Iminodiacetic Acid Ethyl Cellulose Research Articles

Solid phase chelating extraction and separation of inorganic antimony species in pharmaceutical and water samples for graphite furnace atomic absorption spectrometry

A separation procedure for antimony(III) and antimony(V) was developed with the use of chelating celluloses. Sb(III) was separately pre-concentrated on imino diacetic acid–ethyl cellulose in the acidic pH range, in which the uptake of Sb(V) was negligible in the μg L − 1 concentration range. On the other hand, both Sb species Sb(V) and Sb(III) were pre-concentrated on a chloride form of 2,2′-diaminodiethylamine-cellulose. These solid phase extraction procedures were combined with graphite furnace atomic absorption spectrometry (SPE–GFAAS) for Sb detection. Pharmaceutical compounds of organic and inorganic types (ten compounds), as well as mineral water samples (twelve types) were analyzed. Detection limits of 0.18 µg L − 1 Sb(III) and 0.25 µg L − 1 Sb(V) were found in aqueous sample solutions and water samples, respectively, considering a 25-fold pre-concentration. The total Sb, mostly in the form of Sb(V), could be determined in phosphate-containing pharmaceuticals, while in phosphoric acid, Sb(III) was the dominant form. In all other types of samples the Sb content was below the detection threshold, and therefore, the potential suitability of the SPE–GFAAS method for the determination of Sb(III) species was proven by recovery tests of spiked samples. This method ensures the required detection power with regard to the allowable Sb limits established by international organizations.

Study of interference of pharmaceuticals with complexing characteristics in solid phase microextraction of lead on chelating celluloses

Trace lead impurities of drugs in 1–5% solutions can be preconcentrated on imino diacetic acid-ethyl cellulose (IDAEC). The buffered sample was loaded onto a chelating cellulose minicolumn by flow injection followed by the nitric acid elution and graphite furnace atomic absorption spectrometry (GFAAS) determination. The detection limit of the procedure depending on the concentration of drug solution is in the range 2–10 ng g − 1 . The bonding of lead to various pharmaceutical compounds appeared in reduced rate during preconcentration according to the competition between ligands. The first step was focused on the determination of the stability constants of the lead-chelating cellulose species. In the second step, the sorption was estimated from different pharmaceutical matrices considering the lead–drug interaction. In the third experimental step estimated sorption was compared with the determined values for some medicines like aspartic acid, penicillamine, captopril, N-acetyl-cysteine and its pharmaceutical product, ACC 200.

On-site classification of manganese forms in natural waters by membrane filtration and chelating exchange

The possibility of chemical speciation of manganese was studied to explain the behavior and fate of trace metals in the aquatic environment. An operationally defined on-site preconcentration and fractionation scheme was developed that was based on the difference in the thermodynamic and kinetic behavior of manganese species. This scheme was used to distinguish between the different manganese forms in river and karstic groundwater. According to the elaborated “in field” procedure, the water sample was pressed through a membrane filter (0.22 μm) coupled to an imino diacetic acid–ethyl cellulose (IDAEC) chelating exchanger minicolumn by means of a syringe, followed by a batch enrichment. The fractions were analyzed by graphite furnace atomic absorption spectrometry. The dissolved manganese part was in the range of 0.5–1.5 μg l −1 and the on-site spike addition resulted in a satisfactory recovery. The binding behavior of manganese in different classes was characterized by means of stability constants of the Mn-IDAEC complexes.

Determination of Mo and Mn in human brain samples by different techniques

A study was undertaken to determine Mo and Mn concentrations in 5 different brain regions of 5 control and 5 Alzheimer's diseased (AD) patients. The main purpose of this work was to evaluate the performance of our analytical methods including sample preparation. Microwave-assisted digestion was used for sample dissolution. The digested samples were analyzed for Mo by ETAAS and ICP-MS. Low levels of Mo in the digested solutions (ng ml−1) preclude the direct ETAAS analysis (LOD 0.75 ng ml−1). This problem could be solved by preconcentration of Mo on an iminodiacetic acid ethyl-cellulose (IDAEC) chelating microcolumn. The optimal pH range of sorption is between 1.5 and 4. Our ICP-MS method is adequate for Mo determination in human brain samples using 98Mo for the evaluation (LOD 0.05 ng ml−1). The Mn content was determined applying ETAAS, ICP-MS, ICP-AES and NAA. The results of the different techniques were in good agreement. The techniques are compared in terms of accuracy, precision, detection limits, time and sample requirement. The accuracy of the measured data is investigated by the analysis of biological certified reference materials. The mean concentration of Mn in human brain samples is in the range 1.1–2.9 ppm, while for Mo it is between 90 and 330 ppb, for dry weight. Significantly higher values were found in the putamen and a difference in these concentrations between AD (cMo = 330 ± 42 ppb, cMn = 2.90 ± 0.07 ppm) and control patients (cMo = 219 ± 16 ppb, cMn = 2.40 ± 0.08 ppm).

On-line preconcentration and GFAAS determination of trace metals in waters

An on-line separation preconcentration system coupled to electrothermal (graphite furnace) atomic absorption spectrometry was developed. A miniature column packed with iminodiacetic acid ethyl cellulose (IDAEC) was inserted into the loop. A peristaltic pump was used to deliver solutions. A flow of air was driven into the packed column, evacuating it between sample loading, washing and elution. The retained analyte was introduced on-line to graphite furnace using countercurrent elution with HNO 3. The system was applied for the determination of V, Co and Pb in medicinal mineral water samples, and nickel in sea water samples. The detection limits (3σ) were 0.058, 0.022, 0.067, 0.062 μg/l for Co, Pb, V, and Ni, respectively. The R.S.D. ( n=5) was <5% at 0.4–1.0 μg/l concentration range.

Determination of trace elements in pharmaceutical substances by graphite furnace atomic absorption spectrometry and total reflection X-ray fluorescence after flow injection ion-exchange preconcentration

Flow injection iminodiacetic acid ethyl cellulose (IDAEC) microcolumn preconcentration and graphite furnace atomic absorption spectrometry determination of trace metals (Cd, Co, Ni, Pb) were carried out without decomposition of the drug matrix. The two forms of chromium Cr(III) and Cr(VI) were separated using IDAEC and anion exchanger diethylaminoethyl (DE)-cellulose, respectively. The detection limits of trace elements in pharmaceutical substances (sugars, sorbitol, mannitol, paracetamol, amidopyrine, chloral hydrate) after a 10-fold preconcentration in 1–5% m/v solution of pharmaceuticals were in the 0.3–29 ng g −1 range. The measured concentration of trace elements in substances investigated was below 100 ng g −1. The spike recovery was close to 100%. The capability of total reflection X-ray fluorescence technique for the determination of trace elements in pharmaceuticals with and without preconcentation was explored.

The application of flow injection iminodiacetic acid–ethylcellulose membrane preconcentration and separation technique to atomic spectrometry

A flow injection-based on-line iminodiacetic acid–ethylcellulose (IDAEC) membrane preconcentration and separation technique was developed in the present work, which has the advantages of easy operation without membrane plugging problems; a high enrichment factor (more than 10 for most elements); a high sample throughput (30 samples h −1). The characteristics of the IDAEC membrane were systematically studied, including the effect of sample flow rate and analyte concentration on breakthrough point; dynamic capacity and the lifetime of the IDAEC membrane. The technique was successfully applied to pond and seawater analysis in which all elements studied are in ng ml −1 level. The analytical performance was verified with recovery of a standard addition from seawater. Satisfactory results were obtained.

Graphite Furnace Atomic Absorption Spectrometry Determination and On-line Preconcentration of Palladium

Abstract Palladium was determined in pharmaceuticals by direct graphite furnace atomic absorption spectrometry (GFAAS) method. The detection limit was 0.1 μg/g in 5% solution; the recovery of 0.5–2.0 μg/g Pd spike was close to 100%. The flow injection GFAAS method was worked out using oxime and iminodiacetic acid ethyl cellulose (IDAEC) microcolumns for preconcentration of Pd in aqueous and 50% methanol solutions. The optimal pH range for preconcentration was 2–5. At 20-fold enrichment the detection limits for Pd were 0.39 μg/liter for oxime cellulose and 0.42 μg/liter for IDAEC.

Optimization of Flow Injection On-Line Microcolumn Preconcentration of Ultratrace Elements in Environmental Samples prior to Their Spectrochemical Determination

The preconcentration of some elements such as Cd, Co, Ni, and V(IV) was modeled in the presence of complexing agents such as citrate and oxalate at high Ca, Mg, and sulfate concentrations on iminodiacetic acid/ethyl cellulose (IDAEC), a chelating cellulose. The effect of the species present in the solution was studied after construction of the species distribution curves using critical, estimated, and measured stability constants. The stability constants of the IDAEC chelates were determined potentiometrically. The constants were calculated or estimated using computer programs. The diagrams calculated in homogeneous media were used for optimization of the flow injection on-line preconcentration for analysis of ultratrace metals in the highly mineralized water “Hunyadi.”

Determination of trace metals and speciation of chromium ions in atmospheric precipitation by ICP-AES and GFAAS

Sampling and analytical techniques used for determining trace metal concentrations in atmospheric precipitation waters collected in Hungary are presented. The results of the analyses are briefly discussed and special attention is devoted to chromium speciation. For the preconcentration of the trace metals a chelating cellulose, iminodiacetic acid ethylcellulose (IDAEC) microcolumn was used in a flow-injected system. Cd, Co, Cu, Fe, Mn, Ni, Pb, Ti, V and Zn were determined by ICP-AES. In precipitation water the concentrations of the trace elements were in the 0.1–50 μg/l. range. The two forms of chromium, Cr(III) and Cr(VI) were separated using IDAEC and the anion exchanger diethylamine ethylcellulose, respectively. Cr was determined by GFAAS. In atmospheric precipitation the concentration of Cr(III) was in the range of 0.1–0.4 μg/l. while that of Cr(VI) in the range of 0.04–0.1 μg/l.

On-line preconcentration and determination of trace elements by flow injection-inductively coupled plasma atomic emission spectrometry

A study was made of the capabilities of iminodiacetic acid/ethylcellulose (IDAEC) to serve as the chelating resin for preconcentrating trace elements together with a computer-assisted on-line flow injection analysis-inductively coupled plasma atomic emission spectrometry technique. The system was tested with a few analytes of particular clinical and environmental importance (Cd, Co, Cu and Pb) in matrices such as water, sea water and urine. The performance of IDAEC resin was compared with that of carboxymethylated polyethyleneimine-polymethylenepolyphenylene isocyanate (CPPI) and Chelex 100 with regard to enrichment factor, analytical throughput and recovery. With several obvious advantages over the batch procedure, the on-line mode improved the detection power by one to two orders of magnitude and allowed twelve samples per hour to be treated. IDAEC appears to be the most convenient resin in terms of efficiency and long-term performance.

Iminodiacetic acid/ethylcellulose as a chelating ion exchanger: Part 2. Determination of trace metals by inductively-coupled plasma atomic emission spectrometry

A chelate-forming cellulose, iminodiacetic acid/ethylcellulose (IDAEC), is applied to the collection of metals from ammonium citrate and acetate solutions. A method is devised for the i.c.p./a.e.s. determination of metal contaminants in magnesium by separation and preconcentration of the metals with IDAEC.