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Heavy metals have the potential to interact and induce several stress responses in the plants; thus, effects of heavy metal stress on DNA damages and total antioxidants level in Urtica dioica leaves and stems were investigated. The samples are sampled from areas with different metal exposition. Metal content was analyzed by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), for total antioxidants level assessment the Ferric-Reducing Antioxidant Power (FRAP) assay was used, and genomic DNA isolation from frozen plant samples was performed to obtain DNA fingerprints of investigated plant. It was found that heavy metal contents in stems generally changed synchronously with those in leaves of the plant, and extraneous metals led to imbalance of mineral nutrient elements. DNA damages were investigated by Random Amplified Polymorphic DNA (RAPD) technique, and the results demonstrated that the samples exposed to metals yielded a large number of new fragments (total 12) in comparison with the control sample. This study showed that DNA stability is highly affected by metal pollution which was identified by RAPD markers. Results suggested that heavy metal stress influences antioxidant status and also induces DNA damages in U. dioica which may help to understand the mechanisms of metals genotoxicity.

The purpose of this study was to determine the atmospheric deposition of chromium in Croatia by using moss biomonitoring technique and atomic emission spectrometry with inductively coupled plasma (ICP-AES). Moss samples (Hylocomium splendens, Hypnum cupressiforme, Brachythecium rutabulum and Homalothecium Sericeum) were collected from 121 sampling sites evenly distributed over the country, during the summer and autumn of 2010. Collected samples were air dried, then cleaned and digested by using microwave digestion system. The median value obtained in this study (1.94 mg kg⁻¹) compared with the median value of previous investigation performed in 2006 (2.75 mg kg⁻¹) shows that the content of chromium decreased. Higher contents of chromium were found in moss samples collected in the regions of Central Croatia, in/near the cities of Zagreb, Sisak and Kutina, which, in the most of the cases, are result of anthropogenic activities. In Costal Croatia, higher values have a natural origin due to the significantly higher content of Cr in soil from this region. The results were compared with those from similar studies in neighboring and other Balkan countries. It was established that the content of chromium in Croatia is lower than in the most of these countries.

In 2002 and 2005 the moss biomonitoring technique was applied to air pollution studies in the Republic of Macedonia in the framework of the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops under the auspices of the United Nations Economic Commission for Europe (UNECE-ICP Vegetation) Convention on Long-Range Transboundary Air Pollution (LRTAP). In August 2005 samples of the terrestrial mosses Homolothecium lutescens and Hypnum cupressiforme were collected at 72 sites evenly distributed over the territory of the country, in accordance with the sampling strategy of the European moss survey programme. A total of 41 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Cd, Sb, I, Cs, Ba, La, Ce, Sm, Eu, Tb, Dy Hf, Ta, W, Hg, Pb, Th, and U) were determined by instrumental epithermal neutron activation analysis and atomic absorption spectrometry. Principal component analysis was used to identify and characterize different pollution sources. Distributional maps were prepared to point out the regions most affected by pollution and to relate this to known sources of contamination. A few areas, as in 2002, are experiencing particular environmental stress: Veles, Skopje, Tetovo, Radoviš and Kavadarci-Negotino, whereas the agricultural regions in the south, south-west, and south-east show median European values for most elements of mainly pollution origin. A significant increase in the content of Ni is noticed in the 2005 moss survey compared with 2002, due to the increased production of the ferro-nickel smelter in Kavadarci. A higher content of Cd, Hg, and Pb in 2005 relative to 2002 can be explained by pollution from the lead-zinc smelter in Veles, as well as the pollution that comes from the open slag waste dump of this smelter. Protection activities on the dump of slag from the former ferrochromium smelter located near Tetovo resulted in a lower content of Cr in the 2005 moss survey.

The purpose of this study was to establish the atmospheric deposition of various elements in the Kavadarci region, Republic of Macedonia (known for its ferronickel mining and metallurgical activities) using moss biomonitoring, and to determine whether the deposition is anthropogenic or from geogenic influences. The sampling network includes 31 moss samples evenly distributed over a territory of about 600 km(2). A total of 46 elements (Ag, Al, As, Au, Ba, Be, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hg, Ho, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Rb, Sb, Sm, Sr, Tb, Th, Ti, U, V, Yb, Zn, Zr) were determined by mass spectrometry with inductively coupled plasma (ICP-MS). Based on a distribution pattern of elements determined in moss, two anthropogenic geochemical associations (Co-Cr-Cu-Fe-Mg-Ni and As-Cd-Cu-Hg-Pb-Zn), were detected. The distribution of these elements shows an increased content (especially Ni, Co and Cr) in the moss samples from the surroundings of the smelter plant compared to the rest of the samples. Thus, the median value of Ni in moss samples from the whole region (40 mg kg(-1)) is much higher than the median for Macedonia (5.82 mg kg(-1)). Moreover, the median content of Ni in the moss samples from the polluted area (around the smelter) is 178 mg kg(-1) with an enrichment ratio in the moss samples of almost 5.5 times higher than the unpolluted areas (32 mg kg(-1)). This fact confirms the influence of the dust from the ferronickel plant to the air pollution in this region.

The activity concentrations and distribution of natural and anthropogenic radionuclides in soils from the city of Kavadarci, Republic of Macedonia, and its environs were investigated. The purpose of the study, the first of this kind in this region was to evaluate the environmental radioactivity and radiological health hazard, as well as to determine the connection between the concentration of natural radionuclides and the geology of the terrain. A total of 45 surface soil samples were collected from evenly distributed sampling sites. Gross alpha and gross beta activity measurements were made using a gas flow proportional counter, while the activity concentrations of gamma emitting radionuclides were measured using a high purity germanium detector. The average activity concentrations of ⁴⁰K, ²²⁶Ra, ²³²Th and ¹³⁷Cs were found to be 546±118, 38.8±14.6, 43.7±18.4 and 41.5±40 Bq kg⁻¹, respectively. The mean values of gross alpha and gross beta activities were 522±192 and 681±146 Bq kg⁻¹. The mean total absorbed dose rate in air calculated from the concentration of the natural radionuclides was 67.1±20.9 nGy h⁻¹, and the corresponding annual effective dose rate outdoors was 0.082±0.026 mSv y⁻¹. The results of the analysis show strong correlation between the abundance of the natural radionuclides in soils and their geological origin.

Impact assessments of environmental pollutants are important in eco-genotoxicology. A random amplified polymorphic DNA (RAPD) technique was used to detect genotoxicity-induced DNA damage in Phaseolus vulgaris L. from heavy metals at two different concentrations. The results from six 10-base pair (bp) random RAPD primers with 60-70% GC content used, showed a total of 295 RAPD fragments of 700-4000 bp in molecular size in the seedlings of untreated and treated samples, of which only 163 fragments were polymorphic. Polymorphisms became evident as the disappearance and/or appearance of DNA fragments in treated samples compared to the control. A dendrogram constructed using the Numerical Taxonomy and Multivariate Analysis System (NTSYSps), showed that the control group merged with groups treated with CuSO(4)·5H(2)O (150 mg L(-1)) and MnSO(4)·H(2)O (150 mg L(-1)) in a separate cluster. These groups were linked with all of the other samples treated with metals at concentrations of 150 mg L(-1) and CuSO(4)·5H(2)O and Cd(NO(3))(2) at concentrations of 350 mg L(-1). Finally, the samples treated with metals at concentrations of 350 mg L(-1) together with NiSO(4) at the concentration of 150 mg L(-1), clustered separately. The DNA polymorphism detected by RAPD analysis offered a useful biomarker assay for the detection of toxic chemicals genotoxicity in plant model systems.

The main aim of this article was to assess the atmospheric pollution with heavy metals due to copper mining Bučim near Radoviš, the Republic of Macedonia. The open pit and mine waste and flotation tailings are continually exposed to open air, which leads to winds carrying the fine particles into the atmosphere. Samples of attic dust were examined as historical archives of mine emissions, with the aim of elucidating the pathways of pollution. Dust was collected from the attics of 29 houses, built between 1920 and 1970. Nineteen elements (Ag, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Li, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, and Zn) were analyzed by atomic emission spectrometry with inductively coupled plasma. The obtained values of the investigated elements in attic dust samples were statistically processed using nonparametric and parametric analysis. Factor analysis revealed three factors governing the source of individual chemical elements. Two of them grouping Ca, Li, Mg, Mn, and Sr (Factor 1) and Co, Cr, and Ni (Factor 2) can be characterized as geogenic. The third factor grouping As, Cu, and Pb is anthropogenic and mirrors dust fallout from mining operation and from flotation tailings. Maps of areal deposition were prepared for this group of elements, from which correlation of these anthropogenic born elements was confirmed.

Different plant organs (leaves, flowers, stems, or roots) from four plant species-Urtica dioica L. (Urticaceae), Robinia pseudoacacia L. (Fabaceae), Taraxacum officinale (Asteraceae), and Matricaria recutita (Asteraceae)-were evaluated as possible bioindicators of heavy-metal pollution in Republic of Macedonia. Concentrations of Pb, Cu, Cd, Mn, Ni, and Zn were determined in unwashed plant parts collected from areas with different degrees of metal pollution by ICP-AES. All these elements were found to be at high levels in samples collected from an industrial area. Maximum Pb concentration was 174.52 ± 1.04 mg kg⁻¹ in R. pseudoacacia flowers sampled from the Veles area, where lead and zinc metallurgical activities were present. In all control samples, the Cd concentrations were found to be under the limit of detection (LOD <0.1 mg kg⁻¹) except for R. pseudoacacia flowers and T. officinale roots. The maximum Cd concentration was 7.97 ± 0.15 mg kg⁻¹ in R. pseudoacacia flowers from the Veles area. Nickel concentrations were in the range from 1.90 ± 0.04 to 5.74 ± 0.03 mg kg⁻¹. For U. dioica leaves and R. pseudoacacia flowers sampled near a lead-smelting plant, concentrations of 465.0 ± 0.55 and 403.56 ± 0.34 mg kg⁻¹ Zn were detected, respectively. In all control samples, results for Zn were low, ranging from 10.2 ± 0.05 to 38.70 ± 0.18 mg kg⁻¹. In this study, it was found that the flower of R. pseudoacacia was a better bioindicator of heavy-metal pollution than other plant parts. Summarizing the results, it can be concluded that T. officinale, U. dioica, and R. pseudoacacia were better metal accumulators and M. recutita was a metal avoider.

Vrelo Cave is the deepest cave in Macedonia, located in the canyon Matka which is home to many endemic species not found anywhere else in Europe. Until now, Vrelo Cave has not been investigated in terms of its composition and biodiversity. The purpose of this study was to offer some preliminary data for physical and chemical parameters of water and sediments from Vrelo Cave, as well as its microbiological diversity. Samples were taken from 5 locations. They were analysed for a wide array of physico-chemical parameters, macro- and microelements and concentration of selected organic pollutants. All samples were investigated for several groups of bacteria, yeasts and moulds by a conventional selective media approach. Molecular identification of the isolated bacterial species was done by sequencing of the bacterial 16S ribosomal RNA gene. Regarding the total dry components, total hardness, dissolved oxygen, biochemical and chemical consumption of oxygen, water from Vrelo Cave belongs to Class I. All of the investigated groups of microorganisms except anaerobic sporogenic bacteria were present in water and sediment samples. Notably, a large number of coliformic bacteria (total and faecal) were isolated from all of the investigated samples which classify this water in Class IV, as ecologically unsuitable drinking water. Most of the identified non-coliformic bacteria belonged to the genus Bacillus. We have also identified representatives from Staphylococcus, Proteus, Brevundimonas and Enterobacter. Overall findings suggest a possible connection between the water from the cave and surface waters. Further investigation should be performed to determine the origin of these waters.

The results of a study on the spatial distribution of arsenic in topsoil (0-5 cm) over the K. Mitrovica region, Kosovo, are reported. The investigated region (300 km(2)) was covered by a sampling grid of 1.4 km × 1.4 km. In total, 159 soil samples were collected from 149 locations. Inductively coupled plasma-mass spectrometry (ICP-MS) was applied for the determination of arsenic levels. It was found that the average content of arsenic in the topsoil for the entire study area was 30 mg/kg (from 2.1 to 3,900 mg/kg) which exceeds the estimated European arsenic average in topsoil by a factor of 4.3. Contents of arsenic in the topsoil exceeded the optimum value recommended by the new Dutchlist (29 mg/kg As) in 124 km(2). The action value (55 mg/kg As) was exceeded in 64 km(2), with the average content of 105 mg/kg (from 55 to 3,900 mg/kg As).

This investigation was undertaken to determine the atmospheric pollution with heavy metals due to copper mining Bucim near Radovis, the Republic of Macedonia. Moss samples (Hyloconium splendens and Pleurozium schrebery) were used for biomonitoring the possible atmospheric pollution with heavy metals in mine vicinity. Sixteen elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mn, Na, Ni, Pb, Sr, and Zn) were analysed by application of flame and electrothermal atomic absorption spectrometry (FAAS and ETAAS) and atomic emission spectrometry with inductively coupled plasma (ICP-AES). The obtained values were statistically processed using nonparametric and parametric analysis. The median value for copper obtained from moss samples (10 mg kg(-1)) was much lower compared with the same values for the whole territory of the Republic of Macedonia (22 mg kg(-1)). The range of values (2.1-198 mg kg(-1)) shows much higher content of this element in the samples taken from the study area compared to the appropriate values for the whole territory of Macedonia. The association of elements As, Cd, Cu, Fe, Pb, and Zn was singled out by factor analysis as a characteristic anthropogenic group of elements. Maps of area deposition were made for this group of elements, wherefrom correlation of these anthropogenic born elements was confirmed.

The aim of this study was to determine and compare Ba, Cr, Cd, Fe, Sr, Pb, and Zn content in medicinal herbs Urtica dioica L., Taraxacum officinale, and Matricaria recutita growing in polluted and unpolluted areas of the Republic of Macedonia. The metal content was determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). In the unpolluted area of Mt. Plackovica the metal content in Taraxacum officinale was in the descending order: Fe>Sr>Zn>Ba>Cr, while Pb and Cd were below the limit of detection. In the polluted area of Veles, the order was as follows: Fe>Zn>Sr>Pb>Ba>Cd>Cr. Our results suggest that quality assurance and monitoring of toxic metals is needed for plants intended for human use and consumption. Medicinal plants should be picked in areas free of any contamination sources.

The results of a first systematic study of spatial distribution of different elements in surface soil over the Veles region (50 km(2)) known for its lead and zinc industrial activity in the recent past are reported. A total of 201 soil samples were collected according to a dense net in urban area and less dense net in rural area. The total of 42 elements were analyzed by epithermal neutron activation analysis (ENAA) and by atomic absorption spectrometry (AAS). The content of elements such as As, Au, Cd, Cu, Hg, In, Pb, Sb, Se, Zn in soil samples around the lead and zinc smelter and in the adjacent part of the town of Veles has appeared to be much higher than in those collected in the surrounding areas due to the pollution from the plant. Thus, the content of Cd (three times); Pb and Zn (two times) is even higher than the corresponding intervention (critical) values according to the Dutch standards. The results obtained by two complementary analytical techniques, AAS and ENAA, are discussed in terms of multivariate statistics. GIS technology was applied to depict the areas most affected by contamination from the lead and zinc smelter., ((c) 2009 Elsevier B.V. All rights reserved.)

A systematic study of soil radioactivity in the metallurgical centre of the Republic of Macedonia, the city of Veles and its environs, was carried out. The measurement of the radioactivity was performed in 55 samples from evenly distributed sampling sites. The gross alpha and gross beta radioactivity measurements were made as a screening, using a low background gas-flow proportional counter. For the analysis of (40)K, (238)U, (232)Th and (137)Cs, a P-type coaxial high purity germanium detector was used. The values for the activity concentrations of the natural radionuclides fall well within the worldwide range as reported in the literature. It is shown that the activity of man-made radionuclides, except for (137)Cs, is below the detection limit. (137)Cs originated from the atmospheric deposition and present in soil in the activity concentration range of 2-358 Bq kg(-1) is irregularly distributed over the sampled territory owing to the complicated orography of the land. The results of gamma spectrometry are compared to the K, U, and Th concentrations previously obtained by the reactor neutron activation analysis in the same soil samples.

A fast flotation method for determination of cadmium and lead in aquatic systems by two chromium(III) collectors is described. The first collector is a colloid precipitate of hydrated chromium(III) oxide, Cr2O3 x xH2O, while the second is a bulk chromium(III) pentamethylenedithiocarbamate, Cr(PMDTC)3. Cadmium and lead present in water are incorporated into the collector mass at pH 7.5 by addition of 20 mg of Cr(III) and 0.4 mmol of pentamethyleneammonium pentamethylenedithiocarbamate, PMA-PMDTC, to 0.5 L water sample. A solid precipitate was separated from the processed water system by air bubbles. After dissolving with strong acid, the solution is tested by electrothermal atomic absorption spectrometry (ETAAS). The limit of detection for Cd by flotation/ETAAS method is 0.002 microg L(-1), while for Pb is 0.04 microg L(-1). The precision of the method is expressed as relative standard deviations ranging of 5.0% for Cd (concentration range from 0.1 to 0.5 microg L(-1)) and 4.25% for Pb (concentration range from 0.5 to 5 microg L(-1)). The characteristic mass (mass that gives an integrated absorbance of 0.0044 s) of 1.06 pg for Cd and 16.7 pg for Pb were obtained. The method was validated by the standard additions and by its application to the reference materials (Surface water-SPS-SW-1, River Thames Water-LGC-6019).

Contents of Zn, Cu, Fe, Mn, Cd, Na, K, Ca and Mg in 123 honey samples from different regions of the Republic of Macedonia were determined by atomic absorption spectrometry. A microwave digestion system was applied for digestion of the samples. The mean content for the elements determined was found to be: 2.252, 0.696, 1.885, 1.752, 0.004, 29.52, 984.8, 40.11, 18.24 mg kg(-1) for Zn, Cu, Fe, Mn, Cd, Na, K, Ca and Mg, respectively. Based on a comparison of statistical parameters, the spatial distribution of particular elements in Macedonian honey and the results of factor analysis, two natural and one anthropogenic geochemical associations were identified. The natural geochemical associations (Mg, Mn, Ca, K and Fe, Zn, Ca, -K, -Na) are influenced mainly by lithology. The anthropogenic associations (Cd and -Cu) are mostly a result of metallurgical activities, namely lead production in the town of Veles.

A simple, rapid and precise HPLC method has been developed for the assay of verapamil in human plasma. The clean up of the plasma samples was tested using several adsorbents for solid-phase extraction and best recovery was obtained using mixed-mode cartridges (HLB - hydrophilic-lipophilic balance) ranging between 94.70 and 103.71%. HPLC separation was performed with isocratic elution on Lichrospher 60 RP-select B column (250 mm x 4 mm I.D., 5 microm particle size). The mobile phase was 40% acetonitrile and 0.025 mol/L KH2PO4 with pH 2.5 at flow rate of 1 mL/min. Diltiazem was used as internal standard and the detection wavelength was 200 nm. The calibration curves were linear in the range of 10-500 ng/mL. The developed method is convenient for routine analysis of verapamil in human plasma.

Analytical procedure for the determination of toxicologically relevant arsenic (the sum of arsenite, arsenate, monomethylarsonate and dimethylarsinate) in urine by flow injection hydride generation and collection of generated inorganic and methylated hydrides on an integrated platform of a transverse-heated graphite atomizer for electrothermal atomic absorption spectrometric determination (ETAAS) is elaborated. Platforms are pre-treated with 2.7 micromol of zirconium and then with 0.10 micromol of iridium which serve both as an efficient hydride sequestration medium and permanent chemical modifier. Arsine, monomethylarsine and dimethylarsine are generated from diluted urine samples (10-25-fold) in the presence of 50 mmol L(-1) hydrochloric acid and 70 mmol L(-1)l-cysteine. Collection, pyrolysis and atomization temperatures are 450, 500, 2100 and 2150 degrees C, respectively. The characteristic mass, characteristic concentration and limit of detection (3sigma) are 39 pg, 0.078 microg L(-1) and 0.038 microg L(-1) As, respectively. The limits of detection in urine are ca. 0.4 and 1 microg L(-1) with 10- and 25-fold dilutions. The sample throughput rate is 25 h(-1). Applications to several urine CRMs are given.

This article describes reverse phase high-performance liquid chromatography (RPHPLC) methods for determination of diuretics in different human body fluids (whole blood, plasma, serum or urine). Sample preparation procedures, including solid-phase extraction, liquid-liquid extraction, dilution, precipitation as well as automated RPHPLC procedures, are discussed in order to present the advantages and disadvantages of each type of sample preparation. Also, values of analytical recovery of each procedure used for sample preparation are summarized. The most important RPHPLC parameters (detection mode, stationary phase, mobile phase, sensitivity, etc.) are also summarized and discussed.

A method is described for direct electrothermal atomic absorption spectrometric (ETAAS) determination of cadmium in untreated samples of wine. Pyrolytic graphite tubes and graphite tubes with standard L'vov pyrolytic platforms were tested as atomizers. The detection limit achieved was 0.08 microg L(-1) Cd in wine. The relative standard deviation for the concentration range from 0.2 to 10 microg L(-1) Cd ranged from 1 to 7%. The accuracy of the method was confirmed by comparing the current results with those found for wet digested wine samples and by the analysis of spiked samples. By applying the proposed method it was found that the cadmium concentration in Macedonian wines ranges from 0.10 to 0.90 microg L(-1).

An accurate, fast, and simple method for determination of thallium in environmental water samples with Zeeman electrothermal atomic absorption spectrometry (ZETAAS) by previous flotation preconcentration is given. The possibility of using cobalt(III) hexamethylenedithiocarbamate as a colloidal precipitate collector for simultaneous flotation separation of Tl(I) and Tl(III) from water matrices was studied. All experimental parameters influencing a proper flotation of both thallium ions were ascertained. The developed procedure with Co(HMDTC)3 is applied for preconcentration and separation of total thallium in water matrix before ZETAAS. The results of ZETAAS analysis are compared with those obtained by inductively coupled plasma-atomic emission spectrometry. The ZETAAS limit of detection of thallium preconcentrated by Co(HMDTC)3 is 0.031 microg/L.

A high-performance liquid chromatographic method was developed, validated and applied for the determination of hydrochlorothiazide in human plasma. The effects of mobile phase composition, buffer concentration, mobile phase pH and concentration of organic modifiers on retention of hydrochlorothiazide and internal standard were investigated. The method involves solid-phase extraction on RP-select B cartridges followed by isocratic reversed-phase chromatography on a Hibar Lichrospher 100 RP-8 column with UV detection at 230 nm. The recovery, selectivity, linearity, precision and accuracy of the method were evaluated from spiked human plasma samples. Limit of quantification was 10 ng mL(-1). The method has been implemented to monitor hydrochlorothiazide levels in patient samples., (Copyright 2004 John Wiley & Sons, Ltd.)

A selective, sensitive and accurate high-performance liquid chromatographic method has been developed, validated and applied for the determination of ranitidine and cimetidine in plasma samples. The effects of mobile phase composition, buffer concentration, mobile phase pH and concentration of organic modifiers on retention of investigated drugs were investigated. Sample preparation was carried out by adding an internal standard, famotidine, and the clean-up procedure was accomplished using solid-phase extraction (SPE). This method uses ultraviolet detection, the separation used a Lichrocart Lichrospher 60 RP-select B column and the mobile phase consisted of 0.2% triethylamine (TEA), 0.04 mol l(-1) KH2PO4 at pH 6.8 and 14% acetonitrile. The recovery, selectivity, linearity, precision and accuracy of the method were evaluated from spiked human plasma. The method has been implemented to monitor ranitidine levels in clinical samples.

A selective, sensitive, and accurate high-performance liquid chromatographic method for determination of diltiazem in plasma samples has been developed and validated. The effects of mobile phase composition, buffer concentration, mobile phase pH, and concentration of organic modifiers on retention of diltiazem and internal standard were investigated. Solid-phase and liquid-liquid extraction were examined and proposed for isolation of the drug and elimination of endogenous plasma interferences. A 5 microm Lichrocart Lichrospher 60 RP-select B chromatographic column was used; the mobile phase was acetonitrile-0.025 mol L(-1) KH(2)PO(4) (pH 5.5), 35:65 ( v/ v) at a flow-rate of 1.5 mL min(-1). The detection wavelength was 215 nm. The calibration plots were linear in the concentration range 20.0-500.0 ng mL(-1). The method has been implemented to monitor diltiazem levels in patient samples.

Problems and possibilities of the determination of Co in serum and urine samples by electrothermal atomic absorption spectrometry (ETAAS) are described. Optimal instrumental parameters as well as a suitable atomizer, calibration procedure and hydrogen peroxide as modifier are proposed for direct ETAAS measurement of Co in serum and urine. The detection limit achieved was 0.1 microg L(-1) for both matrices and relative standard deviations varied in the range 5-20% depending on the Co concentration in the sample. Validity of the method was verified by the analyses of standard reference materials. For serum samples with a Co content lower than the detection limit, a separation and preconcentration procedure based on liquid/liquid extraction is suggested prior to determination of Co in the organic phase by ETAAS. This procedure permits determination of 0.02 microg L(-1) Co in serum samples with a relative standard deviation of 10-18%.

A new simple and rapid high-performance liquid chromatographic (HPLC) method with UV detection for the determination of indapamide in biological fluids has been developed. Indapamide and internal standard were isolated from serum and whole blood samples by solid-phase extraction with RP select B cartridges. The chromatographic separation was accomplished on a reversed-phase C(8) column with a mobile phase composed of 0.1% (v/v) triethylamine in water (pH 3.5) and acetonitrile (63:37, v/v). UV detection was set at 240 nm. The calibration curves were linear in the concentration range of 10.0-100.0 ng/ml for serum, and 50.0-500.0 ng/ml for whole blood, and the limits of quantification were 10.0 and 50.0 ng/ml, respectively.

Methods for the direct determination of Ni in human blood serum and urine by electrothermal atomic absorption spectrometry (ETAAS) are described. Hydrogen peroxide was proposed as matrix modifier, assisting thermal decomposition of proteins during the ashing step. A pyrolysis temperature of 1,200 degrees C was found to be optimal while 2,100 degrees C and 2,200 degrees C were found to be optimal atomizing temperatures for Ni in serum and urine respectively. Calibration was performed by using a calibration curve prepared with aqueous standard solutions of Ni (glycine must be used as modifier for Ni in aqueous solutions). The limits of detection, defined as the blank values plus 3 times the standard deviation of the blank values, were 0.2 microg/L for both serum and urine samples. Relative standard deviations for serum samples with concentrations of Ni in the range 0.5-2 microg/L were 10-15% and for urine samples with Ni concentrations in the range 0.5-2.5 microg/L were 8-10%.

A mixed matrix modifier of nickel and strontium nitrates was used as a chemical modifier for the determination of selenium in wines by Zeeman electrothermal atomic absorption spectrometry. Wine samples were heated on a boiling water bath with small amounts of nitric acid and hydrogen peroxide. For complete elimination of interference, especially from sulfates and phosphates, selenium is complexed with ammonium pyrolidinedithiocarbamate (APDTC), extracted into methyl isobutyl ketone (MIBK), and measured by ETAAS. The graphite furnace temperature program was optimized for both aqueous and organic solutions. Pyrolysis temperatures of 1300 degrees C and 800 degrees C were chosen for aqueous and organic solutions, respectively; 2700 degrees C and 2100 degrees C were used as optimum atomization temperatures for aqueous and organic solutions, respectively. The optimum modifier mass established is markedly lower than those presented in the literature. The platform atomization ensures pretreatment stabilization up to 1100 degrees C and 1600 degrees C, respectively, for organic and aqueous selenium solutions. The procedure was verified by the method of standard addition. The investigated wine samples originated from the different regions of the Republic of Macedonia. The selenium concentration varied from not detectable to 0.93 microg L(-1).

A fast method for separation, preconcentration and determination of cadmium in drinking (source, well, tap) and water for irrigation is described. Iron(III) hexamethylenedithiocarbamate, Fe(HMDTC)3, has the role of colloid precipitate flotation collector. The determination of cadmium in final water solutions preconcentrated by flotation can be performed by flame (FAAS) or electrothermal atomic absorption spectrometry (ETAAS). The method applied, either FAAS or ETAAS, depends of the concentration level of analyte in the water sample investigating. The AAS results are compared with inductively coupled plasma-atomic emission spectrometric measurements (ICP-AES) as an independent method. The ETAAS detection limit of cadmium is 0.002 microgram/L.

Co(III) hexamethylenedithiocarbamate has been applied as a collector in colloid flotation preconcentration of Cd from water prior to electrothermal atomic absorption spectrometry (ETAAS). All experimental parameters necessary for successful flotation have been studied and optimized. The ETAAS results were compared with those obtained by inductive coupled plasma-atomic emission spectrometry (ICP-AES). The ETAAS detection limit was found to be 0.003 microg L(-1) Cd.

Tl(I) and Tl(III) are preconcentrated simultaneously from aqueous solutions by colloid precipitate flotation using two collectors: hydrated iron(III) oxide (Fe(2)O(3).xH(2)O) and iron(III) tetramethylenedithiocarbamate (Fe(TMDTC)(3)). After the coprecipitation step and the addition of foaming agents, Tl(I) and Tl(III) were separated from the water by a stream of air bubbles. Various factors affecting Tl(I) and Tl(III) recoveries during the separation from water, including the collector mass, the nature of the supporting electrolyte, pH, zeta potential of the collector particle surfaces, type of tenside, etc., were investigated. Within the optimal pH range (6-6.5), establishing by a recommended procedure, Tl(I) and Tl(III) were separated quantitatively (94.9-100.0%) with 30 mg Fe(III). Both Tl ions were simultaneously separated without any previous conversion of one type of Tl ion to the other. Total Tl determination was performed by electrothermal atomic absorption spectrometry by previous matrix modification of the concentrated samples. The determination limit of Tl by this method is 0.108 mug l(-1).

Thallium(III) forms a ternary complex of yellow colour with iodoacetic acid and organic bases, especially hexamethylenetetramine. The complex is soluble in water and various organic solvents. Zinc, copper, cadmium and iron do not form complexes with these reagents, so that a spectrophotometric determination of thallium in zinc and its alloys is possible. The limit of detection is 15 microg g(-1), the molar absorption coefficient about 2000 mol(-1) l(-1) cm(-1).

Composition of the essential oil of Thymus moesiacus Velen. from Macedonia was examined by GC and GC-MS methods. The main constituents of the oil were geraniol, linalool, geranyl acetate, and terpenyl acetate.