Ion Chromatographic Procedure Research Articles

Single-step chromatographic isolation of lithium from whole-rock carbonate and clay for isotopic analysis with multi-collector ICP-mass spectrometry

An ion chromatographic procedure allows isolation of lithium from carbonate and clay material prior to isotope ratio determination with MC-ICP-MS.

Optimization of capillary isotachophoretic method for determination of major macroelements in blue honeysuckle berries (Lonicera caerulea L.) and related products.

A reliable and repeatable isotachophoretic method for the simultaneous determination of K(+), Na(+), Ca(2+), Mg(2+), and ammonium in berries of different blue honeysuckle cultivars was developed. The usefulness of the complex-forming equilibria in determining the cations mentioned above was studied. The addition of 7.5 mM 18-crown-6 and 2 mM α-hydroxyisobutyric acid to sulfuric acid enhanced the separation capacity of the leading electrolyte. The terminating electrolyte of 10 mM TRIS buffered to pH 4.30 was chosen as most appropriate for these studies. An ultrasound-assisted procedure for the extraction of macroelements from dried fruit of Lonicera caerulea L. was investigated using response surface methodology. The Box-Behnken experimental design showed the optimal extraction conditions as follows: temperature of 36 °C, extraction time of 42.3 min and solid-to-liquid ratio of 1:800 v/w. Detection limits for the method ranged from 0.030 to 0.097 mg/l with precision expressed by RSD ranging from 1.4 % for Mg to 4.4 % for Na. The results showed that blue honeysuckle berries are a good source of potassium, from 199 to 402 mg/100 g FW, especially 'Zielona' and 'Zojka' cultivars. The average content of other analytes in these berries was 5.2 mg Na, 24.8 mg Ca, 7.5 mg Mg and 52.0 mg ammonium per 100 g FW. The berry products contained lower amounts of minerals especially Mg and K. However, a glass of freshly squeezed juice can provide almost 20 % of the RDI of potassium. The results obtained using both the developed isotachophoretic method and ion chromatographic procedure did not differ significantly.

Synthesis, characterization and evaluation of nanocrystalline anatase titania for the degradation of dibutyl phosphate

Degradation of dibutyl phosphate (DBP) in aqueous solution was successfully demonstrated in this paper using nanoparticles of anatase titania. Nanocrystalline anatase titania employed for the degradation study was synthesized in house by solgel route under stirring mode using titanium ethoxide precursor. The catalyst was characterized using XRD, DRS, BET, TEM, TG–DTA and Raman spectroscopy to establish the catalytic activity and surface morphology. A cylindrical photoreactor was used for the photocatalytic experiments. 10 mg of nano anatase titania and 0.5 mL of 30 % H2O2 were used as catalysts for the degradation of 1,000 mL of 240 mg/L DBP. Ion chromatographic procedure was used for following the DBP degradation. More than 95 % of DBP degradation could be in less than 45 min and the kinetics of DBP was found to follow pseudo first order. It was demonstrated that the photocatalytic efficiency of the synthesized titania was better than P-25 titania.

Determination of bromide in canine plasma using ion chromatography

A new ion chromatographic procedure has been developed and validated for the determination of bromide in canine plasma. Following a simple dilution, samples were separated on a Metrosep A Supp 5 column. The mobile phase was an isocratic mixture of 2.2 mM Na 2CO 3, 1.0 mM NaHCO 3, and 1% acetonitrile, with a flow-rate of 0.7 ml/min. The procedure produced a linear curve over the concentration range of 50–2500 μg/ml. The development of the assay permitted the determination of therapeutic levels after oral administration of potassium bromide to dogs being treated for epilepsy.

Ion chromatographic precision measurement procedure for electrolytes in human serum: validation with the aid of primary measurement procedures

In order to make analytical measurement results traceable to the SI units in the field of clinical chemistry, an ion chromatographic (IC) measurement procedure has been developed which allows the amount of substance of the four so-called electrolytes Na, K, Mg and Ca as well as that of Li to be determined efficiently in human serum and with high accuracy. The IC measurement procedure was validated using primary measurement procedures confirmed by international comparison measurements and is proposed for use as a transfer standard when comparing measurements with clinical reference laboratories. The solutions used for calibration were gravimetrically prepared from pure substances (salts). Their chemical compositions had been iteratively fitted to those of the samples. The serum samples were mineralized by microwave-assisted digestion. The following relative expanded uncertainties for the average elemental contents were obtained: Li 0.4%, Na 0.14%, K 0.6%, Mg 0.8% and Ca 0.4%.

Development and validation of an assay for citric acid/citrate and phosphate in pharmaceutical dosage forms using ion chromatography with suppressed conductivity detection

The paper describes the development and validation of a simple, rapid, accurate, and sensitive ion chromatographic procedure to assay total citrate (citric acid/citrate) and phosphate in nine dosage forms. The dosage forms chosen represent all dosage forms in USP27-NF22 for which the respective monographs require an assay for either citric acid/citrate or citric acid/citrate and phosphate. Citrate and phosphate were separated in <10 min by a hydroxide-selective column using anion-exchange chromatography with a 20 mM potassium hydroxide eluent and detected by suppressed conductivity. The method showed linear responses over the concentration ranges 0.2–100 μg ml −1 ( r 2 > 0.9990) for citrate and 0.2–60 μg ml −1 ( r 2 = 0.9999) for phosphate, with limits of quantitation (signal-to-noise (S/N) = 10) of 0.2 μg ml −1 for both analytes. The accuracy of the procedure, determined by spiked recovery measurements, was within 95–105%. The intraday and the interday precision were demonstrated by the relative standard deviations (R.S.D.) of <1 and <2%, respectively, for both analytes. The ruggedness was determined by a full factorial design using analyst, equipment, column lot, and eluent preparation procedure as variables. The results show an overall R.S.D. of <3% and that an electrolytically generated 20 mM KOH eluent produces assay results equivalent to a manually prepared 20 mM NaOH eluent.

Ion chromatographic determination of thyroxine in urine

Thyroxine (3,5,3′,5′-tetraiodo thyronine) is administered to patients suffering from endemic goiter as also in cases of non-iodine deficient ethiology and hypothyroidism. It is suggested that the uptake of thyroxine can be monitored by assessing the levels of the same in the urine of patients under treatment. For the purpose, a highly sensitive and selective ion chromatographic procedure is developed. The sample of urine is treated with sodium hydroxide and UV irradiated to convert iodine in thyroxine to iodide. Subsequently, iodide is separated on an anion exchanger AS 4A column using 50 mM NaOH as the eluent and determined spectrophotometrically at 226 nm.

Determination of trace iodide in seawater by capillary electrophoresis following transient isotachophoretic preconcentration: Comparison with ion chromatography

Usefulness of capillary electrophoresis (CE) in combination with transient isotachophoresis (tITP) as on-line preconcentration technique was examined for routine analysis of trace iodide in seawater. The combined method was based on an electrolyte system where 0.5 mol l −1 sodium chloride and 25 mmol l −1 cetyltrimethylammonium chloride at an acidic pH and 0.5 mol l −1 2-( N-morpholino)ethanesulfonate (pH 6.0) served as carrier and terminating electrolyte, respectively. Under optimized tITP-CE conditions (a carrier electrolyte pH of 2.4), the peak of 1 μg l −1 iodide in artificial seawater can be clearly detected at 226 nm, with the detection limit as low as 0.2 μg l −1. Calibration curve was linear in the range of 0–40 μg l −1 ( n=10; regression coefficient = 0.99992). Relative standard deviation values of the migration time, peak height and area of surface seawater iodide (0.6, 3.1 and 1.5%, respectively) proved an excellent run-to-run reproducibility performance of the proposed method. The method was applied to seawater samples containing sub- and low-μg l −1 levels of iodide, and the results obtained agreed well with ion chromatographic data. Detection of nitrate and nitrite was also possible in the same tITP-CE run (limits of detection 25 and 20 μg l −1, respectively, at 210 nm). The analytical characteristics of the method were discussed in comparison with an ion chromatographic procedure previously developed in authors’ laboratory.

The determination of methanesulphonic acid content of busulfan drug substance and busulfan (Myleran®) tablets by ion chromatography

A robust ion chromatographic procedure is described for the determination of the methanesulphonic acid content of busulfan drug substance and busulfan (Myleran®) 2 mg tablets. The sample was dissolved in aqueous acetonitrile, butanesulphonic acid was added as an internal standard and the solution was injected onto an ion selective column, with ion suppression and conductivity detection. The method has been fully validated and is linear over the concentration range 0.295–14.73 μg of methanesulphonic acid/ml. The method has been demonstrated to be stability indicating.

The use of nitrite ion in the chromatographic determination of large amounts of hypochlorite ion and of traces of chlorite and chlorate ions

An ion chromatographic procedure was developed for the one-run determination of ClO–, ClO2– and ClO3– present at very different concentration levels in the same sample. The method is based on the quantitative and fast reduction of HClO in slightly acidic medium by added sodium nitrite, followed by the ion chromatographic determination of ClO2–, ClO3– and the generated NO3–. The possibility of amperometric titration of the ‘free chlorine’ with a standard solution of NaNO2 was also ascertained. The performance characteristics of the analysis were defined.

Cation analysis in electronics-grade organic solvents by ion chromatography

Many organic solvents are used in the manufacture of semiconductor products, especially as components of the photoresist or as rinse solvents. Assessing the concentration of trace alkali and alkaline earth metal contaminants in these materials is important in order to control circuit defects brought about by the presence of ionic contaminants deposited on the surface during the manufacturing process. This paper describes an ion chromatographic (IC) procedure for the analysis of alkali and alkaline earth metals in the water-immiscible organic solvents methyl n-amyl ketone (2-heptanone, MAK), n-butyl acetate (NBA), and propylene glycol monomethyl ether acetate (PM acetate, PMA). The procedure consists of in-vial aqueous extraction of the organic solvent followed by on-line preconcentration of the extracted cations onto a Dionex CG-12A guard column and subsequent analysis by ion chromatography. The IC analysis uses a Dionex CS-12A column with isocratic sulfuric acid eluent at elevated temperature and rubidium cation added as internal standard. Data obtained using this method compares well with data from inductively coupled plasma MS analysis of the same materials. Reporting limits for the method are at the one part-per-billion ( w/ w) level for all cations (Li, Na, K, Ca, Mg). The method is simple to implement, automatable, and relatively free from the possibility of contamination during the analysis.

Ion-chromatographic determination of iodide in sea water with UV detection

A highly sensitive and selective ion-chromatographic procedure with UV detection at 227 nm was developed for the determination of trace amounts of iodide. The procedure utilizes 0.1M NaOH as eluent, which enables the determination of 1–100 μg I−1 I− with a precision of ca. 6%. 1000-fold amounts of other anions such as fluoride, chloride, phosphate, sulphate, bromide, nitrite and nitrate do not interfere. The method has been applied to determine iodide in sea water samples from the Indian coast.

Ion chromatographic determination of inorganic anions in vinegar samples

AbstractAn ion chromatographic procedure (IC) with chemical suppression is described for the simultaneous determination of the anions Cl−, NO, HPO and SO at ppm levels in vinegar samples. The moderately strong eluent composed of NaHCO3/Na2CO3 was chosen and sample pretreatment was required to reduce the influence of acetate on the chloride peak. The results obtained by IC were compared to those from standard methods.

Ion chromatographic determination of monosaccharides from trace amounts of glycosides isolated from grape musts

In isocratic ion chromatographic procedure for the determination of monosaccharides from the hydrolysis of trace amounts of glycosides present in grape musts is described. A laboratory-made ultramicroband electrode, tested previously with reference compounds, was used in the pulsed amperometric detection of the recovered sugars. The very low detection limits (lower than 1 mg/1) allowed the identification of xylose (not previously detected in grape musts) and apiose. The correctness of using the peak height as the measurement of the sugar concentrations also for partially overlapped peaks was checked by a deconvolution procedure based on the simplex method.

Analysis of fluid inclusion leachates from quartz by ion chromatography

20 chemical species have been detected and quantified in standard solutions using a Dionex 2000i-SP ion Chromatograph. These species are (minimum detection limits in ppb in injected sample follow each species; anions and cations listed in order of increasing retention time): F − (14), CH 3COO − (12), HCOO − (4), Cl − (6), NO − 2 (9), Br - ̊ (19), NO − 3(16), HPO 2− 4 (28), SO 2− 4 (26), C 2O 2− 4 oxalate (250), I − (20), Li + (0.5), Na +(0.7), NH + 4 (0.6), K + (1.6), Rb + (3.5), Cs + (5.9), Mg 2+ (5), Ca 2+ (15) and Sr 2+ (100). A technique has been developed to clean fluid inclusion-bearing samples and obtain fluid inclusion leachates by hand crushing ~1–2 g samples under leaching solutions in an agate mortar and then separating the leachates by vacuum filtration. High-efficiency ion removal from the crushed sample is required since gas Chromatographic H 2O analyses of sample splits have been used to calculate species concentrations in fluid inclusions. Three separate crushes using different leaching solutions are required for a complete analysis. Cleaning procedures have been established for all components involved in the crush/leach procedure, and a system blank has been obtained by crush/leach analysis of heat-treated Brazilian quartz. The contact time between the leachate and the component (i.e., agate mortar) has been established as an important control on blank levels. The technique has been applied to three samples from the Tanco granitic pegmatite: the analyses show both a ‘pegmatitic’ and a possibly external fluid component. A combined, single sample, gas and ion Chromatographic procedure has been developed to link directly the fluid inclusion volatile and leachate data.

Optimization of the procedure for the determination of alkali and alkaline-earth elements in sea water by suppressed ion chromatography

An ion chromatographic procedure is described for the determination of alkali and alkaline-earth metal ions in sea water the molar ratios of which, referred to lithium, are: 2.5 · 10 4 for sodium, 5 · 10 2 for potassium and calcium, and 3.5 · 10 3 for magnesium. Lithium, potassium, magesium and calcium are simultaneously analyzed after a 50-fold dilution, sodium is determined separately after a 2000-fold dilution. For all these elements, a dynamic range of several orders of magnitude and a R.S.D. varying from 0.2–2.2%, though typically lower than 1%, were found.

Simultaneous ion chromatographic determination of selenium and metal ions in waters at trace level

An ion-chromatographic procedure is described for the determination of selenium (VI) at μg L−1 level in the presence of anions and heavy metal ions. Maximum permissible concentrations and effects from each interfering substance were investigated for the Se concentration range 12.5–1,000 μg L−1. The method, optimized for the detection of SeO42−, gives results suitable for speciation analysis. Total selenium can be determined after complete conversion to selenate ion by oxidation with KMnO4. The detection limit of selenium is 4.8 μg L−1 (0.96 ng for 200 μL sample).

ETHYL CARBAMATE FORMATION IN GRAIN BASED SPIRITS: PART II THE IDENTIFICATION AND DETERMINATION OF CYANIDE RELATED SPECIES INVOLVED IN ETHYL CARBAMATE FORMATION IN SCOTCH GRAIN WHISKY

Ion chromatographic procedures are described for the identification and determination of a series of cyanide related precursors involved in ethyl carbamate formation in maturing grain whisky produced by the continuous distillation Coffey still process. These precursors include cyanide and copper cyanide complex anions, lactonitrile and isobutyraldehyde cyanohydrin (collectively determined as “measurable cyanide” or MC) and cyanate and thiocyanate anions. The components comprising MC may be determined individually using a pre-chromatographic separation procedure based on anion exchange resins. These techniques have been shown to be applicable for monitoring precursors involved in post-distillation ethyl carbamate formation in maturing grain whisky. Similar ion chromatographic procedures are described for the detection of a range of copper salts, incorporating cyanide, cyanate and thiocyanate, which are naturally occurring deposits within the copper Coffey still. These results are correlated with those based upon X-ray diffraction and secondary ion mass spectrometric techniques. Species identified included cuprous cyanide, cuprous thiocyanate, cuprous oxide, cuprous and cupric sulphide and copper cyanide cluster ions such as CuCN−, Cu(CN)2−, Cu2(CN)3− and Cu3(CN)4− and mixed species Cu(CN)2S−, CuSCN− and CuCNO+. In addition, an ion chromatographic procedure developed to investigate the role of carbamyl phosphate in ethyl carbamate formation, showed that conversion took place by means of its thermal decomposition into cyanate ion.

Ion chromatographic determination of plasma oxalate in healthy subjects, in patients with chronic renal failure and in cases of hyperoxaluric syndromes

An ion chromatographic procedure for the determination of plasma oxalate is proposed, in which the ultrafiltered sample is injected into an ion-chromatographic system. Sample processing appears effective in avoiding spontaneous oxalogenesis. Sensitivity (down to 1.0 μmol/1) allows determinations in normal and pathological samples; recoveries from plasma ultrafiltration are 94.6 ± 11.7%. Protein binding was investigated and precautions to improve recoveries from plasma ultrafiltation are proposed. The technique is simple to perform and rapid enough to be useful for routine purposes. Plasma oxalate concentrations from healthy controls averaged 6.75 ± 26.2 μmol/1 (mean ± S.D. n = 18); samples from patients with primary hyperoxaluria and chronic renal failure undergoing regular dialysis were also analysed and some of the data obtained are reported and discussed.

Selective and rapid ion-chromatographic determinations of alkaline earth metals and applications to the analysis of baryte

An ion-chromatographic procedure is described for the determination of Mg, Ca and Sr in the presence of an excess of Ba in baryte samples after a soda-potash digestion. The procedure is performed by coupling a strong acid exchanger (based on silica gel) and a post-column derivatisation using PAR-Zn-EDTA reagent and photometric detection at 495 nm. Further optimizations resulted in a mobile phase consisting of a citrate-oxalate-ethylendiamine solution. Details of the optimization procedures and the results of some baryte analyses are presented. The concentrations of Mg, Ca and Sr ranged between 0.01 and 2%. These results were verified using two reference methods (AAS and complexometric titration).