Zeeman Correction Research Articles

Zinc content in cow milk and its correlation with amino acid composition

Zinc (Zn) is one of the essential elements for all life forms on Earth. Investigation of zinc levels in milk is a topical issue for dairy farming and processing industry. The dynamics of zinc content in milk of cows during 6 months is presented. Milk was obtained from Black-and-White cows at the age of 3–4 years (2–3rd lactation). The strength and direction of correlations with the amino acid composition of milk were established. 132 milk samples from a breeding farm (Krasnodar Territory) were studied in this work. A random sample of 22 lactating cows was drawn from the dairy herd from January through July 2022 (excluding April). Atomic-adsorption analysis with electrothermal atomization, deuterium and Zeeman correction were used in order to accurately determine the level of zinc in milk. Correlations between amino acids and zinc in cow milk samples (in winter-spring-summer period) were obtained, as well as correlation coefficients (r) and coefficients of determination (r2) at certain levels of significance. The zinc content of milk varies greatly from month to month. Insignificant differences relative to January were established in May (higher by 1.54%), June (higher by 9.72%) and July (lower by 7.66%). Significant reliable differences were found in February – higher by 58.15% (p ˂ 0.001) – and in March – higher by 97.34% (p ˂ 0.001) relative to January. All obtained correlations of zinc with amino acids in milk are positive, e.g. for threonine in January r = 0.50 (r2 = 0.25, p = 0.02), in February r = 0.82 (r2 = 0.67, p ˂ 0.01), in March r = 0.25 (r2 = 0.06, p = 0.04), in May r = 0.35 (r2 = 0.12, p ˂ 0.01).

On the Relationship between Hair Mercury Concentrations and Cardiovascular Diseases (based on the example of the Vologda Region)

Introduction: Mercury is considered by the World Health Organization as one of the top ten chemicals of major public health concern. Fish consumption is known to be the main source of exposure to mercury. It has been previously established that freshwater fish of the water bodies of the Vologda Region can be a significant source of mercury exposure in the local population. Objective: To establish the relationship between hair mercury concentrations in residents of the Vologda Region and diseases of the cardiovascular system. Materials and methods: The study involved 849 participants (274 men and 575 women) aged 18 to 94 years living in the city of Cherepovets (Vologda Region: 59° 07' N 37° 54' E). Occipital hair was sampled in accordance with WHO recommendations and then tested using the RA-915M mercury analyzer with a PYRO-915+ pyrolysis attachment (measurement range: 0.002–200 mg/kg) without preliminary sample preparation, by atomic absorption with Zeeman correction of non-selective absorption. The measurement accuracy was verified using the NIMD-01 certified reference material with the mercury concentration of 0.794 ± 0.050 µg/g. Results: The mean hair mercury concentration in the study subjects from the Vologda Region was 0.572 ± 0.686 mg/kg, which is 3.5 and 1.5 times lower than safe mercury levels of 2.2 and 1 mg/kg established by WHO and US EPA, respectively. Mean hair mercury levels in the study participants with/without cardiovascular diseases were 0.646 ± 0.727 mg/kg and 0.459 ± 0.589 mg/kg, respectively. The highest mercury levels were observed in male subjects with myocardial infarction (> 0.73 mg/kg) and in females with stroke and acute coronary syndrome (> 0.687 mg/kg). Conclusions: Mercury in the hair of people with diagnosed cardiovascular diseases (myocardial infarction, acute coronary syndrome, cerebrovascular accident, unstable angina, etc.) and without them has been found. The accumulation of mercury in the body can be one of the risk factors for the development of vascular and heart diseases.

Analysis of toxicological safety of feed by atomic absorption spectroscopy

Currently, one of the main indicators characterizing the safety of feed for productive animals is the content of toxic elements in them. According to the requirements of MDU No. 123-4 / 281-8-87 "Temporary maximum allowable level (MRL) of the content of certain chemical elements and gossypol in feed for farm animals and feed additives", mercury, cadmium, lead are of the highest veterinary, sanitary and toxicological significance, arsenic, selenium. The danger of these substances lies in the ability to accumulate in the body of an animal and cause various pathologies, affecting the urinary, hematopoietic, digestive and nervous systems, generally retard the growth and development of farm animals, reduce resistance, productivity and increase the risk of detecting toxicants in agricultural products of animal origin.The purpose of the study was to assess the safety of plant foods for the content of mercury, arsenic, selenium, lead and cadmium using atomic absorption spectroscopy. The study materials were 76 samples of various plant foods for productive animals: grass meal, linseed cake, oats, vegetable feed. The amount of toxic elements was determined according to GOST R 55447-2013 and GOST 31651-2012 using an MGA-1000 atomic absorption spectrometer with Zeeman correction of non-selective absorption (LUMEX Group of Companies).As a result of the studies, it was found that in all samples of plant-derived feed for productive animals, the amount of toxic elements did not exceed the maximum allowable level. Thus, the amount of mercury in the studied samples averaged 0.55±0.04 mg/kg, cadmium - 0.86±0.04 mg/kg, lead -0.29±0.01 mg/kg, arsenic - 0 .24±0.01 mg/kg, selenium – 0.44±0.02 mg/kg. The established concentrations of toxic elements did not exceed 1.0 mg/kg and were less than 1.5% of the maximum allowable level, which meets the requirements for the toxicological safety of feed for productive animals.

ASSESSING MERCURY POLLUTION USING BLACK STORK EGGSHELLS

Female birds whose bodies contain environmental contaminants produce eggs with shells that are likewise contaminated, making bird eggshells appropriate indicators for monitoring environmental toxins. Common contaminants include organic mercury compounds, especially methylmercury, which are known to bioaccumulate and biomagnify in the food chain. Black storks (Ciconia nigra) predominantly consume fish and are thus at risk for high mercury intake. In this study, we used eggshells of black storks as a proxy to reconstruct the concentration levels and distribution of mercury, a well-known toxic element, in various parts of Latvia. Preliminary analyses have shown that deposition levels of mercury vary in different parts of the eggshell. Specifically, the shell and shell membrane differ in their level of mercury contamination by an average factor of nine; therefore, we measured the mercury content in these components separately whenever possible. We analysed 34 eggshell samples from nesting sites in Latvia using an atomic absorption spectrometer with Zeeman correction Lumex RA-915M and its attachment for pyrolytic combustion. We found that mercury concentrations varied from 5 to 22 ng/g in eggshells and from 42 to 293 ng/g in shell membranes. We discuss possible contamination sources and reasons behind this disparity.

Environmental Effects of A Marine Fish Farm of Sea Bass and Sea Bream in The Eastern Mediterranean Sea on Water Column and Sediment

Concentration of selected Metallic Element Contaminants (MECs) (Cd, Pb, Hg,Cu, Fe, Zn, Mn, Mg, Ca, Na and K), Total Organic Carbon (TOC) and Total Nitrogen (TN) in the superficial layer of sediments from four fish farms in the Eastern Mediterranean Sea were studied in order to evaluate the environmental effects of marine aquaculture and to establish correlations between aquaculture and accumulation of selected Metallic Elements Contaminants (MECs)(Cd, Pb, Hg, Cu, Fe, Zn, Mg, Mn, K, Na and Ca). The levels of nutrients (Nitrate (NO3, Nitrite (NO2), Ammonium (NH4), Phosphate (PO4), Silicate (Si), Total Nitrogen (TN) and Total Phosphorus (TP) in the water column was evaluated.
 The concentrations of Cd, Pb and Cu were determined by atomic absorption spectrophotometry with graphite furnace and Zeeman correction (Varian 220 Z). The Metallic Element Fe, Zn, Mg, Mn, K, Na and Ca were measured by the flame atomic absorption spectrophotometry (Varian AA 10). Hg was analyzed by Direct Analyzer of Mercury.
 Nutrients analyses were carried out by Autoanalyzer using the standard colorimetric methods according to Strickland and Parsons.
 The results suggested that MECs enrichment in the sediments may be attributed to the fish farm effluents, although metal concentrations are not likely to cause harmful effects in the marine ecosystem. Continuous monitoring and further studies of the area are recommended to determine long-term effects.
 The nutrient levels in the water column can be due to sources arising from various anthropogenic activities within the study area. Moreover, the spatial variability was due to increasing nutrient concentrations at the localities close to nonpoint sources.

Atomic Absorption Spectrometry Methods to Access the Metal Solubility of Aerosols in Artificial Lung Fluid

Recent studies to quantify the health risks that fine particulate matter with an aerodynamic less than 2.5 µm (PM2.5) pose use invitro approaches. One of these approaches is to incubate PM2.5 in artificial lysosomal fluid for a given period at body temperature. These body fluids used have a high ionic strength and as such can be challenging samples to analyze with atomic spectroscopy techniques. As PM2.5 is a primary health hazard because it is tiny enough to penetrate deep into the lungs and could, in addition, dissolve in the lung fluid it is important to quantify elements of toxic and/or carcinogenic concerns, reliably and accurately. Sophisticated instrumentation and expensive pre-treatment of challenging samples are not always available, especially in developing countries. To evaluate the applicability of graphite furnace atomic absorption spectrometry (GFAAS) without Zeeman correction capability to detect trace quantities of heavy metals leached from PM2.5 on to artificial lung fluid, univariate and multivariate approaches have been used for optimization purposes. The limits of quantification, LOQ, obtained by the optimized method were: 2 µg L-1 (Cu), 3 µg L-1 (Cr), 1 µg L-1 (Mn), and 10 µg L-1 (Pb). The addition/recovery experiments had a mean accuracy of: (Cu) 99 ± 7%; 110 ± 8% (Cr); 95 ± 9% (Mn), and 96 ± 11% (Pb). The average soluble fractions of PM2.5 incubated in artificial lysosomal fluid (ALF) for 1 h were: 1.2 ± 0.01 ng m-3 Cu, 0.4 ± 0.01 ng m-3 Cr, 0.6 ± 0.01 ng m-3 Mn, and 4.8 ± 0.03 ng m-3 Pb. Using historical elemental averages of PM2.5 in Curitiba (Cu 3.3 ng m-3, Cr 2.1 ng m-3, Mn 6.1 ng m-3, Pb 21 ng m-3), the percentage bioaccessibility were determined to be Cu 38%, Cr 20%, Mn 10%, and Pb 23%. The elemental values of the atmospheric soluble fraction of Cu, Cr, and Mn were below the inhalation risk concentrations. However, for Pb, the atmospheric soluble fraction exceeded the inhalation unit risk of 0.012 ng m-3. This robust and straightforward GF AAS method is pivotal for low and middle-income countries were most air pollution adverse effects occur and established lower-cost technologies are likely unavailable.

Method for mapping Hg0 emissions from gold shops in artisanal and small-scale gold mining communities

Gold shops in artisanal and small-scale gold mining communities represent major point sources of airborne mercury pollution. Concentrations of elemental mercury (Hg0) emitted by these shops can be determined using a portable atomic absorbance spectrometer (AAS) with Zeeman correction. These measured Hg0 concentrations can then be correlated to position as determined by a hand-held GPS unit, and the resulting data mapped using a Geographic Information System (GIS). A detailed method for obtaining and analyzing data collected near gold shops in Mazuko, Peru is provided. Maps generated using this method were employed to identify point sources of Hg0 contamination originating from gold shops in ASGM communities and were shared with local city managers to assist in urban planning.•A detailed method is provided to collect and process data, ultimately generating a map that allows for the screening of a community to identify point sources of Hg0 contamination.•Raw data is provided, as well as a video detailing data processing and mapping using a common spreadsheet program and an open-source GIS.•The generated map can be used for determining areas where people may be exposed to elevated Hg0 concentrations and/or occupational mercury vapor exposure, targeted enforcement, or outreach to limit Hg0 pollution.

Relativistic two-dimensional hydrogen-like atom in a weak magnetic field

A two-dimensional (2D) hydrogen-like atom with a relativistic Dirac electron, placed in a weak, static, uniform magnetic field perpendicular to the atomic plane, is considered. Closed forms of the first- and second-order Zeeman corrections to energy levels are calculated analytically, within the framework of the Rayleigh–Schrödinger perturbation theory, for an arbitrary electronic bound state. The second-order calculations are carried out with the use of the Sturmian expansion of the two-dimensional generalized radial Dirac–Coulomb Green function derived in the paper. It is found that, in contrast to the case of the three-dimensional atom (Stefańska, 2015), in two spatial dimensions atomic magnetizabilities (magnetic susceptibilities) are expressible in terms of elementary algebraic functions of a nuclear charge and electron quantum numbers. The problem considered here is related to the Coulomb impurity problem for graphene in a weak magnetic field.

Pomegranate juice attenuates neurotoxicity and histopathological changes of the nervous system induced by aluminum in mice

Aluminum (Al) is an element with ubiquitous presence on the earth crust that may cause neuropathological, neurobehavioral, neurophysical, and neurochemical changes linked to its bioavailability. The purpose of the present study was to determine the neuroprotective potential of pomegranate juice on Al induced neurotoxicity. Three groups of 7 female albino Swiss mice were used: the control group received only drinking water; the positive control group was exposed daily to 500 mg/kg of AlCl 3 orally; and the third treated group received pomegranate juice (v/v in water) supplied in dark bottles for 4 h/day followed by AlCl 3 at a dose of 500 mg/kg orally for 20 h/day for 90 days. After 90 days, the mice were subjected to behavioral and memory tests. Cortex cerebral and hippocampus injuries were determined with hematoxylin and eosin staining and Al accumulation was measured by graphite furnace atomic absorption with Zeeman correction. The Al deposition in the brain caused neural degeneration and decreased cell density inducing a state of anxiety, depression, and a deficit of learning and memory. Pomegranate juice treatment attenuated neurobehavioral alterations, decreased Al in the brain and restored the histological structure. Highperformance liquid chromatography with a diode-array detector (HPLC-DAD) revealed a range of bioactive molecules (i.e., gallic acid, quercetine, luteolin) in the pomegranate juice that may have neuroprotective value for the nervous disorders caused by Al intoxication.

Measuring the Rydberg constant using circular Rydberg atoms in an intensity-modulated optical lattice

A method for performing a precision measurement of the Rydberg constant, $R_{\infty}$, using cold circular Rydberg atoms is proposed. These states have long lifetimes, as well as negligible quantum-electrodynamics (QED) and no nuclear-overlap corrections. Due to these advantages, the measurement can help solve the "proton radius puzzle" [Bernauer, Pohl, Sci. Am. 310, 32 (2014)]. The atoms are trapped using a Rydberg-atom optical lattice, and transitions are driven using a recently-demonstrated lattice-modulation technique to perform Doppler-free spectroscopy. The circular-state transition frequency yields $R_{\infty}$. Laser wavelengths and beam geometries are selected such that the lattice-induced transition shift is minimized. The selected transitions have no first-order Zeeman and Stark corrections, leaving only manageable second-order Zeeman and Stark shifts. For Rb, the projected relative uncertainty of $R_{\infty}$ in a measurement under the presence of the Earth's gravity is $10^{-11}$, with the main contribution coming from the residual lattice shift. This could be reduced in a future micro-gravity implementation. The next-important systematic arises from the Rb$^+$ polarizability (relative-uncertainty contribution of $\approx 3 \times10^{-12}$).

Mineral content of tree sap from the Subcarpathian region

but also as medicinal substance in folk medicine. Traditionally, it was used to treat various conditions, mostly anaemia and chronic fatigue. This study has been designed to establish the content of metallic elements (sodium, potassium, calcium, magnesium, zinc and copper) in sap collected from eight different species (silver birch, downy birch, hornbeam, Norway maple, boxelder maple, black walnut, black alder and white willow) and to identify which sap has mineral content which would be most beneficial for human health. We measured concentrations of calcium, magnesium, sodium, potassium and zinc on an atomic absorption spectrometer equipped with single-element, hollow cathode lamps and an air/acetylene burner. The content of copper was determined using an atomic absorption spectrometer with Zeeman correction equipped with an electrothermal atomizer and argon as inert gas. White willow sap was determined to have the highest concentrations of magnesium, zinc, calcium and potassium. Moreover, this sap contained the lowest concentration of sodium among all the tree species. The sap with the lowest detected concentration of the metallic elements originated from black alder and boxelder. In conclusion, tree sap can be a valuable source of metallic elements, namely copper, zinc and magnesium, in human diet. Tree sap tapped from white willow is the most valuable in terms of its mineral content. Moreover, the most popular sap of sliver birch has proven to be a rich source of magnesium and zinc.

Cadmium Concentration in Mother's Blood, Milk, and Newborn's Blood and Its Correlation with Fatty Acids, Anthropometric Characteristics, and Mother's Smoking Status.

The aim of this study was to determine cadmium concentration in mothers' blood, milk, and newborns' blood from Szczecin (Poland) as a result of environmental cadmium exposure and evaluate the correlation (1) between cadmium levels in analyzed matrices, (2) between cadmium and fatty acids in those matrices, and (3) between cadmium and some selected personal variables, such as anthropometric characteristics, mothers' smoking status, and fruit and fish consumption by mothers. The concentration of cadmium in whole blood and milk of mothers and in the umbilical cord blood of newborns was determined by atomic absorption spectrometry with graphite furnace atomization and Zeeman correction. The fatty acid concentrations were determined by gas chromatography in our previous study. The mean concentrations of cadmium in maternal blood, newborn's blood, and breast milk were 0.61 ± 0.62μg/L, 0.05 ± 0.04μg/L, and 0.11 ± 0.07μg/L, respectively, and differed significantly between analyzed matrices. Cadmium concentrations in the umbilical cord blood were 15% (range 0-83%) of the concentration in maternal blood, whereas cadmium concentrations in breast milk constituted 35% (range 3-142%) of the concentration in mothers' blood. No correlation was found between cadmium levels in three analyzed matrices. The correlation analysis revealed significant low positive correlation between maternal blood cadmium concentrations and concentrations of elaidic, oleic, and cis-vaccenic acids in mothers' milk (correlation coefficients 0.30, 0.32, and 0.31, respectively). Mothers' blood cadmium correlated with mothers' age (r = -0.26, p = 0.03), maternal smoking before pregnancy (r = 0.55, p < 0.000), maternal smoking during pregnancy (r = 0.58, p < 0.000), and fruit consumption by mothers after delivery (r = -0.44, p = 0.003). Mothers' height was the only variable that correlated significantly with breast milk cadmium levels. Newborns' blood cadmium concentrations correlated significantly with mothers' height (r = 0.28, p = 0.02), newborns' birth weight (r = 0.26, p = 0.03), maternal smoking during pregnancy (r = 0.24, p = 0.048), and fish consumption by mothers after delivery (r = 0.37, p = 0.02). The concentrations of cadmium in Polish mother-newborn pairs are among the lowest in Europe and within the norms established by different institutions. The results of our study confirm the existence of effective partial barriers (such as the placenta and mammary gland) restricting cadmium passage from mother to newborn. The significant positive correlations between maternal blood Cd and concentrations of oleic, elaidic, and cis-vaccenic acids in breast milk might suggest the increased cadmium toxicity to infant, taking into consideration even low cadmium passage to milk. Maternal smoking during pregnancy increases both maternal and newborn's blood cadmium level. Promotion of nonsmoking among pregnant women could substantially reduce prenatal and neonatal exposure to cadmium. Moreover, the results of our study point to the need of establishing complex biomonitoring of cadmium in mother-infant pairs in order to better protect children from this toxic and carcinogenic metal exposure.

Influence of MRP1 G1666A and GSTP1 Ile105Val genetic variants on the urinary and blood arsenic levels of Turkish smelter workers

To understand the cellular mechanisms responsible for arsenic metabolism and transport pathways plays a fundamental role in order to prevent the arsenic-induced toxicity. The effect of MRP1 G1666A and GSTP1 Ile105Val polymorphisms on blood and urinary arsenic levels were determined in 95 Turkish smelter workers. Blood and urinary arsenic concentrations were measured by GF-AAS with Zeeman correction and gene polymorphisms were investigated by PCR-RFLP method. The mean blood and urinary arsenic levels were 21.60±12.28μg/L and 5.58±4.37μg/L, respectively. A significant association between MRP1 1666A allele and urinary arsenic levels was found (p=0.001). GSTP1 Ile105Val polymorphism was detected not to be associated with either blood or urinary arsenic levels (p=0.384, p=0.440, respectively). Significant association was also detected between MRP1A(-)/GSTP1Val(-) genotypes and urinary arsenic levels (p=0.001). This study suggested that MRP1 G1666A alone and, also, combined with GSTP1 Ile105Val were associated with inter-individual variations in urinary arsenic levels, but not with blood arsenic levels.

Influence of MRP1 G1666A and GSTP1 Ile105Val genetic variants on the urinary and blood arsenic levels of Turkish smelter workers

To understand the cellular mechanisms responsible for arsenic metabolism and transport pathways plays a fundamental role in order to prevent the arsenic-induced toxicity. The effect of MRP1 G1666A and GSTP1 Ile105Val polymorphisms on blood and urinary arsenic levels were determined in 95 Turkish smelter workers. Blood and urinary arsenic concentrations were measured by GF-AAS with Zeeman correction and gene polymorphisms were investigated by PCR-RFLP method. The mean blood and urinary arsenic levels were 21.60±12.28μg/L and 5.58±4.37μg/L, respectively. A significant association between MRP1 1666A allele and urinary arsenic levels was found (p=0.001). GSTP1 Ile105Val polymorphism was detected not to be associated with either blood or urinary arsenic levels (p=0.384, p=0.440, respectively). Significant association was also detected between MRP1A(-)/GSTP1Val(-) genotypes and urinary arsenic levels (p=0.001). This study suggested that MRP1 G1666A alone and, also, combined with GSTP1 Ile105Val were associated with inter-individual variations in urinary arsenic levels, but not with blood arsenic levels.

Assessing Heavy Metals Pollution in the Agricultural Lands of Gaza Strip that Has Undergone Three Successive Wars

The intensive airstrikes on agricultural lands in the Gaza Strip create craters of 20 m diameter and 10 m depths. Samples from the craters are collected from fourteen different locations, were analyzed to assess the impact of war activities on soil pollution. Soil samples were analyzed for major heavy metals (Ni, Cr, Cu, Mn, Co and Pb) by using hotplate digestion and A Perkin-Elmer Analyst 600 GF-AAS analyzer, equipped with pyrolytically coated graphite tube with integrated platform Zeeman background and correction. The results showed that most of the soils had mean Ni concentration that was over four times higher than the control, Cr was five times, Cu was thirty one times higher, Mn was greatly higher than the control (114 times), Co was five times higher while Pb was twelve times higher than the control. Due to its texture, some samples from sandy soil origins had not significant higher metals concentration than the control. Ni, Cr, Cu, Mn, Co and Pb clearly contributed by the content of munitions of the airstrike. Soil pollution by Cu, Mn and Pb was more widespread than the other heavy metals, which was contributed mostly by munitions. The results also indicate that the concentration of specific heavy metals depends on the type of the explosives material and the soil texture. The current research highlighted the danger and risk of munitions on the agricultural lands. It is highly recommend for the relevant institutions to monitor and follow up research program to investigate the fate of the metals in soil, groundwater and food chain to protect the environment and health.

Optimisation of Direct Copper Determination in Human Breast Milk Without Digestion by Zeeman Graphite Furnace Atomic Absorption Spectrophotometry with Two Chemical Modifiers.

Milk is an important food in the human diet, and copper (Cu) in human milk is indispensable to children's normal growth and development. It is consequently important that Cu deficiency, occurring in malnourished women or in malabsorption following bariatric surgery, be prevented. The objective of this work is to provide hospital-based paediatricians with a tool enabling rapid measurement of Cu in human breast milk through a technique that biology laboratories can easily apply. Using electrothermal atomic absorption spectrophotometry with Zeeman correction, we have optimized this method with two chemical modifiers and without digestion for analytical procedure. Detection limits and quantification limits for Cu in human milk were found to be 0.077 and 0.26 μmol/L, respectively. Within-run (n = 30) and between-run (n = 15) variations in a pool of human milk samples were 1.50 and 3.62%, respectively. Average recoveries ranged from 98.67 to 100.61%. The reliability of this method was also confirmed by analysing certified reference material (10%). In breast milk samples collected from 100 lactating mothers, Cu mean (±1 SD) was 7.09 ± 1.60 μmol/L. In conclusion, with minimal preparation and quick determination, the method proposed is suitable for measurement of Cu in human breast milk.

Blood and serum samples collection and storage for further selenium measurements

The aim of the study was to determine the right storage and transport conditions for blood and serum samples intended for later selenium measurements. Blood and serum samples were stored in different temperature conditions (+4°C and -20°C). After 3, 7 and 14 days the selenium level was measured in each sample and the results were compared with the initial selenium level. Selenium was quantitatively measured using graphite furnance atomic absorption spectrometry (GF-AAS) with Zeeman correction (AAnalyst 600, PerkinElmer). Storage of whole blood samples in -20°C occurred to be inappropriate. Centrifugation of serum for the measurement was not possible even after the shortest time of incubation. However, samples stored at +4°C were measured and analyzed. After the period of 3, 7 and 14 days the selenium level in the sample was higher than initially (7%, 11% and 24% respectively). On the other hand, neither the temperature nor the time of storage of centrifuged serum samples had any influence on selenium level. In all analyzed cases the selenium level did not differ more than 10% of initial level. The experiment clearly showed how blood or serum samples should be stored before the measurement to obtain correct and repeatable results of selenium level. The experiment will be also very helpful in creation of a set of rules for laboratories in different places in Poland and Europe for proceeding with samples after collection to assure the highest quality of results.

Determination of strontium in rat plasma and plasma ultrafiltrate by Zeeman Furnace atomic absorption spectroscopy and its application to a pharmacokinetic study

A rapid and sensitive analytical assay for the determination of total strontium concentrations in rat plasma was developed and validated. The total strontium levels were determined by use of graphitefurnace atomic-absorption spectrometry (GF-AAS) with Zeeman correction, 1000°Ci n ashing temperatures and 2700°C in atomization temperatures after 3.5% HNO 3 protein precipitation. The accuracy was between 95.46 and 102.24% (intra-day variation), and 101.74 and 102.15% (inter-day variation). The precision was between 1.86 and 8.24% (intra-day variation), and 1.27 and 11.20% (interday variation). Linear calibration curves were obtained over the concentration range 0.2 to 10 μg/ml(r = 0.9993). Validation data were within the acceptable limits for analytical methods. This assay was successfully applied to evaluate the pharmacokinetics of strontium fructose 1, 6-diphosphate (Sr-FDP), a new compound in rats and free strontium after plasma ultrafiltrate was also performed by direct determination. Significantly different pharmacokinetics between total and free strontium were observed that provided more information for the pharmacokinetic study of Sr-FDP. Key words : Graphite furnace atomic-absorption spectrometry (GFAAS), strontium fructose 1, 6-diphosphate, strontium, ultrafiltrate, anti-osteoporosis.

Zebrafish larvae as a model for the evaluation of inorganic arsenic and tributyltin bioconcentration

The European REACH legislation establishes the need to study the toxicity, persistence and bioaccumulation of those chemicals with an exceeding production of 100 tons and/or chemicals considered PBTs substances (Persistence, Bioaccumulation and Toxicity). Currently, the OECD technical guideline 305 is the most used protocol to determine bioconcentration factors of contaminants in aquatic environments. However, this procedure implies high cost and amount of adult fishes. Zebrafish ( Danio Rerio) has been selected since this animal model has several advantageous features over other vertebrates, mainly fast embryonic development and easy growth. The analytical methodology here developed has been applied to calculate the bioconcentration factors (BCFs) of two contaminants: inorganic arsenic and tributyltin (measured as arsenic and tin). The method is based on the use of an ultrasonic probe assisted extraction for accelerating the sample treatment followed by detection using graphite furnace atomic absorption spectrometry with Zeeman correction (ZGFAAS). Results obtained for the BCFs values are in good agreement with previously reported data on freshwater aquatic organisms. In the case of arsenic, after exposing larvae to concentrations of 5 and 50 μg L −1, very low BCFs were observed (between 2.2 and 9.5); while for tributyltin, the BCFs observed were within the range 840–1280 after exposure to concentrations of 0.2 and 2.0 μg L −1, respectively. This study shows the use of zebrafish larvae together with the proposed analytical approach as a promising alternative to the OECD 305 test to evaluate the BCFs of classical and emergent contaminants.

The effect of L-ascorbic acid and/or tocopherol supplementation on electrophysiological parameters of the colon of rats chronically exposed to lead

SummaryBackgroundThe aim of this study was to assess the effect of diet supplementation with L-ascorbic acid (500 mg/L), tocopherol (3 mg/kg b.w.), and/or a water soluble analog of tocopherol (Trolox) (48 mg/L) on ion transport in the colon of rats subjected to a chronic exposure (9 months) to 0.1% lead acetate in drinking water.Material/MethodsThe electrophysiological parameters of the colon wall were measured with Ussing methods. Lead content in the whole blood was analyzed by graphite furnace atomic absorption spectrometry (GFAAS) using Zeeman correction. L-ascorbic acid and tocopherol in plasma was measured by high performance liquid chromatography. Immunohistochemical reaction was carried out for visualization of occludin, the intracellular tight junction protein.ResultsWe showed a strong inhibitory effect of lead on the electrophysiological parameters, changes in intestinal permeability, disappearance of junctional occludin, decreased amount of mucus covering the colon surface, and the accumulation of PAS-positive substance in the apical region of the cytoplasm in the absorptive cells.ConclusionsSupplementation with tocopherol or Trolox did not exert a beneficial influence on the studied parameters. L-ascorbic acid positively influenced the examined electrophysiological parameters, as it cancelled the inhibitory influence of lead on ion transport in the rat colon. L-ascorbic acid also protected against tight junction disruption of epithelial cells in the colon of the lead-treated rats. A similar effect was observed in the group of rats receiving lead and supplemented with L-ascorbic acid plus Trolox.