Flow Injection Atomic Absorption Spectrometry Research Articles

Determination of As by UV-photochemical generation of its volatile species with AAS detection

This work was focused on the development of an analytical method for determination of arsenic in liquid (aqueous solutions of arsenite) by UV-photochemical generation of its volatile compounds. The study contains the optimization, method characterisation and also a study of the influence of selected compounds on the signal measured. The method involves a combination of flow injection analysis, UV-photochemical generation of volatile compounds of arsenic in flow injection arrangement and atomic absorption spectrometry using an externally heated quartz tube atomizer. The attained absorbance was very low after the optimization. In the next step, the influence of selected compounds on UV-photochemical generation was investigated with the aim to find a suitable reaction modifier that would improve the sensitivity of arsenic determination. Bi(III) was found as the best reaction modifier not only for causing the increase of the signal of arsenic measured but also for its persisting effect. The activation with concentration of 10 mg dm−3 of Bi(III) increases the absorbance of arsenic approximately eleven times compared to signals without activation. Following method characteristics were achieved under the optimum experimental conditions: the limit of detection of 18 µg dm−3, the repeatability of 4.5 % expressed as % RSD at 200 µg dm−3, and linear dynamic range 60–500 µg dm−3 of arsenic.

Distribution of the Total Arsenic Content in Drinking Water Obtained from Different Water Sources in the Republic of Macedonia

The present study investigates the total arsenic (As) content in the samples of drinking water in the Republic of Macedonia, which is obtained from different water sources, such as: springs, surface accumulations, underground accumulations and drilled wells. From January 2013 to December 2013, a total of 780 samples obtained from the public water supply systems at 35 measurement points distributed throughout the whole territory of the Republic of Macedonia were analyzed on the total As content. A flow injection atomic absorption spectrometry (FIAS) was employed for the determination of the total As content after wet digestion of the samples with nitric acid (67%, W/V) and hydrogen peroxide (30%, V/V). The results of the study revealed that in 96.7% of the tested samples, As content was below established maximum allowable concentration (MAC) of 10 μg/L. As concentrations up to 26.4 μg/L were found in the samples of drinking water that comes from the water sources located in the vicinity of Kozhuf Mountain, which is due to the mineral composition of the mountain body rich with As containing minerals: lorandite, orpiment, realgar, arsenopyrite etc. Higher As concentrations (5.47 μg/L – 26.6 μg/L) were also found in the samples of drinking water obtained from the water supply system of the towns from the Dojran Municipality which are located in the vicinity of thermal-mineral area of Mala Boshka – Toplec. It can be concluded that the presence of total As in the potable water in the Republic of Macedonia comes only from natural sources.

Indirect determination of free cyanide in water and industrial waste water by flow injection-atomic absorption spectrometry

A simple and rapid flow injection system is proposed for indirect determination of cyanide by flame atomic absorption spectrometry. It consists of a microcolumn of immobilized salen (N,N′-bis(salicylidene)ethylenediamine) on sodium dodecyl sulfate (SDS)-coated alumina saturated with silver ion and a carrier of dilute solution of sodium hydroxide (10−5 mol L−1). The micro-column was located between the injection valve and nebulizer of atomic absorption spectrometry. Injection of 250 µL of aqueous cyanide standard or sample solution at pH range of 9–11 cause elution of silver as silver cyanide complexes, which was then measured by flame atomic absorption spectrometry. The absorbance was proportional to the concentration of cyanide in the sample. The graph of absorbance (as peak height) vs. cyanide concentration was linear over the concentration range of 0.1–10 mg L−1 of cyanide, and the detection limit was 0.06 mg L−1. The relative standard deviation at 1 and 3 mg L−1 of cyanide concentration were 4.1 and 4.7%, respectively. The method was successfully applied to determination of cyanide in water and industrial waste waters, and the accuracy was examined through independent analysis by accepted method of pyridine-barbituric acid.

Derivative flame atomic absorption spectrometry and its application in trace analysis

Flame atomic absorption spectrometry (FAAS) is an accepted and widely used method for the determination of trace elements in a great variety of samples. But its sensitivity doesn’t meet the demands of trace and ultra-trace analysis for some samples. The derivative signal processing technique, with a very high capability for enhancing sensitivity, was developed for FAAS. The signal models of conventional FAAS are described. The equations of derivative signals are established for FAAS, flow injection atomic absorption spectrometry (FI-FAAS) and atom trapping flame atomic absorption spectrometry (AT-FAAS). The principle and performance of the derivative atomic absorption spectrometry are evaluated. The derivative technique based on determination of variation rate of signal intensity with time (dI/dt) is different from the derivative spectrophotometry (DS) based on determination of variation rate of signal intensity with wavelength (dI/dλ). Derivative flame atomic absorption spectrometry (DFAAS) has higher sensitivity, lower detection limits and better accuracy. It has been applied to the direct determination of trace elements without preconcentration. If the derivative technique was combined with several preconcentration techniques, the sensitivity would be enhanced further for ultra-trace analysis with good linearity. The applications of DFAAS are reviewed for trace element analysis in biological, pharmaceutical, environmental and food samples.

Determination of cadmium by flow injection atomic absorption spectrometry with cold vapor generation by a tetrahydroborate-form anion-exchanger

A volatile derivative was formed on passage of an acidified cadmium solution through a strong anion-exchange resin in the tetrahydroborate(III) form. The efficiency of four resins, Amberlite IRA-400, Amberlite IRA-410, Amberlyst A-26 and Dowex-1, were investigated. Amberlite IRA-400 (160 mg, 50 mm × 3 mm id) gave the highest sensitivity for both peak height and peak area. The effects of column dimensions, concentration of tetrahydroborate, loading time, carrier reagent flow rate, carrier gas flow rate, acidity of sample, stripping coil length, the direction of loading and injection were studied and the relationship between sample volume and limit of detection were evaluated. The column was regenerated after each determination. From a study of masking agents, thiourea, L-cysteine, sodium fluoride, cupferron, EDTA, tartaric acid, 5-sulfosalicylic acid for the plant and soil matrices, it was found that thiourea and L-cysteine were suitable, whereas cupferron, EDTA, tartaric acid and 5-sulfosalicylic acid suppressed the signal. Passing the sample through an anion-exchange column before the immobilized tetrahydroborate column improved the signal for plant and soil matrices. Less suppression by some elements was observed than for generation by reaction with tetrahydroborate in aqueous solution, and smaller amounts of reagents were required. The limits of detection (3s) in 0.2 mol l−1 nitric acid solution with 1% thiourea, and with 1% thiourea plus 1 mg l−1 Co, were 40 and 30 ng l−1, respectively, with a sampling frequency of 30–45 h−1. The relative standard deviation (n = 5) was 5%, 2.0% and 3.2% at 0.5, 1.0 and 3.0 μg l−1, respectively. The method was applied to the analysis of natural waters, wine, human saliva, orange juice, human urine and human hair, for which 1% thiourea and 1 mg l−1 Co were added. For plant and soil analysis, 0.1% L-cysteine and 1 mg l−1 Co were added. Pre-digestion spike recoveries were in the range of 81–110%. The detection limits (3s) were in the range of 0.04–0.05 μg l−1 in natural water samples and 0.02–0.40 μg g−1 in human hair and plant samples. The results obtained for the analysis of four NIST standard reference materials, freeze-dried urine (SRM 2670), Montana soil (SRM 2711), spinach leaves (SRM 1570a), and tomato leaves (SRM 1573a), were in agreement with the certified values.

Determination of Arsenic in Food Samples by Hydride Generation ? Atomic Absorption Spectrometry

A method for the determination of trace amounts of arsenic in food samples using flow injection analysis and atomic absorption spectrometry with hydride generation (FI-HG AAS) was developed. The parameters of the flow injection system and the hydride generation were optimized with respect to reagent concentrations, atomization temperature, injection volume, reaction coil length and carrier flow rate. The limits of detection and quantification were 0.34 µg L−1 and 1.2 µg L−:1, respectively, and the analytical curve is linear up to 30.0 µg L−1 arsenic. The relative standard deviation for 12 replicates varies between 5% for 4.0 µg L−1 As and 1.8% for 30.0 µg L−1 As, with an injection frequency of up to 135 h−1. Interferences from Ni(II), Cu(II), Fe(III), Cr(III), Mo(II), Bi(III), Se(IV), Se(VI), Sb(III) and Sb(V) could be masked with a mixture of ascorbic acid-KI in a 5.0 mol L−1 HCl solution. The accuracy of the proposed method was evaluated by using certified reference materials of biological samples, and the method was used to determine the content of arsenic in fish and coffee beans.

Trace enrichment and determination of silver by immobilized DDTC microcolumn and flow injection atomic absorption spectrometry

Flow injection (FI) system incorporating a microcolumn of immobilized diethyldithiocarbamate (DDTC) on surfactant-coated alumina was combined with atomic absorption spectrometry for on-line trace enrichment and determination of silver in different matrices. Silver was deposited on the microcolumn by processing a standard or solution of analyte at pH 3–4 on the column. Injection of 250μl of ethanol then served to elute the retained species to atomic absorption spectrometry (AAS). A sample volume of 20ml resulted in a pre-concentration factor of 125, and precision at the 20μgl−1 was 4% (R.S.D.). The procedure was applied to tap water, well water, rain water, sea water, radiology film, and lead concentrate samples. The accuracy was assessed through recovery experiments, independent analysis by furnace-AAS, and analysis of certified reference material.

Trace enrichment and determination of silver by immobilized DDTC microcolumn and flow injection atomic absorption spectrometry

Flow injection (FI) system incorporating a microcolumn of immobilized diethyldithiocarbamate (DDTC) on surfactant-coated alumina was combined with atomic absorption spectrometry for on-line trace enrichment and determination of silver in different matrices. Silver was deposited on the microcolumn by processing a standard or solution of analyte at pH 3–4 on the column. Injection of 250 μl of ethanol then served to elute the retained species to atomic absorption spectrometry (AAS). A sample volume of 20 ml resulted in a pre-concentration factor of 125, and precision at the 20 μg l −1 was 4% (R.S.D.). The procedure was applied to tap water, well water, rain water, sea water, radiology film, and lead concentrate samples. The accuracy was assessed through recovery experiments, independent analysis by furnace-AAS, and analysis of certified reference material.

Ozone treatment for mercury determination in white wines

A method was developed for the generation of mercury vapour by means of cold-vapour flow-injection atomic absorption spectrometry (FI-CV-AAS) from white wine samples after ozonation as sample pre-treatment. Two different reactors designs for sample ozonation were developed and investigated. The limit of detection and the limit of quantification were, respectively, 0.5 and 1.7 μg l −1, and the relative standard deviation ( n=10) was 2% for a concentration of 50 μg l −1 and 7% for a concentration of 5 μg l −1. The pre-treatment with ozone has allowed to reduce drastically the amount of chemical reagents (e.g. carrier agent and reducing agent) used in the FI-CV-AAS system. The mercury content of wine samples was also determined by FI-CV-AAS after pre-concentration in the presence of HNO 3 and H 2O 2. In general, there was no significant difference among data obtained from both methodologies, but pre-treatment with ozone is much faster.

Determination of essential metals in complete diet feed by flow injection and flame atomic absorption spectrometry

A prior study of different sample pre-treatments for the determination of metallic elements in complete diet feeds was performed in order to choose the most suitable for these samples. The studied pre-treatment were: acid extraction (lixiviation), wet digestion (on microwave oven) and dry ashing mineralization (calcination). Lixiviation (acid extraction) with hydrochloric acid was selected due to its accuracy, fast and simple pre-treatment procedure. Due of the different levels of concentration of the metallic elements in the samples, the same manifold was used but with small variations. Copper (with on-line pre-concentration by chelating Chelex-100 resin), calcium (with on-line dilution) and iron determination gave suitable accuracy and precision and required a little time for analysis. Five different samples were analyzed by flow injection and the results were contrasted with dry ashing mineralization in batch procedure and with the labeled contents.

Speciation without chromatography : Part 2. Determination of tributyltin by chloride generation flow injection atomic absorption spectrometry

A procedure is described for the quantitation of tributyltin in aqueous samples and extracts based on its relatively high volatility in halide media, permitting vapour phase sampling from the headspace above such samples. Tributyltin chloride (TBT-Cl) was purged from various chloride containing aqueous matrices and collected on the surface of an iridium treated graphite tube for subsequent quantitation by graphite furnace atomic absorption. Iodide, bromide and chloride matrices were compared for their generation efficiency. The effect of acidity of the sample was also studied. An absolute detection limit of 1.3 ng TBT (as tin) was estimated, corresponding to a detection limit of 0.33 ng ml−1 for a 4 ml sub-sample. Method validation was achieved using NRCC PACS-2 (sediment) Certified Reference Material, for which reasonable agreement between certified and measured values of tributyltin content was obtained. A procedural concentration limit of detection of 66 ng g−1 TBT in the sediment could be achieved.

Continuous automatic determinations of organic compounds by flow injection–atomic absorption spectrometry

A review with 44 references is presented on the development of indirect flow injection determinations of organic compounds by atomic absorption spectrometry, covering the field from the first publications to the present. The characteristics, advantages and potential of this methodology are discussed and examined. It is shown that these systems are compatible with established techniques such as gas chromatography and high-performance liquid chromatography.

A practical exercise for the determination of As(III) by flow injection hydride generation-atomic absorption spectrometry

A practical exercise is presented for determination of very low amounts (ng/l) of As(III) by flow injection (FI) and hydride generation and atomic absorption spectrometry detection. The exercise is directed towards students at the advanced undergraduate level, and it is intended to be an introduction to procedures of FI, which by relatively uncomplicated equipment provide analysis with excellent performance. With the method presented, it can be shown that assays of As(III) in natural waters can be performed only if an on-line preconcentration step is incorporated into the FI manifold. The method offers a unique illustration of the versatility of the FI approach in sample manipulation to reach low detection limits as well as a demonstration of cleverly exploiting kinetic discrimination schemes for promoting the main reaction and eliminating potential side reactions and interferences.

Online Trace Enrichment and Determination of Cobalt Ion as an Anionic Complex by Flow Injection Atomic Absorption Spectrometry

A flow injection system incorporating a microcolumn of activated alumina was combined with atomic absorption spectrometry for on-line trace enrichment and determination of cobalt in waters and vitamin B12. Deposition of cobalt as its cyano complex was effected with the use of an acidic alumina microcolumn, and injection of ammonia solution (500 μl, 2 M) served to elute species retained on the atomic absorption spectrometer. A sample volume of 15 ml resulted in a preconcentration factor of 120, and precision at the 500 and 50 μg liter−1 levels was ±3.1 and ±3.3% (RSD), respectively. The procedure was applied to mineral water, spring water, river water, and vitamin B12 and accuracy was assessed through a recovery experiment.

Determination of iron in soils by flow injection atomic absorption spectrometry

A single‐channel flow injection system was optimized for the determination of available iron (Fe) in soil extracts by atomic absorption spectrophotometry. This method of introducing the samples in the spectrophotometer worked particularly well in preventing blockage of the burner head which was observed in the conventional introduction of Fe for its determination by atomic absorption spectrophotometry. The appropriate selection of the manifold parameters, such as injection volume, tube length and flow rate, allowed introduction of any soil extract without requiring any pre‐treatment. This system allowed determinations at a detection limit of 0.36 mg L‐1 to 5 mg L‐1, with an output of 300 determinations per hour. The results obtained for analysis of 15 soil extracts were in good agreement with those provided by the colorimetric method, with average relative deviations of 1.6%. Relative standard deviations of 4.8, 2.5, and 2.3% were obtained for contents of 1.03, 1.85, and 3.99 mg Fe L‐1, respectively.

Determination of copper, cadmium, manganese and lead in saline water with flow injection and atom trapping atomic absorption spectrometry

Download options Please wait... Article information DOI https://doi.org/10.1039/A801287C Article type Paper Download Citation J. Anal. At. Spectrom., 1998,13, 631-634 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Determination of copper, cadmium, manganese and lead in saline water with flow injection and atom trapping atomic absorption spectrometry L. A. Ellis and D. J. Roberts, J. Anal. At. Spectrom., 1998, 13, 631 DOI: 10.1039/A801287C To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author Lyndon A. Ellis David J. Roberts

Incorporation of electrodialysers into the conduits of flow injection–atomic absorption spectrometry systems. Determination of copper(ii) ions in multivitamin tablets after enhancement of mass transfer through a passive neutral membrane

An electrodialyser unit was designed, incorporated into the conduits of a flow injection (FI) system and employed for the removal of suspended solids before detection by AAS. The combined electrodialyser–FI–AAS system was applied to the determination of copper(ii) in multivitamin and mineral tablets. The proposed system is fully computerised and is able to determine copper(ii) in samples at a frequency of 14 samples h–1 with a sample interaction of 0.058%. The electrodialysis efficiency was 94%, which is a dramatic improvement over previous systems with passive neutral membranes. The calibration graph is linear between 1 and 60 mg l–1. The detection limit is 1.44 mg l–1. The results obtained for copper(ii) in multivitamin and mineral tablets with the proposed system compared favourably with those obtained with the standard manual AAS method.

Flow-injection atomic absorption spectrometry system for mercury determination in water

Flow-injection atomic absorption spectrometry system for mercury determination in water

Flow-injection atomic absorption spectrometry system for mercury determination in water

A homemade FIA device for mercury determination in water is presented, as well as the influence of different operation parameters. The method is based upon the mercury(II) ion reduction with SnCl2 to elementary mercury, followed by the extraction of the latter from the liquid phase by means of an air flow, the mercury vapor then being passed into the flow cell of an atomic absorption spectrometer. The measurement sensitivity is good as the method allows for analyses within 0.01–1 μg Hg2+ mL−1 concentration range. The time required for one determination is approximately 2 minutes as a function of the injected sample volume with an excellent reproducibility of the determinations and a relative standard deviation of 1.02%. This FIA device for Hg2+ determination has been successfully employed for analyzing water samples from chlorosodic industry. © 1998 John Wiley & Sons, Inc. Lab Robotics and Automation 10: 355–359, 1998

Determination of Lead Contamination in Spanish Wines and Other Alcoholic Beverages by Flow Injection Atomic Absorption Spectrometry

A rapid, accurate, and precise method is described for the direct determination of lead in wine and other alcoholic beverages, using a flow injection−hydride generation−atomic absorption spectrometry system (FI-HG-AAS). Lead hydride was generated in HNO3−H2O2 medium using NaBH4 as the reducing agent. To increase the efficiency of lead hydride generation and to produce mineralized samples, a microwave oven was coupled on-line to the FI-HG-AAS system for some samples. This method was used with 70 samples of wine produced in Spain and with 64 samples of other alcoholic beverages widely consumed in that country. The concentrations of lead ranged in wine from not detectable (ND) to 1125.00 μg/L and in other alcoholic beverages from ND to 444.70 μg/L. Keywords: Lead contamination; wine; alcoholic beverages; atomic absorption spectrometry