Characterization and Quantification of Heavy Metals in Wine Using ICP-OES Spectrometry

Importance of the Topic

Monitoring trace metals in wine is critical to ensure food safety, regulatory compliance and consumer protection. Heavy metals such as copper and antimony can originate from vineyard treatments, winemaking processes or packaging materials. Their accurate detection and quantification support quality control, prevent off-flavors and minimize long-term health risks.

Objectives and Study Overview

This study demonstrates a rapid, sensitive and multi-element approach for measuring heavy metals in wine using inductively coupled plasma optical emission spectrometry (ICP-OES). It evaluates method performance for copper (Cu), antimony (Sb) and other relevant elements under European wine regulations. Practical aspects such as sample preparation, calibration and analysis of samples stored in different packaging types are covered.

Methodology and Instrumentation

Sample Preparation:

• Wine samples diluted 1:4 with deionized water.
• Standard solutions prepared with 3.5% ethanol to match the wine matrix.

Instrumentation Used:

• Shimadzu ICPE-9820 simultaneous ICP-OES with CCD detector.
• Vertical-mounted mini torch in dual-view mode (axial and radial observation).
• Coaxial nebulizer with a cyclonic spray chamber.

Operating Parameters:

• RF generator power: 1.2 kW.
• Cooling gas flow: 10 L/min.
• Plasma gas flow: 0.6 L/min.
• Carrier gas flow: 0.7 L/min.
• Exposure time: 15 seconds per element.

Key Results and Discussion

Copper Analysis:

• Calibration range: 250–1000 µg/L (r > 0.9998).
• Limit of detection: < 0.02 µg/L.
• Regulatory limit in wine: 2 mg/L; elevated levels can cause metallic taste and fermentation issues.

Antimony in Packaging:

• Samples from PET bottles reached Sb levels up to 20 µg/L.
• Glass-bottled vodka showed < 1 µg/L Sb.
• Migration of Sb from PET indicates a risk for alcoholic beverages stored in plastic.
• European drinking water limit for Sb: 5 µg/L.

Other Elements:

• Al, As, Cd, Pb, Sn and Zn were monitored according to maximum allowable concentrations in wine.
• Arsenic and lead determination addresses residues from historical vineyard treatments.

Practical Benefits and Applications

This ICP-OES method offers:

• High sensitivity and wide dynamic range for multi-element detection.
• Rapid throughput with minimal sample preparation.
• Compliance with European wine and food safety regulations.
• Capability to monitor packaging-related contamination.

Future Trends and Opportunities

Upcoming research directions include:

• Extending analysis to new packaging materials and film components.
• Automation and coupling with flow injection or speciation techniques.
• Method miniaturization for field or on-line monitoring.
• Investigation of additional trace elements and isotopic fingerprinting for origin authentication.

Conclusion

The optimized ICP-OES approach using the Shimadzu ICPE-9820 system provides reliable, accurate and high-throughput quantification of heavy metals in wine. It supports regulatory compliance, ensures product quality and highlights the influence of packaging on contamination levels.