Determination Of Total Inorganic Arsenic Research Articles

A novel block copolymer containing gadolinium oxide nanoparticles in ultrasound assisted-dispersive solid phase microextraction of total arsenic in human foodstuffs: A multivariate optimization methodology

A new poly(3-hydroxy butyrate)-b-poly(dimethyl amino ethyl methacrylate) amphiphilic block copolymer containing gadolinium oxide nanoparticles (PHB-PDMAEMA-Gd2O3-NPs) were synthesized and used as composite adsorbent for extraction of total arsenic. Characterization of the composite adsorbent material PHB-PDMAEMA-Gd2O3-NP was studied using spectroscopic techniques. Plackett-Burman design and central composite design were employed to screening and optimization of the experimental parameters. This composite adsorbent was utilized in ultrasound assisted-dispersive solid phase microextraction (UA-dSPµE) for the determination of total inorganic arsenic in foodstuffs through hydride generation atomic absorption spectrometry (HG-AAS). It demonstrates a linear relationship across arsenic concentration range of 0.07–1.12 µg/L with a correlation coefficient (0.996). It’s showed an enrichment factor of 128 and a limit of detection 0.02 µg/L for total inorganic arsenic determination. Accuracy of the developed method was confirmed through the analysis of certified reference materials with 96.0–98.5% recovery. It proved to be significantly useful UA-dSPµE method for determining total inorganic arsenic in different foodstuffs.

Voltammetric determination of inorganic arsenic in mildly acidified (pH 4.7) groundwaters from Mexico and India

Routine monitoring of inorganic arsenic in groundwater using sensitive, reliable, easy-to-use and affordable analytical methods is integral to identifying sources, and delivering appropriate remediation solutions, to the widespread global issue of arsenic pollution. Voltammetry has many advantages over other analytical techniques, but the low electroactivity of arsenic(V) requires the use of either reducing agents or relatively strong acidic conditions, which both complicate the analytical procedures, and require more complex material handling by skilled operators. Here, we present the voltammetric determination of total inorganic arsenic in conditions of near-neutral pH using a new commercially available 25 μm diameter gold microwire (called the Gold Wirebond), which is described here for the first time. The method is based on the addition of low concentrations of permanganate (10 μM MnO4−) which fulfils two roles: (1) to ensure that all inorganic arsenic is present as arsenate by chemically oxidising arsenite to arsenate and, (2) to provide a source of manganese allowing the sensitive detection of arsenate by anodic stripping voltammetry at a gold electrode. Tests were carried out in synthetic solutions of various pH (ranging from 4.7 to 9) in presence/absence of chloride. The best response was obtained in 0.25 M chloride-containing acetate buffer resulting in analytical parameters (limit of detection of 0.28 μg L−1 for 10 s deposition time, linear range up to 20 μg L−1 and a sensitivity of 63.5 nA ppb−1. s−1) better than those obtained in acidic conditions. We used this new method to measure arsenic concentrations in contrasting groundwaters: the reducing, arsenite-rich groundwaters of India (West Bengal and Bihar regions) and the oxidising, arsenate-rich groundwaters of Mexico (Guanajuato region). Very good agreement was obtained in all groundwaters with arsenic concentrations measured by inductively coupled plasma-mass spectrometry (slope = +1.029, R2 = 0.99). The voltammetric method is sensitive, faster than other voltammetric techniques for detection of arsenic (typically 10 min per sample including triplicate measurements and 2 standard additions), easier to implement than previous methods (no acidic conditions, no chemical reduction required, reproducible sensor, can be used by non-voltammetric experts) and could enable cheaper groundwater surveying campaigns with in-the-field analysis for quick data reporting, even in remote communities.

An electrochemical sensor for the detection of arsenic using nanocomposite-modified electrode

The aim of this research is to develop an electrochemical sensor based on a conducting polymer, polyaniline, and a cationic polymer, poly(diallyldimethylammonium chloride), reinforced with graphene oxide nanosheets functionalized with acrylic acid. The two-dimensional nature of acrylic acid functionalized graphene oxide nanosheets and clusters made of conductive polymers and acrylic acid functionalized graphene oxide nanosheets were confirmed by microscopic tests. The prepared nanocomposite was deposited on the glassy carbon electrode in order to prepare an electrochemical sensor for the detection of arsenic by cyclic voltammetry and differential pulse voltammetry methods. It should be mentioned that the presence of acrylic acid functionalized graphene oxide nanosheets increases the surface area due to the nano size effect and better dispersion of this nanomaterial, poly(diallyldimethylammonium chloride), increases the adsorption capacity of the analyte due to electrostatic interaction between the negatively charged analyte and positively charged surface, and polyanilin increases the charge transfer rate due to the good conductivity. The results show that the prepared electrode has a sensitivity equal to 1.79 A/M with 0.12 μM as the detection limit. The proposed sensor could be used for the determination of total inorganic arsenic by first oxidative pretreatment for conversion of As(III) to As(V).

Capillary electrophoresis coupled to electrospray mass spectrometry for the determination of organic and inorganic arsenic compounds in water samples

Some compounds of arsenic are extremely toxic to the human body even at low levels. Long-term exposure from drinking contaminated water causes adverse health effects. This has led the European Union and other global organizations to reduce the maximum residue limit for the total arsenic up to 10 μg L−1 in water for human consumption. The toxicity of arsenic depends on the oxidation state, chemical structure and solubility in the biological environment. Main analytical procedures report on the determination of arsenic species in water samples which have been developed based on atomic spectroscopy –speciation performed in the sample treatment step– and inductively coupled plasma-mass spectrometry (ICP-MS). In such cases, speciation is performed by coupling to high-performance liquid chromatography (HPLC). As far as we know, the determination of arsenic species in water samples at low concentration levels by capillary electrophoresis (CE) coupled to electrospray mass spectrometry (ESI-MS) has not been described up to now. In this research CE-ESI(−)-MS is proposed for the identification and simultaneous quantification of organic and inorganic arsenic species in water samples for human consumption. The target compounds were dimethylarsinate (DMA), mono-methylarsonate (MMA), arsenite (i-As(III)) and arsenate (i-As(V)). Optimization of the composition and nature of both the electrophoretic separation medium –using hexafluoro-2-propanol (HFIP) as an additive– and the sheath liquid was performed and aimed at achieving the best sensitivity and separation efficiency for the CE-ESI(−)-MS coupling. Two simple sample treatments were proposed: one based on dispersive liquid-liquid micro-extraction (DLLME) intended for a rapid determination of the total content of inorganic arsenic in the water sample; and the second based on partial evaporation of the water sample to detect each of the four main arsenic species. For the second, limits of detection between 0.02 and 0.04 μg L-1 were found, which are similar results as the ones achieved with methods based on HPLC-ICP-MS.The DLLME + CE-ESI(−)-MS method was applied to the determination of total inorganic arsenic in eleven water samples in the province of Salamanca (Spain). Five of the analyzed samples had values close to, or superior to the maximum residue limit for the total of arsenic in water intended for human consumption (10 μg L-1). The validated method CE-ESI(−)-MS for arsenic speciation was applied with success to the analysis of the weakly mineralized water sample (dry residue < 50 mg L-1) of both groundwater and bottled water.

Determination of total inorganic arsenic in water samples by cadmium ion assisted photochemical vapor generation-atomic fluorescence spectrometry

A novel approach based on cadmium ions assisted photochemical vapor generation (PVG) combined with atomic fluorescence spectrometry (AFS) was proposed for sensitive and accurate detection of total inorganic arsenic. In this work, the prereduction step of As(V) to As(III) was avoided. An approximate 10-fold improvement in sensitivity was achieved for both As(III) and As(V) with the existence of 20 mg L−1 Cd2+ in the 30% (v/v) acetic acid solution for 60 s UV irradiation. Under the optimal experimental conditions, detection limits of 0.05 μg L−1 were obtained for As(III) and As(V). The relative standard deviations (RSD) of the 20 μg L−1 As(III)/As(V) standard solution from 11 times measurements were both within 2%. The accuracy of the proposed approach was verified by analyzing of several surface water samples using standard addition method, Yangtze river waters and Funan river waters, with recoveries from 94% to 105%, which were in good agreement with the results from ICPMS determination.

Anodic stripping voltammetric determination of total arsenic using a gold nanoparticle-modified boron-doped diamond electrode on apaper-based device.

A multistep paper-based analytical device (mPAD) was designed and applied to the voltammetric determination of total inorganic arsenic. The electrodeposition of gold nanoparticles on a boron-doped diamond (AuNP/BDD) electrode and the determination of total inorganic arsenic is accomplished with a single device. Total inorganic arsenic can be determined by first reducing As(V) to As(III) using thiosulfate in 1.0molL-1 HCl. As(III) is then deposited on the electrode surface, and total inorganic arsenic is quantified as As(III) by square-wave anodic stripping voltammetry the potential range between -0.25V and 0.35V (vs. Ag/AgCl), best at around0.05 V. Under optimal conditions, the voltammetric response for As(III) detection is linear in the range from 0.1 to 1.5μgmL-1 and the limit of detection (3SD/slope) is 20ngmL-1. The relative standard deviation at 0.3, 0.7 and 1.0μgmL-1 of As(III) are 3.6, 4.3 and 3.3, respectively (10 different electrodes). The results show that the assay has high precision, a rather low working potential, and excellent sensor-to-sensor reproducibility. The method was employed to the determination of total inorganic arsenic in rice samples. Results agreed well with those obtained by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Graphical abstract A multistep paper-based analytical device (mPAD) is described thatintegrates a AuNP/BDD electrode preparation step and a detection step into a single device. The AuNPs are easily deposited on the BDD electrode by applying electrodeposition potential. The total inorganic arsenic concentration in rice samples wasdeterminedby using square-wave anodic stripping voltammetry.

Bifunctional magnesium oxide crystal successively as adsorbent and matrix modifier for preconcentration and determination of arsenic by graphite furnace atomic absorption spectrometry

A novel method for determination of total inorganic arsenic in water samples, based on magnesium oxide crystals quantitatively preconcentration and graphite furnace atomic absorption spectrometry (GFAAS) detection has been developed. As the MgO crystals could successively act as the adsorbent and matrix modifier, the method presents great potential in practical routine analysis of inorganic arsenic. With optimization of the experimental conditions, 1.5mg of MgO was added into 4.0mL water sample and ultrasonic dispersing 15min for adsorbing the arsenic at first. Then, the mixture was centrifuged 5min for separating the adsorbents and the water solution; the deposits were collected and dissolved with HNO3 for arsenic determination. The enrichment factor of 13, limit of detection (LOD) of 0.087μgL−1, relative standard deviation (RSD) of 4.5% (n=7, c=2.0μgL−1) were achieved under the optimized conditions. The procedure was validated by analysis of certified water sample (GBW08605), which results in good agreement between the certified and the found values. The method was further demonstrated for analysis of lake water, snow water and tap water, and satisfactory spiked recoveries of 98.5% to 103.0% were achieved for these samples. These preliminary results indicated the present method was practical and accurate for analysis of trace-arsenic in natural water samples.

Distribution of inorganic arsenic species in groundwater from Central-West Part of Santa Fe Province, Argentina

The distribution of inorganic arsenic species in groundwater used as drinking water supply by the peri-urban and rural population from central-western area of Santa Fe Province, Argentina, was studied. An analytical methodology based on an online system of atomic absorption spectrometry with hydride generation and flow injection (FI-HGAAS) was used for total inorganic arsenic determination. For speciation purposes, the distinction between As(V) and As(III) was performed through the on line coupling of FI-HGAAS to a solid phase system based on an anionic exchanger able to retain As(V) as oxyanion, allowing As(III) to be selectively determined. The concentration of As(V) was calculated as the difference between total arsenic and As(III) concentrations. Effects of matrix interference due to the nonselective behavior of the exchange resins were carefully laid. Results for 59 samples collected from 27 localities showed an almost exclusive predominance of pentavalent forms.

Improvement of Determination of Trace Amounts of Arsenic and Selenium in Slim Coffee Products by HG-ICP-OES

A method for the determination of total inorganic arsenic and selenium in slim instant coffees using hydride generation inductively coupled plasma optical emission spectrometry (HG-ICP-OES) was proposed. Various sample preparation procedures, including the traditional total decomposition by the hot-plate or microwave heating in a HNO3/H2O2 mixture and alternative procedures based on the solubilisation in aqua regia or tetramethyl ammonium hydroxide (TMAH) and the dilution only with water or a low concentrated HNO3 solution were examined and compared. Corresponding As and Se hydrides were generated in the reaction of an acidified sample solution with the NaBH4 reductant in the presence of antifoam A. A small sample preparation with aqua regia in an ultrasonic bath followed by the pre-reduction with KI–ascorbic acid in the HCl medium for total As and the boiling with HCl for total Se were found to be optimal. The external calibration using standards treated and measured as the same as samples were applied for the analysis. Limits of detection (LODs) of 0.96 and 0.55 ng ml−1 were assessed for As and Se, respectively. The precision (as the relative standard deviation [RSD]) was within 1.6–7.1 %. The accuracy of the method was confirmed by the recovery test and the analysis of a standard reference material (non-fat milk powder, SRM 1459). The developed procedure was applied for the analysis of six commercial instant slim coffee products available in the Polish market and it was found that these products contain traces of As (0.114–0.247 μg g−1) and Se (0.089–0.137 μg g−1).

Determination of trace total inorganic arsenic by hydride generation atomic fluorescence spectrometry after solid phase extraction-preconcentration on aluminium hydroxide gel

We describe a simple, effective, inexpensive and rapid method for the determination of trace amounts of total inorganic arsenic in water samples by means of a modified solid phase preconcentration procedure using an aluminium hydroxide gel sorbent and hydride generation atomic fluorescence spectrometry (HGAFS). This method avoids the traditional extraction procedures that are time- and solvent-consuming. The effects of quantity of adsorbent, solution pH, adsorption time and potentially interfering ions were studied. Under the optimal conditions, the detection limit is 3 ng•L−1, and the enrichment factor is 167. The calibration plot is linear in the range from 0.05 to 10 μg•L−1, with a correlation coefficient of 0.9992. The relative standard deviation (RSD) was less than 6.1 % (n = 5) and recoveries in spiked environmental water were >100 %. The method was successfully applied to the determination of total inorganic arsenic in natural water samples.

ODREĐIVANJE SPECIJA ANORGANSKOG ARSENA U EKSTRAKTIMA ZEMLJIŠTA JEDNOSTAVNOM SPEKTROFOTOMETRIJSKOM METODOM

UDK 631.4:546.19&#x0D; A simple and inexpensive method for the determination of inorganic As(III) and As(V) at low ppb levels was developed. The method is based on formation of hydride from a sample solution and its reaction with mercury bromide on a solid support. Formation of a yellow-brownish product was optically detected.&#x0D; Amidosulfonic acid was used as a reaction medium for determination of total inorganic arsenic, while citrate buffer (0.1 mol/dm3, pH=5.5) was used as a reaction media for determination of As(III) alone. As(V) was calculated as a difference of total inorganic arsenic and As(III).&#x0D; This method has been applied to soil extracts. Extraction of inorganic arsenic from soil samples was done in three-step sequential extraction with the following extractants: NH4H2PO4 (0.05 mol/dm3); NH4-oxalate buffer (0.2 mol/dm3, pH=3.25); and mixture of NH4-oxalate buffer (0.2 mol/dm3) and ascorbic acid (0.1 mol/dm3) at pH=3.25. The method was suitable for determination of inorganic arsenic species in soil extracts covering concentration range of the analyte between 0.2 - 20 ppb.

Single Laboratory Validation of a Method for the Determination of Total Inorganic Arsenic by Hydride Generation Atomic Absorption Spectrometry

The purpose of this study consists in reporting of single laboratory validation of a method for the determination of total inorganic arsenic by hydride generation atomic absorption spectrometry from natural and residual water samples. Applicability, fitness for purpose, selectivity, and sensitivity were discussed. A calibration study was realized, linear working range (0.4–4 μg·L−1), detection (0.11 μg·L−1), and quantification (0.38 μg·L−1) limits being determined. It was also proven that the method is accurate and precise. Following the bottom-up approach measurement, uncertainty was estimated (method validation data were used).

Spectrophotometric determination of total inorganic arsenic with hexamethylene ammonium-hexamethylenedithiocarbamate in nonionic triton X-100 micellar media

We have developed a cost-effective and sensitive spectrophotometric method for the determination of arsenic at trace level using a new reagent, hexamethylene ammonium-hexamethylenedithiocarbamate (HMA-HMDTC). Here we show that arsenic reacts with HMA-HMDTC in acidic conditions to yield the As(HMDTC)3 complex. We studied the Beer’s law at 256 nm, which showed linearity over the concentration range 0.2–1.0 µg/mL of arsenic. We have shown that molar absorptivity, Sandell’s sensitivity and the detection limit of the method are 6.06 × 104 L/mol cm, 0.0012 μg/cm2 and 0.060 μg/mL, respectively. We have applied this new method to the determination of arsenic in drinking water.

A solid phase extraction procedure for the simultaneous determination of total inorganic arsenic and trace metals in seawater: Sample preparation for total-reflection X-ray fluorescence

In this paper we present a procedure allowing total-reflection X-ray fluorescence spectrometry (TXRF) determinations of arsenic in water samples, especially in seawater samples. The procedure consists of an arsenate reduction step (performed by using a l-cysteine solution) followed by a complexation of As +3 with sodium dibenzyldithiocarbamate and solid phase extraction. The new procedure is a modification of a method developed by Prange and allows a simultaneous determination of As together with V, Fe, Ni, Cu, Zn, Pb, and U in seawater by TXRF. The procedure was tested using the Certified Reference Material CASS-4 and was later applied to regular seawater samples collected from the North Sea. The detection limit for arsenic is 10 ng L − 1 .

Total inorganic arsenic detection in real water samples using anodic stripping voltammetry and a gold-coated diamond thin-film electrode

An accurate method for total inorganic arsenic determination in real water samples was developed using differential pulse anodic stripping voltammetry (DPASV) and a Au-coated boron-doped diamond thin-film electrode. Keys to the method are the use of a conducting diamond platform and solid phase extraction for sample preparation. In the method, the As(III) present in the sample is first detected by DPASV. The As(V) present is then reduced to As(III) by reaction with Na 2SO 3 and this is followed by a second detection of As(III) by DPASV. Interfering metal ions (e.g., Cu(II)) that cause decreased electrode response sensitivity for arsenic in real samples are removed by solid phase extraction as part of the sample preparation. For example, Cu(II) caused a 30% decrease in the As stripping peak current at a solution concentration ratio of 3:1 (Cu(II)/As(III)). This loss was mitigated by passage of the solution through a Chelex 100 cation exchange resin. After passage, only a 5% As stripping current response loss was seen. The effect of organic matter on the Au-coated diamond electrode response for As(III) was also evaluated. Humic acid at a 5 ppm concentration caused only a 9% decrease in the As stripping peak charge for Au-coated diamond. By comparison, a 50% response decrease was observed for Au foil. Clearly, the chemical properties of the diamond surface in the vicinity of the metal deposits inhibit molecular adsorption on at least some of the Au surface. The method provided reproducible and accurate results for total inorganic arsenic in two contaminated water samples provided by the U.S. Bureau of Reclamation. The total inorganic As concentration in the two samples, quantified by the standard addition method, was 23.2 ± 2.9 ppb for UV plant influent water and 16.4 ± 0.9 ppb for Well 119 water ( n = 4). These values differed from the specified concentrations by less than 4%.

Optimization of a GFAAS method for determination of total inorganic arsenic in drinking water

The new 10 μg l −1 arsenic standard in drinking water has been a spur to the search for reliable routine analytical methods with a limit of detection at the μg l −1 level. These methods also need to be easy to handle due to the routine analyses that are required in drinking water monitoring. Graphite furnace atomic absorption spectrometry (GFAAS) meets these requirements, but the limit of detection is generally too high except for methods using a pre-concentration or separation step. The use of a high-intensity boosted discharge hollow-cathode lamp decreases the baseline noise level and therefore allows a lower limit of detection. The temperature program, chemical matrix modifier and thermal stabilizer additives were optimized for total inorganic arsenic determination with GFAAS, without preliminary treatment. The optimal furnace program was validated with a proprietary software. The limit of detection was 0.26 μg As l −1 for a sample volume of 16 μl corresponding to 4.2 pg As. This attractive technique is rapid as 20 samples can be analysed per hour. This method was validated with arsenic reference solutions. Its applicability was verified with artificial and natural groundwaters. Recoveries from 91 to 105% with relative standard deviation <5% can be easily achieved. The effect of interfering anions and cations commonly found in groundwater was studied. Only phosphates and silicates (respectively at 4 and 20 mg l −1) lead to significant interferences in the determination of total inorganic arsenic at 4 μg l −1.

Determination of arsenic(III) and total inorganic arsenic in water samples using an on-line sequential insertion system and hydride generation atomic absorption spectrometry

A simple and robust on-line sequential insertion system coupled with hydride generation atomic absorption spectrometry (HG-AAS) was developed, for selective As(III) and total inorganic arsenic determination without pre-reduction step. The proposed manifold, which is employing an integrated reaction chamber/gas–liquid separator (RC-GLS), is characterized by the ability of the successful managing of variable sample volumes (up to 25 ml), in order to achieve high sensitivity. Arsine is able to be selectively generated either from inorganic As(III) or from total arsenic, using different concentrations of HCl and NaBH 4 solutions. For 8 ml sample volume consumption, the sampling frequency is 40 h −1. The detection limit is c L = 0.1 and 0.06 μg l −1 for As(III) and total arsenic, respectively. The precision (relative standard deviation) at 2.0 μg l −1 ( n = 10) level is s r = 2.9 and 3.1% for As(III) and total arsenic, respectively. The performance of the proposed method was evaluated by analyzing the certified reference material NIST CRM 1643d and spiked water samples with various concentration ratios of As(III) to As(V). The method was applied for arsenic speciation in natural waters samples.

Determination of total inorganic arsenic in water using on-line pre-concentration and hydride-generation atomic absorption spectrometry

A rapid and sensitive method for the on-line separation and pre-concentration of inorganic arsenic in water samples is described. The analyte in the pentavalent oxidation state is reduced to its trivalent form with l-cysteine and the total inorganic arsenic is sorbed onto activated alumina in the acid form in a mini-column coupled to a FI-HG AAS system. Afterwards, it is eluted with 3 mol l −1 HCl. An enrichment factor of 7 was obtained, allowing an analytical flow rate of about 28 determinations per hour. The limits of detection (3 σ) and of quantification (10 σ) were calculated as LOD = 0.15 μg l −1 of As and LOQ = 0.5 μg l −1 of As, respectively. Relative standard deviations ( n = 10) less than 8% were obtained for different arsenic concentrations and the accuracy was verified by analysing certified reference materials. Different kinds of samples, such as mineral water, drinking water, river water and natural spring water were analyzed and good agreement was obtained with the values from spiked experiments.

Voltammetric determination of inorganic As(III) and total inorganic As in natural waters

The paper describes a voltammetric method for the determination of As(III) and total inorganic As at ppb and sub ppb level using cathodic stripping voltammetry. This method is based on the formation of a copper-arsenic intermetallic at HDME during the preconcentration step. Sodium dithionite is used for the reduction of As(V) to As(III). As(III) is then determined in HBr supporting electrolyte. Compared to the procedures described in previous literature, the determination of total inorganic arsenic in such conditions needs shorter deposition times and less amount of copper. Moreover, better linear response current versus concentration and peaks repeatability are obtained. In the described working conditions LOQ for As(III) and As(V) are 0.010 and 0.020 ppb respectively, for a deposition time of 300 s. Standard deviation for 1 ppb arsenic concentration ( n = 7) is 5%. The method was applied to thermal, spring and sea waters and accuracy was verified by a recovery test on spiked samples. Total arsenic concentrations are in good agreement with those obtained in ICP-OES-HG.

Multisyringe flow-injection system for total inorganic arsenic determination by hydride generation-atomic fluorescence spectrometry

A software-controlled time-based multisyringe flow-injection system for total inorganic arsenic determination by hydride generation atomic fluorescence spectrometry (HGAFS) has been developed. By using a multisyringe burette coupled with one multiport selection valve, the time-based injection provides precise known volumes of sample, a reducing sodium tetrahydroborate solution and a pre-reducing solution which are dispensed into a gas–liquid separation cell. An argon flow delivers the arsine into the flame of an atomic fluorescence spectrometer. A hydrogen flow has been used to support the flame.Linear calibration graphs for arsenic concentrations between 0.25 and 12μgl−1 were obtained. The detection limit of the proposed technique (3σb/S) was 0.07μgl−1. A sample throughput of 36 samples/h (108 injections) has been achieved. The proposed technique has been validated by means of reference solid and water materials with good agreement with the certified values. This method was compared with those reported in previous sequential injection analysis (SIA) and flow-injection analysis (FIA) systems. The proposed method offers a number of advantages in front the usual AFS applications, which are mainly a higher sampling frequency and a significant reduction in reagent consumption.