Monitoring of selenium in water samples using dispersive liquid–liquid microextraction followed by iridium-modified tube graphite furnace atomic absorption spectrometry

Exploitation of environmental DNA (eDNA) for ecotoxicological research: A critical review on eDNA metabarcoding in assessing marine pollution

The rise in worldwide population has led to a noticeable spike in the production, consumption, and transportation of energy and food, contributing to elevated environmental pollution. Marine pollution is a significant global environmental issue with ongoing challenges, including plastic waste, oil spills, chemical pollutants, and nutrient runoff, threatening marine ecosystems, biodiversity, and human health. Pollution detection and assessment are crucial to understanding the state of marine ecosystems. Conventional approaches to pollution evaluation usually represent laborious and prolonged physical and chemical assessments, constraining their efficacy and expansion. The latest advances in environmental DNA (eDNA) are valuable methods for the detection and surveillance of pollution in the environment, offering enhanced sensibility, efficacy, and involvement. Molecular approaches allow genetic information extraction from natural resources like water, soil, or air. The application of eDNA enables an expanded evaluation of the environmental condition by detecting both identified and unidentified organisms and contaminants. eDNA methods are valuable for assessing community compositions, providing indirect insights into the intensity and quality of marine pollution through their effects on ecological communities. While eDNA itself is not direct evidence of pollution, its analysis offers a sensitive tool for monitoring changes in biodiversity, serving as an indicator of environmental health and allowing for the indirect estimation of the impact and extent of marine pollution on ecosystems. This review explores the potential of eDNA metabarcoding techniques for detecting and identifying marine pollutants. This review also provides evidence for the efficacy of eDNA assessment in identifying a diverse array of marine pollution caused by oil spills, harmful algal blooms, heavy metals, ballast water, and microplastics. In this report, scientists can expand their knowledge and incorporate eDNA methodologies into ecotoxicological research.

Reliable Quantification of Ultratrace Selenium in Food, Beverages, and Water Samples by Cloud Point Extraction and Spectrometric Analysis

Selenium is a trace element essential for the proper functioning of human body. Since it can only be obtained through our diet, knowing its concentrations in different food products is of particular importance. The measurement of selenium content in complex food matrices has traditionally been a challenge due to the very low concentrations involved. Some of the difficulties may arise from the abundance of various compounds, which are additionally present in examined material at different concentration levels. The solution to this problem is the efficient separation/preconcentration of selenium from the analyzed matrix, followed by its reliable quantification. This review offers an insight into cloud point extraction, a separation technique that is often used in conjunction with spectrometric analysis. The method allows for collecting information on selenium levels in waters of different complexity (drinking water, river and lake waters), beverages (wine, juices), and a broad range of food (cereals, legumes, fresh fruits and vegetables, tea, mushrooms, nuts, etc.).

Determination of trace levels of selenium in natural water, agriculture soil and food samples by vortex assisted liquid-liquid microextraction method: Multivariate techniques

A green vortex assisted based liquid-liquid microextraction (VA-LLME) method was developed for preconcentration of selenium. Ammonium pyrrolidine dithiocarbamate (APDC) was used to form a hydrophobic complex with selenium in natural water, agricultural soil and food samples by GFAAS. Whereas Triton X-114, a nonionic surfactant and 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid were used for Se extraction as a dispersing medium. The conical flasks contents were shack on a vortex mixer to increase the extraction efficiency. Multivariate techniques were used to evaluate extraction parameters; pH, vortex time, APDC amount, volume of ionic liquid and Triton X-114 and centrifugation rate on the recovery of Se. The central composite design (CCD) was used for further optimization of the essential extraction parameters. The enhancement factor and limit of detection were obtained as 98.7 and 0.07 µg L^-1. The certified reference materials was used for accuracy of method and the related standard deviation was found to be 3.51%. The resulted data indicated that concentrations of Se in all types of water samples were below the permissible limit recommended by WHO.

Deep-eutectic-solvent-based dispersive and emulsification liquid-liquid microextraction methods for the speciation of selenium in water and determining its total content levels in milk formula and cereals

Rapid and environmentally friendly ultrasound-assisted dispersive liquid-liquid microextraction (US-DLLμE) and vortex assisted-emulsification liquid-liquid microextraction (VA-ELLμE) methods are proposed for the speciation of selenium in domestic and mineral water samples. A deep eutectic solvent (DES) prepared with different ratios of choline chloride and phenol is used as an extractant for hydrophobic tetravalent Se complexed with diethyldithiocarbamate in different water samples. The total inorganic Se species levels in water samples were determined via reducing Se(vi) to Se(iv), using sodium thiosulphate as a reducing agent. The total Se levels in formula milk and cereal samples were determined after microwave acid digestion. The different heating steps in GFAAS were also optimized. The analytical parameters for US-DLLμE and VA-ELLμE, including pH, the volume of complexing agent, the ultrasound and vortex mixing shaking times, and the volume and composition of the deep eutectic solvent, were optimized. The accuracies of both methods were confirmed based on the analysis of a certified reference material (CRM) BCR 189 (wholemeal flour). The enhancement factor (EF) and limit of detection (LOD) for Se(iv) via US-DLLμE were found to be 90.8 and 0.029 μg L^-1, respectively, whereas an EF of 81.8 and LOD of 0.036 μg L^-1 were obtained via VA-ELLμE. The % relative standard deviation (%RSD) values obtained based on the analysis of six replicate standards under the optimized conditions for US-DLLμE and VA-ELLμE were found to be 4.2 and 5.8%, respectively. The optimized methods were applied to different drinking water samples, and acid-digested milk formula and baby cereal food samples.

A new derivatization method for the determination of propineb in black tea and infant formula samples using dispersive liquid-liquid microextraction followed by gas chromatography-mass spectrometry

A novel derivatization method for the determination of propineb by gas chromatography-mass spectrometry (GC-MS) was developed in this study. This was achieved by isothiocyanate derivatization of the analyte by potassium persulfate and potassium carbonate in water medium. Dispersive liquid-liquid microextraction (DLLME) was employed to isolate and preconcentrate the derivatized analyte into an organic phase. All method parameters including concentration/volume of potassium persulfate and potassium carbonate salts, type/period of mixing for derivatization reaction and microextraction process were systematically optimized to lower the detection limit. Under the optimum experimental conditions, the limit of detection (LOD) and limit of quantitation (LOQ) values were calculated as 0.15 mg/kg and 0.52 mg/kg, respectively. The developed method was checked for its accuracy and applicability by spiking black tea and infant formula samples, and the respective percent recovery results were found to be in the range of 99-102% and 98-103%, respectively.

Corporate social irresponsibility towards the planet: a study of heavy metals contamination in groundwater due to industrial wastewater

Purpose

The purpose of this study is to collaborate with environmental engineering and management making an effort to provide evidence for the irresponsible behavior of small business set up in north India with special reference to Aligarh City. Corporates have huge accountability for sustainable development, and they cannot overlook the major responsibilities which are lying on their shoulders. CSR is related to the concept of “doing good” but, beyond “doing good” businesses have the responsibility for “avoiding bad” to avoid corporate social irresponsibility (CSI), such as damaging the environment by polluting land, water and air, cheating customers, violating human rights, or doing any unethical practices.

Design/methodology/approach

In this study, random groundwater samples were collected from “Aligarh Nagar Nigam” installed hand pumps from industrial influence areas of Aligarh during the month of October and November 2017. These samples were collected nearby small-scale metal plating industries plants. The samples analyzed by the Atomic Absorption Spectrometer (AAS) Perkin Elmer PinAAcle 900 F, for Fe, Mn, Pb, Zn, Cu and Cr (Jahromi et al., 2007; Chen and Teo, 2001; Bidari et al., 2007; Land and Hoops, 1973; de Oliveira et al., 2016; Akoto et al., 2016). In addition, some other parameters also taken in this study and the results obtained are compared with the World Health Organization (WHO) and Bureau of Indian Standard (BIS).

Findings

These results of the study revealed that the penetration of heavy metals like Cr, Pb, Cu, Zn, Fe and Mn into the soil is found much higher than the permissible limit stated by the government. The concentrations of metals in groundwater found to be within limits, but some metals are exceeding the standard limits in few samples. Concentrations of these heavy metals Cr>Cu>Pb>Fe>Mn are exceeding standard limits, Zn found within permissible limits as per WHO and BIS standard. This result proves to be a means to an end for an irresponsible behavior toward the society and environment which leads to serious health and environmental hazards.

Research limitations/implications

The results are beneficial for data generation on various quality parameters of groundwater. The results of this study help in proper decision-making by concerned authorities to prevent, reduce toxic levels and begin to take steps for making water fit for drinking and other purposes. The research is limited in Aligarh City and other cities are like Kanpur, Noida and Ghaziabad are also tested by taking samples of water, as these cities are extensively captured by SME’s and large scale industries.

Practical implications

The results of this study have several implications for both governmental and non-governmental practice and policy development. As society expects positive attitudes of the businesses toward CSR activities and concern about the environment, businesses, institutions and governments should pay more attention to promote the initiative of environment safety to intensify their public concern. The small business unit must know about the serious health hazards of discharging the waste water in the open and therefore regular checking of heavy metal contamination in the groundwater in these areas is needed and use of contaminated water must be prevented to lessen the health risk caused by using the metal contaminated groundwater. The small-scale industries should follow the guidelines for proper disposal of wastewater discharge. The water treatment technology should involve and take possible steps to remove heavy metals contamination.

Originality/value

This study provides real data to municipality and other government offices which can be used as a benchmark to plan strict policy to prohibit the open discharge of wastewater by industries.

On-chip ion pair-based dispersive liquid-liquid extraction for quantitative determination of histamine H2 receptor antagonist drugs in human urine

In the present work, an ion-pair based dispersive liquid-liquid microextraction was performed on a centrifugal chip for the first time. The entire DLLME procedure, including flow direction, desperation, and sedimentation of the extracting phase, can be fulfilled automatically on a solitary chip. The chip was made of Poly(methyl methacrylate) (PMMA) and was of two units for two parallel extractions, each consisting of three chambers (for the sample solution, extracting solvents, and sedimentation). As the chip rotated, fluids flowed within the chip, and the dispersion, mixing, extraction, and sedimentation of the final phase were performed on the chip by simply adjusting the spin speed. Determination of two histamine H₂ receptor antagonist drugs, cimetidine and ranitidine, as the model analytes from the urine samples was done using the developed on-chip ion-pair based DLLME method followed by an HPLC-UV. The effective parameters on the extraction efficiency of the model analytes were investigated and optimized using the one variable at a time method. Under optimized conditions, the calibration curve was linear in the range of 15-2000 μg L^-1 with a coefficient of determination (R²) more than 0.9987. The relative standard deviations (RSD %) for extraction and determination of the analytes were less than 3.7% based on five replicated measurements. LODs less than 10.0 μg L^-1 and preconcentration factors higher than 39-fold were obtained for both of the model analytes. The proposed chip enjoys the advantages of both the DLLME method and miniaturization on a centrifugal chip.

Dispersive liquid-liquid microextraction for rapid and inexpensive determination of tetramethylpyrazine in vinegar

The concentration of tetramethylpyrazine (TMP) in vinegar is an active indicator of vinegar quality. Dispersive liquid-liquid microextraction (DLLME) was first applied to vinegar as a clean-up pre-treatment for the rapid (5 min) determination of TMP by high-pressure liquid chromatography with ultraviolet detection (HPLC-UV), and may serve as an alternative to solid-phase extraction (SPE) or solid-phase microextraction (SPME). High sensitivity of HPLC for TMP determination was obtained using the DLLME pretreatment, with a limit of detection (LOD) of 0.001 mg L^-1 and limit of quantification (LOQ) of 0.005 mg L^-1. The developed method exhibited excellent linearity in the concentration range of 0.050-80.000 mg L^-1, with a correlation coefficient R² > 0.999. Furthermore, the percentage recovery of TMP in vinegar using the developed method was within the range 97.97-105.24%. Therefore, DLLME coupled with HPLC-UV is a sensitive and promising method for vinegar clean-up and TMP assay.

Development of an efficient sample preparation method for the speciation of Se(iv)/Se(vi) and total inorganic selenium in blood of children with acute leukemia

In this study, a new solidified deep eutectic solvent microextraction (SDES-ME) method was applied for the speciation of Se(iv), Se(vi) and total inorganic selenium in the blood of children with leukemia from Kermanshah, Iran, prior to analysis by iridium-modified tube graphite furnace atomic absorption spectrometry (GFAAS).

Speciation of As(ΙΙΙ)/As(V) and Total Inorganic Arsenic in Biological Fluids Using New Mode of Liquid-Phase Microextraction and Electrothermal Atomic Absorption Spectrometry

In this paper, a new extraction method based on countercurrent liquid-liquid microextraction (CLLME) has been developed for the extraction and preconcentration of inorganic arsenic (iAs) in plasma and urine samples prior to their analysis by electrothermal atomic absorption spectrometry (ETAAS). In this method, firstly, 5 ml of water is added to the extraction vessel. Then 30.0 μl of the extracting solvent is added to it in order for the extracting solvent to be placed in the narrow-necked vessel. In total, 10 ml of a standard solution or a pretreated real sample is added to the sample container and it is connected to the extraction vessel via a connector. While opening the embedded valve at the bottom of the sample container and the one in the extraction vessel, the sample solution flows into the extracting solvent with the same flow rate, leading to the successful extraction of metal ligand into the extracting organic solvent. Under the optimum conditions, calibration curves are linear in the range of 0.1-50 μg l^-1, and limit of detections (LODs) are in the range of 0.03-0.05 μg l^-1. The enhancement factor and enrichment factor were in the range of 220-240 and 198-212, respectively. Repeatability (intra-day) and reproducibility (inter-day) of method based on seven replicate measurements of 5.0 μg l^-1 of arsenic were in the range of 2.3-3.5% and 4.0-5.7%, respectively. The applicability of the proposed CLLME and ETAAS methods was demonstrated by analyzing the iAs in spiked urine and plasma samples. The obtained recoveries of the arsenic in the range of 92-107% indicated the excellent capability of the developed method for speciation of arsenic from plasma and urine samples. Graphical Abstract ᅟ.

Ultrasonic assisted dispersive liquid-liquid microextraction method based on deep eutectic solvent for speciation, preconcentration and determination of selenium species (IV) and (VI) in water and food samples

A novel ultrasound-assisted liquid phase microextraction (UALPME) based on environmental friendly extractants, deep eutectic solvent (DES) was first time presented for speciation of selenium. In present study, five DES solvents of different composition was prepared and used as efficient extractive medium for hydrophobic chelate of Se(IV) with 3,3'-Diaminobenzidine (DAB). The total inorganic Se species were determined after pre-reduction of Se(VI) to Se(IV), prior to applying developed method. The concentration of Se(VI) was calculated by the difference of Se(IV) values and total selenium contents. The concentration of Se in DES rich phase was measured with electrothermal atomic absorption spectrometer (ETAAS). The effects of different parameters on extraction efficiency of study analyte, including pH, ligand concentration, type and volume of DES, sonication time, volumes tetrahydrofuran and aqueous samples were examined. At the optimum conditions, limit of detection and quantification, preconcentration factor, and relative standard deviation (RSD %) were determined as 4.61ngL^-1, 15.4ngL^-1, 50% and 4.1%, respectively. The accuracy of the presented method was confirmed by analysis of certified reference material and standard addition method for different water and ice tea samples. The developed method was effectively applied to real water and food samples.

Optimization of a new methodology for trace determination of elements in biological fluids: Application for speciation of inorganic selenium in children's blood

The continuous sample drop flow microextraction (CSDFME) joined with the iridium-modified tube graphite furnace atomic absorption spectrometry (GFAAS) has been developed as a highly sensitive technique for the speciation of selenium in blood samples. In this method 32.0μl carbon tetrachloride is transferred to the bottom of a conical sample cup. Then the 5.0ml of aqueous solution transforms to fine droplets while passing through the organic solvent. At this stage, Se(IV)-APDC hydrophobic complex is extracted into the organic solvent. After extraction, the conical sample cup is transferred to the GFAAS and 20μl of extraction solvent was injected into the graphite tube by the aim of autosampler. Under the optimum conditions, the calibration graph was linear in the range of 0.06-3.0μgl^-1 with detection limit of 0.02μgl^-1. The enrichment factor and enhancement factor were 106 and 91, respectively. Repeatability (intra-day) and reproducibility (inter-day) of method based on seven replicate measurements of 2.5μgl^-1 of selenium were 3.7% and 4.2%, respectively. Total inorganic Se(IV, VΙ) was measured after reduction of Se(VΙ) with gentle boiling in 5M HCl medium for 50min and adjusting pH to 3, and the concentration of Se(VΙ) was calculated by subtracting the Se(IV) concentration from the total selenium concentration.

Simultaneous determination of ultra-low traces of lead and cadmium in food and environmental samples using dispersive solid-phase extraction (DSPE) combined with ultrasound-assisted emulsification microextraction based on the solidification of floating organic drop (UAEME-SFO) followed by GFAAS

Dispersive solid-phase extraction (DSPE) combined with ultrasound-assisted emulsification microextraction (UAEME) for determination of lead and cadmium in food and environmental samples prior to GFAAS.

Magnetic effervescent tablet-assisted ionic liquid dispersive liquid-liquid microextraction of selenium for speciation in foods and beverages

A novel, simple and rapid method based on magnetic effervescent tablet-assisted ionic liquid dispersive liquid-liquid microextraction (MEA-IL-DLLME) followed by graphite furnace atomic absorption spectrometry (GFAAS) determination was established for the speciation of selenium in various food and beverage samples. In the procedure, a special magnetic effervescent tablet containing CO2 sources (sodium carbonate and sodium dihydrogenphosphate), ionic liquids and Fe3O4 magnetic nanoparticles (MNPs) was used to combine extractant dispersion and magnetic recovery procedures into a single step. The parameters influencing the microextraction efficiency, such as pH of the sample solution, volume of ionic liquid, amount of MNPs, concentration of the chelating agent, salt effect and matrix effect were investigated and optimised. Under the optimised conditions, the limits of detection (LODs) for Se(IV) were 0.021 μg l(-)(1) and the linear dynamic range was 0.05-5.0 μg l(-)(1). The relative standard deviation for seven replicate measurements of 1.0 μg l(-)(1) of Se(IV) was 2.9%. The accuracy of the developed method was evaluated by analysis of the standard reference materials (GBW10016 tea, GBW10017 milk powder, GBW10043 Liaoning rice, GBW10046 Henan wheat, GBW10048 celery). The proposed method was successfully applied to food and beverage samples including black tea, milk powder, mushroom, soybean, bamboo shoots, energy drink, bottled water, carbonated drink and mineral water for the speciation of Se(IV) and Se(VI) with satisfactory relative recoveries (92.0-108.1%).

Ultrasound-assisted ionic liquid dispersive liquid-liquid microextraction combined with graphite furnace atomic absorption spectrometric for selenium speciation in foods and beverages

A rapid and environmentally friendly ultrasound assisted ionic liquid dispersive liquid liquid microextraction (USA-IL-DLLME) was developed for the speciation of inorganic selenium in beverages and total selenium in food samples by using graphite furnace atomic absorption spectrometry. Some analytical parameters including pH, amount of complexing agent, extraction time, volume of ionic liquid, sample volume, etc. were optimized. Matrix effects were also investigated. Enhancement factor (EF) and limit of detection (LOD) for Se(IV) were found to be 150 and 12 ng L(-1), respectively. The relative standard deviation (RSD) was found 4.2%. The accuracy of the method was confirmed with analysis of LGC 6010 Hard drinking water and NIST SRM 1573a Tomato leaves standard reference materials. Optimized method was applied to ice tea, soda and mineral water for the speciation of Se(IV) and Se(VI) and some food samples including beer, cow's milk, red wine, mixed fruit juice, date, apple, orange, grapefruit, egg and honey for the determination of total selenium.

Ionic liquid phase microextraction combined with fluorescence spectrometry for preconcentration and quantitation of carvedilol in pharmaceutical preparations and biological media

BACKGROUND

Carvedilol belongs to a group of medicines termed non-selective beta-adrenergic blocking agents. In the presented approach, a practical and environmentally friendly microextraction method based on the application of ionic liquids (ILs) was followed by fluorescence spectrometry for trace determination of carvedilol in pharmaceutical and biological media.

METHODS

A rapid and simple ionic liquid phase microextraction was utilized for preconcentration and extraction of carvedilol. A hydrophobic ionic liquid (IL) was applied as a microextraction solvent. In order to disperse the IL through the aqueous media and extract the analyte of interest, IL was injected into the sample solution and a proper temperature was applied and then for aggregating the IL-phase, the sample was cooled in an ice water-bath. The aqueous media was centrifuged and IL-phase collected at the bottom of the test tube was introduced to the micro-cell of spectrofluorimeter, in order to determine the concentration of the enriched analyte.

RESULTS

Main parameters affecting the accuracy and precision of the proposed approach were investigated and optimized values were obtained. A linear response range of 10-250 μg I(-1) and a limit of detection (LOD) of 1.7 μg I(-1) were obtained.

CONCLUSION

Finally, the presented method was utilized for trace determination of carvedilol in commercial pharmaceutical preparations and biological media.

Determination and speciation of trace and ultratrace selenium ions by energy-dispersive X-ray fluorescence spectrometry using graphene as solid adsorbent in dispersive micro-solid phase extraction

A dispersive micro-solid phase extraction (DMSPE) with graphene as a solid adsorbent and ammonium pyrrolidinedithiocarbamate (APDC) as a chelating agent was proposed for speciation and detemination of inorganic selenium by the energy-dispersive X-ray fluorescence spectrometry (EDXRF). In developed DMSPE, graphene particles are dispersed throughout the analyzed solution, therefore reaction between Se(IV)-APDC complexes and graphene nanoparticles occurs immediately. The concentration of Se(VI) is calculated as the difference between the concentration of selenite after and before prereduction of selenate. A central composite face-centered design with 3 center points was performed in order to optimize conditions and to study the effect of four variables (pH of the sample, concentration of APDC, concentration of Triton-X-100, and sample volume). The best results were obtained when suspension consisting of 200 µg of graphene nanosheets, 1.2 mg of APDC and 0.06 mg of Triton-X-100 was rapidly injected to the 50 mL of the analyzed solution. Under optimized conditions Se ions can be determined with a very good recovery (97.7±5.0% and 99.2±6.6% for Se(IV) and Se(VI), respectively) and precision (RSD=5.1-6.6%). Proposed DMSPE/EDXRF procedure allowed to obtain low detection limits (0.032 ng mL(-1)) and high enrichment factor (1013±15). The proposed methodology was successfully applied for the determination of Se in mineral, tap, lake and sea water samples as well as in biological materials (Lobster Hepatopancreas and Pig Kidney).

Speciation of inorganic selenium in environmental water samples by inductively coupled plasma optical emission spectrometry after preconcentration by using a mesoporous zirconia coating on coal cinder

A simple, novel, and selective flow-injection solid-phase extraction with inductively coupled plasma optical emission spectrometry method was developed for the speciation of inorganic selenium in environmental water samples. A mesoporous zirconia film was simply introduced to coat coal cinder by means of the sol-gel technique, and the adsorptive performance of the coated material for Se(IV)/Se(VI) was investigated in different media. Both Se(IV) and Se(VI) can be retained quantitatively by the material in HCl/NaOH (pH 1.0-9.0) media, while only Se(IV) was adsorbed quantitatively in sodium acetate buffer (pH 3.5-6.0). Thus, the assay of Se(VI) is based on subtracting Se(IV) from total selenium by controlling different adsorptive media without employing any redox procedure. Under the optimum conditions, the detection limit of Se(IV) is 9.0 ng/L with an enrichment factor of 100, and the relative standard deviation is 3.6% (n = 9, C = 5.0 ng/mL). The developed method was successfully applied to the speciation of inorganic selenium in environmental water samples with satisfactory results. In order to further verify the accuracy of the developed method, it was applied to analysis of total selenium in GSBZ 50031-94 certified reference environmental water, and the determined values coincided with the certified values very well.

Indirect spectrophotometric determination of ultra trace amounts of selenium based on dispersive liquid-liquid microextraction-solidified floating organic drop

A novel dispersive liquid-liquid microextraction-solidified floating organic drop (DLLME-SFOD) method combined with fiber optic-linear array detection spectrophotometry has been developed for the indirect determination of selenium. The method is based on the oxidation of the I(-) to iodine by inorganic Se(IV). The produced I2 reacts with the excess of I(-) ions in acidic media to give triiodide ions. The I3(-) is then extracted into 1-undecanol by DLLME-SFOD upon the formation of an ion pair with cetyltrimethylammonium cation. The extracted ion pair is determined by measuring its absorption at 360 nm. The absorbance signal is proportional to the selenium concentration in the aqueous phase. Under optimum conditions, the method provided an enrichment factor of 250 with a detection limit of 16.0 μg L(-1) and a linear dynamic range of 40.0-1000.0 μg L(-1). The relative standard deviation was found to be 2.1% (n=7) at 100.0 μg L(-1) concentration level. The method was successfully applied to th e determination of selenium in water samples and selenium plus tablet.