Solid Sampling Graphite Furnace Atomic Absorption Spectrometry Research Articles

Determination of cadmium in lichens by solid sampling graphite furnace atomic absorption spectrometry (SS-GF-AAS).

The determination of trace metal contents directly from a solid sample is a trend in modern atomic spectrometry. The aim of this study was to develop an analytical method for the routine determination of Cd in lichens using solid sampling graphite furnace atomic absorption spectrometry (SS-GF-AAS). For the determination of Cd, the temperature program of the graphite furnace was optimized using a mixed matrix modifier (Pd + Mg (NO3)2 + Triton X-100). The limit of detection and the limit of quantification were 0.9μg/kg and 3μg/kg, respectively. The analytical method for Cd determination in the plant matrix was verified by the analysis of certified reference materials of lichens, seaweed, and rye grass. The developed procedure was applied to the study of Cd distribution in thalli of Usnea antarctica lichen from James Ross Island, Antarctica. The SS-GF-AAS analytical method is particularly suited for use in environmental studies and plant physiology (the microanalysis of anatomical structures).

High purity polyimide analysis by solid sampling graphite furnace atomic absorption spectrometry

In this work, Cr, Cu, Mn, Na and Ni were determined in high purity polyimides (99.5%) by solid sampling graphite furnace atomic absorption spectrometry (SS-GFAAS) using Zeeman effect background correction system with variable magnetic field, making possible the simultaneous measurement at high or low sensitivity. The following analytical parameters were evaluated: pyrolysis and atomization temperatures, feasibility of calibration with aqueous solution, linear calibration range, sample mass range and the use of chemical modifier. Calibration with aqueous standard solutions was feasible for all analytes. No under or overestimated results were observed and up to 10mg sample could be introduced on the platform for the determination of Cr, Cu, Mn, Na and Ni. The relative standard deviation ranged from 3 to 20%. The limits of detection (LODs) achieved using the high sensitivity mode were as low as 7.0, 2.5, 1.7, 17 and 0.12ngg−1 for Cr, Cu, Mn, Na and Ni, respectively. No addition of chemical modifier was necessary, except for Mn determination where Pd was required. The accuracy was evaluated by analyte spike and by comparison of the results with those obtained by inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass spectrometry after microwave-assisted digestion in a single reaction chamber system and also by neutron activation analysis. No difference among the results obtained by SS-GFAAS and those obtained by alternative analytical methods using independent techniques. SS-GFAAS method showed some advantages, such as the determination of metallic contaminants in high purity polyimides with practically no sample preparation, very low LODs, calibration with aqueous standards and determination in a wide range of concentration.

Determination of Trace Mercury in the Titanium Dioxide by Ultrasonic Oscillation - The Suspension Solid Sampling GF-AAS

Established the analytical method by using ultrasonic vibration - suspension of solid sampling graphite furnace atomic absorption spectrometry (GF-AAS) to test trace mercury in the titanium dioxide, by choosing a suitable concentration of agar solution as dispersing agent, and taking the ultrasonic oscillation technique to prepare uniform and stable titanium dioxide suspended solid solution, and finally using the solid injection sampling GF-AAS method to test trace elements of mercury.. Through the application of solid injection technique, the problem that the titanium dioxide is extremely difficult to digest and mercury volatile loss are solved and the matrix effect of the high titanium is eliminated by standard addition method as well. The paper has tested the conditions of preparation of solid suspension such as agar dispersing agent concentration, dosage, and ultrasonic vibration parameters. and titanium dioxide solid suspensions obtained by the method have the characters of uniformity, stability, mobility features, and preserve a long time. Graphite furnace testing procedures are also optimized: drying temperature 85 °C, time 30 s, by lowering the drying temperature and measures to extend the time to solve the contradiction of water evaporation and mercury volatilization; cancel the ashing step directly into the atomization stage in order to avoid mercury loss after drying. Finally, set atomic temperature 1 000 °C, for 5 s and close the purged argon flow of the internal graphite tube to ensure mercury exists as different forms such as free, particle adsorption or parcels can be effective tested. The detection limit is from 0.000 to 005% and recovery rate is from 93% to 109%, RSD <3.1%. The results of the test is correspond with that of Microwave Digestion and Inductively Coupled Plasma Mass Spectrometry method. The methods can meet the requirement of testing toxic trace elements mercury in high-grade titanium dioxide which used in medical, food, ceramics and other field.

A rapid method for the determination of Pb, Cu and Sn in dried tomato sauces with solid sampling electrothermal atomic absorption spectrometry

In this work, lead, copper and tin were determined in tomato sauces by solid sampling graphite furnace atomic absorption spectrometry (SS-GFAAS) and the results were compared with those obtained after sample digestion. The tomato sauce samples were dried at 90°C for 12h and directly introduced into the graphite furnace by means of solid auto sampler. Alternatively the dried samples were digested with concentrated HNO3 (65%) and pipetted into the graphite furnace. After the optimization of the experimental parameters, the average lead, copper and tin concentrations found by the solid sampling and digestion methods in 10 different kinds of tomato sauce samples were not significantly different at 95% confidence level. For solid sampling technique, the limits of detection (LOD) for Cu, Sn and Pb were 10.4, 3.2 and 0.4ng/g, respectively. Whereas for digestion method, for Cu, Sn and Pb were 6.7, 2.7 and 0.3ng/g, respectively. The proposed solid sampling technique was fast, simple, the risks of contamination and analyte loss were low.

Direct determination of Hg in polymers by solid sampling-graphite furnace atomic absorption spectrometry: A comparison of the performance of line source and continuum source instrumentation

This work explores the potential of solid sampling-graphite furnace atomic absorption spectrometry (SS-GFAAS) for the fast and direct determination of Hg in polymers. Eight certified reference materials with different composition (polyethylene-PE-, polystyrene-PS-, poly vinyl chloride-PVC- and acrylonitrile butadiene styrene-ABS-) were selected for the study, covering a wide Hg content range (from 20 to 1100 μg g − 1 ). The difficulties found in achieving a selective atomization of the analyte from these samples were partially mitigated by the maintenance of the Ar flow during the atomization step, leading to an improved signal-to-background ratio. Even then, when a line source (LS) GFAAS instrument was employed for analysis, it was only possible to develop truly accurate procedures relying on the use of aqueous standards for calibration for PE and PVC samples, and different atomization conditions (1200 °C and 1300 °C, respectively) were needed for the two types of samples. The use of high-resolution continuum source (HR-CS) GFAAS instrumentation permitted to improve this situation significantly thanks to its higher potential for the correction of high and fast changing background. With such an instrument, satisfactory results could be obtained for all the samples under study using the same atomization conditions (1200 °C) and aqueous standard solutions for calibration. Additionally, the HR-CS GFAAS technique presented a lower limit of detection (0.6 μg g − 1 for CS and 2.2 μg g − 1 for LS), a broader linear range (10 to 320 Hg ng for CS, and 20 to 200 ng for LS), and a somewhat improved sensitivity (approximately 0.0030 s ng − 1 for CS using the three central pixels for quantification, and approximately 0.0025 s ng − 1 for LS). Overall, the use of HR-CS GFAAS permits obtaining significant advantages for the determination of this complex analyte in plastics, such as straightforward calibration with aqueous standards, a high sample throughput (15 min per sample), sufficient precision (4–9% RSD), a suitable limit of detection, and reduced risk of analyte loss and contamination.

Novel strategies for rapid trace element analysis of polyamide by graphite furnace atomic absorption spectrometry and inductively coupled plasma mass spectrometry. Dissolution in an organic solvent versus direct solid sampling approaches.

Titanium dioxide is added to polyamide since it efficiently scatters visible light and imparts whiteness, brightness and high opacity. TiO2, however, can degrade easily and to counteract this, it is coated with a layer of inorganic material, containing Al, Mn and Si. For quality control, it is important to develop fast and reliable methods for the determination of these elements. Due to the fact that acid digestion techniques are labor-intensive, time-consuming and bring about the risk of contamination, an alternative dissolution procedure has been developed using formic acid to dissolve polyamide. The solutions thus obtained were measured by means of graphite furnace atomic absorption spectrometry (GFAAS) and inductively coupled plasma mass spectrometry (ICPMS). For the latter technique, sample introduction was performed using a pneumatic nebulization system, containing a membrane desolvating unit to remove the organic solvent. This approach provided satisfactory results in terms of precision (6–10% RSD) and limits of detection (0.1–0.6 μg g−1, except for Si when using ICPMS). Addition of formic acid to the calibration standards was demonstrated to be required. To enhance the sensitivity, increase the sample throughput and reduce the risk of contamination and/or analyte losses, the direct solid sampling methods solid sampling GFAAS and electrothermal vaporization (ETV)-ICPMS were also evaluated. Both techniques provided accurate results using calibration versus aqueous standards, with RSD values of ∼10%. Limits of detection were improved considerably compared to those attainable after dissolution. In contrast to GFAAS, ETV-ICPMS allows the simultaneous determination of all of the analytes.

Minimally-invasive filter paper test in combination with solid sampling-graphite furnace atomic absorption spectrometry for Pb determination in whole blood

This work describes a simple procedure for the determination of blood lead levels in dried-spot filter paper specimens. The method permits the minimally-invasive collection of blood on filter paper and the subsequent direct analysis of discs punched from these filters by solid sampling-graphite furnace atomic absorption spectrometry (SS-GFAAS). A systematic study on the possible effects of different factors (total volume of blood deposited onto the filter paper, potential chromatographic effects affecting the distribution of Pb over the surface, potential differences in the amount of blood deposited per surface area for samples with different hematocrit values) was carried out, leading to the conclusion that the variation of these parameters within the usual clinical range does not result in any significant effect on the amount of Pb deposited in each disc. Thus, a simple methodology was developed based on (i) the performance of Pt as a chemical modifier and (ii) the use of matrix-matched standards for calibration (Pb-free blood samples spiked with known amounts of Pb) treated in the same way as the samples. The method was validated by analysis of a reference material, as well as by comparison of the results obtained for 18 patients from which blood was also taken and analyzed following the standard procedure (venous sampling, blood dilution and GFAAS monitoring). The main analytical features of the method proposed are: a detection limit of 2.5 μg Pb L−1, a working range up to 840 μg Pb L−1, a sample throughput of approximately 10 min per sample (5 replicates) and precision values below 10% RSD. The ease of sample collection, transporting and storing, in combination with the expeditiousness and relative inexpensiveness of the analytical technique used, make the procedure investigated very attractive for the screening of children in order to detect those with blood lead levels above the present threshold of concern (100 μg L−1), particularly in countries/areas were collecting sites might be far away from central laboratories.

Direct determination of phosphorus in two different plastic materials (PET and PP) by solid sampling-graphite furnace atomic absorption spectrometry

P is an element that is difficult to determine accurately by most analytical techniques when present at low levels. In particular, P is an additive in many plastics and its rapid determination is of economic interest. Solid sampling graphite furnace atomic absorption spectrometry (SS-GFAAS) may be an approach that combines high sample throughput with an improvement in sensitivity and it is particularly suitable for dealing with organic matrices when speed is more important than high precision. In this work, SS-GFAAS was used for the determination of P in PET (polyethyleneterephthalate) and PP (polypropylene) materials, showing the suitability of the approach for this kind of analysis. In order to enable P determination, a combination of Pd and ascorbic acid was used as a chemical modifier. The results obtained can be considered satisfactory with regard to the sensitivity (LOD 2.5 µg g−1) and precision achieved (7.8% RSD for the PET sample with a P content of about 45 µg g−1 and 6.7% RSD for the PP sample with a P content of about 1000 µg g−1), values similar to those obtained for less problematic analytes. Previous analysis of the PET material by means of solid sampling-electrothermal vaporization-ICP-MS (SS-ETV-ICP-MS) enabled us to compare the performance of both methods. Special attention was paid to the peculiar relationship between signal and sample mass that SS-GFAAS is reported to display.

Determination of Cu and Cd Content of Groundwater Colloids by Solid Sampling Graphite Furnace Atomic Absorption Spectrometry

Cu and Cd content of standard reference materials (SRMs), minerals (quartz, calcite, kaolinite, and bentonite), and samples of aquifer colloids, obtained under natural gradient flow conditions, were analyzed by solid sampling graphite furnace atomic absorption spectrometry (GFAAS). Pyrolytically coated tubes, designed for the analysis of liquid samples, were successfully used. Recovery of analytes by solid sampling was 106−112% of the certified values of SRMs. Cu concentration in clay minerals, obtained by solid sampling, was about 9-fold (in kaolinite) and 3-fold (in bentonite) higher than that obtained by nitric acid extraction, indicating that Cu is partially incorporated into the crystal lattice of the minerals. Analysis of aquifer colloids shows that within a 6-month period the average content of Cu and Cd decreased by about 87%. Solid sampling GFAAS was demonstrated to be a convenient method for the study of metal content in small (5 mg) samples of groundwater colloids.

Use of Solid Sampling Analysis for the Determination of Trace Elements in Tissues

A short introduction to the basic aspects of the application of solid sampling graphite furnace atomic absorption spectrometry (SS-AAS) to the determination of powdered tissues is given. The well-known advantages of SS-AAS are the speed of analysis and reduced risk on contamination as no time-consuming destruction steps are needed. Another advantage is the possibility of doing many real replicates in a short time. The disadvantages are the strong curvature of the calibration line, fewer possibilities to manipulate the test substance by matrix modification, and occasional problems in finding a suitable standard. A theoretical comparison between classical GF-AAS and SS-AAS is given showing that the high density in the atom cloud in SS-AAS is responsible for the strong curvature of the calibration line. A review of the literature showed that 17 elements have been determined in a variety of animal and human tissues.

Analytical quality control by solid sampling graphite furnace atomic absorption spectrometry in the production of animal tissue reference materials: bovine liver, teeth, bone, muscle, blood and equine renal cortex

The function of solid sampling graphite furnace atomic absorption spectrometry (SS-GFAAS) in the laboratory-internal preparation, production and standardization of several animal tissue reference materials is described. SS-GFAAS is successfully applied in the production of a bovine liver reference material with a low content of Pb and Cd. The lab-internal production of 5 bovine teeth and 2 bovine bone reference materials illustrates some of the basic problems entailed in the analysis of Pb in osseus matrices and in the production of the reference material itself. In the production of muscle tissue reference material focal or generalized calcification is a serious source of endogenous Pb contamination. This is shown, by way of example, in the calcification of the larval states of Taenia saginata (Cysticercus bovis) in the bovine muscle. Finally, as further examples of the application of SS-GFAAS, the lab-internal production of reference material from bovine blood and equine renal cortex is described.

Analytical quality control by solid sampling GFAAS in the production of animal tissue reference materials: lead and cadmium in bovine liver reference materials

The function of solid sampling graphite furnace atomic absorption spectrometry (SS-GFAAS) in the laboratory-internal preparation, production and standardization of bovine liver reference material is described. Analytical quality assurance was achieved by using a wet digestion decomposition procedure and GFAAS (WD-GFAAS) as well as three different methods of SS-GFAAS. It will be shown, that SS-GFAAS is an adequate and efficacious method of analytical quality control in the production of reference materials. Details are given about the preliminary steps of sample selection and preparation, applying SS-GFAAS both as a screening method and for the detection of contamination during the production of the reference materials. The element contents of the four bovine liver materials measured after decomposition with nitric acid in the open system by GFAAS and also by Flame-AAS, using the ‘slotted tube atom trap’, are compared statistically with the results obtained by SS-GFAAS. In solid sampling analyses three different systems were applied: a solid sampling ZAA-spectrometer with platform-boat, a D2AA-spectrometer with solid sampling graphite tube and platform-drawer and an autoprobe-D2AA-spectrometer with solid sampling autoprobe and graphite tube.