Effect of topical fluoride applications on residual monomer release from resin-based restorative materials.

BACKGROUND: The effects of topical fluoride applications on the release of monomer ingredients from resin-based dental materials by immersion in various extraction solutions are unclear. The aim of this study was to determine the effect of topical fluorides (APF and NaF) on the elution of residual monomers (Bis-GMA, TEGDMA, UDMA, and HEMA) from resin-based materials. METHODS: Ninety specimens were prepared, 30 bulk-fill composite resin, 30 nanohybrid universal composite resin, and 30 polyacid-modified composite resin (compomer). These were randomly divided into three groups based on fluoride application procedures. Each specimen was kept in 75% ethanol solution, and residual monomers released from materials were analyzed using high-performance liquid chromatography (HPLC) after 10 min, 1 h, 24 h, and 30 days. The groups were compared using the Mann Whitney U and Kruskal Wallis tests. Measurements were analyzed using the Friedman and Wilcoxon signed-rank tests. RESULTS: Fluoride applications generally had no considerable effect on the amount of residual monomer released from resin-based restorative materials. The amount of monomer release after topical APF application was similar to the release in the control group and was lower than the release in the NaF group. The release of monomers from the resin-based material used in the study did not approach toxic levels at the applied time intervals. The compomer released lower amounts of monomer than other resin-based materials. CONCLUSIONS: Fluoride applications do not increase monomer release from resin-based restorative materials. However, compomers should be employed by clinicians due to their lower monomer release compared to other resin restorative materials. The release of monomers from all the resin-based materials did not approach toxic levels at the applied time intervals.

Chromium speciation in environmental samples by solid- phase extraction using lewatit ionac SR-7 resin and flame atomic absorption spectrometry.

A new method for the speciation, preconcentration, and separation of Cr(lll) and Cr(VI) species in different matrixes was developed using SPE combined with flame atomic absorption spectrometry. Theprocedure is based on the exchange of Cr(VI) ions as CrO(4)(2-) with CI- ions on Lewatit lonac SR-7 ion-exchange resin. After the oxidation of Cr(lll) to CrO(4)(2-) ions by concentrated H202 in basic medium, the procedure was applied to the determination of total Cr. Cr(lll) was calculated as the difference between the total Cr and Cr(VI) contents. The influence of the analytical parameters including the pH of the solution, amount of resin, eluent type, sample volume, and flow rates of the sample and eluent solutions were investigated. No considerable interferences were observed from: other anions and cations investigated in the Cr speciation. The preconcentration factor was found to be 500. The LOD for Cr(VI), corresponding to three times the SD of the blank, was 0.003 µg/L. The sorption capacity and binding equilibrium constant were calculated as 17.2 mg/g and 2.54 L/mg, respectively. The accuracy of the method was verified by analyzing certified reference materials. The proposed method was applied to the speciation of Cr species in real samples with satisfactory results.

Determination of Arsenic(III) and Total Arsenic at Trace Levels in Baby Food Samples via a New Functionalized Magnetic Graphane Oxide Nanocomposite.

Baby food safety is an essential issue in health policy. For this reason, a simple, cheap, and fast analytical procedure to developed arsenic(III) and total arsenic determination in baby food samples using functionalized magnetic graphane oxide nanocomposite. A new nanocomposite anchored of tiopronin (TSH) magnetic graphane oxide (GO-PG4@Fe3O4-TSH) was first synthesized/characterized and used as an adsorbent to determine arsenic(III) and total arsenic for baby food samples. Arsenic(III) was directly determined on GO-PG4@Fe3O4-TSH nanocomposite at pH 4.5. The determination of total arsenic used KI and L( +) ascorbic acid solution as reducing reagents. The parameters influential on arsenic(III) determination in the baby food samples including the sample's pH, adsorption time, amount of GO-PG4@Fe3O4-TSH, eluent type, sample volume, reducing reagent type and amount, and also foreign ion effect were investigated. The GO-PG4@Fe3O4-TSH carrying As(III) could easily be separated from baby food samples via applying an external magnetic field. The detection limit for arsenic(III) was found as 0.11 µg L-1, while the limit of quantification values was computed as 0.37 µg L-1. The precision of results, expressed as relative standard deviation, was always lower than 1.6% at 1 mg L-1 As(III) levels. The accuracy of this method was confirmed by analysis of certified reference material. The method was successively applied to determine arsenic(III) and total arsenic in baby food samples.

Application of quantum dot-based biosensor to the conjunctiva in Wistar albino rats.

This study was conducted to get an idea about the distribution of the lymphatic fluid in conjunctiva throughout the body parts. For this purpose, Qdot655 (QD), fluorescence nanoparticles, spread onto the conjunctiva were used on Wistar albino rats. Drainage of QD particles from conjunctiva was followed up via fluorescence images at different hours on body parts such as eye, ears, forearms, hind legs and tails. The first fluorescence signals within the 30th minutes following administration of QD were observed in the nasal region and the anterior extremities. Whereas within 60th minutes following QD spread, fluorescent signals were obtained from the ears, forearms, hind legs and tail of the female and male rats.

Morphological analysis of aqueous humor drainage using QD nanoparticles and indocyanine green.

This study represents the first morphological description of the lymphatic drainage of the ciliary body in vivo by comparative hyperspectral fluorescence imaging techniques of Quantum Qdot655 (QD) nanoparticles and indocyanine green (ICG). A volume of 1.25 µl of QD was injected into the left anterior camera of all rats. Similarly,1.25 µl of ICG diluted at a ratio of one-fourth with physiological saline solution was injected into the right anterior camera of all rats. The thickness of the skin in the mandibular area, connective tissue, and the depth of the mandibular lymph node (MLN) made image retrieval difficult. For QD, 302 nm UV excitation and 605 nm fluorescence peak emission were applied. The detection of QD and ICG used in this study in the MLNs is definitive evidence that aqueous humor (AH) follows a uveolymphatic pathway. Scanning electron microscope and the energy dispersive X-ray analyzer spectrum were used to examine both the Schlemm's canal and the MLN. For the first time, the QD was detected in the cortex of MLN. The QCM analysis of both QD-AH and ICG-AH was used to determine whether there was any interaction between them. This comparative study shows the importance of experimental animal modeling in pharmacological studies regarding eye research and drugs. In a female rat, the signal was taken from the parotid lymph node with QD injections.

A new fluorescence reagent: Synthesis, characterization and application for speciation of arsenic (III)/(VI) species in tea samples.

A sensitive and selective fluorimetric method for the rapid determination of trace amounts of As(III)/As(V) species in certain tea samples forms the basis of the study. 3',6'-bis(diethylamino)-2-{[(1E)-(4,5-dimethyl-2-furyl)methylene]amino}spiro[isoindole-1,9'-xanthen]-3(2H)-one (DMBD), was synthesized and characterized as a new fluorescence reagent for the speciation of As(III)/As(V) species. As(III) was quantitatively recovered with fluorescence reagent at concentrations between 0.5 and 1.5 mol L-1 of HNO3, while As(V) was not quantitatively recovered at any pH. The optimum conditions for the speciation of As(III)/As(V) species were investigated on certain commonly tested experimental parameters such as acidity and pH of the sample, amount of reagent, effects of temperature, and interfering ions etc. In order to determine trace amounts of total arsenic, KI and l(+) ascorbic acid were used to reduce As(V) to the trivalent state in the sample solution prior to determination. The concentration of As(V) in the sample solution were calculated by the difference in concentration between As(III) and the total arsenic in the sample solution. The study yielded a linear function of the concentration of As(III) in the 0-5 mg L-1 range with a detection limit of 0.22 µg L-1. The relative standard deviation was found to be 0.3% for the 0.5 mg L-1 As(III) level. The proposed method was successfully applied for the determination of trace amounts of As(III) and As(V) in certain tea samples. The results of analysis of the certified reference material (INCT-TL-1 tea sample) was found to be in good agreement with the certified value.

A new turn-on fluorimetric method for the rapid speciation of Cr(III)/Cr(VI) species in tea samples with rhodamine-based fluorescent reagent.

A new fluorimetric method with rhodamine-based fluorescent agent was developed for the rapid speciation of Cr(III)/Cr(VI) in tea, soil and water samples. The system, which utilizes a fluorescent reagent, was used for the first time after synthesis/characterization of 3',6'-bis(diethylamino)-2-{[(1E)-(2,4-dimethoxyphenyl)methylene] amino}spiro[isoindole-1,9'-xanthen]-3(2H)-one (BDAS). The reagent responds instantaneously at room temperature in a 1:1 stoichiometric manner to the amount of Cr(III). The selectivity of this system for Cr(III) over other metal ions is remarkably high, and its sensitivity is below 0.01mgL-1 in aqueous solutions which enables a simplification without any pretreatment of the real sample. The method has a wide linear range of 0.1-10mgL-1 and a detection limit of 0.15µgL-1 for Cr(III) while the relative standard deviation was 0.1% for 0.1mgL-1 Cr(III) concentration. The results of detection and recovery experiments for Cr(III) in tea, soil and water were satisfactory, indicating that the method has better feasibility and application potential in the routine determination and speciation of Cr(III)/Cr(VI). The results of analysis of the certified reference material (INCT-TL-1 tea sample and CWW-TM-D waste water) are in good agreement with the certified value.

A New Turn-On Fluorometric Detection Method for the Determination of Ag(I) in Some Food and Water Samples.

A new sensitive and selective turn-on fluorometry procedure for the determination of silver using a laboratory-built fluorometry system is described herein. After synthesis and characterization, a [2-((E)-{[3',6'-bis(ethylamino)-2',7'-dimethyl-3-oxospiro[isoindole-1,9'-xanthen]-2(3H)-yl]imino}methyl)cyclopenta-2,4-dien-1-yl] (cyclopenta-2,4-dien-1-yl)iron (DKMS) fluorescent reagent was used for the first time. Ag(I) was complexed with the new fluorescent reagent, and direct measurements were made using fluorometry without any separation/preconcentration. The fluorescence intensity of the Ag(I)-DKMS complex remained unchanged for over 18 h at room temperature and was a linear function of the concentration of Ag(I) in the 0-2.5 mg/L range. The optimum determination conditions were established by testing different reagent quantities, the acidity and pH of the sample, and the effect of temperature and interfering ions. The LOD of the method was 1.00 µg/L whereas the RSD was 0.1% for 0.1 mg/L Ag(I) concentration. "The developed method was applied successfully for the Ag(I) determination of silver in burn cream, anode slime, some food and water samples". Results of the analysis of Certified Reference Materials (NCS DC73349 Bush Branches and Leaves - Trace Elements, and CWW-TM-D Certified Wastewater and Trace Metals) are in good agreement with the certified values.

Synthesis, characterization and application of a new fluorescence reagent for the determination of aluminum in food samples.

A new sensitive fluorimetry method for the simple and rapid measurement of aluminum in some food samples, which used 3',6'-bis(diethylamino)-2-{[(1E)-(4-ethoxyphenyl) methylene] amino}spiro[isoindole-1,9'-xanthen]-3(2H)-one (DEMAX) for Al(III) chelation is described herein. The fluorescence intensity of the aluminum-DEMAX complex remains unaltered for over 24h at room temperature and is a linear function of the concentration of aluminum in the 0-1000mg/L range with a detection limit (LOD, defined as 3s/b) of 3.02µgL-1 and quantification limit (LOQ, defined as 10Sb/m) of 30µgL-1. The relative standard deviation (RSD) was 0.1% for a 1µgL-1 aluminum level. The influences of the analytical parameters such as pH, waiting time of aluminum-DEMAX complex, amount of reagent, effect of temperature etc. were investigated. The developed method was successfully used for assaying aluminum in some food samples and dialysis solution, measured by the new home-made fluorimetric system. The results of analysis of the certified reference material (INCT-TL-1) are in good agreement with the certified value.

A New Chelating Reagent: Its Synthesis/Characterization and Application for the Determination of Cd(II) and Ni(II) in Various Food and Make-Up Product Samples by FAAS Using Simultaneous Microextraction Sampling.

A new and simple dispersive liquid-liquid simultaneous microextraction procedure was developed for the rapid separation and simultaneous extraction/preconcentration of Cd(II) and Ni(II) at ultratrace amounts. Microextraction of the analytes was carried out in the presence of 2-methyl-5-[(Z)-pyridin-4-yldiazenyl]quinolin-8-ol as the chelating reagent. Chloroform and ethanol were used as the extraction and dispersive solvents. Various parameters that influence the microextraction procedure's efficiency-such as pH, centrifugation rate and time, reagent concentration, and sampling volume on the recovery of analytes-were examined. The calibration curves were linear in the range of 0.01-1.25 and 0.075-5 mg/L with LODs of 0.25 and 0.84 µg/L, and with a preconcentration factor of 94, for Cd(II) and Ni(II), respectively. Precision was >1.0%. The accuracy of the method was confirmed by analyzing the Certified Standard Reference Material (CWW-TMD: Certified wastewater-Trace metals, wastewater). The results show that the dispersive liquid-liquid simultaneous microextraction pretreatment is a sensitive, rapid, simple, green, and safe method for the separation/preconcentration of cadmium and nickel.

Dispersive Liquid-Liquid Microextraction of Bismuth in Various Samples and Determination by Flame Atomic Absorption Spectrometry.

A dispersive liquid-liquid microextraction method for the determination of bismuth in various samples by flame atomic absorption spectrometry is described. In this method, crystal violet was used as counter positive ion for BiCl4 (-) complex ion, chloroform as extraction solvent, and ethanol as disperser solvent. The analytical parameters that may affect the extraction efficiency like acidity of sample, type and amount of extraction and disperser solvents, amount of ligand, and extraction time were studied in detail. The effect of interfering ions on the analyte recovery was also investigated. The calibration graph was linear in the range of 0.040-1.00 mg L(-1) with detection limit of 4.0 µg L(-1) (n = 13). The precision as relative standard deviation was 3% (n = 11, 0.20 mg L(-1)) and the enrichment factor was 74. The developed method was applied successfully for the determination of bismuth in various water, pharmaceutical, and cosmetic samples and the certified reference material (TMDA-64 lake water).

A new synthesis, characterization and application chelating resin for determination of some trace metals in honey samples by FAAS.

In this study, we developed a simple and rapid solid phase extraction (SPE) method for the separation/preconcentration and determination of some trace metals by flame atomic absorption spectrometry (FAAS). A new chelating resin, poly [2-(4-methoxyphenylamino)-2-oxoethyl methacrylate-co-divinylbenzene-co-2-acrylamido-2-methyl-1-propanesulfonic acid] (MPAEMA-co-DVB-co-AMPS), was synthesized and characterized. This chelating resin was used as a new adsorbent material for determination of Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Mn(II), Pb(II), and Zn(II) ions. The parameters influential on the determination of this trace metals were examined. Under the optimum conditions, the detection limits (DL) of the method for trace metals were found to be (3s) in the range of 0.9-2.2 µg L(-1) (n=21), the preconcentration factor was calculated as 200 and the relative standard deviation was obtained achieved as ⩽2% for n=11. The method was performed for the determination of trace metals in some honey samples and standard reference materials.

A new chelating reagent and application for coprecipitation of some metals in food samples by FAAS.

A new, simple and rapid coprecipitation method has been developed to separate and preconcentrate traces of Co(II), Cu(II), Fe(III), Pb(II) and Mn(II) in different samples prior to their determinations by flame atomic absorption spectrometry (FAAS). 2-[(E)-(8-hydroxy-2-methylquinolin-5-yl) diazenyl] benzoic acid (QAN) was firstly synthesized and characterized as a new chelating reagent for determination of some metals. IR spectra, (1)H-NMR spectrum and elemental analysis were evaluated for the characterization of the reagent. These metals were quantitatively recovered with Ni(II)/QAN precipitate in pH range of 8-10. Different factors such as sample volume, amount of QAN, and Ni(II) as carrier element, sample volume, and matrix effects for improving the quality of the preconcentration procedure were optimized. Under optimized experimentally established conditions, analytical detection limits were in the range of 0.03-0.83µgL(-1), while precision (RSD) was <3.5%, and enrichment factor was obtained as 100. The accuracy of the presented coprecipitation method was verified by the analysis of certified reference materials. The method was applied to the determination of the analytes in real samples such as food samples and make up products, and accuracy was found high (recoveries >95%).

Determination of some metal ions in various meat and baby food samples by atomic spectrometry.

In this paper, we report a simple and rapid solid phase extraction system for the separation/preconcentration and determination of Cd(II), Co(II), Cu(II), Fe(III), Cr(III), Pb(II), and Zn(II) ions by flame atomic absorption spectrometry (FAAS). This method is based upon the retention of metal ions on a column packed with poly[N-(3-methyl-1H-indole-1-yl)]-2-methacrylamide-co-2-acrylamido-2-methyl-1-propane sulphonic acid-co divinylbenzene] (MMAD) resin as a solid-phase extraction (SPE) sorbent at pH 8. At the optimized conditions, the limits of detection (3 s/b) between 0.12 and 1.6 µg L(-1), preconcentration factor of 100, and the relative standard deviation of ⩽1.8% were achieved (n=10). The accuracy of the method was verified by analyzing certified reference materials (CRMs) and performing recovery experiments. The developed method was successfully applied to the various natural water, meat products and baby food samples. The recoveries of analyte ions were found in added real samples and CRMs from 95% to 102%.

Synthesis, characterization and application of a new chelating resin for solid phase extraction, preconcentration and determination of trace metals in some dairy samples by flame atomic absorption spectrometry.

In this study, a simple and rapid solid phase extraction/preconcentration procedure was developed for determination of Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Mn(II), Pb(II), and Zn(II) trace metals by flame atomic absorption spectrometry (FAAS). A new chelating resin, poly(N-cyclohexylacrylamide-co-divinylbenzene-co-2-acrylamido-2-methyl-1-propanesulfonic acid) (NCA-co-DVB-co-AMPS) (hereafter CDAP) was synthesized and characterized. The influences of the analytical parameters such as pH of the sample solution, type and concentration of eluent, flow rates of the sample and eluent, volume of the sample and eluent, amount of chelating resin, and interference of ions were examined. The limit of detection (LOD) of analytes were found (3s) to be in the range of 0.65-1.90µgL(-1). Preconcentration factor (PF) of 200 and the relative standard deviation (RSD) of ⩽2% were achieved (n=11). The developed method was applied for determination of analytes in some dairy samples and certified reference materials.

A solid phase extraction procedure for the determination of Cd(II) and Pb(II) ions in food and water samples by flame atomic absorption spectrometry.

A relatively rapid, accurate and precise solid phase extraction method is presented for the determination of cadmium(II) and lead(II) in various food and water samples. Quantitation is carried out by flame atomic absorption spectrometry (FAAS). The method is based on the retention of the trace metal ions on Dowex Marathon C, a strong acid cation exchange resin. Some important parameters affecting the analytical performance of the method such as pH, flow rate and volume of the sample solution; type, concentration, volume, flow rate of the eluent; and matrix effects on the retention of the metal ions were investigated. Common coexisting ions did not interfere on the separation and determination of the analytes. The detection limits (3 σb) for Cd(II) and Pb(II) were found as 0.13 and 0.18 µg L(-1), respectively, while the limit of quantification values (10 σb) were computed as 0.43 and 0.60 µg L(-1) for the same sequence of the analytes. The precision (as relative standard deviation was lower than 4% at 5 µg L(-1) Cd(II) and 10 µg L(-1) Pb(II) levels, and the preconcentration factor was found to be 250. The accuracy of the proposed procedure was verified by analysing the certified reference materials, SPS-WW2 Batch 108 wastewater level 2 and INCT-TL-1 tea leaves, with the satisfactory results. In addition, for the accuracy of the method the recovery studies (⩾ 95%) were carried out. The method was applied to the determination of the analytes in the various natural waters (lake water, tap water, waste water with boric acid, waste water with H2SO4) and food samples (pomegranate flower, organic pear, radish leaf, lamb meat, etc.), and good results were obtained. While the food samples almost do not contain cadmium, they have included lead at low levels of 0.13-1.12 µg g(-1).

On-line solid-phase separation/preconcentration for the determination of copper in urine by flame atomic absorption spectrometry.

A new on-line separation/preconcentration system was developed for the determination of Cu(II) ions by flame atomic absorption spectrometry in urine samples. A newly synthesized chelating resin, by anchoring eriochrome blue black R reagent to Amberlite XAD-16 resin, was used as a packing material for the selective separation/preconcentration of Cu(II) ions. The influence of the parameters on the determination of Cu(II) ions such as pH of sample solution, amount of the resin, eluent type, interfering ions and flow variables was studied. The detection limit of the method was 1.0 µg L(-1) while precision was 2.3% (n=15) at 50 µg L(-1) Cu(II) level. The adsorption capacity of the resin was 217 µg g(-1) Cu(II). The accuracy of the method was proven using TMDA-64 standard lake water and synthetic urine sample. The developed method has been applied successfully to the determination of copper in urine with satisfactory results.

Resting eggs as new biosorbent for preconcentration of trace elements in various samples prior to their determination by FAAS.

In this study, the resting eggs of aquatic creatures living in freshwater (Daphnia, Cladocera, Crustacean) ecosystems were used as a novel biosorbent extractant for synchronous preconcentration of trace Cd(II), Co(II), Cu(II), Mn(II), and Ni(II) previous to measurement by flame atomic absorpiton spectrometry (FAAS). Using column procedures, optimization studies were conducted to realize the effective adsorption of the analyte ions such as the solution pH, amount of the biosorbent, volume of the sample, interfering ions, etc. A high preconcentration factor of 67 and low relative standard deflection of ≤4.1% (n=8) were obtained. The invention constrains based on the 3 s/b criterion were 2.4 for Cd(II), 41.4 for Co(II), 4.2 for Cu(II), 3.0 for Mn(II), and 9.6 µg L(-1) for Ni(II). The accuracy of the method was verified by analysis of a certified standard reference material. The used procedure was applied to the definition of the analytes in diverse environmental samples with convincing results. Consequently, the resting eggs of Daphnia can be used as a biosorbent for preconcentration and biosorption studies.

Comparison of bone tissue trace-element concentrations and mineral density in osteoporotic femoral neck fractures and osteoarthritis.

PURPOSE: This study examined the role of trace elements in osteoporosis by comparing the trace-element concentrations in bone and the radiographic bone density and bone mineral density (BMD) of patients with osteoporotic femur fractures and osteoarthritis. PATIENTS AND METHODS: The study enrolled 30 patients operated on for proximal femoral fractures after falls, and another 30 patients undergoing hip arthroplasty at the same center for hip osteoarthritis. Bone samples were obtained during the surgical procedures. The density of the bone samples was assessed using computed tomography and the Hounsfield scale. The levels of Ca(II), Mg(II), and other trace elements in the bone samples were determined using flame atomic absorption spectrometry and inductively coupled plasma mass spectrometry. In addition, BMD, Z-scores, and T-scores were measured in the unaffected hips of all patients using dual-energy X-ray absorptiometry. RESULTS: Magnesium (1,908 ± 507 versus 2,540 ± 435, P<0.05), calcium (10.4 ± 3.5 versus 13.9 ± 3.7, P<0.05), and zinc (2,342 ± 1,252 versus 3,145 ± 1,604, P<0.05) µg g(-1), levels were significantly lower in the bone samples in the fracture group. The groups did not differ in the other biochemical parameters. All dual-energy X-ray absorptiometry findings were significantly worse in the fracture group than in the osteoarthritis group. However, the groups did not differ in femoral neck density assessed radiologically using the Hounsfield scale. The following parameters were negatively correlated with age: magnesium, r=-0.436, P<0.001; calcium, r=-0.331, P=0.01; T-score, r=-0.381, P=0.003; Z-score, r=-0.267, P=0.043; and BMD, r=-0.365, P=0.004. CONCLUSION: Ca(II), Mg(II), and Zn(II) appear to play important roles in bone breakdown/synthesis. Further studies of the roles of trace elements in the etiology and treatment of osteoporosis are warranted. We found decreased bone levels of Ca, Mg, and Zn in patients with osteoporotic fractures compared to subjects with osteoarthritis.

Development of a new on-line system for the sequential speciation and determination of chromium species in various samples using a combination of chelating and ion exchange resins.

A new on-line flow injection (FI) procedure for the sequential separation, preconcentration and speciation of Cr(III)/Cr(VI) species in different matrices is described based on the combining of solid phase extraction and flame atomic absorption spectrometry (FAAS). Poly 2-(5-methylisoxazol)methacrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid-co-divinyl-benzene and Dowex 21K resins were used as chelating and ion-exchange materials for the separation/preconcentration of Cr(III) and Cr(VI) ions, respectively. Trace amounts of chromium retained on the resins were eluted sequentially with HNO3 and then introduced directly to the nebulizer-burner system of FAAS. The optimum conditions such as pH of the sample solution, amount of the resin, volume of the sample and interfering ions, which are effective on the quantitative recovery of the analytes, were investigated for sequential determination of Cr(III) and Cr(VI) ions. The preconcentration factors were found to be 48 and 30 for Cr(III) and Cr(VI), and the detection limits corresponding to three times the standard deviation of the blank (3s/b) were 0.05 and 0.3 µg L(-1), respectively. The method was verified by analyzing a certified reference material. The proposed method was applied to the determination based on the speciation of chromium in various real samples with satisfactory results.