Efficient Photochemical Vapor Generation from Low Concentration Formic Acid Media.

Herein, we report on surprisingly efficient photochemical vapor generation (PVG) of Ru, Re, and especially Ir, achieved from very dilute HCOOH media employing a thin-film flow-through photoreactor operated in flow injection mode. In the absence of added metal ion sensitizers, efficiencies near 20% for Ir and approximately 0.06% for Ru and Re occur in a narrow range of HCOOH concentrations (around 0.01 M), significantly higher than previously reported from conventionally optimized HCOOH concentrations (1-20 M). A substantial enhancement in efficiency, to around 9 and 1.5%, could be realized for Ru and Re, respectively, when 0.005 M HCOONa served as the PVG medium. The addition of metal ion sensitizers (particularly Cd2+ and Co2+) to 0.01 M HCOOH significantly enhanced PVG efficiencies to 17, 2.2, and 81% for Ru, Re, and Ir, respectively. Possible mechanistic aspects occurring in dilute HCOOH media are discussed, wherein this phenomenon is attributed to the action of 185 nm radiation available in the thin-film flow-through photoreactor. An extended study of PVG of Fe, Co, Ni, As, Se, Mo, Rh, Te, W, and Bi from both dilute HCOOH and CH3COOH was undertaken, and several elements for which a similar phenomenon appears were identified (i.e., Co, As, Se, Te, and Bi). Although use of dilute HCOOH media is attractive for practical analytical applications employing PVG, it is less tolerant toward dissolved gases and interferents in the liquid phase due to the likely lower concentrations of free radicals and aquated electrons required for analyte ion reduction and product synthesis.

Highly Efficient Photochemical Vapor Generation for Sensitive Determination of Iridium by Inductively Coupled Plasma Mass Spectrometry.

Herein, we describe the highly efficient photochemical vapor generation (PVG) of a volatile species of Ir (presumably iridium tetracarbonyl hydride) for subsequent detection by inductively coupled plasma mass spectrometry (ICPMS). A thin-film flow-through photoreactor, operated in flow injection mode, provided high efficiency following optimization of identified key PVG parameters, notably, irradiation time, pH of the reaction medium, and the presence of metal sensitizers. For routine use and analytical application, PVG conditions comprising 4 M formic acid as the reaction medium, the presence of 10 mg L-1 Co2+ and 25 mg L-1 Cd2+ as added sensitizers, and an irradiation time of 29 s were chosen. An almost 90% overall PVG efficiency for both Ir3+ and Ir4+ oxidation states was accompanied by excellent repeatability of 1.0% (n = 15) of the peak area response from a 50 ng L-1 Ir standard. Limits of detection ranged from 3 to 6 pg L-1 (1.5-3 fg absolute), dependent on use of the ICPMS reaction/collision cell. Interferences from several transition metals and metalloids as well as inorganic acids and their anions were investigated, and outstanding tolerance toward chloride was found. Accuracy of the developed methodology was verified by analysis of NIST SRM 2556 (Used Auto Catalyst) following peroxide fusion for sample preparation. Practical application was further demonstrated by the direct analysis of spring water, river water, lake water, and two seawater samples with around 100% spike recovery and no sample preparation except the addition of formic acid and the sensitizers.

Non-chromatographic Speciation Analysis of Tellurium by HG-ICP-MS/MS at Sub ng L-1 Concentration in Natural Waters Using TiIII as a Pre-Reducing Agent.

An automated and high-throughput (36 h-1) method for extremely sensitive determination of the two main tellurium species in the environment, namely, tellurite (TeIV) and tellurate (TeVI), was developed. Flow injection hydride generation was interfaced for the first time with inductively coupled plasma triple quadrupole mass spectrometry (ICP-MS/MS) detection to assure interference-free tellurium analysis. ICP-MS/MS conditions were studied in detail. Using a mixture of He + O2 gases in the reaction cell, the background signals significantly dropped and Xe isobaric interference was eliminated, allowing measurement with the most abundant Te isotopes, that is, 128Te and 130Te, and offering a huge increase in sensitivity. Volatile H2Te was selectively generated by a HCl/NaBH4 reaction from TeIV or from both TeIV and TeVI (TeIV+VI) after pre-reduction of TeVI by a TiCl3 solution. The optimum conditions for TiCl3 as a pre-reductant and the pre-reduction kinetics were also investigated. Different reduction rates were found depending on the sample stabilization media (HCl, HNO3, or EDTA). The same sensitivity was found for TeIV and TeVI, measured after pre-reduction, and no significant matrix effect was observed in both fresh and seawaters. Therefore, external calibration was used for quantification in real samples. Under optimal conditions, this method reached an unprecedented limit of detection of 0.07 ng L-1 for both TeIV and TeIV+VI and an intra-day repeatability of 5.2% at the 5 ng L-1 level. The methodology was successfully applied to the speciation analyses in commercially available certified reference materials of river water and seawater, and in bottled water and lake water samples.

Ultrasensitive Detection of Ruthenium by Coupling Cobalt and Cadmium Ion-Assisted Photochemical Vapor Generation to Inductively Coupled Plasma Mass Spectrometry.

An extremely sensitive methodology for the determination of Ru was developed by coupling photochemical vapor generation (PVG) analyte introduction with inductively coupled plasma mass spectrometry (ICPMS). PVG was undertaken with a thin-film flow-through photoreactor in a medium comprising 8 M formic acid in the presence of 10 mg L-1 Co2+ and 25 mg L-1 Cd2+. The volatile product (presumably ruthenium pentacarbonyl) was generated in a flow injection mode, yielding an overall efficiency of 29% at a sample flow rate of 1.4 mL min-1. The presence of both Co2+ and Cd2+ sensitizers enhanced PVG efficiency by 3,200-fold, permitting a 31 s irradiation time. Although enhanced efficiency (≈40%) could be obtained with increased Co2+ concentration, this was not suitable for routine use due to co-generation of cobalt carbonyl. Excellent repeatability (<2.5%) and reproducibility (4%) were achieved for 200 ng L-1 Ru3+. Limits of detection ranged from 20 to 42 pg L-1 (10-21 fg absolute) depending on the measured isotope and operational mode of the ICPMS reaction/collision cell. Interferences from inorganic acids and their anions, several transition metals, and metalloids were investigated. Practical application of the methodology was demonstrated by the analysis of seven water samples of various matrix complexities (well water, spring water, contaminated water, and seawater).

A mass spectrometric study of hydride generated arsenic species identified by direct analysis in real time (DART) following cryotrapping.

Hydride generation (HG) coupled to cryotrapping was employed to introduce, separately and with high selectivity, four gaseous arsanes into a direct analysis in real time source for high-resolution mass spectrometry (DART-HR-MS). The arsanes, i.e., arsane (AsH3), methylarsane (CH3AsH2), dimethylarsane ((CH3)2AsH), and trimethylarsane ((CH3)3As), were formed under HG conditions that were close to those typically used for analytical purposes. Arsenic containing ion species formed during ambient ionization in the DART were examined both in the positive and negative ion modes. It was clearly demonstrated that numerous arsenic ion species originated in the DART source that did not accurately reflect their origin. Pronounced oxidation, hydride abstraction, methyl group(s) loss, and formation of oligomer ions complicate the identification of the original species in both modes of detection, leading to potential misinterpretation. Suitability of the use of the DART source for identification of arsenic species in multiphase reaction systems comprising HG is discussed.

Cadmium Assisted Photochemical Vapor Generation of Tungsten for Detection by Inductively Coupled Plasma Mass Spectrometry.

Efficient photochemical vapor generation (PVG) of tungsten has been achieved for the first time using a 19 W thin film flow-through photoreactor. The volatile product (most probably tungsten hexacarbonyl) was generated using a flow injection mode and 40% (v/v) formic acid as the reaction medium. An inductively coupled plasma mass spectrometer was utilized for ultrasensitive detection. The addition of Cd2+ as a sensitizer was critical, enhancing the overall PVG efficiency some 30 000-fold. At an optimal irradiation time of 19 s, a 6.1-fold enhancement factor and an overall PVG efficiency of 43% were determined from a comparison of the response to direct solution nebulization when using a sample flow rate of 2 mL min-1 and 500 mg L-1 Cd2+ as a sensitizer. A limit of detection of 0.9 ng L-1 and repeatability (RSD) of 2% at 100 ng L-1 were achieved. Interference from inorganic acids (HNO3, HCl, H2SO4, and HF) was investigated with respect to analytical application to real samples. The accuracy and practical feasibility of this ultrasensitive methodology was successfully verified by analysis of Certified Reference Material CTA-FFA-1 (Fine Fly Ash) and six natural water samples with low W concentrations.

Efficient Photochemical Vapor Generation of Molybdenum for ICPMS Detection.

Photochemical vapor generation (PVG) of Mo was accomplished using a 19 W high-efficiency flow-through photoreactor operating in a flow injection mode using 30-50% (w/v) formic acid as a reaction medium. The generated volatile product (most probably molybdenum hexacarbonyl) was directed by an argon carrier gas to a plastic gas-liquid separator and introduced into the spray chamber of an inductively coupled plasma mass spectrometer for detection. Particular attention was paid to the determination of overall PVG efficiency relative to that for liquid nebulization. Utilizing a sample flow rate of 1.25 mL min-1, corresponding to an irradiation time of 38 s, PVG efficiencies in the range 46-66% were achieved. The efficiency could be further enhanced by the presence of mg L-1 added Fe3+ ions. A limit of detection of 1.2 ng L-1 and precision of 3% (RSD) at 250 ng L-1 were achieved. Interferences from inorganic anions likely to be encountered during analytical application to real samples (NO3-, Cl-, SO42-, NO2-, and ClO4-) were investigated in detail. The accuracy and applicability of this sensitive methodology was successfully verified by analysis of fresh water Standard Reference Material NIST 1643e, two seawater Certified Reference Materials (NASS-7 and CASS-6), and by analysis of two samples of commercial dietary supplements solubilized in formic acid.

Direct Speciation Analysis of Arsenic in Whole Blood and Blood Plasma at Low Exposure Levels by Hydride Generation-Cryotrapping-Inductively Coupled Plasma Mass Spectrometry.

A method for analysis of toxicologically important arsenic species in blood plasma and whole blood by selective hydride generation with cryotrapping (HG-CT) coupled either to atomic absorption spectrometry (AAS) with a quartz multiatomizer or to inductively coupled plasma mass spectrometry (ICPMS) has been validated. Sample preparation, which involved only 5 times dilution with addition of Triton X-100, Antifoam B, and l-cysteine, suppressed excessive foaming in a hydride generator. Calibration slopes for whole blood and blood plasma spiked with arsenate, monomethylarsonate, and dimethylarsinate at 0.25-1 µg L-1 As and 0.025-0.1 µg L-1 As for AAS and ICPMS detection, respectively, did not differ from slopes in aqueous solutions. HG-CT-AAS was used to analyze samples with elevated levels of arsenic species-blood plasma from patients treated with arsenic trioxide for acute promyelocytic leukemia and whole blood from mice fed an arsenic-containing diet. A good agreement between results of the direct analysis and analysis after mild digestion in phosphoric acid proved the good efficiency of the direct HG-CT procedure for the arsenic species in these types of biological samples. In the next step, plasma and whole blood from healthy donors that were spiked with the plasma from leukemia patients at levels of 0.15-0.4 µg L-1 As were analyzed by direct HG-CT-ICPMS. Good recoveries for all species even at these low levels (88-104%) were obtained. Limits of detection in blood and plasma were 0.014 µg L-1 for inorganic arsenic and below 0.002 µg L-1 As for methylated arsenic species. Thus, the ultrasensitive direct HG-CT-ICPMS method is uniquely suited for analyses of blood plasma and whole blood from individuals at low exposure levels.

Achieving 100% Efficient Postcolumn Hydride Generation for As Speciation Analysis by Atomic Fluorescence Spectrometry.

An experimental setup consisting of a flow injection hydride generator coupled to an atomic fluorescence spectrometer was optimized in order to generate arsanes from tri- and pentavalent inorganic arsenic species (iAs(III), iAs(V)), monomethylarsonic acid (MAs(V)), and dimethylarsinic acid (DMAs(V)) with 100% efficiency with the use of only HCl and NaBH4 as the reagents. The optimal concentration of HCl was 2 mol L(-1); the optimal concentration of NaBH4 was 2.5% (m/v), and the volume of the reaction coil was 8.9 mL. To prevent excessive signal noise due to fluctuations of hydride supply to an atomizer, a new design of a gas-liquid separator was implemented. The optimized experimental setup was subsequently interfaced to HPLC and employed for speciation analysis of arsenic. Two chromatography columns were tested: (i) ion-pair chromatography and (ii) ion exchange chromatography. The latter offered much better results for human urine samples without a need for sample dilution. Due to the equal hydride generation efficiency (and thus the sensitivities) of all As species, a single species standardization by DMAs(V) standard was feasible. The limits of detection for iAs(III), iAs(V), MAs(V), and DMAs(V) were 40, 97, 57, and 55 pg mL(-1), respectively. Accuracy of the method was tested by the analysis of the standard reference material (human urine NIST 2669), and the method was also verified by the comparative analyses of human urine samples collected from five individuals with an independent reference method.

Demethylation of Methylated Arsenic Species during Generation of Arsanes with Tetrahydridoborate(1-) in Acidic Media.

Demethylation during generation of volatile hydrides (HG), i.e. formation of noncorresponding arsanes from monomethylarsonic acid (MAs(V)), dimethylarsinic acid (DMAs(V)), and trimethylarsine oxide (TMAs(V)O) by the reaction of sodium tetrahydridoborate(1-) (THB) with different acids under analytical conditions, was investigated and characterized. Pronounced demethylation of MAs(V), DMAs(V), and TMAs(V)O was found during the reaction of THB with HCl, H2SO4, and HClO4, while HG from CH3COOH or TRIS buffer after prereduction with l-cysteine resulted in the formation of only the corresponding hydrides. In the case of HNO3 formation of corresponding hydrides was preserved for MAs(V) and DMAs(V) but not for TMAs(V)O. The extent of demethylation strongly depends on concentration of the acid and THB. It can be strongly suppressed in HCl medium by partial hydrolysis of THB with optimal concentration of acid before it reacts with MAs(V), DMAs(V), or TMAs(V)O. It appears that the demethylation is due to the action of specific hydrolytic products of THB (most probably by the first and second one).

Speciation analysis of arsenic by selective hydride generation-cryotrapping-atomic fluorescence spectrometry with flame-in-gas-shield atomizer: achieving extremely low detection limits with inexpensive instrumentation.

This work describes the method of a selective hydride generation-cryotrapping (HG-CT) coupled to an extremely sensitive but simple in-house assembled and designed atomic fluorescence spectrometry (AFS) instrument for determination of toxicologically important As species. Here, an advanced flame-in-gas-shield atomizer (FIGS) was interfaced to HG-CT and its performance was compared to a standard miniature diffusion flame (MDF) atomizer. A significant improvement both in sensitivity and baseline noise was found that was reflected in improved (4 times) limits of detection (LODs). The yielded LODs with the FIGS atomizer were 0.44, 0.74, 0.15, 0.17 and 0.67 ng L(-1) for arsenite, total inorganic, mono-, dimethylated As and trimethylarsine oxide, respectively. Moreover, the sensitivities with FIGS and MDF were equal for all As species, allowing for the possibility of single species standardization with arsenate standard for accurate quantification of all other As species. The accuracy of HG-CT-AFS with FIGS was verified by speciation analysis in two samples of bottled drinking water and certified reference materials, NRC CASS-5 (nearshore seawater) and SLRS-5 (river water) that contain traces of methylated As species. As speciation was in agreement with results previously reported and sums of all quantified species corresponded with the certified total As. The feasibility of HG-CT-AFS with FIGS was also demonstrated by the speciation analysis in microsamples of exfoliated bladder epithelial cells isolated from human urine. The results for the sums of trivalent and pentavalent As species corresponded well with the reference results obtained by HG-CT-ICPMS (inductively coupled plasma mass spectrometry).

Speciation without chromatography using selective hydride generation: inorganic arsenic in rice and samples of marine origin.

Because of the toxicity of inorganic arsenic (iAs), only iAs needs to be monitored in food and feedstuff. This demands the development of easy and quick analytical methods to screen large number of samples. This work focuses on hydride generation (HG) coupled with an ICPMS as an arsenic detector where the HG is added as a selective step to determine iAs in the gaseous phase while organically bound As remains in the solution. iAs forms volatile arsine species with high efficiency when treated with NaBH4 at acidic conditions, whereas most other organoarsenic compounds do not form any or only less volatile arsines. Additionally, using high concentrations of HCl further reduces the production of the less volatile arsines and iAs is almost exclusively formed, therefore enabling to measure iAs without a prior step of species separation using chromatography. Here, we coupled a commercially available HG system to an ICPMS and optimized for determination of iAs in rice and samples of marine origin using different acid concentrations, wet and dry plasma conditions, and different reaction gas modes. Comparing this method to conventional HPLC-ICPMS, no statistical difference in iAs concentration was found and comparable limits of detections were achieved using less than half the instrument time.

Selective hydride generation- cryotrapping- ICP-MS for arsenic speciation analysis at picogram levels: analysis of river and sea water reference materials and human bladder epithelial cells.

An ultra sensitive method for arsenic (As) speciation analysis based on selective hydride generation (HG) with preconcentration by cryotrapping (CT) and inductively coupled plasma- mass spectrometry (ICP-MS) detection is presented. Determination of valence of the As species is performed by selective HG without prereduction (trivalent species only) or with L-cysteine prereduction (sum of tri- and pentavalent species). Methylated species are resolved on the basis of thermal desorption of formed methyl substituted arsines after collection at -196°C. Limits of detection of 3.4, 0.04, 0.14 and 0.10 pg mL-1 (ppt) were achieved for inorganic As, mono-, di- and trimethylated species, respectively, from a 500 µL sample. Speciation analysis of river water (NRC SLRS-4 and SLRS-5) and sea water (NRC CASS-4, CASS-5 and NASS-5) reference materials certified to contain 0.4 to 1.3 ng mL-1 total As was performed. The concentrations of methylated As species in tens of pg mL-1 range obtained by HG-CT-ICP-MS systems in three laboratories were in excellent agreement and compared well with results of HG-CT-atomic absorption spectrometry and anion exchange liquid chromatography- ICP-MS; sums of detected species agreed well with the certified total As content. HG-CT-ICP-MS method was successfully used for analysis of microsamples of exfoliated bladder epithelial cells isolated from human urine. Here, samples of lysates of 25 to 550 thousand cells contained typically tens pg up to ng of iAs species and from single to hundreds pg of methylated species, well within detection power of the presented method. A significant portion of As in the cells was found in the form of the highly toxic trivalent species.

Ultra-sensitive speciation analysis of tellurium by manganese and iron assisted photochemical vapor generation coupled to ICP-MS/MS.

Photochemical vapor generation (PVG) of Te4+ was undertaken with a simple reactor consisting of a polytetrafluoroethylene reaction coil wrapped around a low-pressure mercury tube lamp and using a flow-injection for sample delivery. The composition of a reaction medium, the influence of irradiation time and the effect of added sensitizers and interferents were investigated using high-resolution continuum source atomic absorption spectrometry and a miniature diffusion flame atomizer. A mixture of 5 M acetic acid and 3.5 M formic acid and sample flow rate of 4 mL min-1 permitting a 36 s irradiation time were found optimal for PVG of Te4+. The addition of 250 mg L-1 Mn2+ and 15 mg L-1 Fe2+ ions as sensitizers enhanced the overall PVG efficiency 2.75-fold to 50 ± 2%. In order to achieve higher sensitivity necessary for determination of Te in real environmental samples, PVG was coupled to inductively coupled plasma triple quadrupole mass spectrometer and detection was performed with O2 in the reaction cell utilizing a mass shift mode of measurement (m/z 128 → m/z 144) to ensure interference free ion detection. A limit of detection 1.3 ng L-1 and repeatability (RSD) 0.9% at 250 ng L-1 were achieved. This ultrasensitive methodology was validated for speciation analysis of Te in water samples of various matrix complexities (fresh water, well water, seawater and contaminated water). Since no response was observed from Te6+ under optimal PVG conditions, Te4+ was selectively determined by direct PVG. The sum of Te4+ and Te6+ was determined after pre-reduction of Te6+ in 6 M HCl (95 °C), evaporation to dryness and reconstitution in the reaction medium containing sensitizers. Very good accuracy was demonstrated by spiked recoveries for both Te4+ and total Te in water samples and also by total Te determination in fresh water Standard Reference Material NIST 1643f.

Arsenic species and their health risks in edible seaweeds collected along the Chinese coastline.

Edible seaweeds with a relatively high total arsenic concentration have been a global concern. As the largest seaweed producer, China contributes about 60 % of the global seaweed production. The present study investigated 20 seaweed species collected from representative seaweed farming sites in the six provinces along the Chinese coastline, of which Saccharina japonica, Undaria pinnatifida, Neopyropia spp., Gracilaria spp., Sargassum fusiforme were listed as the most consumed seaweeds in Food and Agriculture Organization of the United Nations (FAO). The inorganic arsenic (iAs) concentration in most of the seaweeds was below maximum limits (0.3 mg iAs/kg) as seaweed additives for infant food in the National Food Safety Standard of Pollutants in China (GB2762-2017, 2017), except for the species Sargassum, in which the iAs concentration significantly exceeded the limit and ranged from 15.1 to 83.7 mg/kg. Arsenic speciation in 4 cultivated seaweeds grown in both temperate and subtropical zones is reported for the first time. No significant differences in total As and iAs concentration were identified, except slightly higher total As concentration were found in Saccharina japonica growing in the temperate zone. The estimated daily intake (EDI) of toxic iAs via seaweed consumption was generally below the EFSA CONTAM Panel benchmark dose lower confidence limit (0.3 µg/kg bw/day) except for all Sargassum species where the EDI was significantly higher than 0.3 µg/kg bw/day. Moreover, the first-ever reported data on As speciation indicated very high iAs concentrations in Sargassum hemiphyllum and Sargassum henslowianum. To minimize the food chain iAs exposure, reducing both human intake of Sargassum spp. and the used of Sargassum spp. for animal feed is highly recommended. CAPSULE: This study showed that edible seaweed Sargassum spp. consumption may pose a health risk related to inorganic arsenic (iAs) exposure. The risk of iAs exposure via seaweed consumption or livestock is a concern that needs to be monitored. The arsenic accumulation and speciation may be predominantly species-dependent rather than environmental-dependent.

Effect of additives on cadmium chemical vapor generation and reliable quantification of generation efficiency.

Chemical vapor generation (CVG) of cadmium was optimized based on response from atomic absorption spectrometry (AAS) with a heated quartz tube atomizer (QTA). Effect of several modifiers on analytical performance was studied. These additives were: inorganic salts of Cr3+, Ti4+ and Co2+ and their on-line synthesized complexes with KCN and thiourea, respectively. The use of these additives resulted in sensitivity enhancement, better repeatability and correspondingly in improvement of overall CVG efficiency. The latter was quantified by two independent approaches: a) by means of 115mCd radioactive indicator, b) from comparison of sensitivities obtained with conventional solution nebulization and with CVG, both coupled simultaneously to inductively coupled plasma mass spectrometry. Both approaches provided comparable results. The highest efficiency, between 60 and 70%, was reached in the presence of Cr3+/KCN and Ti4+/KCN while 19% was achieved in Co2+/ascorbic acid/thiourea environment. Highly irreproducible results with low CVG efficiency ranging from 2.5 to 15% were reached in the absence of any additives. The generated cadmium species were identified to be mostly free atoms regardless of the additives presence or their absence. Cr3+/KCN environment was selected as the most robust for CVG of Cd reaching sensitivity of 6.6 s ng-1 Cd and limit of detection of 60 pg mL-1 Cd (9 pg Cd absolute) with detection by QTA-AAS.

Natural or intended mummification? Specific case of a child mummy.

The aim of this work was to document and analyze an exceptionally preserved mummified body of a six-year-old boy found in a family tomb in Skalná, Czech Republic. The boy died of scarlet fever in 1887, and was buried under ground in a cemetery in an unknown coffin shortly after death. His parents exhumed his cadaver and entombed it in the family crypt in two tin coffins a year later. This secondary burial and violent opening of the coffins in the end of the World War II leaving the body exposed to external climatic conditions led to its natural (spontaneous) dry mummification. The computed tomography scan of the corpse showed that the majority of internal organs were well preserved. And surprisingly, parts of the central nervous system estimated to be about 70% of the original size with distinguishable neural structures. We tested the cerebellum, tentorium and hair for mercury and arsenic, and the body was assessed by a forensic examiner for possible signs of an artificial embalming, and pathology. We did not confirm the hypothesis of the eventual preservation using the salts of mercury and/or arsenic or other fixation common for embalming in the 1800s. The anthropogenic mummification can be excluded due to the presence of fly larvae, historical records confirmed the burial of the individual right after death, and the different degree of organs condition. It appears that the unique preservation of the mummy and its internal organs was most likely caused by stable conditions of the environment.

Na+/K+-ATPase and lipid peroxidation in forebrain cortex and hippocampus of sleep-deprived rats treated with therapeutic lithium concentration for different periods of time.

Lithium (Li) is a typical mood stabilizer and the first choice for treatment of bipolar disorder (BD). Despite an extensive clinical use of Li, its mechanisms of action remain widely different and debated. In this work, we studied the time-course of the therapeutic Li effects on ouabain-sensitive Na+/K+-ATPase in forebrain cortex and hippocampus of rats exposed to 3-day sleep deprivation (SD). We also monitored lipid peroxidation as malondialdehyde (MDA) production. In samples of plasma collected from all experimental groups of animals, Li concentrations were followed by ICP-MS. The acute (1 day), short-term (7 days) and chronic (28 days) treatment of rats with Li resulted in large decrease of Na+/K+-ATPase activity in both brain parts. At the same time, SD of control, Li-untreated rats increased Na+/K+-ATPase along with increased production of MDA. The SD-induced increase of Na+/K+-ATPase and MDA was attenuated in Li-treated rats. While SD results in a positive change of Na+/K+-ATPase, the inhibitory effect of Li treatment may be interpreted as a pharmacological mechanism causing a normalization of the stress-induced shift and return the Na+/K+-ATPase back to control level. We conclude that SD alone up-regulates Na+/K+-ATPase together with increased peroxidative damage of lipids. Chronic treatment of rats with Li before SD, protects the brain tissue against this type of damage and decreases Na+/K+-ATPase level back to control level.

Longitudinally monitored lifetime changes in blood heavy metal concentrations and their health effects in urban birds.

Urban heavy metal pollution can impair the health of humans and other organisms inhabiting cities. While birds are suggested as one of the appropriate bioindicators for essential and non-essential trace element monitoring, the process of particular elements' accumulation in blood and its possible adverse health effects during ageing of individuals remain unexplored. We have investigated lifetime changes in blood lead (Pb), cadmium (Cd), arsenic (As) and zinc (Zn) concentrations and searched for links to health-related traits in sub-urban free-living great tit (Parus major) population monitored over a long period of time. The blood As concentrations were under the limit of detection in most samples. The blood Pb levels showed a non-linear relationship to individuals age, where the highest Pb concentrations were measured in nestlings and in a very small group of highly senescent birds (over 7 years old), while no clear trend was observed for the majority of the adult age stages. No age-related patterns were found for blood Cd or Zn concentrations. The positive relationship between date of capture and blood Cd and Zn levels may reflect seasonal changes in diet composition. We did not reveal any anaemia-like conditions (decreased total erythrocyte count or increased immature erythrocyte count) in relation to blood heavy metal concentrations in the investigated birds. Total leukocyte counts, heterophil/lymphocyte (H/L) ratio and total heterophil and lymphocyte counts increased with increasing Pb, Cd and Zn concentrations in blood. This study demonstrates the suitability of avian blood for actual heavy metal spatial and temporal biomonitoring even in situations when the precise age of the individuals remains unknown.

Na+/K+-ATPase level and products of lipid peroxidation in live cells treated with therapeutic lithium for different periods in time (1, 7, and 28 days); studies of Jurkat and HEK293 cells.

Regulation of Na+/K+-ATPase in bipolar disorder and lithium therapy has been investigated for more than 40 years. Contradictory results in this area may be caused by the difference between acute and long-term Li effects on cell metabolism and variance in responsiveness of different cell types. We compared the time-course of Li action focusing on Na+/K+-ATPase and lipid peroxidation in two widely different cell models-Jurkat and HEK293. Na+/K+-ATPase expression level was determined in cells cultivated in the absence or presence of 1 mM Li for different time spans (1, 7, and 28 days) using [3H] ouabain binding and immunoblot assay of α-subunit. In parallel samples, the formation of malondialdehyde (MDA) was quantified by HPLC, and 4-hydroxy-2-nonenal (4-HNE) protein adducts were determined by immunoblot. Cultivation of Jurkat cells in 1 mM Li medium resulted in downregulation of Na+/K+-ATPase (decrease of [3H] ouabain-biding sites and intensity of immunoblot signals) in all Li-groups. In HEK293 cells, the decrease of Na+/K+-ATPase was observed after the acute, 1-day exposure only. The long-term treatment with Li resulted in Na+/K+-ATPase upregulation. MDA and 4-HNE modified proteins were decreased in Jurkat cells in all Li-groups. On the other hand, in HEK293 cells, MDA concentration was decreased after the acute, 1-day Li exposure only; the long-term cultivations, for 7 or 28 days, resulted in a significant increase of lipid peroxidation products. The Li-induced decrease of lipid peroxidation products was associated with the decrease of Na+/K+-ATPase level and vice versa.