Total Mercury in Cork Stoppers Using Direct Mercury Analysis

This application note demonstrates the ability of the NIC MA-3000 direct mercury analyzer to analyze new cork samples with accuracy and precision, in compliance with US EPA Method 7473-Mercury in Solids and Solutions by Thermal Decomposition, Amalgamation, and Atomic Absorption Spectrophotometry.

In a 2014 study (Lopes, C.B., et al. Environ Sci Pollut Res (2014) 21: 2108), it was shown that stopper-derived cork is an effective biosorbent towards bivalent mercury at environmentally relevant concentrations and conditions. Only 25 mg/L of cork powder was able to achieve 94% of mercury removal for an initial mercury concentration of 500 µg/L. When cork is employed for remediation, it is important to quantify the absorbed mercury.

Wine corks are also recycled into other consumer products, where the mercury uptake from the wine may need to be quantified. Mercury is dangerous to both natural ecosystems and humans because it is highly toxic, especially due to its ability to damage the central nervous system. Mercury poses a particular threat to human development in utero and in early childhood. Thus, to prevent mercury poisoning, it is necessary to accurately quantify total mercury in recycled cork and cork used intentionally for mercury remediation.

Experimental Conditions

Calibration is done using certified aqueous ionic-mercury standard solution diluted to the required concentration. The least-squares regression method is used to create and complete the calibration curve.

Analysis was performed using the NIC MA-3000 dedicated direct mercury analyzer that selectively measures total mercury by thermal decomposition, gold amalgamation and cold vapor atomic absorption spectroscopy. The MA-3000 analyzer measures mercury in virtually any sample matrix-solid, liquid, and gas-and offers quick results without time-consuming or elaborate sample preparation processes.

Rice flour (1568a) measured after all cork samples for reliability assurance.

Results

Rice flour (NIST 1568a): Certificated values 5.3~6.3 µg/kg

Conclusion

This report demonstrates that NIC MA-3000 analyzes new cork samples with accuracy and precision and analyzes rice flour (NIST 1568a) after repeated analysis of new cork. It is a perfect solution to today's increasing laboratory demand for easy, fast, and accurate mercury measurements.

References

(1) WHO HP: http://www.who.int/ipcs/assessment/public_health/mercury/en/.

(2) Research paper: https://link.springer.com/article/10.1007%2Fs11356-013-2104-0.

(3) FDA HP: http://www.gpo.gov/fdsys/pkg/CFR-2005-title21-vol7/pdf/CFR-2005-title21-vol7-chapI-subchapG.pdf.

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