Analysis of Harmful Elements in Herbal Medicines by ICPE-9800 Series

Importance of the Topic

Herbal medicines are widely consumed as over-the-counter drugs, dietary supplements, and functional foods. However, they can accumulate toxic elements such as arsenic, cadmium, mercury, and lead. Ensuring safety requires reliable multi-element analysis to meet international regulatory standards.

Study Objectives and Overview

This application note demonstrates the use of the Shimadzu ICPE-9800 series inductively coupled plasma atomic emission spectrometer (ICP-AES) for rapid, simultaneous determination of harmful elements in various herbal medicines. The aim is to verify sensitivity, accuracy, and throughput against WHO and China import/export guidelines.

Methodology and Instrumentation

• Instrumentation: Shimadzu ICPE-9800 multi-type ICP-AES with echelle optics, CCD detector, mini-torch plasma, Eco mode, and vacuum-housed spectrometer to reduce gas consumption.
• Sample Preparation: Microwave-assisted acid digestion of 0.5 g dry sample with HNO3 and HCl, diluted to 25 mL. Spike-and-recovery solutions prepared for accuracy assessment.
• Analytical Conditions: RF power 1.2 kW; plasma gas 10 L/min; auxiliary gas 0.6 L/min; carrier gas 0.7 L/min; cyclone mist chamber; axial observation; 2.5 min per sample including rinse.

Main Results and Discussion

Qualitative screening revealed major matrix elements (e.g., Ca up to 3.7 wt%, K 1.1 wt%). Quantitative analysis of As, Cd, Cr, Cu, Hg, Pb, and Sn in eight herbal samples returned values below detection limits or regulatory thresholds. Detection limits (e.g., 0.2 µg/g for As, 0.007 µg/g for Cd) are below WHO and China reference values. Spike-and-recovery rates between 96 % and 102 % confirm method accuracy. Spectral profiles for Cd, Cr, and Pb displayed clear peak resolution with negligible matrix interference.

Benefits and Practical Applications

• Simultaneous all-element analysis increases throughput and reduces analysis time.
• Mini-torch plasma and Eco mode lower operational cost by minimizing gas usage.
• High-temperature plasma suppresses ionization interference from coexisting elements.
• Suitable for routine quality control of herbal medicines, dietary supplements, and related products.

Future Trends and Opportunities

Ongoing improvements in detector sensitivity, plasma stability, and data processing software will further enhance analytical performance. Integration with automated sample preparation and laboratory information management systems can facilitate higher throughput. Expanding applications to emerging contaminants and trace elements in botanical products is anticipated.

Conclusion

The Shimadzu ICPE-9800 ICP-AES delivers high sensitivity, accuracy, and cost-effectiveness for monitoring harmful elements in herbal medicines. Its capability for simultaneous multi-element detection with low detection limits meets regulatory requirements and supports rigorous quality assurance.

Reference

1. WHO Guidelines for Assessing Quality of Herbal Medicines with Reference to Contaminants and Residues, March 2009.
2. Green Trade Standards of Importing & Exporting Medicinal Plants & Preparations, Ministry of Foreign Trade and Economic Cooperation (China), July 2001.