High-resolution Continuum Source Flame Research Articles

Sediment matrix characterization as a tool for evaluating the environmental impact of heavy metals in metal mining, smelting, and ore processing areas

In this work, the matrix characterization (mineralogy, total and local chemical composition, and total organic (TOC) and inorganic carbon (TIC) contents) of different types of sediments from mining- and metallurgy-influenced areas and the assessment of the impact of the matrix on the association of potentially hazardous metals with the mineral phases of these samples, which affect their mobility in the environment, are presented. For these purposes, sediment samples with different origins and from different locations in the environment were analyzed. Anthropogenic sediments from metal-rich post-flotation tailings (Lintich, Slovakia) represent waste from ore processing, natural river sediments from the Hornád River (Košice, Slovakia) represent areas influenced predominantly by the metallurgical industry, and lake sediments from a water reservoir Ružín (inflow from the Hornád and Hnilec Rivers, Slovakia) represent the impact of the metallurgical and/or mining industries. The total metal contents were determined by X-ray fluorescence (XRF) analysis, the local chemical and morphological microanalysis by scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), and the TOC and TIC contents by infrared (IR) spectrometry. The mobility/bioavailability of Cu, Pb, and Zn in/from sediments at the studied areas was assessed by ethylenediaminetetraacetic acid (EDTA) and acetic acid (AA) extraction and is discussed in the context of the matrix composition. The contents of selected potentially hazardous elements in the extracts were determined by the high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS).

Extraction method based on emulsion breaking for the determination of Cu, Fe and Pb in Brazilian automotive gasoline samples by high-resolution continuum source flame atomic absorption spectrometry

This work reports a new method for extraction of Cu, Fe and Pb from Brazilian automotive gasoline and their determination by high-resolution continuous source flame atomic absorption spectrometry (HR-CS FAAS). The method was based on the formation of water-in-oil emulsion by mixing 2.0mL of extraction solution constituted by 12% (w/v) Triton X-100 and 5% (v/v) HNO3 with 10mL of sample. After heating at 90°C for 10min, two well-defined phases were formed. The bottom phase (approximately 3.5mL), composed of acidified water and part of the ethanol originally present in the gasoline sample, containing the extracted analytes was analyzed. The surfactant and HNO3 concentrations and the heating temperature employed in the process were optimized by Doehlert design, using a Brazilian gasoline sample spiked with Cu, Fe and Pb (organometallic compounds). The efficiency of extraction was investigated and it ranged from 80 to 89%. The calibration was accomplished by using matrix matching method. For this, the standards were obtained performing the same extraction procedure used for the sample, using emulsions obtained with a gasoline sample free of analytes and the addition of inorganic standards. Limits of detection obtained were 3.0, 5.0 and 14.0μgL−1 for Cu, Fe and Pb, respectively. These limits were estimated for the original sample taking into account the preconcentration factor obtained. The accuracy of the proposed method was assured by recovery tests spiking the samples with organometallic standards and the obtained values ranged from 98 to 105%. Ten gasoline samples were analyzed and Fe was found in four samples (0.04–0.35mgL−1) while Cu (0.28mgL−1) and Pb (0.60mgL−1) was found in just one sample.

Graphene oxide modified expanded perlite as a new sorbent for Cu(II) and Pb(II) prior to determination by high-resolution continuum source flame atomic absorption spectrometry

ABSTRACTGraphene oxide (GO) modified expanded perlite (EP) was prepared as a new sorbent for solid phase extraction of Cu(II) and Pb(II) prior to determination by high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS). Characterization of the synthesized sorbent was proved by Fourier transform infrared spectroscopy (FT-IR); X-ray diffraction (XRD); Brunaer, Emmet, and Teller (BET); specific surface area; and scanning electron microscopy (SEM) techniques. Several parameters such as pH, eluent type and concentration, flow rate, sample volume, interfering ions, adsorption capacity of sorbent were investigated and optimized. The proposed method was successfully applied for spiked analysis of Cu(II) and Pb(II) ions in tap water and fruity sodas sample, and fine recoveries (relative error <10%) were obtained.

Application of high-resolution continuum source flame atomic absorption spectrometry to reveal, evaluate and overcome certain spectral effects in Pb determination of unleaded gasoline

High-resolution continuum source and line source flame atomic absorption spectrometry (HR-CS FAAS and LS FAAS, respectively) were applied for Pb determination in unleaded aviation or automotive gasoline that was dissolved in methyl-isobutyl ketone. When using HR-CS FAAS, a structured background (BG) was registered in the vicinity of both the 217.001nm and 283.306nm Pb lines. In the first case, the BG, which could be attributed to absorption by the OH molecule, directly overlaps with the 217nm line, but it is of relatively low intensity. For the 283nm line, the structured BG occurs due to uncompensated absorption by OH molecules present in the flame. BG lines of relatively high intensity are situated at a large distance from the 283nm line, which enables accurate analysis, not only when using simple variants of HR-CS FAAS but also for LS FAAS with a bandpass of 0.1nm. The lines of the structured spectrum at 283nm can have “absorption” (maxima) or “emission” (minima) character. The intensity of the OH spectra can significantly depend on the flame character and composition of the investigated organic solution. The best detection limit for the analytical procedure, which was 0.01mgL−1 for Pb in the investigated solution, could be achieved using HR-CS FAAS with the 283nm Pb line, 5pixels for the analyte line measurement and iterative background correction (IBC). In this case, least squares background correction (LSBC) is not recommended. However, LSBC (available as the “permanent structures” option) would be recommended when using the 217nm Pb line. In LS FAAS, an additional phenomenon related to the nature of the organic matrix (for example, isooctane or toluene) can play an important role. The effect is of continuous character and probably due to the simultaneous efficient correction of the continuous background (IBC) it is not observed in HR-CS FAAS. The fact that the effect does not depend on the flame character indicates that it is not radiation scattering. For LS FAAS, the determination of Pb using the 283nm line, a 0.1nm bandpass and a fuel lean flame is strongly recommended. The analysis of certified reference materials, recovery studies and the analysis of real samples with low Pb content supported the satisfactory accuracy of Pb determination in automotive or aviation gasoline when the recommended analytical variants are applied.The studies in this work shed new light on spectral phenomena in air-acetylene flames. The structured background due to absorption by the OH molecules must be taken into account during Pb determination in other materials as well as in some other elemental determinations, especially at low absorbance levels. The usefulness of HR-CS FAAS for revealing and investigating a structured background was demonstrated. HR-CS FAAS does not reveal fully corrected spectral effects with a continuous character, which can be found in LS FAAS.

Determination of total sulfur concentrations in different types of vinegars using high resolution flame molecular absorption spectrometry

Total sulfur concentrations in vinegars were determined using molecular absorption of carbon monosulfide (CS) determined with a high-resolution continuum source flame atomic absorption spectrometer. The molecular absorption of CS was measured at 258.056nm in an air–acetylene flame. Due to non-spectral interference, as well as the different sensitivities to some sulfur compounds, all sulfur species were oxidized to sulfate using a HNO3 and H2O2 mixture and the analyte addition technique was applied for quantification. The limit of detection (LOD) and limit of quantification (LOQ) were 11.6 and 38.6mgL−1, respectively. The concentrations of sulfur in various vinegars ranged from ⩽LOD to 163.6mgL−1.

Preconcentration and Determination of Copper(II) by Novel Solid-Phase Extraction and High-Resolution Continuum Source Flame Atomic Absorption Spectrometry

ABSTRACTAmberlite XAD-4 modified with N-para-anisidine-3,5-di-tert-butylsalicylaldimine was investigated as a new chealting sorbent for the selective separation and preconcentration of Cu(II). The metal ion was retained by chemical sorption on the modified resin, eluted by hydrochloric acid, and determined by high-resolution continuum source flame atomic absorption spectrometry. The prepared resin was characterized for the solid-phase extraction of Cd2+, Co2+, Cr3+, Cu2+, Fe3+, Mn2+, Ni2+, Pb2+, and Zn2+ in a column. The influence of the pH, the mass of solid phase, eluent, flow rate, and sample volume was optimized. Using the optimum conditions, only Cu(II) showed quantitative sorption at the 95% confidence level, and the recoveries of the other metal ions were below 80%. A preconcentration factor 125 was obtained for Cu(II) with a limit of detection of 0.56 µg L−1. The method was used for the determination of Cu(II) in tap water, river water, tomato leaves, and fish. The relative standard deviation and the relative error were lower than 7%.

Spectral aspects of the determination of Si in organic and aqueous solutions using high-resolution continuum source or line source flame atomic absorption spectrometry

High-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was applied to reveal and investigate spectral interference in the determination of Si. An intensive structured background was observed in the analysis of both aqueous and xylene solutions containing S compounds. This background was attributed to absorption by the CS molecule formed in the N2O–C2H2 flame. The lines of the CS spectrum at least partially overlap all five of the most sensitive Si lines investigated. The 251.611nm Si line was demonstrated to be the most advantageous. The intensity of the structured background caused by the CS molecule significantly depends on the chemical form of S in the solution and is the highest for the most-volatile CS2. The presence of O atoms in an initial S molecule can diminish the formation of CS. To overcome this S effect, various modes of baseline fitting and background correction were evaluated, including iterative background correction (IBC) and utilization of correction pixels (WRC). These modes were used either independently or in conjunction with least squares background correction (LSBC). The IBC+LSBC mode can correct the extremely strong interference caused by CS2 at an S concentration of 5% w:w in the investigated solution. However, the efficiency of this mode depends on the similarity of the processed spectra and the correction spectra in terms of intensity and in additional effects, such as a sloping baseline. In the vicinity of the Si line, three lines of V were recorded. These lines are well-separated in the HR-CS FAAS spectrum, but they could be a potential source of overcorrection when using line source flame atomic absorption spectrometry (LS FAAS). The expected signal for the 251.625nm Fe line was not registered at 200mgL−1 Fe concentration in the solution, probably due to the diminished population of Fe atoms in the high-temperature flame used. The observations made using HR-CS FAAS helped to establish a “safe” level of the matrix components S, V, and Fe in the determination of Si using both HR-CS FAAS and LS FAAS. Under the best conditions, the instrumental detection limits for LS FAAS and for HR-CS FAAS, as well as the characteristic concentration values, were similar. Unusual calibration curves were observed in HR-CS FAAS. The curves showed an inflexion point that divided them into two linear parts with distinctly different slopes.

Separation and Preconcentration of Aluminum by Candida albicans Immobilized on Cellulose Acetate Biomass

In the present study, separation parameters of aluminum ions from aqueous solutions by Candida albicans immobilized on the cellulose acetate biomass (CAICAB) were investigated. The optimum experimental conditions for the preconcentration of aluminum were investigated. Amount of CAICAB, effect of common matrix ions and capacity of CAICAB were also obtained. 5 mL of 2 mol L−1 HCl were used for elution of adsorbed aluminum ions on CAICAB. After elution, analyte ions were determined by high resolution continuum source flame atomic absorption spectrometry. Under the optimized conditions, limit of detections for aluminum and adsorption capacity of CAICAB were 0.12 and 327.5 µg g−1, respectively. The method developed was applied to the separation and determination of aluminum in water samples.

Preparation of Fe$_{3}$O$_{4}$ @ montmorillonite composite as an effective sorbent for the removal of lead and cadmium from wastewater samples

A magnetic Fe$_{3}$O$_{4}$ @ montmorillonite composite was prepared and used for the separation of lead and cadmium from aqueous solutions. For this purpose, magnetite (Fe$_{3}$O$_{4})$ was generated by co-precipitation of FeSO$_{4}$ and FeCl$_{3}$ onto montmorillonite. The effects of various experimental parameters such as pH of the solution, amount of sorbent, initial concentration of analytes, and contact time on the sorption efficiencies of lead and cadmium ions were investigated and optimized by applying a batch technique. The concentrations of analytes were determined by high resolution continuum source flame atomic absorption spectrometry. The maximum adsorption occurred at pH 2.0. The adsorption capacity of Fe$_{3}$O$_{4}$ @ montmorillonite composite was 5 mg g$^{-1}$ Pb and 2 mg g$^{-1}$ Cd. The quantitative retention in acidic medium was an advantage for the removal of metals from acidic water samples. Under optimized conditions, lead and cadmium were quantitatively removed from wastewater (between 95% and 98%) in a contact time of less than 5 min. The results showed that Fe$_{3}$O$_{4}$ @ montmorillonite can be efficiently used for the removal of lead and cadmium from aqueous solutions.

Speciation of Chromium in Water Samples after Dispersive Liquid-Liquid Microextraction, and Detection by Means of High-Resolution Continuum Source Atomic Absorption Spectrometry

A newly analytical method has been developed to determine total chromium and speciation of this element in water samples through dispersive liquid-liquid microextraction combined with a high-resolution continuum source flame atomic absorption spectrometry. The most significant variables affecting complexation and extraction were optimized by using response surface methodology and univariate optimization. The best conditions for both the complexation and extraction elements in this study were: complexing agent ammonium pyrrolidine dithiocarbamate (APDC 6.0 mmol L-1); pH at 2.0 (CrVI) and at 7.0 (Cr total); NaCl (5% m/v); 1-undecanol (50 µL) and ethanol 300 (CrIV) and 275 µL (total Cr). Under optimal conditions, this method resulted in a 20-100 µg L-1 linear range for CrVI and total chromium, detection limits of 0.35 (CrVI) and 6.7 µg L-1 (total Cr), as well as enriching factor of 26 (CrVI) and 19 for total Cr. The method accuracy was carried out by using certified water reference material (NIST CRM 1643e), and the results achieved were in agreement with the certified value (t-test at a confidence interval of 95%). The method developed was applied in samples of mineral water, tap water (the recovery values ranged from 88 to 115%) and seawater.

Determination of trace silver by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) after separation/preconcentration on Rhodococcus ruber bacterial biomass

In the present study, a preconcentration method was developed by using Rhodococcus ruber bacterial biomass (RrBB) for the determination of silver in various water samples by HR-CS FAAS.

Determination of Ca, Cd, Cu, Fe, K, Mg, Mn, Mo, Na, Se, and Zn in Foodstuffs by Atomic Spectrometry After Sample Preparation Using a Low-Cost Closed-Vessel Conductively Heated Digestion System

Establishing fast, simple, low-cost, and efficient sample preparation procedures to determine elements in foodstuffs is a relevant aspect for nutritional and health purposes. For this reason, the recently proposed closed-vessel conductively heated digestion system (CHDS) was evaluated for the digestion of milk powder, chocolate powder, and soluble coffee samples aiming for Ca, Cu, Fe, K, Mg, Mn, Na, and Zn determinations by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) and Cd, Mo, and Se determinations by inductively coupled plasma mass spectrometry with tandem configuration (ICP-MS/MS). The accuracy was evaluated by analyzing two milk certified reference materials digested by the CHDS and a microwave oven for comparison. When using the CHDS, recoveries for the analytes varied from 91 to 104 %. For microwave digestions, recoveries within the 94–109 % intervals were obtained. The method was then applied to the samples. For comparative purposes, the analytes were also determined in the samples after microwave digestion, and the results between the two digestion systems showed no differences based on a paired t test at a 95 % confidence level. Similar analytical blanks were obtained because quartz digestion tubes were used in both digestion systems. The CHDS with quartz tubes is an interesting alternative for laboratories dedicated to large-scale routine analysis because volatile elements usually found in very low concentrations in food samples such as Cd and Se can also be determined.

Direct Determination of Cd, Co, Cu, Fe, Mn, Na, Ni, Pb, and Zn in Ethanol Fuel by High-Resolution Continuum Source Flame Atomic Absorption Spectrometry

A method to determine nine elements (Cd, Co, Cu, Fe, Mn, Na, Ni, Pb, and Zn) in ethanol fuel using high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was developed. The proposed method consists of the direct analysis of samples, making use of inorganic standards for calibration and multi-element sequential determination. To evaluate the accuracy of the proposed method, the obtained results were compared to the results obtained by the following methods: (i) the standard method NBR 11331 for the determination of Cu and Fe in ethanol fuel by line source flame atomic absorption spectrometry (LS-FAAS), (ii) the standard method NBR 10422 for the determination of Na in ethanol fuel by flame photometry, and (iii) recovery tests for the other elements. Good accuracy was attained because the results obtained for Cu, Fe, and Na by the proposed method and the standard methods were not significantly different within a 95% level of confidence (Student’s t test) and the recovery tests for the other analytes ranged from 97 to 105%. Limits of detection of 0.006, 0.02, 0.001, 0.02, 0.003, 0.1, 0.04, 0.06, and 0.024 mg kg–1 were obtained for Cd, Co, Cu, Fe, Mn, Na, Ni, Pb, and Zn, respectively. The relative standard deviations were in general lower than 3.0% for all analytes. The proposed method was shown to be an excellent alternative for the determination of metals in ethanol fuel, emphasizing multi-element sequential analysis, reducing the costs and analysis time, and, thus, can be recommended for routine analysis.

Use of High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS) for Sequential Multi-Element Determination of Metals in Seawater and Wastewater Samples

The objective of this work is to develop a method for the determination of metals in saline matrices using high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). Module SFS 6 for sample injection was used in the manual mode, and flame operating conditions were selected. The main absorption lines were used for all the elements, and the number of selected analytical pixels were 5 (CP±2) for Cd, Cu, Fe, Ni, Pb and Zn, and 3 pixels for Mn (CP±1). Samples were acidified (0.5% (v/v) nitric acid), and the standard addition method was used for the sequential determination of the analytes in diluted samples (1:2). The method showed good precision (RSD(%) < 4%, except for Pb (6.5%)) and good recoveries. Accuracy was checked after the analysis of an SPS-WW2 wastewater reference material diluted with synthetic seawater (dilution 1:2), showing a good agreement between certified and experimental results.

Multivariate optimization of ultrasound-assisted extraction for determination of Cu, Fe, Ni and Zn in vegetable oils by high-resolution continuum source atomic absorption spectrometry

An assisted liquid–liquid extraction of copper, iron, nickel and zinc from vegetable oil samples with subsequent determination by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was optimized by applying a full factorial design in two levels and the response surface methodology, Box–Behnken. The effects of the acid concentration and the amplitude, cycle and time of sonication on the extraction of the analytes, as well as their interactions, were assessed. In the selected condition (sonication amplitude=66%, sonication time=79s, sonication cycle=74%), using 0.5molL−1 HCl as the extractant, the limits of quantification were 0.14, 0.20, 0.21 and 0.04μgg−1 for Cu, Fe, Ni and Zn, respectively, with R.S.D. ranging from 1.4% to 3.6%. The proposed method was applied for the determination of the analytes in soybean, canola and sunflower oils.

The content of Ca, Cu, Fe, Mg and Mn and antioxidant activity of green coffee brews

A simple and fast method of the analysis of green coffee infusions was developed to measure total concentrations of Ca, Cu, Fe, Mg and Mn by high resolution-continuum source flame atomic absorption spectrometry. The precision of the method was within 1–8%, while the accuracy was within −1% to 2%. The method was used to the analysis of infusions of twelve green coffees of different geographical origin. It was found that Ca and Mg were leached the easiest, i.e., on average 75% and 70%, respectively. As compared to the mug coffee preparation, the rate of the extraction of elements was increased when infusions were prepared using dripper or Turkish coffee preparation methods. Additionally, it was established that the antioxidant activity of green coffee infusions prepared using the mug coffee preparation was high, 75% on average, and positively correlated with the total content of phenolic compounds and the concentration of Ca in the brew.

Fast sequential multi-element determination of major and minor elements in environmental samples and drinking waters by high-resolution continuum source flame atomic absorption spectrometry

The fast sequential multi-element determination of 11 elements present at different concentration levels in environmental samples and drinking waters has been investigated using high-resolution continuum source flame atomic absorption spectrometry. The main lines for Cu (324.754nm), Zn (213.857nm), Cd (228.802nm), Ni (232.003nm) and Pb (217.001nm), main and secondary absorption lines for Mn (279.482 and 279.827nm), Fe (248.327, 248.514 and 302.064nm) and Ca (422.673 and 239.856nm), secondary lines with different sensitivities for Na (589.592 and 330.237nm) and K (769.897 and 404.414nm) and a secondary line for Mg (202.582nm) have been chosen to perform the analysis. A flow injection system has been used for sample introduction so sample consumption has been reduced up to less than 1mL per element, measured in triplicate. Furthermore, the use of multiplets for Fe and the side pixel registration approach for Mg have been studied in order to reduce sensitivity and extend the linear working range. The figures of merit have been calculated and the proposed method was applied to determine these elements in a pine needles reference material (SRM 1575a), drinking and natural waters and soil extracts. Recoveries of analytes added at different concentration levels to water samples and extracts of soils were within 88–115% interval. In this way, the fast sequential multi-element determination of major and minor elements can be carried out, in triplicate, with successful results without requiring additional dilutions of samples or several different strategies for sample preparation using about 8–9mL of sample.

A simple and fast method for assessment of the nitrogen–phosphorus–potassium rating of fertilizers using high-resolution continuum source atomic and molecular absorption spectrometry

The determination of N, P, and K in fertilizers by high-resolution continuum source flame atomic and molecular absorption spectrometry is proposed. Under optimized conditions, measurements of the diatomic molecules NO and PO at 215.360 and 247.620nm, respectively, and K using the wing of the alternative line at 404.722nm allowed calibration curves to be constructed in the ranges 500–5000mgL−1 N (r=0.9994), 100–2000mgL−1 P (r=0.9946), and 100–2500mgL−1 K (r=0.9995). Commercial fertilizers were analyzed by the proposed method and the concentrations of N, P, and K were found to be in agreement with those obtained by Kjeldahl, spectrophotometric, and flame atomic emission spectrometry methods, respectively, at a 95% confidence level (paired t-test). A phosphate rock certified reference material (CRM) was analyzed and the results for P and K were in agreement with the reference values. Recoveries from spiked CRM were in the ranges 97–105% (NO3−-N), 95–103% (NH4+-N), 93–103% (urea-N), 99–108% (P), and 99–102% (K). The relative standard deviations (n=12) for N, P, and K were 6, 4, and 2%, respectively.

Determination of sulfur in food by high resolution continuum source flame molecular absorption spectrometry

In the present work, a fast, simple and sensitive analytical method for determination of sulfur in food and beverages by high resolution continuum source flame molecular absorption spectrometry was developed. The determination was performed via molecular absorption of carbon monosulfide, CS. Different CS rotational lines (257.959nm, 258.033nm, 258.055nm), number of pixels and types of standard solution of sulfur, namely: sulfuric acid, sodium sulfate, ammonium sulfate, sodium sulfite, sodium sulfide, dl-cysteine, and l-cystine, were studied in terms of sensitivity, repeatability of results as well as limit of detection and limit of quantification. The best results were obtained for measurements of absorption of the CS molecule at 258.055nm at the wavelength range covering 3pixels and dl-cysteine in 0.2molL−1 HNO3 solution as a calibration standard. Under optimized conditions the limit of detection and the limit of quantification achieved for sulfur were 10.9mgL−1 and 36.4mgL−1, respectively. The repeatability of the results expressed as relative standard deviation was typically <5%.The accuracy of the method was tested by analysis of digested biological certified reference materials (soya bean flour, corn flour and herbs) and recovery experiment for beverage samples with added known amount of sulfur standard. The recovery of analyte from such samples was in the range of 93–105% with the repeatability in the range of 4.1–5.0%. The developed method was applied for the determination of sulfur in milk (194±10mgkg−1), egg white (2188±29mgkg−1), mineral water (31.0±0.9mgL−1), white wine (260±4mgL−1) and red wine (82±2mgL−1), as well as in sample rich in ions, such as bitter mineral water (6900±100mgL−1).

Application of High Resolution-Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS): Determination of trace elements in tea and tisanes

A new application of HR-CS FAAS (High Resolution-Continuum Source Flame Atomic Absorption Spectrometry) has been developed for the determination of several trace elements (Ca, Co, Cu, Fe, Mn, Ni, Na and Zn) in infusions made from tea, rooibos and tea with seaweed samples. The proposed methods are fast, inexpensive and show good performances: the mean analytical recovery was approximately 100%. The mean limit of detection was 29.4μg/l, and the mean limit of quantification was 98.0μg/l (both limits refer to the brewed samples). Due to the matrix effect observed, the standard addition method had to be applied. Preliminary classification (based on metal contents) using chemometric techniques such as PCA (Principal Component Analysis) and CA (Cluster Analysis), was successful for infusions made from rooibos and tea with seaweed, but inconclusive for black and green teas.