Pb In Wine Research Articles

DETERMINATION OF HEAVY METALS CONCENTRATION IN WINE USING INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY (ICP-MS)

The determination of metals in different type of wines is of high importance for the nutritional, as well as toxic effects of these elements. The main purpose of this research is to determine the concentration of Cu, Fe, Mn, Cd, Zn and Pb in wine. The analyzed samples were wine samples obtained under micro-vinification conditions and from grapevine cultivars for the white wines (Feteasca Alba, Feteasca Regala, Babeasca Gri, Sarba) and for the red wines (Merlot, Feteasca Neagră, Cabernet Sauvignon). The highest concentrations were obtained in the cultivars of grapevine for the red wines (49.86 ± 1.32 μg/L Pb) recorded by the Feteasca Neagra cultivar and (0.23 ± 0.01 μg/L Cd) for the Merlot cultivar. In the case of Cu, Zn, Fe and Mn, the highest concentrations were recorded by the vines for white wines (532.48 ± 13.79 μg/L Cu, 1845.23 ± 32.58 μg/L Zn, 1654.98 ± 26.68 μg/L Fe, 221.32 ± 17.49 μg/L Mn) in comparison to the cultivars of vines for red wines. The conclusions obtained from the analysis of heavy metals in wines through ICP-MS are as follows: grapevine cultivars for red wine recorded the highest concentrations of Cd and Pb and the grapevine cultivars for white wines recorded the highest concentrations of Cu, Zn, Fe and Mn.Wine samples do not have a metal ion concentration higher than the maximum concentration allowed by law.The storage temperature does not affect the concentration of heavy metals, dry wine has a higher concentration of heavy metals in its composition.

Classification of wines according to several factors by ICP-MS multi-element analysis

Wines from different grape varieties, geographical zones, soil types, foliar N application, SO2 addition and oak ageing were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). For this purpose, ICP-MS methodology was optimized. The elements which allowed differentiate wines from studied grape varieties were Sr, Ca, Mg and Mn. Geographical zones were classified according to Sr, Ba, Ni, and Cu. Cs and Pb were the main elements to discriminate the wines from the 3 soil types. Wines from several N foliar doses application were classified by Pb, Ni, Mn and Zn. The content of Cs, Mg, Cu and Pb in wines characterized the SO2 addition. Finally, wines storage in barrels were differentiate by Na and Cs concentration. The discriminant functions classify 100% of the wines, with the exception of grape variety (97.0%) and oak ageing (95.8%). Consequently, ICP-MS can be applied to classified wines according to viticultural and oenological factors.

Determination of Lead in Croatian Wines by Graphite Furnace Atomic Absorption Spectrometry

A method has been developed for direct determination of lead in wine by graphite furnace atomic absorption spectrometry (GFAAS) with Zeeman-effect background correction. The thermal behaviour of Pb during pyrolysis and atomisation stages was investigated without matrix modifier and in the presence of Pd(NO(3))(2), Pd(NO(3))(2) + Mg(NO(3))(2) × 6H(2)O, and NH(4)H(2)PO(4) + Mg(NO(3))(2) × 6H(2)O as matrix modifiers. A simple 1:1 dilution of wine samples with Pd(NO3)2 as a matrix modifier proved optimal for accurate determination of Pb in wine. Mean recoveries were 106 % for red and 114 % for white wine, and the detection limit was 3 μg L(-1). Within-run precision of measurements for red and white wine was 2.1 % and 1.8 %, respectively. The proposed method was applied for analysis of 23 Croatian wines. Median Pb concentrations were 33 μg L(-1), range (16 to 49) μg L(-1) in commercially available wines and 46 μg L(-1), range (14 to 559) μg L(-1) in home-made wines. There were no statistically significant differences (P<0.05) in Pb concentration between commercial and home-made wines or between red and white wines.

Direct determination of Cd, Cu and Pb in wines and grape juices by thermospray flame furnace atomic absorption spectrometry

The applicability of thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) was evaluated for direct determination of Cu, Cd and Pb in wines and grape juices. The developed procedure does not require preliminary acid digestion of the samples. The optimum conditions for determination of Cu, Cd and Pb in wines were studied and the performance was compared to those typically obtained by flame atomic absorption spectrometry (FAAS). A sample volume of 150 μL was introduced into a heated nickel tube at a flow rate of 0.54 mL min −1 and 0.14 mol L −1 HNO 3 was used as sample carrier flowing at 2.5 mL min −1 for determining all analytes. The effect of ethanol concentrations on Cu, Cd and Pb absorbance signals were studied. All determinations were carried out by adopting optimized conditions and quantification was based on the standard additions method. Limits of detection (LOD) of 12.9, 1.8 and 5.3 μg L −1 ( n = 14) for Cu, Cd and Pb, respectively, were obtained for wine samples (3 σ blank/slope, n = 14). Relative standard deviations (R.S.D., %) of 2.7, 2.1 and 2.6 for Cu, Cd and Pb, were obtained ( n = 6) for wine samples. The values determined for grape juice samples were similar to these ones. The analytical throughput was 45 determinations h −1 and accuracy was checked by addition-recovery experiments.

On the determination of lead in wine by electrothermal atomic absorption spectrometry

Abstract The parameters of analytical procedures developed for direct ETAAS determination of Pb in wine are discussed. Atomic absorption spectrometers based on transversal and longitudinal Zeeman effect, wall and integrated platform atomization with two main approaches: (i) measurements in the presence of modifier and (ii) measurements without using any modifier are compared. The optimal temperature programs are defined according to the pre-treatment and atomization curves constructed in the presence of different types of wines. For all investigated instrumental systems, 1:1 dilution of wine sample with 0.2 mol L−1 HNO3 is recommended. Matrix interferences observed, call for standard addition calibration method for Pb quantification in wines. The detection limit (3σ) achieved for wine diluted in the ratio of 1:1 varied from 0.8 to 1.9 μg L−1 depending on the instrument used. The relative standard deviation for the concentration range of 10 to 80 μg L−1 Pb in wine is typically between 4–8%. The accuracy of the analytical procedures recommended was confirmed by comparing the results obtained with those found for wine samples previously digested with HNO3-H2O2 mixture, by added/found method and by parallel analysis using different instruments. A total of 66 wine samples from different regions of Macedonia were analyzed.

Determination of lead in wine by hydride generation atomic fluorescence spectrometry in the presence of hexacyanoferrate(III)

A rapid, accurate, and precise method is described for the determination of Pb in wine using continuous-flow hydride generation atomic fluorescence spectrometry (CF-HGAFS). Sample pretreatment consists of ten-fold dilution of wine followed by direct plumbane generation in the presence of 0.1 mol L(-1) HCl and 1% m/v K(3)[Fe(CN)(6)] with 1% m/v NaBH(4) as reducing agent. An aqueous standard calibration curve is recommended for Pb quantification in wine sample. The method provides a limit of detection and a limit of quantification of 0.3 microg L(-1) and 1 microg L(-1), respectively. The relative standard deviation varies between 2-6% (within-run) and 4-11% (between-run) at 3-30 microg L(-1) Pb levels in wine. Good agreement has been demonstrated between results obtained by CF-HGAFS and direct electrothermal atomic absorption spectrometry in analyses of red and white wines within the concentration range of 9.2-25.8 microg L(-1) Pb.

The high-accuracy analysis of lead in wine by exact-matching isotope dilution mass spectrometry using ICP-MS

An isotope dilution technique was developed for the analysis of Pb in wine using an exact-matching isotope dilution mass spectrometry (IDMS) approach. A metrological approach was used to examine potential biases and ensure that this potentially primary method of analysis provided appropriate accuracy, and an expanded uncertainty at the 95% confidence level of <2% was achieved. The accuracy of this method was demonstrated in an international CCQM intercomparison (CCQM-P12) involving other national metrology institutes. The result submitted for this intercomparison was in very good agreement with results from the majority of other laboratories, all of whom used IDMS.

PIXE determination of Pb in wine

The permissible level of the Pb content in wine varies in the range of 200–300 μg/l in different countries. These values are below the detection limit for standard PIXE spectrometry. Initiated by an intercomparison action of The International Measurement Evaluation Programme (IMEP, Geel, Belgium), an attempt was made to lower the detection limit of PIXE without introducing any additional chemical steps. Wine samples of 5 ml were gradually condensed below an infrared lamp and 8 μl aliquots were taken from time to time and pipetted onto filter paper. The samples were analysed by standard PIXE technique, with the analyte addition method used for calibration. A detection limit of about 50 ppb was finally achieved. Comparing this value to the permissible levels, this simple and fast technique can be used for screening purposes. As an application, the lead content of three Hungarian market wines was also measured.

Evaluation and application of bismuth as an internal standard for the determination of lead in wines by simultaneous electrothermal atomic absorption spectrometry.

A method for the direct determination of Pb in wines by simultaneous multi-element atomic absorption spectrometry (SIMAAS) using a transversely heated graphite atomizer, Zeeman-effect background corrector and internal standardization is proposed. Bismuth was used as an internal standard and Pd(NO3)2 plus Mg(NO3)2 as chemical modifier to stabilize both the analyte and the internal standard. The implementation of two pyrolysis steps avoided any build-up of carbonaceous residues on the graphite platform. All diluted samples (1 + 1 v/v) in 0.2% v/v HNO3 and reference solutions (5.0-50 microg l(-1) Pb in 0.2% v/v HNO3) were spiked with 25 microg l(-1) Bi. For a 20 microl aliquot dispensed into the graphite tube, a good correlation (r = 0.9997) was obtained between the ratio of the analyte signal to the internal standard signal and the analyte concentration of the reference solutions. The electrothermal behaviour of Pb and Bi in red, white and rosé wines were compared. In addition, absorbance variations due to changes in experimental conditions, such as atomizer temperature, integration time, injected sample volume, radiation beam intensity, graphite tube surface, dilution and sample composition, were minimized by using Bi as internal standard. Relative standard deviations of measurements based on integrated absorbance varied from 0.1 to 3.4% and from 0.5 to 7.3% (n = 12) with and without internal standard correction, respectively. Good recoveries (91-104%) for Pb spikes were obtained. The characteristic mass was 45 pg Pb and the limit of detection based on integrated absorbance was 0.9 microg l(-1) Pb. Internal standardization increased the lifetime of the tube by 25%. Direct determinations of Pb in wines with and without internal standardization approaches were in agreement at the 95% confidence level. The repeatability and the tube lifetime were improved when using Bi as internal standard. The improvement in accuracy using an internal standard was only observed when the analytical results were affected by errors.

Determination of lead and arsenic in wines by electrothermal atomic absorption spectrometry

Methods for the determination of As and Pb in wines by electrothermal atomic absorption spectrometry (ETAAS) are proposed. For As, 8 ml of wine were diluted with 1 ml of nitric acid in a PTFE bomb, followed by heating to 150 °C for 90 min. The transparent solution obtained was diluted to 10 ml with de-ionized water. The integrated absorbances of the solutions were measured by ETAAS using 5 µg of Pd, as a chemical modifier. For Pb, the integrated absorbances were measured after diluting the wine sample, 1 + 4, with 0.2% nitric acid, using a mixture of 10 µg of Pd and 15 µg of Mg as modifier. The detection limits (k= 3) were 6.6 and 15.5 ng ml–1 for As and Pb, respectively, 20–30 times below the maximum limits proposed by the control agencies. Three wine samples were analysed and the concentrations found were below the maximum permissible concentrations. Recoveries were approximately 100%, for analytical solutions containing 10% v/v and 0.2% v/v of nitric acid, for As and Pb, respectively. No interference was observed.

Accurate determination of lead in wines by inductively coupled plasma mass spectrometry

The capability of inductively coupled plasma mass spectrometry (ICP-MS) for Pb determinations in wine samples is studied. An evaluation is made of the signal behaviour in aqueous ethanolic medium. The effect of preliminary sample preparation on signal suppression or enhancement is investigated in conjunction with the ability of internal standardization to correct for it. As a result, an accurate and precise method of analysis is described in which the sample preparation is limited to a 10-fold dilution and external calibration is applied for quantitation. A detection limit of 0.2 μg 1−1 Pb in wine is achieved. The Pb content of ten different wines was found to range around 40 μg 1−1 with extreme values of 1.63 and 58.8 μg 1−1.