Conventional Atomic Absorption Spectrometry Research Articles

Use of fish scales in environmental monitoring by the application of Laser-Induced Breakdown Spectroscopy (LIBS)

The objective of this study was to evaluate the efficiency of Laser-Induced Breakdown Spectroscopy (LIBS) to detect the presence of bioaccumulated Fe and Pb in scales of Salminus brasiliensis and Prochilodus lineatus, and to compare the results from this technique with those obtained using the conventional atomic absorption spectrometry technique. The study used fish collected in the Amambai River, Upper Paraná River, Brazil. The LIBS technique detected the presence of Fe in S. brasiliensis scales and Fe and Pb in P. lineatus scales on different regions. Using atomic absorption spectrometry, we verified a significant difference in Fe concentration in scales between the species analyzed, with a higher concentration in S. brasiliensis than in P. lineatus (p = 0.0004). Pb was not detected using atomic absorption spectrometry in either species because the concentration of this element was below the limit of detection of this technique. The LIBS technique was efficient in detecting Fe and Pb in scales of the two species analyzed, proving to be a promising tool for environmental monitoring.

Metallic Profile of Whole Blood and Plasma in a Series of 99 Healthy Children.

In recent years, special emphasis has been put on heavy metals. Children are very sensitive to accumulation of metals. Furthermore, as regards elements, the reference values in children are scarce in the literature as it is difficult to obtain the large quantity of blood necessary to analyze many metals by the conventional atomic absorption spectrometry technique. An inductively coupled plasma mass spectrometry (ICP-MS) procedure that uses a reduced sample of 0.3 mL whole blood or plasma is adapted to multielemental determinations. We applied a previously validated technique for adults that simultaneously quantifies 25 elements by ICP-MS in whole blood and 23 in plasma in a series of 99 healthy children ranging from under 5 years to <18 years, without exposure to metal or drug-containing metals. The aims of the study were to compare metallic concentrations according to the age among children and metallic concentration differences between children and adults. The blood and plasma pediatric metallic profile is a practical useful tool for many purposes in clinical toxicology, forensic toxicology and any cases of metal environmental exposure.

Metal content in fruit-bodies and mycorrhizas of Pisolithus arrhizus from zinc wastes in Poland

&lt;i&gt;Pisolithus arrhizus&lt;/i&gt; has been selected for investigation as one of the ectomycorrhizal species most resistant to stress factors. Metal content in fruit-bodies and mycorrhizas was estimated to evaluate their role as bioindicators and to check whether mycorrhizas have any special properties for heavy metal accumulation. Fruit-bodies and mycorrhizas were collected from zinc wastes in Katowice-Wełnowiec and analyzed using conventional atomic absorption spectroscopy and energy dispersive spectroscopy accompanying scanning electron microscopy. Differences in tendencies to accumulate metals within sporophores and mycorrhizas were found. The fruit-bodies accumulated Al (up to 640 µg g&lt;sup&gt;-1&lt;/sup&gt;), while high concentrations of Al, Zn, Fe, Ca and Si were noted in the outer mantle of the mycorrhizas. in the material secreted and in the mycelium wali. The content of elements varied depending on the agę of mycorrhizas. The ability of extramatrical mycelium and hyphae forming mycorrhizal mantle to immobilize potentially toxic elements might indicate biofiltering properties though thc next step should include investigations on ability of the fungus to prevent element uptake by the plant.

Evaluation of the laser-induced breakdown spectroscopy technique for determination of the chemical composition of copper concentrates

Laser-induced breakdown spectroscopy (LIBS), like many other spectroscopic techniques, is a comparative method. Typically, in qualitative analysis, synthetic certified standard with a well-known elemental composition is used to calibrate the system. Nevertheless, in all laser-induced techniques, such calibration can affect the accuracy through differences in the overall composition of the chosen standard. There are also some intermediate factors, which can cause imprecision in measurements, such as optical absorption, surface structure and thermal conductivity. In this work the calibration performed for the LIBS technique utilizes pellets made directly from the tested materials (old well-characterized samples). This choice produces a considerable improvement in the accuracy of the method. This technique was adopted for the determination of trace elements in industrial copper concentrates, standardized by conventional atomic absorption spectroscopy with a flame atomizer. A series of copper flotation concentrate samples was analyzed for three elements: silver, cobalt and vanadium. We also proposed a method of post-processing the measurement data to minimize matrix effects and permit reliable analysis. It has been shown that the described technique can be used in qualitative and quantitative analyses of complex inorganic materials, such as copper flotation concentrates. It was noted that the final validation of such methodology is limited mainly by the accuracy of the characterization of the standards.

Multi-element atmospheric deposition study in Croatia

For the first time the moss biomonitoring technique and two complementary analytical techniques − neutron activation analyses (NAA) and atomic absorption spectrometry (AAS) − were applied to study multi-element atmospheric deposition in the Republic of Croatia. Moss samples were collected during the summer of 2006 from 98 sites evenly distributed over the country. Sampling was performed in accordance with the LRTAP Convention - ICP Vegetation protocol and sampling strategy of the European Programme on Biomonitoring of Heavy Metal Atmospheric Deposition. Conventional and epithermal NAA and AAS made it possible to determine concentrations of 41 elements including key toxic metals such as Pb, Cd, Hg, and Cu. Factor analysis (Principal component analysis with varimax rotation) was applied to distinguish elements mainly of anthropogenic origin from those predominantly originating from natural sources. Geographical distribution maps of the elements over the sampled territory were constructed using GIS technology. For the elements included in the European programme, the median values for Croatia were generally around the average median values observed in Europe. The Adriatic coastline of Croatia may be considered as an environmentally pristine area. This study was conducted in order to provide a reliable assessment of air quality throughout Croatia and to produce information needed for better identification of pollution sources and improving the potential for assessing environmental and health risks in Croatia associated with toxic metals.

Highly sensitive and selective fluorescent assay for quantitative detection of divalent copper ion in environmental water samples

It was found that Cu2+ has a great catalytic effect on p-cresol oxidation by hydrogen peroxide under alkaline conditions, leading to an intense fluorescence signal due to the fast formation of 2,2′-dihydroxy-5,5′-dimethylbiphenyl, an oxidation product of p-cresol. Investigation of the fluorescence spectra of the p-cresol–hydrogen peroxide system demonstrated the catalytic behavior of Cu2+. On this basis, a very simple, sensitive, and selective fluorescent method was established for the determination of trace copper in this study. Under the optimal conditions, the proposed system could respond down to 1.0 × 10−8 mol L−1 of Cu2+ with a linear calibration range of 3.0 × 10−7 mol L−1 to 5.0 × 10−5 mol L−1. The relative standard deviation (RSD) was 2.1% for 7.0 × 10−6 mol L−1Cu2+ (n = 15). The proposed method was successfully applied in the determination of trace Cu2+ in lake, river and swimming pool water samples with satisfactory results. The results obtained by the proposed method are in good agreement with those obtained by a conventional atomic absorption spectroscopy method.

Zinc supplementation improves the outcome of chronic hepatitis C and liver cirrhosis.

We treated patients with C-viral chronic hepatitis (CH) and liver cirrhosis (LC) with polaprezinc and determined prospectively the effect on long-term outcome. 62 patients were enrolled. Of these, 32 were administered 1.0 g polaprezinc and the remainder were not administered polaprezinc. We measured the serum zinc concentrations using conventional atomic absorption spectrometry and conducted a prospective study to determine the long-term outcome of the polaprezinc therapy. Changes of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in the polaprezinc administration group were significantly lower than those of the untreated group. The decrease in platelet count was clearly less than that of the untreated group. The factors that inhibited increases in serum zinc concentrations following administration of polaprezinc included low serum zinc concentration states. Furthermore, the reductions of AST and ALT levels in the low zinc group were significantly greater than those of the high zinc group. When the patients who were administered polaprezinc were divided into two groups whose zinc concentrations increased (zinc responders) or remained stable or decreased (zinc non-responders), the zinc responders had a clearly lower cumulative incidence of HCC than the zinc non-responders. We conclude zinc supplementation improved the long-term outcome in C-viral CH and LC patients.

Characterization of inorganic species in coal by laser-induced breakdown spectroscopy using UV and IR radiations

In this work, the capability of laser-induced breakdown spectroscopy for process control in a thermal power plant is presented through quantitative compositional characterization of the coal used for combustion. Laser-induced emission signal of seven samples with a range of concentrations was calibrated for quantification purposes. The eighth sample was subsequently analyzed five times as unknown in order to determine the precision and accuracy of the measurements. Two modes of operation, dynamic and static and two laser wavelengths, 1064 nm and 355 nm were employed in this study for comparison. The results revealed that UV wavelength provided better results than IR radiation in terms of accuracy for the quantification of inorganic species in coal after the comparison with conventional atomic absorption spectrometry characterization.

Clinical Significance of Evaluation of Serum Zinc Concentrations in C-Viral Chronic Liver Disease

We evaluated zinc concentrations in patients with hepatitis C virus (HCV)-positive chronic liver disease and correlated them with the clinical profiles of the patients. A total of 100 patients with chronic hepatitis (CH), 29 with liver cirrhosis (LC), and 6 who were asymptomatic HCV carriers (ASC) were examined. All of the patients were positive for serum HCV RNA. One hundred eighteen HCV antibody-positive hepatocellear carcinoma (HCC) patients and 11 healthy subjects also were included in this study. Serum zinc concentrations were evaluated using conventional atomic absorption spectrometry. The median concentration of zinc in patients with CH was statistically lower than that in healthy control subjects. The median zinc concentrations of the LC and HCC groups were significantly lower than that of the CH group. A significant correlation was observed between the zinc concentrations and the platelet counts and albumin concentrations. The zinc concentrations did not correlate with tumor size and number and decreased with the development of Child-Pugh stage. The cumulative survival rate after therapy for HCC nodules in the low zinc concentration group was significantly lower than in the high group. We conclude that the serum concentration of zinc influences the clinical profiles in patients with C-viral chronic liver disease.

Investigation of chemical modifiers for phosphorus in a graphite furnace using high-resolution continuum source atomic absorption spectrometry

Phosphorus is not one of the elements that are typically determined by atomic absorption spectrometry, but this technique nevertheless offers several advantages that make it attractive, such as the relatively great freedom from interferences. As the main resonance lines for phosphorus are in the vacuum–ultraviolet, inaccessible by conventional atomic absorption spectrometry equipment, L´vov and Khartsyzov proposed to use the non-resonance doublet at 213.5 / 213.6 nm. Later it turned out that with conventional equipment it is necessary to use a chemical modifier in order to get reasonable sensitivity, and lanthanum was the first one suggested for that purpose. In the following years more than 30 modifiers have been proposed for the determination of this element, and there is no consensus about the best one. In this work high-resolution continuum source atomic absorption spectrometry has been used to investigate the determination of phosphorus without a modifier and with the addition of selected modifiers of very different nature, including the originally recommended lanthanum modifier, several palladium-based modifiers and sodium fluoride. As high-resolution continuum source atomic absorption spectrometry is revealing the spectral environment of the analytical line at high resolution, it became obvious that without the addition of a modifier essentially no atomic phosphorus is formed, even at 2700 °C. The absorption measured with line source atomic absorption spectrometry in this case is due to the PO molecule, the spectrum of which is overlapping with the atomic line. Palladium, with or without the addition of calcium or ascorbic acid, was found to be the only modifier to produce almost exclusively atomic phosphorus. Lanthanum and particularly sodium fluoride produced a mixture of P and PO, depending on the atomization temperature. This fact can explain at least some of the discrepancies found in the literature and some of the phenomena observed in the determination of phosphorus using line source atomic absorption spectrometry.

A discussion about the significance of Absorbance and sample optical thickness in conventional absorption spectrometry and wavelength-modulated laser absorption spectrometry

One of the most frequently used concepts in atomic absorption spectrometry (AAS) is that of Absorbance, an easily measurable quantity that is linear with the concentration of the analyte over a large range of concentrations whenever Beer's law is valid. Laser-based modulation techniques, however, in particular wavelength modulated diode laser absorption spectrometry (WMAS), do not measure exactly the same physical quantities as conventional AAS techniques do, since they do not rely upon separate measurements of the intensities in the presence and in the absence of the sample, but rather (a certain fraction of) the difference between the signals ‘on’ and ‘off’ resonance. Hence, Absorbance is not as natural for the modulated laser-based absorption techniques as it is for the conventional AAS techniques. The entity called sample optical thickness (SOT) appears to be a natural entity as well as a natural unit (denoted SOT units) for the quantification of signals in WMAS. The present paper discusses the concept of measurable quantities and their units in WMAS in some detail and compares them (theoretical and practical considerations) with those of conventional AAS. In particular, it makes a distinction between the ‘observed’ sample optical thickness and the ‘true’ sample optical thickness and shows how these two entities are related to the Absorbance entity. Finally, this work also introduces a dimensionless sensitivity of the WMAS technique, and shows this quantity to be equal to the nth Fourier coefficient of the wavelength modulated, peak-normalized line shape function.

DETERMINATION OF PLATINUM IN CLINICAL SAMPLES

ABSTRACT The discovery of Pt-containing anticancer drugs in the 1970s has led to the synthesis of a multitude of new Pt compounds which may provide improved therapies for the disease. Unfortunately, many of these drugs have toxic side effects, so they are administered in small doses at low concentration. To understand the in vivo behavior of these compounds, the drugs or their metabolites must be detected at dilute levels in various body fluids and tissues. The challenge for the analytical chemist, then, is to accurately determine these species at or below the part per billion level in the native sample. An obvious strategy to Pt-drug detection is to apply the very sensitive and selective techniques already available for the determination of Pt metal. Clinical specimens can be treated with acid or digested at high temperature. Analysis may then be performed by conventional atomic absorption spectrometry, atomic emission spectrometry, atomic mass spectrometry, or even stripping voltammetry. This manuscript will discuss these techniques as they pertain to Pt in clinical samples. The analytical figures of merit, sample preparation procedures, and specific clinical applications of each technique will be reviewed. Finally, preconcentration and speciation methods will be described.

Leaf secretion composition of the mangrove species Avicennia germinans (L.) in relation to salinity: a case study by using total-reflection X-ray fluorescence analysis

The aim here was to use total-reflection X-ray fluorescence (TXRF) to determine the elemental composition (besides Na), and the relative contribution of each element in leaf secretion of the mangrove species Avicennia germinans, grown under contrasting salinities (0–865 mol m −3 NaCl). Na was determined by conventional atomic absorption spectrometry (AAS). Total secretion was 2.00±0.28 mmol m −2 per day in control plants (at 0 NaCl) and increased progressively up to 46.87±7.14 mmol m −2 per day at 865 mol m −3 NaCl. Na and Cl accounted for 85.91±1.81% of the total secretion in control plants and about 96.32±0.30% in salt-treated plants. The excretion of Na exceeded that of Cl when salinity increased and this led to a progressive increase in Na/Cl ratios from 0.46±0.02 in control plants up to 2.75±0.42 (at 865 mol m −3 NaCl). Other elements were also secreted in sizeable amounts such as K, S, Ca, Br and Zn. However, the relative importance of these elements, in terms of total secretion, was considerable in control plants (15% of the total secretion) and declined significantly under salinity treatments (<5% of the total secretion). In conclusion, TXRF has been shown to be a powerful tool allowing quantitative determination of Cl (1.2–13 mmol m −2 per day), secreted in relatively large quantities, as well as other elements secreted in intermediate (S, Ca and K; 0.07–1.00 mmol m −2 per day) and in trace quantities (Br and Zn; 0.6–4 μmol m −2 per day).

Simple spectrophotometric determination of Fe in oxalate and HCl soil extracts

We describe a spectrophotometric method to determine the sum of Fe(II) plus Fe(III) in HCl and oxalate extracts. The principle of the method is to reduce Fe(III) by ascorbate in near-neutral solution and to sequester the Fe(II) formed as a tri-ferrozine complex, which is then determined photometrically at 562 nm. Because the complex is stable, the reaction is irreversible and complete. Fe(III) in HCl solution reacted very rapidly, whereas oxalate decelerated the overall reaction so that pseudo first-order kinetics with respect to Fe(III) was detected. However, when extractions were conducted at the recommended soil:solution ratio, the absorption reached 98% of its final value within a few minutes. To test the method, four soils differing considerably in texture and carbonate, organic matter, and Fe(III)(hydr)oxide contents were extracted with oxalate in the dark for amorphous (Fe o), and with boiling oxalate for total Fe(III)(hydr)oxide (Fe bo). This newly developed spectrophotometric method showed excellent correspondence with the conventional atomic absorption spectroscopy (AAS) method. The method presented here can therefore be used as an alternative method to determine the Fe content of oxalate and hydrochloric acid extracts if AAS is not available. Oxalate extracts low in Fe content, which cannot be diluted, are easier to determine by the photometric method than by AAS.

Atomic absorption spectrometry — pregnant again after 45 years

Because atomic absorption spectrometry (AAS) seems to be so simple at first glance, its forthcoming end and replacement by more exciting techniques has been forecasted more than once over the past 45 years. However, AAS has received strong impetus again and again, e.g. by the introduction of the graphite furnace technique, and of flow injection, to mention but a few. Although more and more researchers, and even more instrument manufacturers are turning their back on AAS these days, this author believes that AAS is about to give birth to new offspring in the very near future. The most important ones are solid sampling and speciation analysis on the application side, a much deeper exploitation of the potential of flow injection analysis, the use of diode lasers as radiation sources, and the introduction of continuum-source AAS on the instrumental side. The latter could replace conventional line-source AAS in the foreseeable future because of its obvious advantages in essentially all analytical aspects.

Development of highly sensitive cadmium iondashselective electrodes by titration method and its application to cadmium ion determination in industrial waste water

Characteristics of cadmium iondashselective electrode made cadmium sulphide (CdS)-silver sulphide (Ag 2S) mixture were studied. CdS-Ag 2S mixtures were obtained by gas/solid-phase reaction between silver-cadmium mixed powder and hydrogen sulphide gas (dry method) and by ionic reaction between cadmium-silver mixed ions and sulphide ion (wet method). As a result, it was found that the CdS-Ag 2S mixture had to be made in the condition of excess existence of sulfur and had better regulate the excess sulfur quantity minimum, for the CdS-Ag 2S pressed membrane gave a good Nernstian response against the cadmium ion concentration change. As the best way, CdS-Ag 2S mixture was obtained by adding sulphide ion solution to 5 mol% cadmium ion and 95 mol% silver ion mixed solution while measuring silver sulphide (Ag 2S) electrode potential as an indicator electrode. According to the reaction was stopped when the potential variation from the initial potential in the sulphide ion solution reached at 87–116 mV which the sulphide ion concentration became 10 −3 – 10 −4 of the initial concentration, the cadmium ion membrane pressed diameter of 8 mm and thickness of 2 mm showed a Nernstian response from 10 −8 to 10 −1 M of cadmium ion concentration. Furthermore, aiming to its application for industrial waste water, masking buffer for interfering metal ions such as lead ion (Pb 2+) and copper ion (Cu 2+), which were possibly coexisted and to adjust total ionic strength and pH of sample was developed. The present Cd 2+ iondashselective electrode was applied to the determination of Cd 2+ in the industrial waste water. The good regression line with correlation factor of 0.984 was obtained compared with the conventional atomic absorption spectroscopy.

Cleaning Technologies using Electrolytic Ionized Water and Analysis Technology of Fine Structures for Next Generation Device Manufacturing

ABSTRACTTo reduce the consumption of chemicals and ultra pure water (UPW) in cleaning processes used in device manufacturing, we have developed wet processes that use electrolytic ionized water (EIW), which is generated by the electrolysis of a diluted electrolyte solution or UPW. EIW can be controlled for wide ranges of pH and oxidation-reduction potential. Anode EIW with diluted electrolyte, which has high oxidation potential, can remove metallic contamination such as Cu and Fe on Si surfaces. EIW contains less than 1/100 of the amount of chemicals contained in conventional cleaning solutions, thus drastically reduces chemical consumption in wet processes. Moreover, electrolyzed UPW can be used as a substitute for conventional UPW to achieve better rinsing characteristics. Electrolyzed UPW reduces the level of residual SO42− ions after SPM cleaning more efficiently than conventional UPW. Thus the amount of rinse water needed is reduce to 1/6 that of the conventional UPW rinse.We also developed a method for analyzing remaining metallic contamination and residual ions in deep-submicron-diameter holes with high aspect ratios. The method is based on conventional atomic absorption spectrometry (AAS), and uses device patterns with high density contact holes. With this method, metallic (Fe) contamination on the order of 1010 atoms/cm2 can be easily analyzed inside 0.1 μm-diameter holes with an aspect ratio of 10. The residual ions in the fine holes can also be detected by thermal desorption spectroscopy (TDS).

A flow injection-flame-atomic absorption spectrometry system for the determination of the real stoichiometry of small CuInSe2 semiconductor crystals

A method for the rapid determination of the real stoichiometry of small CuInSe2 semiconductor crystals is presented. The powdered crystal samples have been weighed and acid dissolved in a closed dissolution system connected to a FI manifold for flame atomic absorption spectrometry (AAS) determination. The accuracy has been assessed by comparing the results obtained with those by conventional AAS, and by analyzing CuInSe2 polycrystals of known stoichiometry. The results obtained with the proposed method are in a good agreement with the expected values. The method allows the dissolution of the crystals without any detectable loss of selenium and has been applied to the analysis of small samples of CuInSe2 monocrystals as a method for routine monitoring during the development of synthesis methods and in homogeneity studies of the crystal ingots.

Performance of a modular thermospray interface for signal enhancement in flame atomic absorption spectrometry coupled on-line to flow injection or liquid chromatography

A modular thermospray interface for improving sample transport efficiency in conventional flame atomic absorption spectrometry (AAS) burners has been developed and optimized for flow injection (Fl)-AAS and high-performance liquid chromatography (HPLC)–AAS applications. The installation of this interface required no modification of the conventional flame AAS burner. The thermospray unit consisted of two separate thermoelectric elements which heated a 50 µm silica capillary carrying the mobile phase and the nebulizer gas (air), respectively. The capillary and the nebulizer gas were guided through their respective heating elements using inexpensive quartz tubes–Swagelok fittings assemblies. The capillary tube was inserted into the sample aspiration needle of the heated nebulizer nozzle and positioned in the mixing chamber where the overheated mobile phase expanded as a fine thermospray. Under optimum conditions, the thermospray unit completely nebulized 1 ml min l–1 of the analyte solution. The unit was chemically compatible with water as the flow injection (Fl) carrier and 0.1 mol l–1 ammonium carbonate, 0.1 mol l–1 pyridinium ion or 10–100 mmol–1 TRIS-HCl [TRIS =tris(hydroxymethyl)methylamine] buffer as HPLC mobile phases. In the Fl-thermospray-AAS mode the signal-to-noise ratios were improved 6–8 times over conventional Fl sample introduction, providing signal enhancements that were comparable to figures obtained with more complex and costly systems. An additional contribution to signal enhancement by the heated nebulizer gas (air) was attributed to desolvation of the thermospray aerosol in the mixing chamber. The absolute limits of detection were 1.9 ng of cadmium, 8.5 ng of copper and 27 ng of lead. The interface was also applied for the speciation of cadmium–metallothionein isoforms I and II in the HPLC–AAS mode.

The Applicability of a Multiple-Mode Diode Laser in Flame Atomic Absorption Spectroscopy

A multiple-mode laser diode is used to supply the primary radiation for atomic absorption spectroscopy (AAS). The multiple wavelength characteristics of the laser allow peak ratio measurements and possible background correction by the monitoring of the absorption spectrum with a diode-array spectrometer. In this demonstration, lithium is used as the analyte and air/acetylene flame is used as the atom reservoir. The detection sensitivity (1% absorption) is 20 ng/mL and the detection limit (2 σ of blank) is 4 ng/mL; these values are comparable to those of the conventional flame AAS with the use of a hollow cathode lamp as the source radiation.