Nitric Acid In Acetone Research Articles

Al(III), Cu(II), Co(II), Pb(II), Mn(II), and Fe(III) DETERMINATIONS IN VARIOUS SAMPLES by FAAS AFTER SOLID PHASE EXTRACTION

In this study, a novel method for the preconcentration of of Al(III), Cu(II), Co(II), Pb(II), Mn(II), and Fe(III) in the form of their hematoxylin chelates using a column filled with Amberlite XAD-16 resin was proposed. Metal chelates collected on the resin were eluted by 1 mol/L nitric acid in acetone and determined by flame atomic absorption spectrometry (FAAS). The influences of some analytical parameters including pH, flow rates, sample volume, the type and concentration of eluent on the preconcentration efficiency were examined. Effects of some interfering ions on the recovery values of analytes were also investigated. While optimum pH value was 8.5 for Cu(II), Co(II), Mn(II), and Fe(III) ions, it was 6.5 for Al(III) and Pb(II) ions. Appropriate eluent for quantitative elution was 8 mL of 1 mol/L nitric acid in acetone. Sample and eluent flow rates were found to be 2 mL/min. The maximum sample volume was established by changing the sample volume from 50 mL to 2500 mL. The sample volume does not significantly affect recovery within the range of 50-2000 mL of the sample volume for the investigated metal ions. The preconcentration factor obtained was 400. Under optimized conditions, the detection limits found as concentration which is threefold of the standard deviation of the blank solution were 0.053, 0.080, 0.620, 1.310, 0.330 and 0.120 µg/L for Al(III), Cu(II), Co(II), Pb(II), Mn(II), and Fe(III) ions, respectively and the adsorption capacities for these ions were 0.47 ± 0.02, 0.81 ± 0.01, 0.66 ± 0.01, 0.58 ± 0.01, 0.91 ± 0.01, and 0.73 ± 0.02 mg/g, respectively. By using the certified reference materials, the accuracy of the method was verified. The proposed method was successfully applied to cigarette, hair, and some vegetable species.

Simultaneous extraction and preconcentration of Cu2+, Ni2+ and Zn2+ ions using Ag nanoparticle-loaded activated carbon: Response surface methodology

A solid phase extraction (SPE) procedure for the simultaneous separation and preconcentration of trace amounts of nickel (Ni2+), copper (Cu2+) and Zinc (Zn2+) ions on Ag nanoparticle-loaded activated carbon(Ag-NP-AC) sorbent modified by (2-nitrobenzylidene)-2-(2-(2-nitrophenyl)imidazolidine-1-yl) ethaneamine (NBNPIEA) was applied. The chelating agents were used as efficient accumulating agents, which permit the achievement of higher selectivity following chelation. The efficient elution of retained metal ions by 5.0mL of 2.2molL−1 nitric acid in acetone made it possible to monitor these analytes, accurately and repeatable from diluted and complicated matrices. Central composite design (CCD) under response surface methodology (RSM) was applied to investigate the individual and interaction effects of variables such as pH, amount of ligand, amount of Ag-NP-AC and the concentration of eluent on responses. At optimal conditions, the linear responses for Cu2+, Ni2+ and Zn2+ ions were found to be in the ranges of 0.01–0.16, 0.03–0.25 and 0.01–0.19mgL−1, respectively. Their corresponding detection limits were found to be 3.7, 3.3 and 3.4ngmL−1, respectively. The proposed method showed a preconcentration factor of 200, recoveries higher than 94% and reasonable relative standard deviation less than 5% with a high tolerance limit for foreign ions.

Determination of Cadmium, Nickel, Lead, and Zinc in Fish Tissue by Flame and Graphite Furnace Atomic Absorption after Extraction with Pyrrolidine Dithiocarbamate and Activated Carbon

A solid phase extraction (SPE) technique using an activated carbon column was developed for the extraction of trace levels of Cd, Ni, Pb, and Zn in aqueous solution which was obtained from the digestion of fish tissue. Ammonium pyrrolidin edithiocarbamate (APDC) was used to form metallic complexes that could be retained in a SPE column which was packed with powder activated carbon. The analytes were eluted from the column by nitric acid in acetone. The metal concentrations were determined by flame and graphite atomic absorption spectroscopy. The effects of flow rate, APDC concentration, and pH were investigated. The proposed method was validated. The method detection limits were 11.7, 13.4, 10.1, and 25.3 µg kg−1 for Cd, Ni, Pb, and Zn, respectively. The recoveries and RSDs were within the range of 81.9–101.1% and 0.6–6.0%, respectively. The method has potential merit for heavy metal determination in fish tissue.

Flame atomic absorption spectrometric (FAAS) determination of copper, iron and zinc in food samples after solid-phase extraction on Schiff base-modified duolite XAD 761

The present study involves the development of solid-phase extraction (SPE) procedure for the preconcentration of trace amounts of copper (Cu2+), iron (Fe3+) and zinc (Zn2+) ions on duolite XAD 761 modified by bis(2-hydroxyacetophenone)-2,2-dimethyl-1,3-propanediimine(BHAPDMPDI). The complexation between the metal ions and the proposed ligand was investigated potentiometrically. The metal ions retained on the sorbent were quantitatively determined via complexation with BHAPDMPDI. The complexed metal ions were efficiently eluted using 6mL of 4molL−1 nitric acid in acetone. The influences of the analytical parameters, including pH, amounts of the ligand and the solid phase, eluent conditions and sample volume, on the recoveries of the metal ions were optimized. Using the optimized parameters, the linear response of the SPE method for Cu2+, Zn2+ and Fe3+ ions were in the ranges of 0.01–0.34, 0.01–0.28 and 0.02–0.31μgmL−1, respectively, and the detection limits for Cu2+, Zn2+ and Fe3+ ions were 1.8, 1.6 and 2.4μgmL−1, respectively. The proposed method exhibits a preconcentration factor of 208 for all of the ions studied and an enhancement factor for Cu2+, Fe3+ and Zn2+ ions of 34, 28 and 38, respectively. The presented results demonstrate the successful application of the proposed method for the determination of these metal ions in some real samples with high recoveries (> 95%) and reasonable relative standard deviation (RDS <5%).

Flame atomic absorption spectrometric determination of copper, zinc and manganese after solid-phase extraction using 2,6-dichlorophenyl-3,3-bis(indolyl)methane loaded on Amberlite XAD-16

A simple and selective method for the determination of Cu2+, Zn2+ and Mn2+ ions in real samples by FAAS after solid-phase extraction was developed. The method is based on the sorption of metal ions on Amberlite XAD-16 modified by 3-((2,6-dichlorophenyl)(1H-indol-3-yl)methyl)-1H-indole (DCPIMI) at a pH of 5.0. The metal ions retained on solid phase by complexation with ligand were then eluted with 6mL of 4molL−1 nitric acid in acetone. In order to obtain a reversible uptake and elution of metal ions, the influence of flow rates of eluent and sample solution, ligand concentration and amount of surfactant and condition of elution solution was also investigated. A preconcentration factor of 225 was achieved by passing 1350mL of sample through the solid phase, while the limit of detection (LOD) of Cu2+, Zn2+ and Mn2+ ions were found to be 1.9, 1.5 and 2.6ngmL−1, respectively, and the corresponding precision at 20μgL−1 was 2.1%, 2.3%, 3.0%.

Preconcentration and separation of trace amount of copper (II) on N 1, N 2-bis(4-fluorobenzylidene)ethane-1,2-diamine loaded on Sepabeads SP70

A sensitive and simple method for the preconcentration of copper (II) ions has been reported. The method is based on the adsorption of copper ion N 1, N 2-bis(4-fluorobenzylidene)ethane-1,2-diamine loaded on Sepabeads. The sorpted copper content was eluted by 8 ml of 4 M nitric acid in acetone. The influences of the analytical parameters including pH and sample volume were investigated. The interference effects of matrix ions on the retentions of the copper (II) ions were also examined. The recovery of understudy analyte was generally higher than 95%. The method has been successfully applied to the evaluation of copper contents in some real samples including water samples, vegetable samples and milk samples.

Preconcentration and separation of trace amount of heavy metal ions on bis(2-hydroxy acetophenone)ethylendiimine loaded on activated carbon

A sensitive and simple method for simultaneous preconcentration of trace heavy metal ions in some food samples has been reported. The method is based on the adsorption of Cr 3+, Fe 3+, Cu 2+, Ni 2+, Co 2+ and Zn 2+ on bis(2-hydroxy acetophenone)ethylendiimine (BHAPED) loaded on activated carbon (AC). The adsorbed metals on activated carbon were eluted using 2 mol L −1 nitric acid in acetone. The influences of the analytical parameters including pH and sample volume were investigated. The effects of matrix ions on the recoveries of analyte ions were also investigated. The recoveries of analytes were generally higher than 94%. The method has been successfully applied for analysis of the metal contents in real samples including natural water samples.

The determination of some heavy metals in food samples by flame atomic absorption spectrometry after their separation-preconcentration on bis salicyl aldehyde, 1,3 propan diimine (BSPDI) loaded on activated carbon

A sensitive and simple method for the simultaneous preconcentration of Cr 3+, Fe 3+, Cu 2+, Ni 2+, Co 2+ and Zn 2+ in real samples has been reported. The method is based on the adsorption of analytes on bis salicyl aldehyde, 1,3 propan diimine (BSPDI) loaded on activated carbon. The adsorbed metals on modified activated carbon were eluted using 8 mL of 2 mol L −1 nitric acid in acetone or 10 mL of 4 mol L −1 HNO 3. The influences of the analytical parameters including pH and sample volume were investigated. The effects of matrix ions on the retentions of the analytes were also examined. The recoveries of analytes were generally quantitative. The method has been successfully applied for these metals content evaluation in some food samples.

A multi-element solid-phase extraction method for trace metals determination in environmental samples on Amberlite XAD-2000

A method for the preconcentration of some transition elements at trace level was proposed using a column filled with Amberlite XAD-2000 resin. Metal ions were adsorbed on XAD-2000 as their diethyldithiocarbamate chelates, then analytes retained on the resin were eluted by 1 mol L −1 nitric acid in acetone and determined by flame atomic absorption spectrometry (FAAS). The influences of some analytical parameters including pH of sample solution, ligand amount, the type, concentration and volume of elution solution, flow rates of the sample and eluent solutions, adsorption capacity of the resin and sample volume on the preconcentration efficiency have been investigated. The influences of some matrix elements were also examined. The detection limit ( N = 20, 3 sigma) for Mn(II), Fe(II), Co(II), Cu(II), Cd(II), Zn(II), Pb(II) and Ni(II) were found as 0.20, 0.35, 0.25, 0.20, 0.20, 0.15, 0.45 and 0.25 μg L −1, respectively. The validation of the procedure was carried out by analysis of certified reference materials. The proposed method was applied to natural waters and kale vegetable ( Brassica oleracea var. acephala).

Solid phase extraction method for selective determination of Pb(II) in water samples using 4-(4-methoxybenzylidenimine) thiophenole

A sensitive and selective extractive preconcentration procedure for the determination of traces of lead in water samples has been developed. An alumina-sodium dodecyl sulfate (SDS) coated modified with 4-(4-methoxybenzylidenimine) thiophenole (MBITP) was used for preconcentration and determination of Pb(II) by flame atomic absorption spectrometry. Lead was adsorbed quantitatively on modified column due to its complexation with MBITP and quantitatively eluted using 5 mL 1 mol L −1 nitric acid in acetone. The effects of parameters such as pH, amount of solid phase, amount of MBITP, flow rate, type and concentration of eluting agent were examined. The effect of interfering ions on the determination of Pb(II) was also investigated. The response of proposed method is linear in the concentration range 0.05–1.2 μg mL −1 of Pb(II). The limit of detections (3S.D. b/ m, n = 4) and relative standard deviations ( n = 11) are 1.6 ng mL −1 and 0.9%, respectively. The presented procedure was successfully applied for determination of lead content in real samples such as river, spring, waste and drinking water.

Highly Selective and Sensitive Preconcentration of Mercury Ion and Determination by Cold Vapor Atomic Absorption Spectroscopy

A simple and selective method based on a sodium dodecyl sulfate (SDS)–coated chromosorb P modified by 2‐mercaptobenzoxazole (MBO) has been developed to selectively separate and concentrate ultra trace amounts of mercury(II) ions for its highly sensitive measurement by cold vapor atomic absorption spectrometry (CVAAS). The mercury ions were adsorbed quantitatively on SDS‐coated chromosorb due to its complexation with MBO, while the retained Hg2+ ions were then stripped from the column with minimal amounts of 2 M nitric acid in acetone. The eluting solution was sent to CV‐AAS for evaluating Hg2+ ion content and results indicate that the calibration curve was linear for Hg2+ ion in the range of 0.05–85.6 ng mL−1 and 0.09–9.6 µg mL−1 of Hg2+ ions. Maximum capacity of the SDS‐coated chromosorb modified with 40 mg of the ligand was found to be 498±30 µg of mercury(II), the limit of detection was 0.01 ng mL−1, and enrichment factors were about 300, which make it suitable it for dilute solution analysis. The method was successfully applied to the determination of Hg2+ ion content in real samples.

A novel preconcentration method for determination of iron and lead using Chromosorb-103 and flame atomic absorption spectrometry

Syringe connected-minicolumn (SCM) method for the preconcentration/separation of iron and lead prior to their determination by flame atomic absorption spectrometry (FAAS) was developed. The proposed method is substituted for classical batch and column methods. The method proposed was compared with the column method with respect to easiness, rapidness, simplicity and some analytical performance criteria such as recovery, precision, accuracy and risk of contamination. A minicolumn was filled with Chromosorb-103 as a sorbent and connected with a syringe. The experimental conditions such as pH of sample, concentration and amount of eluent, flow rates of sample and eluent, concentration of 8-hydroxyquinoline (oxine) as a complexing agent were optimized. The sample solution with or without oxine was drawn into the syringe and discharged manually passing through the resin. Analytes were retained at pH ≥5 and eluted with 1 M nitric acid in acetone quantitatively. Analyte elements could be concentrated up to 200-fold. The iron and lead in river-water samples and in certified reference Bovine Liver (NIST 1577b) were quantitatively recovered with relative standard deviation lower than 10%.

Use of a Packed Minicolumn Connected to a Syringe for Determination of Trace Elements in Biological and Water Samples by Flame Atomic Absorption Spectrometry

In this study, a syringe-connected minicolumn resin was used for the separation and enrichment of cadmium, copper, nickel and zinc prior to their determination by flame atomic absorption spectrometry. The proposed technique was compared with classical batch and column techniques in terms of rapidness, simplicity, enrichment and risk of contamination. The minicolumn was filled with Chromosorb-103 resin and connected to a syringe. If the samples were treated with ammonium pyrrolidine dithiocarbamate or 8-hydroxyquinoline, the analytes were quantitatively retained at pH ≥ 2 and pH ≥ 5 on the resin, respectively. On the other hand, if no chelating agent was added, the analytes were quantitatively retained at pH ≥ 10. The analytes retained by the resin were quantitatively eluted by drawing and discharging nitric acid in acetone. The analytes in spiked river-water samples and in certified standard reference Bovine-Liver (NIST SRM 1577 b) were quantitatively (≥ 94%) recovered. The relative standard deviations for the determinations were found to be 1.0–10%.

Separation and Enrichment of Gallium(III) as 4-(2-Thiazolylazo) Resorcinol (TAR) Complex by Solid Phase Extraction on Amberlite XAD-4 Adsorption Resin

A rapid, sensitive, and facile method for enrichment and separation of trace amounts of gallium was established by using mini column filled Amberlite XAD-4. Gallium(III) as a 4-(2-thiazolylazo) resorcinol (TAR) complex is sorbed on the Amberlite XAD-4 resin and is easily eluted by using 1 M nitric acid in acetone. The determinations of gallium were performed by atomic absorption spectrometry. The influences of the analytical parameters including amounts of reagents, pH of the solutions, and type of eluent were also investigated. The influences of several ions, as interferents, were discussed. The accuracy of the method was demonstrated by recovery on spiked samples. The presented procedure was applied to the determination of gallium in reference standard sediment material (GBW 07309) and water samples with satisfactory results (recovery 95%; relative error 3%; relative standard deviation 10%).

SEPARATION AND ENRICHMENT OF CHROMIUM, COPPER, NICKEL AND LEAD IN SURFACE SEAWATER SAMPLES ON A COLUMN FILLED WITH AMBERLITE XAD-2000

A separation/enrichment procedure has been established for atomic absorption spectrometric determination of some trace metal ions by using a column filled Amberlite XAD-2000 resin. It is based on the sorption of metal ions on XAD-2000 as 1-(2-pyridylazo) 2-naphtol (PAN) chelates. Following washing of the XAD-2000 column with blank solution, metal-chelates were eluted by 1 M nitric acid in acetone and determined by flame atomic absorption spectrometry (FAAS). The influences of some analytical parameters including pH, amounts of PAN, sample volume, also effects of concomitant ions were investigated. The procedure was applied to sea water samples collected from Mersin Bay-Mediterranean Sea with satisfactory results (recoveries >95%, relative standard deviations <9%).

Preconcentration and Separation of Trace Metal Ions From Sea Water Samples by Sorption on Amberlite XAD-16 After Complexation with Sodium Diethyl Dithiocarbamate

Sorption of some trace metal ions (Fe, Ni, Cu, Zn, Cd, Co) after complexation with sodium diethyl dithiocarbamate (Na-DDTC) on Amberlite XAD-16 was investigated in the pH range 2–10. All these metals were retained from pH 3 to 6. The retained metals can be eluted with various eluting agent such as 1 M nitric acid in acetone, 3 M nitric acid in ethanol. The method was applied to trace metal ions in surface sea water samples from Mersin Bay (Mediterranean Sea), Turkey. The relative standard deviations of the determination were less than 8%.

Indirect determination of cyanide by single-column ion chromatography

The procedure was developed by modification of a pneumoamperometric method which uses the reaction of cyanide with iodine, since the final concentration of iodide is proportional to the initial concentration of cyanide. The sample is diluted so that the cyanide concentration is in the range of .5 - 10 ppm, acetate buffer is added to adjust the pH to a value between 4.5 and 6. Excess iodine is added in 95% ethanol, sample is diluted to constant volume and allowed to stand for ca 5 min. Small aliquots of sample are injected slowly into the ion chromatograph through a precolumn containing XAD-4 resin. The excess iodine is adsorbed on this precolumn. The ion chromatograph adsorbs the iodide reaction product on XAD-1 resin. The iodide is removed by elution with sodium phthalate. Retention time is ca 5 min. Contamination of the system may be prevented by the removal of the precolumn for iodine desorption using nitric acid in acetone and water. 2 figures, 3 tables.

STAINING NERVE FIBERS IN MOUNTED SECTIONS WITH ALCOHOLIC SILVER NITRATE SOLUTION

The procedures to be described have developed through experiments designed to test the effects of varying some of the many conditions involved in silver staining. The previous article 1 on staining nerve fibers in unmounted celloidin sections gave the technic from which the present method has evolved. The application of silver solutions to mounted sections with subsequent reduction of adsorbed or chemically combined silver salt is not new. Sand 2 embedded nerve tissue in paraffin after fixation in a strong solution of nitric acid in acetone and later impregnated the mounted sections. Malone 3 described a method for handling paraffin sections to produce a Cajal type of stain. Brandt and Kadanoff 4 investigated the effect of varying the time of impregnation and the concentration of the silver nitrate bath on sections from celloidin, paraffin and gelatin embedded material. They chose gelatin as best suited to the O. Schultze method. More