Continuum Source Flame Atomic Absorption Research Articles

Development, Validation and Application of a Fast Sequential Method for Na, K, Ca and Mg Determination in Hemodialysis Solutions by HR-CS F AAS.

Hemodialysis solutions are liquid concentrates used during hemodialysis sessions. They are commonly used as a renal replacement therapy. This study aimed to develop a method to determine Na, K, Ca and Mg in hemodialysis solutions by high-resolution continuum source flame atomic absorption spectrometry (HR-CS F AAS) using Design of Experiments (DOE). The combination of the Doehlert Matrix with the desirability function was used to establish a compromise condition in the optimization of the significant variables studied: 60 L/h for acetylene flow rate, 8 mm for burner height, 0.25% (w/v) and 0.60% (w/v) for Cs and La concentrations. The method was validated by following the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines and parameters such as the selectivity, linearity, precision, accuracy and robustness were evaluated. Calibration curves with the ranges of 25-130 mg/L for Na, 1.0-5.0 mg/L for K and Ca, and 0.30-0.70 mg/L for Mg were employed. The method proved to be precise (RSD lower than 2.7%) and accurate (mean recovery data, contemplating the three levels added were: 103.0% for Na, 100.5% for K, 101.3% for Ca and 101.5% for Mg). The developed method enables the sequential multielement determination of Na, K, Ca and Mg in a single run. Requiring only one dilution step, this method significantly reduces analysis time for both sample and standard solutions preparation and measurement. This study presents the first method reported in the literature for multielement determination in hemodialysis solutions, offering an alternative approach to the current European Pharmacopeia method.

A simple and accurate method for the determination of Rh, Pd, and Pt in e-waste and spent automotive catalysts using HR-CS FAAS for assessing the value of secondary raw materials

This work presents a simple and accurate method for the fast sequential determination of Rh, Pd, and Pt in spent automotive catalysts and e-wastes using high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). Extensive research was carried out in model systems on the impact of potential interfering substances on analyte's signals measured in two types of flame (air-C2H2 and N2O–C2H2). Mutual analyte interactions were also taken into account. Different background corrections offered by the HR-CS AAS spectrometer were tested to obtain interference-free analyte signals and the best detectability. Using an air-C2H2 flame and 1 % La solution as a spectrochemical buffer provided good sensitivity and accurate determinations of Rh, Pd, and Pt using a simple calibration graph. Microwave-assisted leaching of PGE from waste samples with aqua regia at 240 °C for 60 min efficiently leached all target metals, which significantly simplified and shortened the sample preparation step. The detectability of the method (detection limit of 0.4, 0.6, and 5 mg kg−1 for Rh, Pd, and Pt, respectively) and precision (< 7 %) were satisfactory. The accuracy of the method was confirmed by analysis of certified reference materials (spent automotive catalyst (ERM-EB504), electronic scrap (BAM-M505a)), and calculated zeta score values. The recoveries for Rh, Pd, and Pt in ERM-EB504 were 93, 101, and 96 %, respectively, and for Pd in BAM-M505a, 97 %. The developed method can be used to assess the value of secondary raw materials, such as various types of spent catalysts and e-waste containing Rh, Pd, and Pt.

Validation of high-resolution continuum source flame atomic absorption spectrometry for determination of selected toxic and potential toxic metals in the decontamination process of wastewater discharged in natural receivers.

A new method based on high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS) was validated for the determination of selected toxic and potentially toxic metals in wastewater resulting from mining activity. The results were compared with inductively coupled plasma optical emission spectrometry (ICP-OES). The HR-CS-FAAS method was characterized by detection limits in the range (µg L-1) 0.9(Mn)-33.6(Pb), better than ICP-OES for Cu, Fe, Ni, Co, Pb and Mn, and poorer for Cd, Zn and Cr. The Dunnett's and Tukey's statistical test showed that both methods were not affected by significant bias against certified value and between them. The recovery in HR-CS-FAAS method was in the range of 98-103% with relative extended uncertainty of 9-25%, and precision of 1.5-14.1%. The results indicated that the HR-CS-FAAS method is suitable for the determination of toxic and potentially toxic elements directly in filtered water samples without any chemical treatment.

The Influence of Copper and Zinc on Photosynthesis and Phenolic Levels in Basil (Ocimum basilicum L.), Borage (Borago officinalis L.), Common Nettle (Urtica dioica L.) and Peppermint (Mentha piperita L.).

This work is aimed at relationships which govern zinc and copper uptake by four popular medicinal herbs: basil (Ocimum basilicum L.), borage (Borago officinalis L.), common nettle (Urtica dioica L.) and peppermint (Mentha piperita L.). They are often grown in soils with significant copper or zinc levels. Herbs were cultivated by a pot method in controlled conditions. Manganese, iron, copper and zinc concentrations were determined by High-Resolution Continuum Source Flame Atomic Absorption Spectrometry. The efficiency of photosynthesis was estimated by measuring the chlorophyll content, water use efficiency, net photosynthesis, intercellular CO2, stomatal conductance, and transpiration rate. Phenolic compounds were determined by the Folin-Ciocalteu method. Analysis of variance showed that herbs grown in soil treated with copper exhibited a lower iron content in roots, while manganese behaved in the opposite way. The only exception was borage, where a decrease in the manganese content in roots was observed. Both copper and zinc supplementations increased the total content of phenolics, while the highest increases were observed for common nettle and basil. Peppermint and borage responded less to supplementation. In the majority of samples, zinc and copper did not significantly affect the photosynthesis. Herbal extracts from common nettle and basil had unique antioxidant properties and may be good free radical scavengers.

A MWCNTs@CuAl2O4@SiO2 Nanocomposite for the Speciation of Cr(III), Cr(VI), and Total Chromium Prior to High-Resolution Continuum Source Flame Atomic Absorption Spectrometric Determination

A solid-phase microextraction (SPME) method had been applied to speciate chromium in natural and wastewater samples. MWCNTs@CuAl2O4@SiO2 nanocomposite was synthesized by sol–gel and calcination methods and then characterized using SEM, FTIR, and XRD techniques. MWCNTs@CuAl2O4@SiO2 was used to extract Cr(VI) as pyrrolidine dithiocarbamate chelates. Some analytical parameters involving pH, ligand (APDC) and adsorbent amounts, sample initial and final volume, and the effects of matrices were tested and optimized. For the oxidation of Cr(III) to Cr(VI), potassium permanganate was used, and after that, the presented method was applied to determine the total chromium levels. The calculations were carried out to obtain Cr(III) concentration by finding differences between total chromium and Cr(VI) concentrations. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 6.2 µg L−1 and 20.8 µg L−1, respectively. The proposed method was successfully applied for chromium speciation in wastewater samples.

Zn-doped MoO3 nanorods for dispersive solid phase extraction of trace Pb(II) from water and food samples

A rapid, and environmentally friendly dispersive solid phase extraction method based on Zn-doped MoO3 nanorods for efficient extraction of trace level of Pb(II) from water and food samples was established before high-resolution continuum source flame atomic absorption spectrometric detection. The sorbent characterization studies were carried out using BET, FE-SEM, XRD, and FT-IR techniques. To achieve effective phase separation and accurate analytical data, the adsorption and desorption procedures have been precisely adjusted. The presented approach demonstrated a wide working range (9.3–500 µg L−1), a relatively low detection limit (3.1 µg L−1), and very good extraction recoveries (90–104%) under optimum conditions. The matrix effect was investigated by the addition of interference ions. The presence of many different anions and cations in the environment did not lead to negative results and selectivity towards the analyte was observed. The method was validated by the analysis of certified reference materials (TMDA - 64.3 and INCT-OBTL-5). The enhancement factor has been determined as 10.9. The suggested method worked efficiently to extract and determine Pb(II) from water, tea, and oil samples.

SEQUENTIAL DETERMINATION OF Zn, Fe, Mg, Ca, Na AND K IN SYNTHETIZED BABASSU FAME BY HIGH RESOLUTION CONTINUUM SOURCE FLAME ATOMIC ABSORPTION SPECTROMETRY

In this work, babassu FAME samples were synthesized by transesterification reaction under alkaline catalysis with sodium glyceroxide and by two steps process with KOH followed by H2SO4 as catalysts. A sequential multi-element method for determination of Zn, Fe, Mg, Ca, Na and K in synthesized babassu FAME by high resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was developed. The proposed method is based on a microemulsion formation by mixing the babassu FAME samples with 1-propanol and aqueous phase. The mass proportion of the added components was evaluated through a ternary diagram. External and matrix-matching calibration techniques with inorganic and organic standard were investigated. In the five-level spike-recovery test, satisfactory results were obtained by performing the matrix-matching calibration along with inorganic standard solutions. By using the optimized conditions, limits of detection in the range of 0.002-0.12 mg kg-1 were obtained. Accuracy was attested by the agreement of the results obtained in the analysis of three certified reference materials. By applying the microemulsion system and HR-CS FAAS, the sequential determination of six elements was achieved. Therefore, the proposed method was a suitable alternative for metal determination in babassu FAME samples, with good sensitivities, accuracy, and a wide linear working range.

Alleviation of Aluminum-Induced Oxidative Stress, Trace Element, and Mineral Levels in Rat Tissues Protective Role of Pomegranate Juice (Punica Granatum L.).

The present investigation examined the impact of pomegranate (Punica granatum L.) juice on trace elements, minerals, and oxidative stress in relation to the potential harm inflicted by aluminum chloride (AlCl3) in rats. Rats were split into four groups at random for this purpose: control (C), pomegranate juice (PJ), aluminum chloride (A), and PJ + A. For 30days, PJ was orally administered by gavage at a rate of 4mL/kg every other day, whereas AlCl3 was administered intraperitoneally at 8.3mg/kg. Spectrophotometric analysis was used to measure the levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) enzyme activity in various tissues. In addition, high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was used to determine the amounts of the elements Al, Cu, Fe, Mn, Zn, Ca, and Mg in the tissues. It was discovered that when PJ therapy was applied to all tissues, the antioxidant enzymes SOD and CAT activity increased, the GSH level rose, and the MDA level, a sign of lipid peroxidation, decreased. Al and Ca levels increased in the A group relative to the C group in all tissues, whereas they decreased in the A + PJ group relative to the A group. Group A exhibited a proportionate increase in Fe levels in the liver and renal tissues compared with group C. Furthermore, the A group's brain tissue had a higher Fe level than the C group's. The A + PJ group's brain tissue had a lower Fe level than the A group's. Our findings demonstrate that PJ therapy greatly decreased Al buildup and oxidative stress in tissues while controlling variations in trace element levels. In addition, it is concluded that PJ might have value as a strong chelating agent to prevent Al poisoning.

Utilization of Extraction Procedures for Evaluating Environmental Risk from Waste Materials.

Several procedures for extracting content from different waste materials types were investigated, with the aim of evaluating their environmental impact. The waste materials consisted of wastes from bauxite ore processing by means of the Bayer process (red mud, Ajka, Hungary), bauxite ore using the sintering process followed by the Bayer process (brown-red mud, Žiar nad Hronom, Banská Bystrica region, Slovakia) and sulphide ores (metal-rich post-flotation tailing, Lintich, Slovakia). The extraction procedures were carried out with the aim of isolating "mobilizable" fractions using 0.05 M ethylenediaminetetraacetic acid (EDTA) and 0.43 M acetic acid (AA) (representing environmental risk during changes in normal environmental conditions) and "maximum potentially mobilizable" fractions using 2 M HNO3 (representing the total environmental risk). The content of chosen toxic heavy metals (THMs) (Cd, Cr, Cu, Pb, Ni, Zn) and Fe, Mn as metals creating Fe/Mn oxides in the extracts and solutions after microwave digestion was determined using high-resolution continuum source flame atomic absorption spectrometry (HR CS FAAS). On the basis of the results obtained in this study, it is possible to state that different origin of waste materials is reflected in different mobility of toxic heavy metals into the surrounding environment. From the point of view of toxic heavy metals mobility, disposal site of wastes after bauxite processing are much less of a threat to the environment than disposal site of flotation sludge after processing sulphide ores. The single extraction of 0.43 M AA is more effective than the extraction of 0.05 M EDTA for the purposes of determining the content of metals in the mobilizable fraction of tailing waste materials. The mobility of the studied toxic heavy metals in the Lintich tailing decreases in the direction from the lagoon to the dam, which may indicate the fact that the dam serves to a certain extent to inhibit the mobility of metals into the surrounding ecosystem.

Assessment of some element content and potential health risks in infant formulas available in Turkish markets

Accurately determining the composition of essential and toxic elements in commercial infant formulas is critical to ensuring safe nutrition for infants. In this study, the concentrations of essential and toxic elements (Pb, Ni, Cd, Al, Cr, Cu, Fe, Mn, Zn, Co) in infant formulas were determined using high-resolution continuum-source flame atomic absorption spectrometry (HR-CS FAAS) and have been evaluated for health risk. The measured values for concentrations from lowest to highest were (in mg/kg): 36.38–77.45 (Zn), 6.28–12.88 (Al), 2.37–4.91 (Cu), 22.01–51.64 (Fe), and 0.55–2.06 (Mn). The highest concentrations of Ni and Cd were 0.18 and 0.09 mg/kg, respectively, while the lowest concentrations for these metals were below the detection limit. The Cr, Co and Pb levels were below the detection limits in all samples. According to the risk assessment conducted for infants aged 0–24 months, which involved calculating the estimated daily intake (EDI), the estimated weekly intake (EWI), the target hazard quotient (THQ), and the hazard index (HI), it was found that the THQ values range from 0.00 to 0.06 for Ni, from 0.00 to 0.69 for Cd, and from 0.17 to 0.22 for Al. However, since the HI for all age groups is less than 1, it can be concluded that there is no health concern for the elements Ni, Cr, Cd, Pb, Al, and Co.

Closed-Vessel Conductively Heated Digestion of Dry Dog Food for Spectrometric Determination of Essential Nutrients

The closed-vessel conductively heated digestion system (CHDS) was evaluated to digest dry dog foods for further determination of K, Na, Cu, Fe, Mn, and Zn by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). The CHDS method was optimized using a fractional factorial design with five variables (HNO3 concentration, H2O2 volume, temperature, holding time, and pre-digestion time) at two levels. The accuracy of the CHDS procedure was checked by the analysis of reference materials from the National Institute of Standards and Technology (NIST SRM 1577b Bovine Liver and 2976 Mussel Tissue) and Brazilian Agricultural Research Corporation (Embrapa MR-E1002A Fish Food). Also, the digestion efficiencies were calculated from residual carbon contents (RCCs). The RCC and blank values in the CHDS digested samples were consistently low, which is suitable for determinations using ICP OES and ICP-MS techniques. For comparison, all samples were also digested by microwave-assisted digestion in closed vessels (MW-AD). Results for Na, K, Cu, Fe, Mn, and Zn determined in sample digests obtained by CHDS were not statistically different at a 95% confidence level from those observed for MW-AD. Limits of quantification (LOQ) calculated from digests in CHDS and MW-AD were comparable, and the values provided adequate limits for elemental determinations in dog foods. Data from mineral composition and moisture were employed in a clustering analysis (HCA) and the discrimination of the samples among different manufacturers and food for dogs at different life stages was possible.

Magnetic Adsorbent Decorated with Poly(N-Isopropylacrylamide) (PNIPAM) Brushes for the Vortex-Assisted Solid Phase Extraction (VASPE) of Lead in Water, Cigarettes and Soil with High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS) Detection

Here is reported the synthesis of a magnetic phosphorus-containing adsorbent decorated with poly(N-isopropylacrylamide) (PNIPAM) brushes via surface-initiated atom transfer radical polymerization (SI-ATRP) and its application for vortex assisted solid phase extraction of lead in water, cigarettes and soil. The adsorbent was characterized using Fourier-transform infrared spectroscopy (FT-IR) and energy dispersive x-ray (EDX) spectroscopy. A high-resolution continuum source flame atomic absorption spectrometer (HR-CS FAAS) was used for the quantification of lead. All factors affecting the extraction efficiency including the solution pH, adsorbent dose, sample volume, vortex time, and elution protocols were optimized. The limits of detection (LOD) and quantification (LOQ) were determined to be 0.05 µg L−1 and 0.18 µg L−1, respectively. The preconcentration and enhancement factors were 20 and 18. Validation was performed using TMDA 64.3 fortified water and INCT-OBTL-5 tobacco leaves certified reference materials with satisfactory recoveries. The method was shown to be sensitive, efficient and reproducible.

The principle of pooled calibrations delivers full correspondence between uncertainties of measurements of Na, Mg and Ni when determined using HR-CS FAAS

Methods for determination of elements in various types of samples are generally considered to be very precise and highly accurate. For reliable analysis of elements Na, Mg and Ni in food samples is it worthwhile to perform an extensive method validation of high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) according to the principle of pooled calibrations (PoPC). Under routine laboratory conditions of analysis, elevated levels of relative uncertainty of measurement reaching values of more than 50% were detected, which jeopardized the validity of results, even when the measurements in the present study were performed with samples of tap water and borehole water. Comparison of relative uncertainties with corresponding literature results indicates that sample-signal differences may be due to detector noise rather than specimen variations.

Closed-Vessel Conductively Heated Digestion System for the Elemental Analysis of Agricultural Materials by High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS)

Novel applications of the closed-vessel conductively heated digestion system (CHDS) are proposed to digest biomass, biochar, oyster shell flour, bone meal and swine manure for the determination of Ca, K, Mg, Na, Cu, Fe, Mn, and Zn by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). The performance of the digestion method using 14 and 7 mol L−1 HNO3 was checked by analyzing soil, rock, and plant certified reference materials (CRMs). For comparative purposes, all samples were analyzed after microwave-assisted digestion (MW-AD). Results obtained for most analytes by the closed-vessel conductively heated digestion system (CHDS) were in agreement with certified values and those attained by the comparative digestion method. The use of 7 mol L−1 HNO3 furnished lower blanks for most analytes and was effective to prepare challenging samples as biomass, biochar, shell and bone meal, swine manure, plants, soil, phosphate rock, and may be a good alternative for elemental determinations using most analytical techniques that rely on solution-based sample introduction systems. The detection limits (dry basis, mg kg−1) for Ca, Cu, Fe, K, Mg, Mn, Na, and Zn were 3, 0.4, 4, 4, 0.7, 0.4, 3, and 2, respectively. The mean relative standard deviations were close to 4.9% for closed-vessel conductively heated digestion (CHDS) and 5.9% for microwave-assisted digestion (MW-AD).

Magnetic solid‐phase extraction of nickel(II) as the 2‐(5‐bromo‐2‐pyridilazo)‐5‐(diethylamino)phenol chelate on magnetite@methacrylic ester copolymer prior to high‐resolution–continuum source flame atomic absorption spectrometric detection

A Fe3O4@ Diaion HP‐2MG resin was used for separation-preconcentration and determination of trace Ni(II) as the 2‐(5‐bromo‐2‐pyridilazo)‐5‐(diethylamino)phenol (PADAP) chelate. Nickel determination was performed by high‐resolution–continuum source flame atomic absorption spectrometry (HR-CS FAAS). Among the parameters affecting the recoveries of Ni(II) on the Fe3O4@ Diaion HP-2MG, the pH, resin mass, and sample volume were optimized. The influence of matrix ions upon the analyte recovery was evaluated and the tolerance limit was determined for common ions. The Fe3O4@ Diaion HP-2MG resin was used 15 times without any degradation in performance. The limit of detection, the limit of quantification, and preconcentration factor were 15.0 µg L−1, 49.0 µg L−1, and 100 respectively. The accuracy of the developed method was validated by the analyzing certified reference materials (NIST 1573a tomato leaves and TMDA-64.3 fortified water). The developed procedure was applied to natural water and food samples.

Ti3AlC2 max phase- graphene oxide (GO) nanocomposite for selective solid phase microextraction of palladium in environmental samples and medical appliances prior to its detection with high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS)

Palladium is an important metal as it has a wide range of applications in different fields but can cause cancer in human beings. Therefore, precise quantification of palladium is important. For this purpose, new material Ti3AlC2 max phase having unique properties like high stability, thermal conductivity and environmental friendly has been synthesized. To increase its surface area of Ti3AlC2 max phase, graphene oxide (GO) has been incorporated to form Ti3AlC2 max phase GO nanocomposite. Ti3AlC2 max phase GO nanocomposite was used as solid phase extracting material for microextraction and preconcentration of Pd(II) in environmental samples and medical appliances. Characterization of the adsorbent was achieved by using fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) and surface area analyzer (SAA). All the parameters that influence the extraction efficiency of the adsorbent like solution pH, amount of adsorbent, volume of sample, vortex time, desorption condition and interferences effect were determined and optimized. The limit of detection (0.327 µg/L) and limit of quantification (1.09 µg/L) show that the method is highly sensitive. The relative standard deviation was calculated as 5.48 % for five repeated measurements, which shows that the developed method is reproducible. The method is highly efficient with large values of preconcentration factor (20) and enhancement factors (20). The method was validated by applying the method to real water samples, soil samples and medical appliances with satisfied recovery results (94–106 %).

Ag modified ZnO nanoflowers for the dispersive micro-solid-phase extraction of lead(II) from food and water samples prior to its detection with high-resolution continuum source flame atomic absorption spectrometry

Ag modified ZnO nanoflowers were synthesized by using hydrothermal method and used as dispersive micro-solid phase extractant for separation and preconcentration prior to its flame atomic absorption spectrometric detection. The Ag modified ZnO nanoflowers has been characterized by FT-IR, XRD, FESEM, EDX and BET. The factors effecting extraction efficiency like pH, Adsorbent dose, sample volume, eluent concentration, eluent volume was optimized. Matrix effects were also studied. The limit of detection and preconcentration factor (PF) were calculated as 8.52 μg L−1, and 100, respectively. The presented dispersive micro-solid phase extraction technique was validated using GBW07424 (GSS-10) soil and GBW07425 (GSS-11) soil certificated reference materials (CRMs) with satisfactory recovery results. The presented dispersive micro-solid-phase extraction (d-μSPE) procedure was successfully applied to food and water samples.

Metal decorated silica-based core-shell magnetic nanocomposite for the solid-phase microextraction of cadmium(II) with determination by high-resolution continuum source flame atomic absorption spectrometry

The present study describes a facile and environmentally friendly hydrothermal method for the fabrication of metal decorated silica-based core-shell magnetic nanocomposite M@Si-MNCs, applied as a sustainable coating material for the solid-phase microextraction of toxic cadmium ions. M@Si-MNCs were characterized by scanning electron microscopy, X-ray-diffraction, Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller analyzer. Relevant parameters have been studied to obtain maximum recovery, including pH, adsorbent dosage, model solution volume, - adsorption and desorption time, and matrix effects. The developed method obtained excellent linearity from 50 to 500 µg/L with a limit of detection of 1.2 µg/L and a limit of quantification of 4.1 µg/L. The new method was applied for separation, preconcentration and determination of cadmium in environmental and tobacco samples.

Fabrication and characterization of MgCo2O4 for solid phase extraction of Pb(II) from environmental samples and its detection with high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS)

Magnesium cobaltite (MgCo2O4) nanosorbent was prepared by hydrothermal synthesis method. It has been characterized by various techniques such as FTIR, XRD and SEM. Enrichment and separation of Pb(II) by using MgCo2O4 on solid phase extraction was investigated. The effects of parameters such as pH of the solutions, amount of adsorbent, vortex time, sample volume, eluent concentration and matrix ions were investigated for optimum recovery of analyte ions. The enrichment factor was 125. The limit of detection (LOD) and limit of quantification (LOQ) under optimal conditions for Pb(II) were determined as 0.39 µg L-1 and 1.30 µg L-1, respectively. The validity of the developed SPE method was obtained by the analysis of certified reference material TMDA-64.3 and IC-INCT-OBTL-5 (Oriental Basma Tobacco Leaves), and when the obtained results were compared with the certified values, acceptable values ​​were obtained. The SPE method under optimized parameters conditions was applied to determination of lead(II) in water and food samples.

Spectrophotometric Determination of Fe(II) and Fe(III) Using 5-(4-Ethylphenyl azo ) 2-Hydroxybenzaldehyde Oxime Reagent

Spectrophotometric Determination of Fe(II) and Fe(III) Using 5-(4-Ethylphenyl azo ) 2-Hydroxybenzaldehyde Oxime Reagent