Performance of ion chromatography in the determination of anions and cations in various natural waters with elevated mineralization

The performance of ion chromatography in the determination of anions and cations in natural mineral waters of different composition and different total mineralization was evaluated. Up to 12 ions of the 20 usually included in extended chemical analysis of natural waters were successfully determined by ion chromatography alone. At least 98.60% and up to 99.96% of total cation composition of mineral waters was determined by ion chromatography. Hydrogen carbonate predominated in anion composition of mineral waters and was determined titrimetrically. The percentage of anions determined by ion chromatography in the remaining anion composition of mineral waters was between 98.90% and 99.96%. The agreement between total concentrations of anions and cations in individual mineral waters determined predominantly by ion chromatography is very good and the performance of ion chromatography for the basic and for the extended chemical analysis of highly mineralized water samples is very high. Method development was assisted by previously developed algorithms and appropriate experimental conditions are also discussed.     

Direct determination of molybdenum in mineral waters by atomic absorption spectrometry with electrothermal atomization

A new method for the direct determination of molybdenum by ETA-AAS in mineral waters without prior separation or concentration is proposed. With careful control of the graphite furnace conditions selective volatilization of the salt matrix is successfully attained. The possible spectroscopic interference due to common metals as well as the reproducibility, precision and repeatability of the method has been studied and the molybdenum content of 21 mineral waters measured.     

Identification of mineral waters using impedance spectroscopy and projection to latent structures

A method is proposed for the rapid identification of mineral waters by impedance spectroscopy combined with chemometric experimental data processing by projection to latent structures. Measurement conditions are optimized and performance characteristics are estimated. Possibilities of the extraction of qualitative and quantitative information on the concentrations of metal ions and anions in water, determination of the nature of mineral waters, degree of mineralization, and conformity to standard samples are shown.     

“Electronic tongue” integrated sensor system based on an array of ion-selective field-effect transistors for multicomponent analysis of liquid media

Results obtained with an “electronic tongue” device based on an array of ion-selective field transistors integrated into a flow-injection system are presented. The component concentrations in mineral waters from Spanish manufacturers are analyzed. Processing of analytical signals by the partial least squares method improves the accuracy of component determination in mineral waters of close compositions. A single chip integrates sensors sensitive to pH, K⁺, Na⁺, Ca²⁺, and Cl⁻ ions. Mineral waters are classified and the concentrations of the main components are calculated with an error not exceeding 10%.     

Rubidium Determination In Mineral and Thermal Waters By Atomic-Absorption Spectrometry

Abstract

A new procedure for rubidium determination in mineral and thermal waters using flame atomic-absorption spectrometry is described. to supress ionisation interference potassium solution was added. Rubidium can be determined in presence of Ca, Mg, Sr, Li, Cs, Fe, Al, CO² ₃, F^? and S^2? at higher levels that levels of these elements in waters. the precision and accuracy of the method were also investigated. In 163 mineral and thermal waters analysed, the rubidium concentration range is between 0.08 to 0.84 μg mL^?1.     

Using a Smartphone in the Identification and Classification of Natural Mineral Waters by Color Measurements of Indicator Papers

Journal of Analytical Chemistry - A test device based on cellulose paper is proposed for the identification and classification of natural mineral waters. It contains indicator zones for determining...     

The quantification of sodium in mineral waters using a quartz crystal microbalance

A sensor for sodium based on a piezoelectric quartz crystal is proposed. The quartz crystal was coated with 5% of bis[(12-crown-4)methyl] dodecylmethylmalonate, 33% of PVC and 62% of NPOE to which KTpClPB in a 22% molar proportion to the ionophore was added. Coating amounts producing a frequency decrease around 18 kHz show optimum linear calibration ranges for the analysis of sodium in commercial mineral waters. Besides sensitivity, coating stability and selectivity of the sensor over other cations were adequate for those analyses. The results obtained analysing commercial mineral waters by the proposed method are not significantly different (α=0.05) from the ones obtained by atomic spectrometry.     

The determination of trace metals in mineral waters : Part I. Atomic Absorption Spectrometric Determination of Cd,Co, Cr,Cu, Ni and Pb by Electrothermal Atomization After Concentration by Co-precipitation

Procedures based on flameless atomic absorption spectrometry are described for the determination of Cd, Co, Cr, Cu, Ni and Pb in mineral waters. Because of matrix effects and the inadequate detection limits for direct determinations, the metals are separated from the macrocomponents by precipitation of their tetramethylenedithiocarbamates with iron(III) as collector, or by co-precipitation on Fe(OH)₃. The detection limits are 0.005, 0.3, 0.08. 0.10, 2 and 0.10 μg l^- for Cd, Co, Cr, Cu, Ni and Pb, respectively, and are satisfactory for the determination of these elements in mineral waters. The precision is 2–7%.     

Determination of beryllium trace contents in mineral waters after preconcentration on a chelating ion-exchanger

Summary A separation-preconcentration procedure for the determination of Be traces in mineral waters is described. The precision and the accuracy of the procedure were checked by the use of artificial as well as of real samples by AAS-ETA and AES-ICP. On the basis of the results and of their statistical evaluation, the proposed procedure allows to obtain reliable results with the necessary limit of determination and can provide important, till now not accessible information on Be-concentration in waters.     

Hydrolytic potentiometric titration of sulphate with application in the analysis of waters

Sulphate is precipitated with barium ion, and excess of barium is precipitated with chromate, excess of which immediately hydrolyses at the end-point to give a sharp jump in pH, measured with a glass electrode. A 1:1 methanol/water medium is optimal. Application to waters requires pretreatment with a cation-exchange resin. River, potable and mineral waters containing 20–2000 mg l^?1 sulpate were analysed accurately with relative standard deviations of 1–2%.     

Application of capillary electrophoresis to the analysis of inorganic ions in environmental samples

A comprehensive review is presented of the state-of-the-art of capillary electrophoresis for application to the analysis of inorganic species, mainly ions, in environmental samples. This brief review covers the developments principally in sensitivity and matrix interference for the determination of inorganic ions in the following samples: drinking, mineral, surface, and ground waters, rainwater, snow, seawater, brine and waste waters, aerosol, and others. References published mainly from 1995 to 1997 were summarized in this review.     

Anreicherung von Spuren Seltener Erden aus Mineralwässern durch Ionenaustausch

In the described analysis of mineral waters, after the throughflow of the sample through a column with Dowex 50 WX 12 in H⁺ form, the main cations are first eluted by 1.6 N HCl and then the rare earths by 6 N HCl. The latter are separated by ion-exchange chromatography on Dowex 50WX8 in NH₄ ⁺ form, the elution being performed with ammonium citrate pH 4.19. The presence of rare earths in the eluate was ascertained spectrophotometrically by means of their reaction with xylenol orange in the presence of cetylpyridinium bromide. In mineral waters from the West-Bohemian spa region it was possible to find traces of trivalent La, Ce, Pr, Nd, Sm + Gd, Y, Dy, Ho, Er, Tm, Yb and Lu.     

Determination of inorganic ions in mineral water by gradient elution moving boundary electrophoresis

A sensitive method was developed for the determination of the major inorganic ions in commercial mineral waters using gradient elution moving boundary electrophoresis with capacitively coupled contactless conductivity detection. This application was the first to demonstrate the separation of cations and anions simultaneously using gradient elution moving boundary electrophoresis. Seven ionic analytes (calcium, chloride, magnesium, nitrate, potassium, sodium, and sulfate) were separated in less than 7 min with detection values in the low μmol/L to sub-μmol/L range. Calculated values of the major ions in three commercial mineral waters were compared to reported values with good correlation. In another application, phosphate and arsenate were separated in less than 2 min with limits of detection of 300 and 140 nmol/L, respectively. For all standard analyses, the RSD for migration times and peak areas were under 3%.     

Determination of Copper in Mineral Waters from Galicia, Spain, by Flame Atomic Absorption Spectrometry Using Preconcentration with Diethyldithiocarbamate Loaded on Silica Gel

Solid phase extraction using sodium diethyldithiocarbamate (DDC) loaded on silica gel has been used for preconcentration of trace amounts of copper from commercial mineral waters prior to its determination by flame atomic absorption spectrometry. The sorption and releasing of copper have been studied under both static and dynamic conditions. A short shaking time is required for quantitative sorption using the batch method, and a high flow-rate (6 ml min⁻¹) can be used in the column method due to the fast sorption and desorption kinetics. The copper concentration found in several mineral waters from Galicia (Spain) ranged from 8.4 to 23.8 μg L⁻¹. There were no significant differences between the solid-phase extraction method and the conventional solvent extraction method which uses DDC as chelating agent.     

Contribution of Biosorption to the Behavior of Radionuclides in the Environment

The biosorption capacities for cesium, technetium, uranium and nickel was determined. Various microbial strains, pH and mineral composition of medium (clay and concrete waters) were tested. For the cesium a column experiment with a biofilm was realised.     

Automatic Potentiometric Analysis of Sodium in River and Mineral Waters

Abstract

An automatic method involving an Auto analyzer system for the direct potentiometric determination of sodium in river and mineral waters is presented. The accuracy and reproducibility of the system proved to be excellent.     

Dissolved inorganic carbon effect in the determination of arsenic and chromium in mineral waters by inductively coupled plasma-mass spectrometry

The analysis of some Italian mineral waters by ICP-MS has revealed errors in the determination of As and Cr in natural effervescent or carbonated waters due to the presence of dissolved inorganic carbon (DIC). This leads to overestimate As and Cr in 1% (v/v) HNO₃ acidified samples, analysed within 1-2 h after the acidification. The overestimation of As concentration is caused by matrix interferences producing a signal enhancement due to the presence of dissolved inorganic carbon. This effect is analogous to that observed in the presence of organic carbon and occurs at millimolar DIC levels. The overestimation of Cr concentration is due to the ⁴⁰Ar¹²C⁺ species interfering with ⁵²Cr⁺ despite the use of the octopole reaction system. The optimization of the He flow in the collision cell can solve the latter problem, but the required increase in the flow rate decreases the sensitivity of the ICP-MS technique. The observed effects in CO₂ rich mineral waters and artificial NaHCO₃ solutions suggest that 5-10 mM DIC levels may affect the determination of As and Cr concentration in thermal waters, rivers, lakes and groundwaters.     

Solid phase spectrophotometric determination of silver using dithizone immobilized in a polymethacrylate matrix

Interaction of silver with Dithizone immobilized in a polymethacrylate matrix was studied. A simple procedure was proposed for the solid phase spectrophotometric determination of silver; the detection limit is 0.01 mg/L. The procedure was used for the analysis of mineral waters and the Protargol medication.     

Determination of Se(IV) and Se(VI) in Italian mineral waters

This paper deals with determination of selenium and analysis of its speciation in some Italian mineral waters. Selenium was determined by differential pulse cathodic stripping voltammetry (DPCSV) even if square wave cathodic stripping voltammetry (SWCSV) was also taken into consideration. The selenium determined in the mineral waters here investigated is not over 600 ng L(-1); in three samples, it was found below the detection limit. Analysis of speciation revealed that Se(VI) is the highly prevailing form present: only two of the examined samples revealed a detectable amount (few ng L(-1)) of Se(IV). DPCSV made possible to detect, in two of the samples, the presence of a specie(s) able to interact with Se(IV). The apparent interaction constant for the adduct formation was evaluated and the species concentration determined. However, the nature of such compound(s) remains unknown.     

Photocatalytic reversible amination of α-keto acids on a ZnS surface: implications for the prebiotic metabolism

We report the enzyme-like reversible amination of four intermediates pertinent to the reductive tricarboxylic acid cycle on a photo-irradiated surface of mineral sphalerite (ZnS). Given its prevalence in the waters of early Earth, we suggest that the mineral-based photochemistry might have catalyzed the homeostasis of prebiotic metabolic systems.