New polluting metals. Quantification in herbal medicines by voltammetric and spectroscopic analytical methods.

A new application of voltammetric techniques in stripping mode to the quantitative determination of metals belonging to the platinum group (PGM) in herbal medicines, at the ultra-trace level, is reported. Pd (II), Pt (II) and Rh (III) are determined by means of square-wave adsorption voltammetry (SWAdSV); Os (VIII) and Ru (III) are determined through square-wave voltammetry in catalytic mode (SWCV); Ir (III) is determined through the application of square-wave catalytic voltammetry in adsorption mode (SWAdCSV). In all the applied methods, the voltammetric cell has the conventional setting with three-electrodes, which sees the presence of a suspended mercury-drop electrode (HMDE) or a glassy carbon electrode (GCE) as working electrodes for the determination of Ir (III). The auxiliary electrode was a platinum electrode, and an Ag∣AgCl∣KClsatd. electrode was employed as reference electrode. Validation of the analytical procedure here proposed has been achieved using reference standards: NIST-SRM 1570a (Spinach Leaves) and NIST-SRM 1573a (Tomato Leaves), both added with pure metal standards, obtaining satisfying precision values, better than the limits set for the validation of quantitative methods. Following the verification of the validity of the here presented procedure, commercially available herbal medicines, based on Eucalyptus globulus, Harpagophytum procumbens DC and Taraxacun officinale weber, were analyzed. Standard samples were also analyzed by atomic absorption spectroscopy, in order to have a reference technique for validating the entire procedure.

A Comparative Assessment of Biological Effects and Chemical Profile of Italian Asphodeline lutea Extracts.

The present study aims to highlight the therapeutic potential of Asphodeline lutea (AL), a wild edible plant of the Mediterranean diet. Roots, aerial parts, and flowers of AL at two different phenological stages were collected from three locations in Italy. The inhibitory activities of extracts on strategic enzymes linked to human diseases were assessed. The antioxidant properties were evaluated in vitro, using six standard bioassays. The phenolic and anthraquinone profiles were also established using HPLC-PDA. Zinc, cadmium, lead, and copper contents were also determined. All the samples inhibited acetylcholinesterase (from 1.51 to 2.20 mg GALAEs/g extract), tyrosinase (from 7.50 to 25.3 mg KAEs/g extract), and α-amylase (from 0.37 to 0.51 mmol ACAEs/g extract). Aloe-emodin and physcion were present in all parts, while rhein was not detected. The phenolic profile and the heavy metals composition of specimens gathered from three different regions of Italy were different. It can be argued that samples collected near the street can contain higher concentrations of heavy metals. The experimental data confirm that the A. lutea species could be considered as a potential source of bioactive metabolites, and its consumption could play a positive and safe role in human health maintenance.

Application of pyrolysis-gas chromatography-mass spectrometry and multivariate analysis to study bacteria and fungi in biofilms used for bioremediation.

Biofilms are communities of microorganisms adhering to a surface and embedded in an extracellular polymeric matrix, frequently associated with disease and contamination, and also used for engineering applications such as bioremediation. A mixed biofilm formed by bacteria and fungi may provide an optimal habitat for addressing contaminated areas. To exploit the potential of natural microbial communities consisting of bacteria and fungi, it is essential to understand and control their formation. In this work, a method to discriminate among bacteria of genera Bacillus, Pseudomonas, Rhodococcus with respect to the fungus Pleorotus in a biofilm by means of pyrolysis-gaschromatography-mass spectrometry and multivariate analysis is reported. Methylated fatty acids were chosen as biomarkers of microorganisms in the pyrolysates. In situ thermal hydrolysis and methylation was applied. Pyrograms were used as fingerprints, thus allowing for the characterization of whole cells analyzed without any sample pretreatment. Normalized pyrographic peak areas were chosen as variables for chemometric data processing. Principal components analysis was applied as a data exploration tool. Satisfactory results were obtained in analyzing a real biofilm. The influence of growth medium on whole bacteria fatty acid cell composition was also explored.

Trace level voltammetric determination of heavy metals and total mercury in tea matrices (Camellia sinensis).

An analytical procedure regarding the voltammetric determination of mercury(II), copper(II), lead(II), cadmium(II) and zinc(II) by square wave anodic stripping voltammetry (SWASV) in matrices involved in food chain is proposed. In particular, tea leaves were analyzed as real samples. The digestion of each matrix was carried out using a concentrated HCl-HNO3-H2SO4 acidic attack mixture; 0.01 mol L(-1) EDTA-Na2+ 0.15 mol L(-1) NaCl + 0.5 mol L(-1) HCl was employed as the supporting electrolyte. The voltammetric measurements were carried out using a conventional three electrode cell, employing, as working electrodes, a gold electrode (GE) and a stationary hanging mercury drop electrode (HMDE). The analytical procedure has been verified on the standard reference materials Spinach Leaves NIST-SRM 1570a, Tomato Leaves NIST-SRM 1573a and Apple Leaves NIST-SRM 1515. For all the elements, the precision as repeatability, expressed as relative standard deviation (sr) was of the order of 3-5%, while the trueness, expressed as relative error (e) was of the order of 3-7%. Once set up on the standard reference materials, the analytical procedure was applied to commercial tea leaves samples. A critical comparison with spectroscopic measurements is also discussed.

Catalytic-adsorptive stripping voltammetric determination of ultra-trace iridium(III). Application to fresh- and sea-water.

An extremely sensitive stripping voltammetric procedure for ultra-trace determination of iridium(III) is reported. The method is based on the interfacial accumulation of the iridium(III)-CTAB complex onto the glassy carbon electrode, followed by the catalytic reduction of the adsorbed complex in the presence of bromate. 0.3 mol L(-1) acetate buffer pH 4.7+6.9×10(-2) mol L(-1) NaBrO(3)+2.7×10(-5)mol L(-1) cetyltrimethylammonium bromide (CTAB)+0.2 mol L(-1) KCl was employed as the supporting electrolyte. The analytical procedure was verified by the analysis of the standard reference materials: Sea Water BCR-CRM 403 and Fresh Water NIST-SRM 1643d. The accuracy, expressed as relative error e%, was satisfactory, being lower than 6%, while precision as repeatability, expressed as relative standard deviation s(r)%, was generally lower than 5%. The limit of detection was of the order of 2-3 ng L(-1). Once set up on the standard reference materials, the analytical procedure was transferred and applied to superficial water sampled in proximity to superhighway and in the Po river mouth area.

Analytical procedure for the simultaneous voltammetric determination of trace metals in food and environmental matrices. Critical comparison with atomic absorption spectroscopic measurements.

An analytical procedure fit for the simultaneous determination of copper (II), chromium(VI), thallium(I), lead(II), tin(II), antimony(III), and zinc(II) by square wave anodic stripping voltammetry (SWASV) in three interdependent environmental matrices involved in foods and food chain as meals, cereal plants and soils is described. The digestion of each matrix was carried out using a concentrated HCl-HNO3-H2SO4 (meals and cereal plants) and HCl-HNO3 (soils) acidic attack mixtures. 0.1 mol/L dibasic ammonium citrate pH 8.5 was employed as the supporting electrolyte. The voltammetric measurements were carried out using, as working electrode, a stationary hanging mercury drop electrode (HMDE) and a platinum electrode and an Ag/AgCl/KClsat electrode as auxiliary and reference electrodes, respectively. The analytical procedure was verified by the analyses of the standard reference materials: Wholemeal BCR-CRM 189, Tomato Leaves NIST-SRM 1573a and Montana Soil Moderately Elevated Traces NIST-SRM 2711. For all the elements in the certified matrix, the precision as repeatability, expressed as relative standard deviation (Sr %) was lower than 5%. The accuracy, expressed as percentage relative error (e %) was of the order of 3-7%, while the detection limits were in the range 0.015-0.103 microg/g. Once set up on the standard reference materials, the analytical procedure was transferred and applied to commercial meal samples, cereal plants and soils samples drawn in sites devoted to agricultural practice. A critical comparison with spectroscopic measurements is also discussed.

Platinum(II), palladium(II), rhodium(III) and lead(II) voltammetric determination in sites differently influenced by vehicle traffic.

The present work reports analytical results relevant to voltammetric determination of Pt(II), Pd(II), Rh(III) [Platinum Group Metals (PGMs)] and Pb(II) in superficial water sampled in sites differently influenced by vehicle traffic, especially considering their temporal behaviour. For all the elements, in addition to detection limits, precision, expressed as relative standard deviation (s(r) %) and accuracy, expressed as percentage recovery (R %) are also reported. In all cases they show to be good, being the former lower than 6% and the latter in the range 94-105%. A critical comparison with spectroscopic measurements is also discussed.

Senio river ecosystem: characterization and distribution of inorganic species in water and sediments.

Analytical results are reported for the determination of inorganic species in water and sediments sampled in the Senio river ecosystem. The species determined are Cu, Pb, Cd, Zn, Co, Cr, Ni, Fe, Mn, Hg, F-, Cl-, Br, NO3-, SO4-, Na+, K+, Ca++, Mg++, NH4+ in integrated water, and Cu, Pb, Cd, Zn, Co, Cr, Ni, Fe, Mn, Hg in sediments. For all the elements, in addition to detection limits, precision and accuracy are given: the former, expressed as relative standard deviation (sr), and the latter, expressed as relative error (e), were good, being in all cases lower than 6%. Limitedly to Cu, Pb, Cd and Zn a critical comparison with voltammetric measurements is also discussed.

Determination of platinum-group metals and lead in vegetable environmental bio-monitors by voltammetric and spectroscopic techniques: critical comparison.

This paper reports voltammetric sequential determination of Pt(II), Pd(II), and Rh(III), by square-wave adsorption stripping voltammetry (SWAdSV), and Pb(II), by square-wave anodic stripping voltammetry (SWASV), in vegetable environmental matrices. Analytical procedures were verified by the analysis of the standard reference materials: Olive Leaves BCR-CRM 062 and Tomato Leaves NIST-SRM 1573a. Precision and accuracy, expressed as relative standard deviation and relative error, respectively, were always less than 6% and the limits of detection (LOD) for each element were below 0.096 mug g(-1). Once set up on the standard reference materials, the analytical procedure was transferred and applied to laurel leaves sampled in proximity to a superhighway and in the Po river mouth area. A critical comparison with spectroscopic measurements is discussed.

Overlapping voltammetric peaks--an analytical procedure for simultaneous determination of trace metals. Application to food and environmental matrices.

Voltammetric methods are very suitable, versatile and rapid techniques for simultaneous determination of metals in complex matrices. The present work, determination of Cu(II), Sn(II), Sb(III), Tl(I), and Pb(II) by square-wave anodic-stripping voltammetry and Cr(VI) by square-wave adsorptive-stripping voltammetry, is an interesting example of the possibility of simultaneous determination of each single element in food and environmental samples, even in the presence of reciprocal interference. Dibasic ammonium citrate, pH 6.3 or 8.2, was employed as supporting electrolyte. The voltammetric measurements were carried out using a stationary hanging mercury drop electrode as working electrode and a platinum electrode and an Ag|AgCl|KCl(sat) electrode as auxiliary and reference electrodes, respectively. The analytical procedure was verified by analysis of standard reference materials--wholemeal BCR-CRM 189, wheat flour NIST-SRM 1567a, rice flour NIST-SRM 1568a, estuarine sediment BCR-CRM 277, river sediment BCR-CRM 320, and Montana soil with moderately elevated traces NIST-SRM 2711. Precision and accuracy, expressed as relative standard deviation and relative error, respectively, were generally below 6% whereas limits of detection for each element were below 0.069 microg g(-1). In the presence of reciprocal interference the standard addition method considerably improved the resolution of the voltammetric technique, even for very high element concentration ratios. After being set up on the standard reference materials the analytical procedure was transferred and applied to commercial samples of meal and soil samples taken from sites devoted to agricultural practice. A critical comparison with graphite furnace atomic-absorption spectroscopy is also discussed.

Heavy metals in tissues of loggerhead turtles (Caretta caretta) from the northwestern Adriatic Sea.

Thirty-five specimens of Caretta caretta were collected dead along the Adriatic Sea coast from the Po Delta to the Reno mouth (Italy). Turtles were classified into four size categories ranging from 24.5 to 74 cm, by measuring the minimum straight-line carapace length (MSCL). Cd, Cu, Fe, Mn, Ni, and Zn levels were assessed in liver, lung, muscle and adipose tissue. Cd, Cu and Fe mainly accumulated in the liver (8.9, 23.7 and 1180 mg/kg dry mass [d.w.], respectively), and Mn in the lung (29.5 mg/kg d.w.). Levels of Ni were higher in adipose (22 mg/kg d.w.) than other tissues, while Zn concentrations were higher in muscle (about 140 mg/kg d.w.). Negative correlations with size were established for Zn in liver and Cu in adipose tissue, while positive correlations were observed for Mn and Ni in adipose tissue. Metal concentrations did not differ between males and females, nor between individuals found stranded and those victims of by-catch. On average, Cd, Cu, Mn and Ni concentrations in our specimens were higher than in loggerhead turtles and other species living in other areas. We hypothesize that trace metals could be used as "acquired markers" to help investigate migration routes of C. caretta.

Determination of heavy metals in environmental matrices sampled inside the Park of the Po Delta.

Analytical results are reported for the determination of heavy metals in environmental matrices, sampled in an ecosystem inside a protected area: the Park of the Po Delta, located near the thermoelectric power station ENEL of Porto Tolle, one of the greater in Italy. The elements determined, in sediments and superficial water, are Ni and V, linked to the fuel oil combustion. However, in order to obtain a complete picture enough of heavy metals polluting load in the study areas, the following elements: Cd, Co, Cr, Cu, Fe, Mn, Pb and Zn are also determined. For all the elements, in addition to the detection limits, precision and accuracy are also given: the former, expressed as relative standard deviation (s(r)), and the latter, expressed as relative error (e), were good, being in all cases lower than 6%.

Radiochemical characterisation, heavy metal determination and morphologic evolution of coastal sediments in the Ravenna area (Italy).

The basic aim of this work was to achieve a preliminary but integrated characterisation of an area of the Ravenna littoral coastline. The use of suitable computerised procedures has allowed the reconstruction of the morphological evolution of this area by means of historical and recent cartography. Coastal sediments were characterised by sampling 3 cores at about 2 km offshore. The following aspects were studied: 1) Mineralogical characterisation of both the total and the fine fraction of sediments by X-ray Diffraction. 2) Characteristion of sedimentary horizons by radiodating. 3)Magnetic susceptibility profiling. 4) Determination of some heavy metals (Cu, Pb, Zn, Cd) by anodic stripping voltammetry.

Determination of zinc (II) in lubricant oils by stripping chronopotentiometry.

A method for the determination of zinc (II) in lubricant oils by stripping chronopotentiometry is described. The only necessary sample pretreatment was the extraction of zinc (II) from the corresponding alkyl derivatives by hot concentrated hydrochloric acid in a suitable extractor. The metal ions were concentrated as the corresponding metals on a glassy carbon working electrode and then stripped by a suitable oxidant. Quantitative analysis was carried out by the method of standard additions; a good linearity was obtained in the range of concentrations examined. Recoveries of 94% were obtained from a lubricant oil spiked at different levels. The detection limit was 0.02 mg g(-1) and the coefficient of variation (mean of nine determinations) was 5.2%. Results obtained on commercial lubricant oils were not significantly different from those obtained by atomic absorption spectrometry.

Analytical procedure for the simultaneous voltammetric determination of toxic metals in dialysis fluids.

A new analytical voltammetric procedure for the simultaneous determination of copper(II), lead(II), cadmium(II), zinc(II), chromium(VI), and manganese(II) in two kinds of dialysis fluid (peritoneal and haemodialysis fluids) is described. The voltammetric measurements were performed using, as working electrode, a stationary mercury electrode, and a platinum electrode and a Agmid R:AgClmid R:KCl ((sat.)) electrode as auxiliary and reference electrodes, respectively, employing 0.1 mol L(-1) dibasic ammonium citrate solution pH 6.9 as supporting electrolyte. For all the elements, the accuracy, expressed as relative recovery R%, was very satisfactory being in the range 94-105%, the precision, expressed as relative standard deviation s(r)%, was lower than 6%, while the limits of detection were of the order of a few units of microg L(-1). The analytical voltammetric procedure has been validated by comparison with spectroscopic (graphite furnace atomic absorption spectroscopy, GFAAS) measurements.

Inorganic species in water and sediments of the Lamone and Marzeno rivers ecosystem.

Analytical results are reported for the determination of inorganic species in water and sediments sampled in the Lamone and Marzeno rivers ecosystem. The species determined are Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn, Hg, F-, Cl- Br-, NO3-, SO4--, Na+, K+, Mg++, Ca++, NH4+ in superficial water, and Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn, Hg in sediments. For all the elements, in addition to detection limits, precision and accuracy are given: the former, expressed as relative standard deviation (s(r)), and the latter, expressed as relative error (e), were good, being in all cases lower than 6%.

Monitoring of inorganic species distribution in water and sediments of Aso river.

Analytical results are reported for the determination of inorganic species in water and sediments sampled in the Aso river ecosystem. The species determined are Cd, Co, Cr, Cu, Fe, Mn, Ni, Zn, Hg, F-, NO3-, SO4--, Na, K, Ca, Mg, NH4+ in water, and Cd, Co, Cr, Cu, Fe, Mn, Ni, Zn, Hg in sediments. For all the elements, in addition to detection limits, precision and accuracy are given: the former, expressed as relative standard deviation (Sr), and the latter, expressed as relative error (e), were good, being in all cases lower than 6%.

Spatial and temporal distribution of inorganic species in water and sediments of the Tronto River ecosystem.

Analytical results are reported for the determination of inorganic species in water and sediments sampled in the Tronto river ecosystem. The species determined are Cd, Co, Cr, Cu, Fe, Mn, Ni, Zn, Hg, F, NO3-, SO4-, Na, K, Ca, Mg, NH4+ in integrated water, and Cd, Co, Cr, Cu, Fe, Mn, Ni, Zn, Hg in sediments. For all the elements, in addition to detection limits, precision and accuracy are given: the former, expressed as relative standard deviation (Sr), and the latter, expressed as relative error (e), were good, being in all cases lower than 5%.

A new voltammetric method for the simultaneous monitoring of heavy metals in sea water, sediments, algae and clams: application to the Goro Bay ecosystem.

Arsenic(III), selenium(IV), copper(II), lead(II), cadmium(II), zinc(II) have been determined in sea water, sediments, algae and clams by differential pulse cathodic (DPCSV) and anodic (DPASV) stripping voltammetry. The voltammetric measurements are carried out using a conventional three-electrode cell and the ammonia-ammonium chloride buffer pH 9.2 as supporting electrolyte. The analytical procedure has been verified by the analysis of the standard reference materials (Estuarine Sediment BCR- CRM 277, Ulva Lactuca BCR-CRM 279 and Mussel Tissue BCR-CRM 278). The precision and the accuracy are less than 5%. This procedure is utilized for the monitoring of heavy metals in the Po river mouth area (Italy).

Employment of peak area as instrumental datum for improving the voltammetric quantitative analysis of heavy metals in fresh and sea water in the presence of surfactants.

Peak area instead of peak height is used for the simultaneous determination of Cu(II), Pb(II), Cd(II), and Zn(II) in fresh and sea water in the presence of anionic and cationic surfactants by differential pulse anodic stripping voltammetry. These species, if present, tend to make more irreversible the electrodic process of the metals. Because the employment of peak area for species having irreversible electrodic processes permits limits of detection about one or 2 orders of magnitude lower, this work shows the possibility of determining heavy metals at ultratrace level concentrations in the presence of surfactants, compounds which are always present in natural waters. The precision and accuracy of the analytical method were checked by the analysis of the standard reference materials (SRM) Fresh Water NIST-SRM 1643d, Sea Water BCR-CRM 403, and Estuarine Water BCR-CRM 505. The former, expressed as relative standard deviation (s(r)), and the latter, expressed as relative error (e), were satisfactory, being in all cases lower than 5%. The analytical procedure has been applied to fresh and sea water sampled in the Po river mouth area (Italy).