Microwave Digestion System - Multiwave 7101/7301/7501

Importance of the topic

Microwave‐assisted acid digestion under high pressure is a cornerstone technique in modern elemental analysis. By combining elevated temperature and pressure in a closed vessel, complete sample decomposition is achieved rapidly and reproducibly, enabling precise quantification by ICP-OES, ICP-MS, or AAS. This approach minimizes contamination, reduces reagent consumption, and accelerates workflows in environmental, food, pharmaceutical, mining, and materials‐science laboratories.

Study overview and objectives

The Multiwave 7101/7301/7501 series integrates Anton Paar’s pressurized digestion cavity (PDC) with advanced microwave heating. Developed to simplify method setup, increase throughput, and ensure user safety, these instruments aim to deliver complete digestions of diverse matrices without extensive method development or sample clustering. Parallel processing of up to 41 samples targets high‐volume elemental analysis workflows.

Methodology and used instrumentation

The PDC system employs a magnetron delivering 2,000 W of microwave power, achieving heating rates up to 70 °C/min and temperatures reaching 300 °C under pressures to 199 bar. Samples and acid reagents are loaded into disposable or reusable vials (quartz, PTFE‐TFM, or borosilicate glass) and sealed with simple plug‐on caps. The lightweight PTFE liner is inserted into the cavity, followed by a software‐guided digestion protocol. Optional stirring, internal cooling, and automated cleaning routines enhance performance and ease of use.

Main results and discussion

Performance testing demonstrates rapid heating to 175 °C in 5.5 minutes, in compliance with EPA 3051A, using less than 55% of installed power. Parallel digestion of up to 41 samples yields high throughput with consistent residual carbon levels and minimal cross‐contamination. The system’s flexibility supports sample masses up to 4 g, broad reagent chemistries including aqua regia and hydrofluoric acid, and matrices from organic to geological.

Benefits and practical applications

• Significant reduction in manual handling and risk of exposure to corrosive reagents.
• Lower blank values and dilution factors through optimized acid consumption.
• Versatile vial options matching sample weight, reagent compatibility, and detection requirements.
• Integrated safety features: drip cups, microwave traps, ventilation, and third‐party certification.
• Compliant software with 21 CFR Part 11 support for reporting and documentation.

Future trends and potential applications

Advances in microwave cavity design, real‐time temperature and pressure monitoring, and AI‐driven method optimization are expected to further streamline acid digestion. Integration with on‐line dilution and direct coupling to mass spectrometers may emerge, enabling near‐continuous workflows. Sustainable reagent recycling and miniaturized high‐pressure vessels could reduce waste and footprint in high‐throughput laboratories.

Conclusion

The Multiwave 7101/7301/7501 systems represent a mature, flexible platform for pressurized microwave digestion. Their combination of high throughput, robust safety, minimal method development, and broad sample compatibility addresses the growing demands of elemental analysis laboratories across multiple industries.

Used instrumention

• Multiwave 7101/7301/7501 microwave digestion system with pressurized digestion cavity
• Magnetron (2,000 W), internal/external cooling options
• Interchangeable quartz, PTFE‐TFM, and borosilicate glass reaction vials
• Software with semi‐automated closing, opening, cleaning, VNC remote control, and data export