Differentiation of Spanish brandies according to their metal content

Eleven metals, namely, aluminium, calcium, cadmium, copper, iron, lead, magnesium, manganese, potassium, sodium and zinc were determined in twenty samples of Sherry brandies and twelve samples of Penedés brandies by applying atomic spectrometry techniques. Flame atomic absorption spectrometry was used for quantitating calcium, copper, iron, magnesium, manganese and zinc; atomic emission spectrometry to determine potassium and sodium; and graphite furnace atomic absorption spectrometry to analyse aluminium, cadmium and lead. A chemometric approach was followed to study the discrimination between brandies from Sherry or Penedés according to the metal profile.     

Determination of Copper,Cadmium, Zinc And Lead In ArgeŞ River In Romania During Four Seasons By Inductively Coupled Plasma Atomic Emission Spectrometry And Anodic Stripping Voltammetry

ABSTRACT

The paper represents a continued study of selected heavy metals concentration in the Arge? River, the fifth river in length from Romania.

For the determination of metal ion concentration in Arge? river was used Atomic Absorption Spectrometry for sodium, potassium and magnesium; Direct Coupled Plasma Atomic Emission Spectrometry for calcium; Inductively Coupled Plasma Atomic Emission Spectrometry for copper, cadmium, zinc, aluminium, lead, titanium, zirconium, chromium, molybdenum, manganese, iron and nickel.

Copper, cadmium, zinc and lead concentration were determined by ICP–AES and ASV and results were reliable.

By comparison of the results a good agreement between these two techniques is observed.     

The microchemical analysis of ferrous and non-ferrous alloys

Satisfactory methods are described for the determination of certain of the alloying constituents in small quantities of steels, aluminium alloys and white metals. In steels, lead is determined by using an extraction procedure with dithizone, whereas the stable colour produced by vanadium with 3 : 3' dimethylnaphthidine is used for determining this element. In aluminium alloys, absorptiometric procedures are recommended for determining copper, nickel, iron and manganese. The determination of silicon is advocated by the absorptiometric technique. For the determination of antimony, in white metals, a micro volumetric procedure with standard potassium bromate is recommended using α-naphthaflavone as indicator.     

Trace metal studies of selected white wines: an alternative approach

A number of white wines from vineyards outside the metropolitan region of Melbourne were analyzed for the trace metals copper, iron, potassium, sodium, magnesium and calcium by atomic absorption spectrometry (AAS). The 24 wines analyzed included Chardonnay, Sauvignon Blanc, Riesling, Gewürztraminer and Pinot Gris. In addition, preliminary transmission near infrared (NIR) spectrometric analyses for these metals in the above wines indicated, using both multiple linear regression (MLR) and partial least squares (PLS), that promising results may be obtained for some metals. The squared correlation coefficients (R²) and the ratios of the standard error of cross validation (SECV) and the standard deviation (S.D.) for the calibration models for potassium, sodium, magnesium and calcium were acceptable, however those for iron and copper were not. Although, only a small number of wines were used in this study, the preliminary data indicated that NIR spectrometry may provide a suitable, rapid method for analysis for some metals in white wines, and warrants a further investigation using a larger number of white wines over a wider range of locations.     

The application of thiosalts in analysis: A new scheme of qualitative analysis - Part C

1. Seveial modifications for improving the efficiency of the new scheme of qualitative analysis have been proposed. 2. It has been shown that 1N sodium sulphide is a more efficient and convenient reagent and may be substituted for concentrated ammonium sulphide. 3. If sodium carbonate is added along with sodium, sulphide, barium, strontium and calcium are precipitated completely with the sulphides and hydroxides and the division of these metals into two groups is prevented. 4. It has been shown that the tedious separation of cerium and thorium from the iron group by means of oxalic acid is unnecessary and these metals can be tested for conveniently with the metals of the iron group. 5. The division of thallium into the iron and copper groups can be avoided and the metal precipitated completely with the copper group by adding potassium iodide in the treatment with 1N hydrochloric acid. 6. Modified procedures liave been provided tor the detection of nickel, tellurium and gold.     

The analysis of copper refinery slimes

Methods are reviewed for the determination of the following constituents of copper refinery slimes: aluminium, antimony, arsenic, barium, bismuth, calcium, cobalt, copper, gold, iron, lead, magnesium, manganese, molybdenum, nickel, platinum metals, selenium, silicon, silver, sulphur, tellurium, tin and zinc.     

Determination of free and total copper and lead in wine by stripping potentiometry

Stripping potentiometry has been employed for the measurement of the labile and total copper concentrations in white wine. Conditions have been optimised for a supporting electrolyte consisting of 1.0 mol/L hydrochloric acid and 0.5 mol/L calcium chloride. Mercury(II) was found to be a more suitable oxidant than O₂ and, for the determination of the labile concentrations, this required the use of medium exchange. With lead, O₂ proved to be an efficient oxidant for the stripping step and this allowed the direct measurement in the wine without the need for medium exchange. It was observed that red wine rapidly binds added lead, demonstrating that wine has a high complexation capacity for lead. A similar complexation effect was also observed for white wine, but the degree of lead complexation was less than that for red wine. The impact of this lead complexation effect for the use of standard additions is discussed.     

A microcalorimetric study of complex formation between alkaline sodium tartrate and iron(III)

The structure of the cellulose solvent ferric sodium tartrate (FeTNa) was studied using a sensitive adiabatic calorimeter. FeTNa was found to be a typical transition metal complex in which three tartrate ligands add in a stepwise fashion to iron. The structure of FeTNa first proposed by Franke is thus confirmed. The equilibrium constant for the addition of the third tartrate ligand to iron is approximately 100, a value typical of those for other cellulose-dissolving metal complexes. There is no calorimetric evidence for addition of more than three tartrate molecules to iron. The increase in molar heats of reaction with increasing ionic strength is consistent with dilute electrolyte solution theory. Based on these data, the probable reaction between FeTNa and cellulose has been postulated.     

Titrages “thermochimiques” par formation de fluorures complexes de fer,aluminium, antimoine,etain et plomb

A thermochemical study of the titration of aluminium, iron, copper, lead, tin and antimony salts with sodium fluoride is described. The destruction of fluoride cumplexes by boric acid has been studied. The measurement apparatus consists of two thermistors and a bridge. Clear breaks were obtained for iron, aluminium, copper and lead but no separation of iron and aluminium was possible. The action of boric acid also gave clear breaks in the curves.     

Determination of iron, copper and aluminium by gas-liquid chromatography

Gas chromatography has been utilised in the analysis of two National Bureau of Standard alloys for quantitative determination of aluminium, iron and copper. In the analysis of N.B.S. 162a the relative mean errors were 3.13% for aluminium, 2.06% for iron and -1.72% for copper and for N.B.S. 164a the relative mean errors were -1.39%, -0.19% and -0.89% for aluminium, iron and copper, respectively. The procedure for analysis involves solution of the alloy, conversion of the metal ions to trifluoroacetylacetonates by solvent extraction and, finally, complete separation of the metal chelates and quantitative determination by gas chromatography using a column containing Gas Pack F coated with Tissuemat E, a polyethylene wax. Other metals present in the N.B.S. samples did not interfere with the determination of aluminium, iron and copper.     

Use of copper and gold electrodes as sensitive elements for fabrication of an electronic tongue: Discrimination of wines and whiskies

A low-cost method is proposed to classify wine and whisky samples using a disposable voltammetric electronic tongue that was fabricated using gold and copper substrates and a pattern recognition technique (Principal Component Analysis). The proposed device was successfully used to discriminate between expensive and cheap whisky samples and to detect adulteration processes using only a copper electrode. For wines, the electronic tongue was composed of copper and gold working electrodes and was able to classify three different brands of wine and to make distinctions regarding the wine type, i.e., dry red, soft red, dry white and soft white brands.     

Evaluation of humic complexes of trace metals in river water by adsorption on indium-treated XAD-2 resin and DEAE-Sephadex A-25 anion exchanger

A combined adsorption procedure for the analytical fractionation of humic/metal complexes in river water is described. It is based on an indium-loaded XAD-2 resin and a DEAE-Sephadex A-25 anion exchanger, respectively. After the separation of suspended particles, an aliquot of the water sample to be analysed is passed through an indium-loaded XAD-2 resin column to collect the metal-humic complexes. A second aliquot is directly passed through a DEAE-Sephadex A-25 anion exchanger column to collect humic complexes and other negatively charged metal species. Both column effluents are analysed by inductively coupled plasma-mass spectrometry or by graphite-furnace atomic absorption spectrometry for various trace metals (e.g., Al, Mn, Fe, Co, Ni, Cu, Zn, Sr, Ba). According to this fractionation procedure, significant amounts of iron, aluminium and copper in river water are found to be humic complexes, and less than 15% of nickel, cobalt and zinc are complexed with humic substances. Manganese, strontium and barium are hardly associated with humic substances.     

DCTA Titration of iron(III) with p-aminosalicylic acid and sodium azide as indicators

Iron(III) has been determined by DCTA titration with p-aminosalicylic acid and sodium azide as indicator at pH 1.4-3.5. The titrations are rapid, simple, accurate and reversible and as little as 0.15 mg of iron(III) can be determined in the presence of up to 100 times as much of certain ions. Cadmium, zinc, lead, copper(II), aluminium, thorium, oxalate, phosphate, fluoride and sulphide interfere. The method is utilized for determination of iron(III) in presence of copper(II) or lead and in limestone, cement and haemetite.     

Coprecipitation with lanthanum phosphate as a technique for separation and preconcentration of iron(III) and lead

The usefulness of coprecipitation with lanthanum phosphate for separation and preconcentration of some heavy metals has been investigated. Although lanthanum phosphate coprecipitates iron(III) and lead quantitatively at pH 2.3, iron(II) can barely be collected at this pH. This coprecipitation technique was applicable to the separation and preconcentration of iron(III) before inductively coupled plasma atomic-emission spectrometric (ICP-AES) determination; the recoveries of iron(III) and iron(II) from spiked water samples were 103-105% and 0.2-0.7%, respectively. The coprecipitation was also useful for separation of 20 microg lead from 100 mL of an aqueous solution that also contained 1-100 mg iron. Coprecipitation of iron was substantially suppressed by addition of ascorbic acid, which enabled recovery of 97-103% of lead added to the solution, bringing the recovery to within 1.6-5.0% of the relative standard deviations. Lanthanum phosphate can also coprecipitate cadmium and indium quantitatively, although chromium(III), cobalt, and nickel and large amounts of sodium, potassium, magnesium, and calcium are barely coprecipitated at pH approximately/= 3.     

TRIEN and TETREN as titrants in potentiometry with a silver indicator electrode

The possibility of application of triethylenetetramine (TRIEN) and tetraethylenepentamine (TETREN) in metal titrations with the silver electrode as indicator was investigated. Copper, cadmium and zinc were determined in the presence of calcium, magnesium, aluminium and iron(III) in the concentration range from 0.02 to 2mM. The errors did not exceed 1%. On a similar basis copper and iron may be successfully determined in their mixtures under carefully controlled conditions. Copper is titrated with TRIEN, and both metals with EDTA at pH 7.5-8.0 in sulphosalicylate medium. The results obtained were in good agreement with those theoretically predicted.     

Validation and evaluation of a high performance liquid chromatographic method for the determination of aluminium in wine

A new method is reported for the determination of aluminium in wine by HPLC, involving derivatisation with 8-hydroxyquinoline (oxine) in the presence of micelles resulting in the formation of a fluorescent derivative. The complex is separated on a C18 column using a mobile phase of oxine - SDS - 35% acetonitrile, in a pH 7 buffer. The method was validated in the range 0.125-2 mg/l in a synthetic wine. The method was applied to the determination of aluminium in white, rosé and red wines and results compared with those obtained by atomic absorption (GFAA). Aluminium concentrations found by HPLC in white wines were greater than those found in red wines. Further investigation using a polyphenol-enriched white wine revealed a statistically significant inverse relationship between wine polyphenol content and the aluminium concentration determined by HPLC. The method may therefore be envisaged for the determination of unbound aluminium in wine.     

A rapid complexometric scheme for analysis of iron, aluminium, calcium and magnesium in slags

A simple and rapid complexometric method has been developed for the simultaneous determination of iron, aluminium, calcium and magnesium in a single solution in slags. Phosphorous and small amounts of chromium (1.5 mg) and vanadium (1 mg) do not interfere in the titration. Titanium and manganese are suitably masked with lactic acid and tetra sodium pyrophosphate, respectively. In a suitable aliquot, iron is titrated at pH 2 with EDTA, using sulphosalicylic acid as indicator. To this solution, excess disodium 1,2-cyclohexane diamine tetra acetic acid (DCTA) is added and aluminium is titrated by titrating the excess DCTA with standard copper sulphate solution at pH 3.5, using 1-(2-pyridylazo)-2-naphthol (PAN) as an indicator. A known excess of EDTA is added, the pH is raised to 10 and calcium and magnesium are jointly titrated by titrating the excess EDTA with copper sulphate solution, using PAN indicator. The Ca-EDTA complex is demasked with ammonium oxalate at pH 5 and the released EDTA equivalent to calcium is titrated with copper sulphate solution at pH 10 with PAN indicator. Results of analysis compare favourably with certified values and values obtained by standard methods for BCS and other slags. A set of five samples can be analysed for iron, aluminium, calcium and magnesium in four hours as compared to three days by the classical conventional method.     

Preparation and properties of some salts of perfluorooctanoic acid

The sodium, potassium, lithium, caesium, barium, calcium, silver, lead and ammonium salts of perfluorooctanoic acid were prepared. Their thermal stabilities, and some spectroscopic data are reported. An attempt is made to correlate some of these measurements with the properties of the metal ions or metals concerned.     

New human hair certified reference material for methylmercury and trace elements

A new human hair certified reference material (NIES CRM No. 13) for mercury speciation and trace element analysis was prepared at the National Institute for Environmental Studies (NIES), Environmental Agency of Japan. Scalp hair from Japanese males, which is identical with the original material for the previous human hair CRM (NIES CRM No. 5), was used. Special attention was paid to reduce contamination from a grinding vessel during the preparation procedure. A newly-prepared ceramic/Teflon disc mill was used for cryogenic grinding of the hair. 1, 000 bottles (3 g each) were produced after sieving and blending of the hair powder. Certified values for total mercury and methylmercury, as well as other trace elements of toxicological and nutritional significance (antimony, cadmium, copper, lead, selenium, and zinc), were determined based on analyses from extensive collaborations. Reference values for 12 elements (aluminium, arsenic, barium, calcium, cobalt, iron, magnesium, manganese, silver, sodium, sulfur and vanadium) were also given.     

Analysis of elements in wine using near infrared spectroscopy and partial least squares regression

The use of visible (VIS) and near infrared spectroscopy (NIRS) to measure the concentration of elements in Australian wines was investigated. Both white (n=32) and red (n=94) wine samples representing a wide range of varieties and regions were analysed by inductively coupled plasma mass spectrometry (ICP-MS) for the concentrations of calcium (Ca), potassium (K), magnesium (Mg), phosphorus (P), sodium (Na), sulphur (S), iron (Fe), boron (B) and manganese (Mn). Samples were scanned in transmittance mode (1mm path length) in a monochromator instrument (400-2500nm). The spectra were pre-treated by second derivative and standard normal variate (SNV) prior to developing calibration models using partial least squares (PLS) regression method with cross-validation. The highest coefficients of determination in cross-validation (R(val)(2)) and the lowest errors of cross-validation (SECV) were obtained for Ca (0.90 and 9.80mgL(-1)), Fe (0.86 and 0.65mgL(-1)) and for K (0.89 and 147.6mgL(-1)). Intermediate R(val)(2) (<0.80) and SECV were obtained for the other minerals analysed. The results showed that some macro- and microelements present in wine might be measured by VIS-NIRS spectroscopy.