Lead In Wine Research Articles

Revealing full chemical forms of lead in wine with combined XRF-NMR technologies

Since 1953, The World Organization of Vine and Wine (OIV) Member States have reduced the lead maximum limits (ML) in wines, down to 0.05 mg/L (2018). Evidently, this ML value is too restrictive for wine industry as it excludes from international market a significant portion of wine production. Currently, the Codex Committee on Contaminants in Foods and OIV had recognized the value of gathering robust and novel data to better assess the best lowest ML for wine industry. Currently, there is not a direct statement within international reference documents, of which chemical form of lead must be controlled and/ or reduced. This work presents for the first time a method combining Energy Dispersive X-Ray analysis (EDAX) and Nuclear Magnetic Resonance (NMR) spectroscopies in order to determine presence and concentrations of major and trace elements of lead and other element moieties in wine that can allow to better redefine lead's ML. By identification of K, L, M, radiation shells with additional αβi labelling of lead's major and minor components with semi-quantitative XRF, combined with chemical-shift analysis of inorganic Pb4+, Pb2+ and/or organo-lead within wine samples, we propose a full discrimination framework to disentangle and quantify different chemical forms of lead.

A closed inline system for sample digestion using 70% hydrogen peroxide and UV radiation. Determination of lead in wine employing ETAAS

This paper proposes a closed inline system for decomposition of wine, aiming at the determination of lead using electrothermal atomization atomic absorption spectrometry (ETAAS). The system is built using a 0.8 mm diameter PTFE tube, which is wrapped around an 8 W UV lamp. The sample in the presence of 70% hydrogen peroxide is circulated on an 8 W UV lamp at the flow rate of 1 mL min−1 for 45 min. Under these conditions, the carbon content varied from 10% to 2% for a red wine sample before and after digestion, respectively. The system has allowed the determination of lead in wine samples using the analytical line 283.306 nm in the presence of aluminum as the chemical modifier and pyrolysis and atomization temperatures of 800 and 1800 °C, respectively. Then, lead can be quantified employing the external calibration technique with limits of detection 0.27 and quantification 0.89 µg L−1, and characteristics mass of 18 pg. The precision expressed by relative standard deviation (RSD%) was 2.13%, calculated using six replicates of a digested solution of a wine sample with the lead content of 16.35 µg L−1. For evaluation of the accuracy method, two wine samples were analyzed simultaneously by the method proposed and also by inductively coupled plasma mass spectrometry (ICP-MS). A statistical test demonstrated no significant difference between the means obtained by these two techniques. Also, experiments involving addition/recovery tests confirmed the method's accuracy. The system was employed for digestion and determination of lead in four Brazilian wine samples. The lead content varied from 2.19 to 43.48 µg L−1.

Tracing changes in atmospheric sources of lead contamination using lead isotopic compositions in Australian red wine

Air quality data detailing changes to atmospheric composition from Australia's leaded petrol consumption is spatially and temporally limited. In order to address this data gap, wine was investigated as a potential proxy for atmospheric lead conditions. Wine spanning sixty years was collected from two wine regions proximal to the South Australian capital city, Adelaide, and analysed for lead concentration and lead and strontium isotopic composition for source apportionment. Maximum wine lead concentrations (328 μg/L) occur prior to the lead-in-air monitoring in South Australia in the later 1970s. Wine lead concentrations mirror available lead-in-air measurements and show a declining trend reflecting parallel reductions in leaded petrol emissions. Lead from petrol dominated the lead in wine (206Pb/207Pb: 1.086; 208Pb/207Pb: 2.360) until the introduction of unleaded petrol, which resulted in a shift in the wine lead isotopic composition closer to vineyard soil (206Pb/207Pb: 1.137; 208Pb/207Pb: 2.421). Current mining activities or vinification processes appear to have no impact with recent wine samples containing less than 4 μg/L of lead. This study demonstrates wine can be used to chronicle changes in environmental lead emissions and is an effective proxy for atmospherically sourced depositions of lead in the absence of air quality data.

Evaluation of influence of the locality, the vintage year, wine variety and fermentation process on volume of cooper and lead in wine

We have focused on the influence evaluation of the locality, the vintage year and fermentation process on the volume of copper and lead into grape must and wine. First of all copper and lead volume was assessed into fresh grape musts. Subsequently the musts were fermented. During the wines analyses we found great decrease of copper by the fermentation process. Assessed Cu2+ values vary from 0.07 to 0.2 mg.L-1 and represent a decrease of the original copper volume from 90 to 97%. On the copper content into grape has probably the significant influence also the precipitation amount, which falling in the second part of the vegetation half a year. Total rainfall in the period before the grape harvesting (the months of August - September) was for the first year 153 mm and for second year 137,5 mm. During both observed vintage years it was concerning to the above average values. Copper is not possible to eliminate totally in the protection of the vine against fungal diseases, because against it does not come into existence resistance into a pathogen. For resolution of this problem it is suitable to combine the copper and organic products. Fermentation affect as a biological filter and influence also lead volume. Into analysed wines we found the decrease of the lead volume from 25 to 94%. Maximal assessed Pb2+ value into wine was 0.09 mg.L-1. The linear relationship between lead and copper into grape must in relationship to the lead and copper into wine was not statistically demonstrated. We found the statistically significant relationship in lead content into grape must by the influence of the vintage year, which as we supposed, it was connected with the atmospheric precipitation quantity and distribution during the vegetation. On the base of the assessed results of the lead and copper volume into wine, we state that by using of the faultless material and appropriate technological equipment during the wine production, it is possible to eliminate almost completely the problems with these heavy metals content into our wines and it is from the view of technological as well as hygienic.

Direct determination of lead in wine materials by atomic absorption spectrometry using an electrothermal atomizer with a graphite filter-insert

The operational parameters of an atomizer with a graphite filter-insert and a Pd-Mg matrix modifier are optimized for direct electrothermal atomic absorption determination of lead in some wines and associated materials. A method is proposed for eliminating interferences from mineral and organic components, as well as from nonatomic absorption, and for increasing the detection sensitivity for the element by up to a factor of two. The lower limit for determining the amount of lead in wines is 0.0025 mg/dm3. The relative standard deviation (S r) does not exceed 10%.

Final report on CCQM-K30.1: Lead in wine

The key comparison CCQM-K30.1 was organized by the Inorganic Analysis Working Group of CCQM to test the abilities of the National Metrology Institutes to measure the mass fraction of lead in wine. CMQ-Fundacion Chile acted as the coordinating laboratory. Twelve institutes registered to participate in the key comparison but only eleven submitted results. One of these agreed that its result should not be included in the key comparison reference value and another indicated after completion of the study that it had recalculated its uncertainty. The participants used different measurement methods, though the most common was isotope-dilution inductively coupled plasma mass spectrometry (ID-ICP-MS). Accounting for the achieved uncertainty, comparability of measurement results was successfully demonstrated by the majority of participating NMIs for this measurement. Participants were also asked to indicate the core capabilities required for their measurements and these are summarized in the report. This comparison may be directly used to support CMCs for lead in wine and indirectly by institutes wishing to support appropriate CMCs via the core capability route.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

An insight into the adsorption and electrochemical processes occurring during the analysis of copper and lead in wines, using an electrochemical quartz crystal nanobalance.

Copper and lead in wine were quantified by anodic stripping voltammetry (ASV), performed onto the gold electrode of a piezoelectric quartz crystal. Both current or mass changes could be used as analytical signals, without a statistical difference in the results (α=0.05). However, the plot of mass vs. potential provided an in depth understanding of the electrochemical processes and allowed studying adsorption phenomena. Copper interaction with fructose is an example of a process which was not possible to ignore by observing the mass change on the gold electrode of the piezoelectric quartz crystal.

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.

Determination of lead in wine and rum samples by flow injection-hydride generation-atomic absorption spectrometry

A method for direct determination of lead in wine and rum samples was developed, using a flow injection hydride generation system coupled to an atomic absorption spectrometer with flame-quartz atomizer (FI-HG-AAS). Lead hyride (PbH 4) was generated using potassium ferricyanide (K 3Fe(CN) 6), as oxidant and sodium tetrahydroborate (NaBH 4) as reductant. Samples were acidified to 0.40% (v/v) HCl for wine and to 0.30% (v/v) HCl for rum, which were then mixed on-line with 3% (m/v) K 3Fe(CN) 6 solution in 0.03% (v/v) HCl prior to reaction with 0.2% (m/v) alkaline NaBH 4 solution. Lead contents of a rum and two different red wine samples were determined by FI-HG-AAS agreed with those obtained by ICP-MS. The analytical figures of merit of method developed were determined. The calibration curve was linear up to 8.0 μg L −1 Pb with a regression coefficient of 0.998. The relative error was lower than 4.58%. The relative standard deviation ( n = 7) was better than 12%. A detection limit of 0.16 μg L −1 was achieved for a sample volume of 170 μL.

Final report on key comparison CCQM-K30: Determination of lead in wine

The CCQM-K30 key comparison was organized by the Inorganic Analysis Working Group (IAWG) of the CCQM to test the capabilities of national metrological institutes (NMIs) to measure the lead content of wine at the ~3 ng/g level. LGC designed and coordinated the study with the samples being prepared and distributed by Fundacion Chile. Eleven NMIs participated in the key comparison, nine of whom used isotope dilution, one used ICP-MS with external calibration and another used GF-AAS with external calibration. The two laboratories who did not use IDMS, subsequently reported technical difficulties and were therefore not used in the calculation of the KCRV. The agreement among the laboratories using IDMS was excellent as evidenced by the small values for both the equivalence statements (Di < 0.2 ng/g) and the associated uncertainties (ui < 0.3 ng/g).A pilot study (P12.1) was performed concurrently with the same sample used in CCQM-K30 by laboratories preferring to participate in the pilot study. The pilot study also included the additional analytes: iron, copper and cadmium. The results of the pilot study are reported separately.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Method development for the determination of lead in wine using electrothermal atomic absorption spectrometry comparing platform and filter furnace atomizers and different chemical modifiers

A method has been developed for the determination of lead in wine by electrothermal atomic absorption spectrometry without any sample preparation and calibration against aqueous standards, using 7.5 μg Pd as a chemical modifier. The results obtained for seven wines using the proposed method and an acid digestion procedure did not show any significant difference using a Student's t-test. Atomization in a transversally heated filter atomizer (THFA) was compared with atomization in a conventional transversally heated platform furnace. The former provided a 2.6-fold higher sensitivity, improving the characteristic mass from 34 to 12 pg and a 1.6-fold better limit of detection (0.3 μg L −1 compared to 0.5 μg L −1) for aqueous solutions using the same injection volume of 20 μL. However, the average precision, expressed as the relative standard deviation for the determination of lead in wine under routine conditions was improved from 4.6% with platform atomization to 0.6% in the THFA. The lead content found in seven arbitrarily chosen white and red wines, five from Brazil, one from Chile and one from Spain, ranged from 6 to 60 μg L −1 Pb with an average content of 11.4 μg L −1 Pb for the wines from South America.

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.

Detection of Zinc and Lead in Wine by Potentiometric Stripping on Novel Dental Amalgam Electrodes

A simple method for detection of zinc and lead in wine by use of potentiometric stripping analyses (PSA) on the dental amalgam electrode is introduced and demonstrated for 10 different wines, both red and white. The combination of PSA and the novel nontoxic electrode offers a fast and easy‐to‐use technique without matrix effects seen in, e.g., voltammetry. Concentrations of zinc in the range of approximately 2.1 × 10−6 M to 11.7 × 10−6 M (3.5% std. dev.) and lead in the range of 9.7 × 10−8 M to 2.4 × 10−7 M (3.5% std. dev.) were found in the actual wine samples. PSA measurements were verified against atomic adsorption spectroscopy analyses (AAS), and a good correlation factor was found (r 2 = 0.96). A simple speciation study was performed by measuring the amount of zinc and lead before and after the addition of acid, giving an approximate ratio between free and total amount of the metals. Estimated detection limits for zinc and lead were calculated to, respectively, 3.0 × 10−7 M and 1.5 × 10−8 M for 120 sec. of plating time.

Lead in wine: a case study on two varieties at two wineries in South Australia

Sources of lead in wine were inferred from systematic assay of grapes must and wine, during winemaking. Two Australian wineries were monitored during the 1994 vintage with respect to vinification of Riesling and Shiraz. Juice and wine samples were collected at several process stages from crushing through to bottling, and were analysed for their total lead concentration by graphite furnace atomic absorption spectrometry. Selected samples were subsequently analysed for lead isotope ratio (fingerprinting method) to infer possible sources of lead in samples. Lead concentration in fermenting must was found to vary during vinification. In particular, lead concentration increased significantly in open-top vessels, in holding bins and during pressing. Juice and wine stored in concrete or waxed wood also had a significantly higher concentration of lead compared to juice or wine stored in stainless steel. Moreover, fining with bentonite or filtering with diatomaceous earth contributed further to final lead concentration, while fermentation, both primary and secondary, removed lead Overall, wines processed via these different systems still contained only traces of lead, and generally less than 30 μg/L (30 micrograms per litre). These trace levels are of no concern to human health when such wines are consumed in moderation.

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.

Simultaneous determination of cadmium and lead in wine by electrothermal atomic absorption spectrometry

A method has been developed for the direct simultaneous determination of Cd and Pb in white and red wine by electrothermal atomic absorption spectrometry (ET-AAS) using a transversely heated graphite tube atomizer (THGA) with longitudinal Zeeman-effect background correction. The thermal behavior of both analytes during pyrolysis and atomization stages were investigated in 0.028 mol l −1 HNO 3 and in 1+1 v/v diluted wine using mixtures of Pd(NO 3) 2+Mg(NO 3) 2 and NH 4H 2PO 4+Mg(NO 3) 2 as chemical modifiers. With 5 μg Pd+3 μg Mg as the modifiers and a two-step pyrolysis (10 s at 400°C and 10 s at 600°C), the formation of carbonaceous residues inside the atomizer was avoided. For 20 μl of sample (wine+0.056 mol l −1 HNO 3, 1+1, v/v) dispensed into the graphite tube, analytical curves in the 0.10–1.0 μg l −1 Cd and 5.0–50 μg l −1 Pb ranges were established. The characteristic mass was approximately 0.6 pg for Cd and 33 pg for Pb, and the lifetime of the tube was approximately 400 firings. The limits of detection (LOD) based on integrated absorbance (0.03 μg l −1 for Cd, 0.8 μg l −1 for Pb) exceeded the requirements of Brazilian Food Regulations (decree #55871 from Health Department), which establish the maximum permissible level for Cd at 200 μg l −1 and for Pb at 500 μg l −1. The relative standard deviations ( n=12) were typically <8% for Cd and <6% for Pb. The recoveries of Cd and Pb added to wine samples varied from 88 to 107% and 93 to 103%, respectively. The accuracy of the direct determination of Cd and Pb was checked for 10 table wines by comparing the results with those obtained for digested wine using single-element ET-AAS, which were in agreement at the 95% confidence level.

On-Line Complexation/Preconcentration System for the Determination of Lead in Wine by Inductively Coupled Plasma–Atomic Emission Spectrometry with Ultrasonic Nebulization

An on-line lead preconcentration and determination system implemented with inductively coupled plasma-atomic emission spectrometry (ICP-AES) with ultrasonic nebulization (USN) in association with flow injection was studied. For the preconcentration of lead, a Pb-quinolin-8-ol complex was formed on-line at pH 6.8 and retained on Amberlite XAD-16 resin. The lead was removed from the microcolumn by countercurrent elution with nitric acid. A total enhancement factor of 225 was obtained with respect to ICP-AES with pneumatic nebulization (15.0 for USN and 15.0 for the column). The detection limit for Pb for the preconcentration of a 10 mL wine sample was 0.15 microg/L. The precision for 10 replicate determinations at a Pb level of 25 microg/L was a relative standard deviation of 2.5%, calculated from the peak heights obtained. The calibration graph obtained by using the preconcentration system for lead was linear with a correlation coefficient of 0.9995 for levels near the detection limit up to > or = 1000 microg/L. The method was successfully applied to the determination of lead in wine samples.

Lead Poisoning from Homemade Wine: A Case Study

A 66-year-old man suffered the symptoms of severe lead poisoning for 2 years before diagnosis. The man had a blood lead level (PbB) on admission to hospital of 98 microg/dL. A detailed investigation revealed that the poisoning occurred as a result of drinking a homemade red wine, for which analyses showed a lead concentration up to 14 mg/L--70 times the Australian maximum limit for lead in wine. The source of the lead was a highly corroded enamel bathtub in which grape crushings and juice were stored for a week prior to bottling. The corrosion of the enamel surface of the bathtub had resulted in pitted patches up to 1 mm in depth along the side of the bathtub. Powdering of the tub surface was evident below a level where wine had been in contact with the sides of the tub. The homemade wine had a pH of 3.8, which would have greatly contributed to the solubilization of metals from the glaze. We conducted a test in which commercial red wine of similar pH and containing &lt; 0.2 mg/L lead was placed in this tub for 7 days. Subsequent testing revealed a lead level of 310 mg/L. This high lead concentration is consistent with the surface area of enamel on the bathtub being in contact with a small liquid volume as in the case of the leaching test using commercial red wine. This case study highlights the importance of the use of food-grade materials for the preparation and storage of homemade beverages or food.