates the amount of anthropogenic chromium. Anthropogenic chromium can be detected only in the case when the contamination does not contain yttrium. This theory was tested in an agricultural–toxicological field experiment where Cr(VI) was added to the soil. Applying the yttrium normalisation method a much smaller anthropogenic effect was detected than by other evaluation methods.