Determination of lead by continuous-flow hydride generation and atomic absorption spectrometry: Comparison of malic acid—dichromate,nitric acid—hydrogen peroxide and nitric acid—peroxodisulfate reaction matrices in combination with sodium tetrahydroborate

A continuous-flow hydride generator is combined with a heated quartz tube atomizeratomic absorption spectrometer system for the trace determination of lead. Malic acid K₂Cr₂O₇, HNO₃—H₂O₂ and HNO₃—(NH₄)₂S₂O₃ are all effective for plumbane generation by means of sodium tetrahydroborate. The relative merits of these systems are investigated in terms of sensitivity, efficiency of plumbane generation and interferences. The sensitivities (0.0044 absorbance) obtained under the recommended conditions for the three systems are 3.2, 1.7 and 1.1 ng Pb ml^-1, respectively, whereas plumbane generation efficiencies are 33%, 47% and >80%, respectively, for 1 μg Pb ml^-1. Silver, Au, Cu and Cd interfere seriously in all reaction systems. A dithizone extraction and back-extraction method is utilized to eliminate interfering ions, followed by reduction of the resulting solution in the peroxodisulphate system. The proposed method is applied to water samples and NBS 1566 oyster tissue.     

Speciation of antimony by atomic absorption spectrometry. Applicability to selective determination of Sb(III) and Sb(V) in liquid samples and of bioavailable antimony in sediments and soil samples

A comparative study was made of several methods to speciale Sb(III) and Sb(V) by AAS: 1) Selective extraction of Sb(III) with lactic acid/malachite green graphite furnace-AAS, 2) Sb(III) and total antimony determination by hydride generation-AAS coupled to flow injection, batch, and continuous flow systems. These methods were applied to determine total antimony and Sb(III) in sea and surface water and total antimony in sediments and in soil. For soils different sample pretreatments were used: HNO₃-H₂SO₄-HC1O₄, HF-HNO₃-H₂SO₄-HC1O₄, cold aqua regia and slurry formation procedures in water and 4M HC1. In each case the recovery of total antimony and the ability to selective determine Sb(III) were studied. The detection limits obtained were 0.01 ng, 0.07 ng, 2.97 ng and 0.21 ppb for GF-AAS, FIA-HG-AAS, HG (Batch)-AAS, and HG (continuous flow)-AAS, respectively.     

Continuous flow hydride generation laser induced fluorescence spectrometry for trace determination of lead in water and sediment samples

Continuous flow hydride generation coupled with laser induced fluorescence spectrometry (HG-LIF) has been used for the determination of Pb in aqueous samples. Lead hydride is generated in K₃Fe(CN)₆-HCl medium using NaBH₄ as the reducing agent. Parameters such as acidity and the concentrations of oxidising and reducing agents have been studied in order to obtain the highest sensitivity. Laser excitation of Pb has been performed at 283.306 nm and fluorescence has been detected at 365 nm and 405.8 nm. The limit of detection calculated for the optimised conditions (1% K₃Fe(CN)₆ in 0.3% Oxalic Acid, 0.055 mol L^?1 HCl, 1% NaBH₄ in 0.1% NaOH) is 0.3 ng mL^?1. However, a significant Pb background was observed for blank measurements, which degraded the limit of detection. The limit of detection that is estimated for a Pb free blank was determined by detuning the laser to a wavelength of 282.806 nm and was found to be 0.45 pg mL^?1. Method repeatability is 3.5% RSD at the 10 ng mL^?1 level. The accuracy of this method has been evaluated by analysis of a water reference material. The results obtained for a multielement standard determined using the HG-LIF approach have been found to be in agreement with those obtained by using a comparison ICP-AES approach. The HG-LIF approach has been applied to the measurement of Pb in a contaminated sediment sample material. The results of this study demonstrate that a small tunable laser system combined with hydride generation sample introduction can be used to measure Pb with high sensitivity, precision and selectivity in different sample matrices.     

Comparison between hydride generation and nebulization for sample introduction in the determination of lead in plants and water samples by inductively coupled plasma mass spectrometry,using external calibration and isotope dilution

Four inductively coupled plasma mass spectrometric methods: nebulization sample introduction with external calibration; hydride generation with external calibration; isotope dilution with nebulization; and isotope dilution with hydride generation, have been tested and compared. Multimode Sample Introduction System (MSIS™) was employed in either nebulization or hydride generation mode. Best limits of detection (below 0.1 μg L^− 1) and accuracy were obtained for isotope dilution techniques in hydride generation and sample nebulization mode. A mixture of HNO₃ and H₂O₂ served both for microwave-assisted digestion as well as a medium for subsequent plumbane generation. Optimal reagent concentrations for hydride generation stage were 0.1 mol L^− 1 HNO₃, 0.28 mol L^− 1 H₂O₂ and 1.5% m/v NaBH₄. Critical effects of acidity, blanks and concomitants have been discussed. Analytical methods were validated by use of plant and water certified reference materials and spiked high-salt solutions (seawater and 20% m/v NaCl) at lead levels in nanograms per gram to micrograms per gram range.     

Determination of inorganic arsenic(III) in ground water using hydride generation coupled to ICP-AES (HG-ICP-AES) under variable sodium boron hydride (NaBH4) concentrations

The determination of inorganic arsenic species in ground water matrices using hydride generation coupled online to ICP-AES (HG-ICP-AES) is suggested on the fact that the As(III)-species shows significantly higher signal intensities at low sodium boron hydride (NaBH₄) concentrations than the As(V)-species. The sodium boron hydride concentration used for the determination of As(III) without any considerable interferences of As(V) was at 13.2 mmol/L NaBH₄ (0.05 wt/v%), whereas the concentration for the total As determination was at 158.4 mmol/L NaBH₄ (0.6 wt/v%). The interferences of As(V) during the As(III) measurements were very small: at concentrations below 100 μg/L of total arsenic, the interferences of As(V) were smaller than 2%. An amount of As(III) higher than 10% of the total As amount could be determined exactly and reliably. The total amount of arsenic is measured after reducing the sample with 20 mmol/L L-cysteine (C₃H₇NO₂S). Finally, the amount of the As(V)-species is calculated by the difference between the As(III)-species and the total arsenic. Therefore, this analytical method requires the absence of organic arsenic species, but if they still appear, they could be frozen out with liquid nitrogen after the hydride generation system. The linearity of calibration reaches from 2 μg/L up to 1000 μg/L with a detection limit routinely of about 1 μg/L for each species. The advantages of this method in comparison to AAS measurements are the higher extent of the linear calibration range (3 orders of magnitude) and a higher sensitivity. Additional merits of the method developed are easy handling and high sampling rates.     

On the determination of lead in wine by electrothermal atomic absorption spectrometry

The parameters of analytical procedures developed for direct ETAAS determination of Pb in wine are discussed. Atomic absorption spectrometers based on transversal and longitudinal Zeeman effect, wall and integrated platform atomization with two main approaches: (i) measurements in the presence of modifier and (ii) measurements without using any modifier are compared. The optimal temperature programs are defined according to the pre-treatment and atomization curves constructed in the presence of different types of wines. For all investigated instrumental systems, 1:1 dilution of wine sample with 0.2 mol L⁻¹ HNO₃ is recommended. Matrix interferences observed, call for standard addition calibration method for Pb quantification in wines. The detection limit (3σ) achieved for wine diluted in the ratio of 1:1 varied from 0.8 to 1.9 μg L⁻¹ depending on the instrument used. The relative standard deviation for the concentration range of 10 to 80 μg L⁻¹ Pb in wine is typically between 4–8%. The accuracy of the analytical procedures recommended was confirmed by comparing the results obtained with those found for wine samples previously digested with HNO₃-H₂O₂ mixture, by added/found method and by parallel analysis using different instruments. A total of 66 wine samples from different regions of Macedonia were analyzed.      

UV photochemical vapor generation-atomic fluorescence spectrometric determination of conventional hydride generation elements

A systematic investigation of UV photochemical vapor generation (photo-CVG) and its potential application for seven typical hydride-forming elements (As, Sb, Bi, Te, Sn, Pb and Cd) when combined with atomic fluorescence spectrometry (AFS) detection is presented. These analyte ions were converted to volatile species following UV irradiation of their aqueous solution to which low molecular weight organic acids (such as formic, acetic or propionic acid) had been added, and introduced to an atomic fluorescence spectrometer for subsequent analytical measurements. The experimental conditions for photo-CVG and the interferences arising from concomitant elements were carefully investigated. Limits of detection as low as 0.08, 0.1, 0.2 and 0.5 ng mL^− 1 were obtained for Te, Bi, Sb and As, respectively, comparable to those by hydride generation-AFS. The RSDs obtained with the proposed method for these elements were better than 5% at 50 ng mL^− 1. It is noteworthy that the presence of TiO₂ nanoparticles combined with UV irradiation remarkably enhances the CVG efficiencies of Se(VI) and Te(VI), which cannot form hydrides with KBH₄/NaBH₄. Moreover, photo-CVG has a greater tolerance toward interferences arising from transition elements than hydride generation, and this facilitates its application to the analysis of complicated sample matrices.     

Influence of oxidising agents in lead determination by hydride generation direct flame atomic absorption spectroscopy

Summary The influence of Cr₂O₇ ^2–, MnO₄ ^–, Ce⁴⁺, H₂O₂ and S₂O₈ ^2– as oxidising agents in lead determination as volatile covalent hydride using NaBH₄ is reported in this paper.The reaction conditions for every oxidising agents (pH, quantity and concentration of the oxidising agent, quantity and concentration of the NaBH₄ and reaction time) are optimized, determining sensitivity and detection limit by measuring the peak height.The recovery of lead from solution has been measured by flameless atomic absorption spectroscopy.A linear relationship the logarithm of absorbance values and the redox potential of the system is obtained with a correlation coefficient of 0.999. The results and their interpretation are given in this paper.

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Der Einflu oxidierender Reagentien auf die Bleibestimmung mittels Flammenatomabsorptionsspektrometrie nach Hydridbildung

Zusammenfassung Es wird über den Einfluß der Oxidantien Cr₂O₇, MnO₄ ^–, Ce⁴⁺, H₂O₂ und S₂O₈ ^{2 –} auf die Bleibestimmung als kovalentes Hydrid berichtet. Für jede oxidierende Substanz werden die Reaktionsbedingungen optimiert (pH, Menge und Konzentration des Oxidans, Menge und Konzentration von NaBH₄ und Reaktionszeit), um Empfindlichkeit und Nachweisgrenze durch Peakhöhenauswertung zu bestimmen.Die Wiederfindungsrate wurde durch elektrothermale Atomabsorptionsspektrometrie von Blei in der Lösung bestimmt.Der Zusammenhang zwischen dem Logarithmus der Extinktion und dem Redoxpotential des Oxidans ergibt eine lineare Beziehung mit einem Korrelationskoeffizienten von 0.999. Die Ergebnisse und deren Interpretation werden in dieser Arbeit beschrieben.

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Paper presented to Euroanalysis V. Cracow, August 1984.     

Evaluation of continuous hydride generation combined with helium and argon microwave induced plasmas using a surfatron for atomic emission spectrometric determination of arsenic,antimony and selenium

The direct coupling of continuous hydride generation with both Ar and He microwave induced plasmas (MIP) sustained in a surfatron has been optimized for the simultaneous determination of arsenic, antimony and selenium with atomic emission spectrometry. While a discharge tube of quartz was found suitable for the Ar plasma, the use of an Al₂O₃ tube led to improved performance of the He plasma. The He MIP was found to be less tolerant to the introduction of hydrogen than the Ar MIP, and correspondingly the hydride generation should be operated at a lower flow rate of 0.5% NaBH₄ solution. The introduction of the H₂O vapour produced during hydride generation into both discharges was found to greatly decrease the sensitivities and to degrade the measurement precision. It could be effectively removed with trapping by concentrated H₂SO₄. The detection limits (3σ) for As, Sb and Se are 1, 0.4 and 1 ng ml⁻¹ with the Ar MIP, and 2, 0.3 and 6 ng ml⁻¹ with the He MIP, respectively. The calibration curves are linear over three decades of concentration. The mutual interferences from As(III), Sb(III), Se(IV), Bi(III) and Sn(IV) were found to be negligible at interferent concentrations below 1 μg ml⁻¹ and in most cases the tolerable interferent concentrations are up to 20 μg ml⁻¹. The proposed method has been applied to the determination of As, Sb and Se in tea samples at μg g⁻¹ levels.     

Determination of lead by hydride generation inductively coupled plasma mass spectrometry (HG-ICP-MS): On-line generation of plumbane using potassium hexacyanomanganate(III)

A hydride generation (HG) procedure has been described for determination of Pb by ICP-MS using potassium hexacyanomanganate(III), K₃Mn(CN)₆, as an additive to facilitate the generation of plumbane (PbH₄). Potassium hexacyanomanganate(III) was prepared in acidic medium as it was unstable in water. The stability of hexacyanomanganate(III) was examined in dilute solutions of HCl, HNO₃ and H₂SO₄. The solutions prepared in 1% v/v H₂SO₄ were found to be stable for over a period of 24 h. The least suitable medium was 1% v/v HNO₃. For generation of plumbane, acidic hexacyanomanganate(III) and sample solutions were mixed on-line along a 5-cm long tygon tubing (1.14 mm i.d.) and then reacted with 2% m/v sodium borohydride (NaBH₄). A concentration of 0.5% m/v K₃Mn(CN)₆ facilitated the generation of PbH₄ remarkably. In comparison to H₂SO₄, HCl provided broader working range for which optimum concentration was 1% v/v. No significant interferences were noted from transition metals and hydride forming elements, up to 0.5 μg mL⁻¹ levels, except Cu which depressed the signals severely. The depressive effects in the presence of 0.1 μg mL⁻¹ Cu were alleviated by increasing the concentration of K₃Mn(CN)₆ to 2% m/v. Under these conditions, the sensitivity was enhanced by a factor of at least 42 to 48. The detection limit (3 s) was 0.008 μg L⁻¹ for ²⁰⁸Pb isotope. Average signal-to-noise ratio (S/N) ranged between 18 and 20 for 1.0 μg mL⁻¹ Pb solution. The accuracy of the method was verified by analysis of several certified reference materials, including Nearshore seawater (CASS-4), Bone ash (SRM 1400), and Mussel tissue (SRM 2976). The procedure was also successfully applied to the determination of Pb in coastal seawater samples by ICP-MS.     

Sequential determination of tin, arsenic, bismuth and antimony in marine sediment material by inductively coupled plasma atomic emission spectrometry using a small concentric hydride generator and L-cysteine as prereductant

A hydride generation system using a small concentric hydride generator combined with inductively coupled plasma atomic emission spectrometry (ICP-AES) was established to determine tin, arsenic, bismuth and antimony in a marine sediment material with L-cysteine as a pre-reductant. Influences of concentrations of three kinds of acids (HCl, HNO₃ and HClO₄), L-cysteine, and sodium tetrahydroborate(III) as well as sodium hydroxide were investigated. The interferences from transition ions were found to be insignificant for determination of the four elements in presence of L-cysteine. Under optimized conditions the detection limits were 0.6 ng/mL for arsenic(III), 0.8 ng/mL for antimony(III), 1.7 ng/mL for tin(IV), and 1.2 ng/mL for bismuth(III). The method was applied to determine the four elements in standard marine sediment materials and the results were in agreement with certified values.     

Sequential determination of tin, arsenic, bismuth and antimony in marine sediment material by inductively coupled plasma atomic emission spectrometry using a small concentric hydride generator and L-cysteine as prereductant

A hydride generation system using a small concentric hydride generator combined with inductively coupled plasma atomic emission spectrometry (ICP-AES) was established to determine tin, arsenic, bismuth and antimony in a marine sediment material with L-cysteine as a pre-reductant. Influences of concentrations of three kinds of acids (HCl, HNO₃ and HClO₄), L-cysteine, and sodium tetrahydroborate(III) as well as sodium hydroxide were investigated. The interferences from transition ions were found to be insignificant for determination of the four elements in presence of L-cysteine. Under optimized conditions the detection limits were 0.6 ng/mL for arsenic(III), 0.8 ng/mL for antimony(III), 1.7 ng/mL for tin(IV), and 1.2 ng/mL for bismuth(III). The method was applied to determine the four elements in standard marine sediment materials and the results were in agreement with certified values. Received: 4 September 1997 / Revised: 14 October 1997 / Accepted: 7 November 1997     

Determination of arsenic, antimony, bismuth, selenium and tin in biological and environmental samples by continuous flow hydride generation ICP-AES without gas-liquid separator

Summary A simple continuous flow hydride generation system without conventional gas-liquid phase separator was developed for the determination of As, Se, Sb, Bi and Sn in biological and environmental samples by sequential ICP-AES with 1.5 kW power. The interchange of operating mode from normal solution nebulization to hydride generation or vice versa can easily be done without interrupting the plasma in this system.Two digestion methods were compared, i.e. the pressurized digestion with HNO₃ in a closed vessel and HNO₃/HClO₄/H₂SO₄ acid digestion in an open system. It was found that further treatment is necessary after normal pressurized digestion for As determination in marine samples, e.g. mussel. Interferences, especially by copper and nickel were examined and completely eliminated up to 10 g/ml by using a mixed reductant (3% NaBH₄ and 2% KI) with lower flow rate as well as the sample solution media of 30% HCl (v/v) and 20% HNO₃ (v/v). The effect of KI on the elemental oxidation states of As, Se and Sb is discussed. The accuracy of the method was validated by the analysis of a number of biological and environmental SRM's of NIST, BCR and NIES. Most results were in agreement with the certified values or reference values. The detection limits for these elements were in the range of 0.x ng/ml.On leave from Shanghai Institute of Metallurgy, Academia Sinica, Shanghai, China 200050     

Preconcentration Atomic Absorption Spectrophotometric Determination of Trace Lead(II) by Hydride Generation Combined with an Adsorbent Water Suspension Sampling Technique

The optimization of preconcentration atomic absorption spectrophotometric determination of trace lead(II) has been studied by using hydride generation and adsorbent water suspension sampling techniques. The uptake of lead(II) by a specially adapted chelate-forming resin, that is, a sulfonated dithizone (DzS)-loaded resin, was complete in the pH range 6.3-10. Lead adsorbed on DzS-loaded resin was successfully converted into its hydride in a medium, HCI --- H₂O₂ --- NaBH₄ without the need for a desorption procedure. Chelating agents except for DzS and DzS-loaded resin interfered seriously with the generation of lead hydride. Severe interference from diverse hydride-forming elements and transition metal ions is eliminated to a great extent by the treatment with DzS-loaded resin. The calibration curve obtained from the lead-bearing resin-water suspension was linear in the range of 5-500 ng/ml, whereas that from aqueous standard solution was in the range of 5-200 ng/ml. The detection limit of the method depends on the concentration factor and is 0.025 ng/ml in the present study. The proposed method was applied to the determination of trace lead(II) in environmental water samples.     

A study of low level selenium determination by hydride generation atomic fluorescence spectrometry in water soluble protein and peptide fractions

Development of a method for very low level selenium determination in water soluble protein and peptide fractions, obtained after various separation procedures, is presented. A hydride generation atomic fluorescence spectrometry (HG-AFS) detection system was optimised and the influence of Cu(II), Sb(V), As(III) and HNO₃ interferences in the measurement of Se by HG-AFS was investigated. A destruction procedure using HNO₃ and H₂O₂ was also optimised and the average recovery of the digestion of a solution of selenomethioneine was 92 ± 4% (n=14). Combination of this digestion with the detection system gave reliable results. Accuracy was tested by comparison with two independent methods. A very low detection limit (DL) of 0.2 ng/g of measuring solution was achieved. The whole procedure from weighing to measuring was performed in the same Teflon tube. The addition of HNO₃ to the fractions before long term storage at -20°C was necessary to prevent adsorption on the test tubes.Selenium was measured in water soluble protein and peptide fractions obtained after extraction, and Sephadex G-75 chromatography performed on liver samples from: i) hens exposed to As₂O₃, ii) hens fed with a high fat feed and iii) the certified reference material dogfish liver (CRM DOLT-2). Because of the very low DL we were able to observe the Se distribution in chromatographic fractions of samples of organisms which were not exposed to excess amounts of Se. The presence of selenium associated with metallothioneins was observed.     

Optimization of Sample Preparation of Carrot-Fruit Juice for Determination of Antimony,Arsenic, and Selenium by Hydride Generation-Inductively Coupled Plasma Optical Emission Spectrometry

Sample preparation procedures for the determination of As, Sb, and Se in carrot-fruit juice by hydride generation inductively coupled plasma optical emission spectrometry (HG-ICP OES) were examined. The applicability of a partial decomposition using aqua regia and simple dilution with a 2% (v/v) HNO₃ solution were tested and compared to a traditional treatment based on the wet digestion with a HNO₃/H₂O₂ mixture. The pre-reduction and hydride generation reaction conditions were evaluated. Under the optimal conditions, the hydrides were produced in the reaction of an acidified sample with NaBH₄ after pre-reduction with ascorbic acid [0.5% (m/v)] and KI [0.5% (m/v)] in 3 mol L^?1 HCl for total As and Sb, and boiling with HCl (6 mol L^?1) for total Se. The best results were obtained for the aqua regia procedure, resulting in limits of detection (LODs) between 1.2–2.4 ng g^?1 in the samples and recoveries from 90.9% to 109.1%. The method was successfully applied (without matrix effects) for the determination of As in dense mousse and pulp juice samples and for Sb in pulp juices. Standard solutions, processed in the same way as samples, were used for the calibration. Undecomposed matrix constituents strongly influenced Se; hence this element was determined using the method of standard addition. Concentrations of studied elements in analyzed products were at the trace level, that is, 6–32 ng g^?1, 4–10 ng g^?1, and 4–13 ng g^?1 for Se, As, and Sb, respectively.     

Solubility in the Na2Cr2O7-(NH4)2Cr2O7-K2Cr2O7-H2O system

Solubility in the Na₂Cr₂O₇-(NH₄)₂Cr₂O₇-K₂Cr₂O₇-H₂O four-component water-salt system at 25, 50, and 75°C was studied for the first time. Phase field boundaries for individual salts and potassium and ammonium dichromate solid solutions, monovariant lines, and invariant points were determined. Experimental data were used to optimize the looped isohydric process of potassium dichromate preparation involving additional salts.     

Determination of picomole amounts of formaldehyde in air and bio-fluids based on its enhanced myoglobin-luminol chemiluminescence reaction

Abstract

The aim of this study was to assess the performance of selected destruction methods for the determination of heavy metals (Cd, Cu, Pb and Zn) in woodlouse (Oniscus asellus). A vigorous total analysis involving microwave destruction with HF, HCl and HNO₃ (method 1) was used as a reference method. Consistently low values for the dry ashing method may indicate incomplete dissolution of the elements and/or losses through volatilisation. Method 3 (concentrated HNO₃) that frequently is used in literature, produced erroneous values for Cd, Cu and Pb. Results were consistent with the microwave digestion, provided H₂O₂ was used during digestion (method 4, HNO₃/H₂O₂). Method 5 (HNO₃/HCIO₄, one destruction step) yielded low recoveries when only one destruction step was applied. Applying two destruction steps (method 6) resulted in values consistent with the microwave method, but was at the expense of reproducibility and rendered the method more lengthy and laborious. Because of the very good performance combined with speed and simplicity, destruction with HNO₃/H₂O₂ (method 4) emerged as the most convenient method.     

The use of optical emission spectrometry with microwave induced plasma (MIP) discharges in a surfatron combined to different types of hydride generation for the determination of arsenic

The stability and analytical figures of merit of argon microwave induced plasma (MIP) discharges in a surfatron as sources for optical emission spectrometry (OES) are described. These MIPs have been used for the determination of arsenic after hydride generation. They could cope with the excess of hydrogen developed during the hydride generation step and thus not necessitated an isolation of the hydrides before releasing them into the MIP. Two methods for the generation of the volatile AsH₃ were applied. First a micro method was used with solid NaBH₄ on which 10 1 of the acidified sample solution is transferred. Its capabilities were compared to those of continuous hydride generation using a 5% (w/w) NaBH₄-solution and continuous liquid removal in a flow cell. Both methods were optimized for an argon MIP operated at a power of 120–160 W and gas flows of 20 l/h Ar. In the case of solid NaBH₄ the detection limit for As has been found to be 1.0 g/ml (10 ng) and with the flow cell hydride generation 50 ng/ml. The calibration curves are linear over three orders of magnitude. Interferences caused by Sb, Fe, Sn and NaCl were investigated. No interferences occurred for Sb up to an interferent concentration of 250 g/ml. The presence of Fe causes a significant depression of the As signal whereas an increase of the As signal was observed in the case of Sn. High NaCl concentrations did not influence the As signals when using continuous hydride generation, but had a great influence when using solid NaBH₄.     

Microwave digestion of ancient peat and determination of Pb by voltammetry

Different acid compositions (HNO₃, H₂O₂, HF and HClO₄) and low pressure microwave digestion were applied to the microwave assisted dissolution of ancient peats. The digests were evaluated with respect to the decomposition of the inorganic and organic fraction of peats and to an optimised determination of Pb by differential pulse anodic stripping voltammetry (DPASV). Addition of hydrofluoric acid was necessary to achieve a complete dissolution of the resistant inorganic phase of the peat and to obtain the total Pb concentration. Addition of perchloric acid decreased the concentration of dissolved organic carbon significantly, enabling reliable voltammetric signals for Pb determinations with satisfying peak shape, baseline, sensitivity, and precision. The limit of detection for Pb in peats was 1 ng/mL in the acid digest, equivalent to 0.2 μg/g in solid peat. This allowed the determination of low, pre-industrial concentrations of Pb in peat bogs from various locations (Europe and SE Asia). A chelation column used to isolate the metals from the complex matrix to further improve the detection limits failed to provide good recoveries for the peats and plants. Received: 12 June 1998 / Revised: 24 July 1998 / Accepted: 28 July 1998