An Easy Solution to Monitor Printing Residual Solvents in Packaging Material using an Agilent 7820 GC system and an Agilent 7697A Headspace Sampler

Importance of the Topic

Residual solvents used in printing inks for packaging materials can migrate into food or consumer goods, posing health risks and affecting product quality. Regulatory standards require sensitive, accurate monitoring of these volatile compounds to ensure compliance and safety.

Study Objectives and Overview

This application note demonstrates an automated headspace gas chromatography method using an Agilent 7820 GC system coupled with an Agilent 7697A headspace sampler. The goal is to rapidly detect, qualify, and quantify 13 common printing solvents in flexible packaging materials, following ASTM F1884-04 as a reference.

Methodology and Instrumentation

The workflow involves:

• Headspace sampling: 7697A sampler with 5-minute equilibration and single extraction of a 20 mL vial at 15 psi.
• GC separation: Agilent 7820 GC with a DB-WAX column (10 m × 0.18 mm, 0.18 µm film), split inlet at 180 °C with a 100:1 ratio, and helium carrier gas at 0.8 mL/min constant flow.
• Detection: Flame ionization detector at 250 °C.

Reagents and standards: Thirteen solvents prepared in DMSO across calibration levels from 0.005 to 5 mg/mL by external standard mode.

Main Results and Discussion

Calibration across all 13 solvents yielded correlation coefficients (R2) ≥ 0.9990 over the tested range. Retention time and peak area repeatabilities were below 0.05% and 1.4% RSD, respectively. A fast temperature program and optimized column allowed full elution within 3 minutes. Headspace throughput with a 12-vial tray delivered a total cycle time under 7 minutes. Spike recoveries in a simulated ink matrix ranged from 98.0% to 101.5%.

Benefits and Practical Applications

This method provides:

• Rapid analysis with minimal sample preparation.
• High accuracy and precision meeting regulatory standards.
• Short cycle times (<7 minutes) suitable for high-throughput QC.
• Cost-effective instrumentation for packaging suppliers and laboratories.

Future Trends and Potential Applications

Advancements may include integration with mass spectrometry for enhanced compound identification, further automation of sample handling, miniaturized and portable GC systems for on-site analysis, and development of faster, more selective columns to expand the scope to additional volatile contaminants.

Conclusion

The Agilent 7820 GC coupled with the 7697A headspace sampler delivers a robust, fast, and reliable solution for monitoring residual printing solvents in packaging materials. It satisfies regulatory requirements and supports high-throughput quality control with excellent sensitivity and reproducibility.

Reference

1. ASTM F1884-04: Standard Test Methods for Determining Residual Solvents in Packaging Materials.
2. D. Louvier and E. Martine, “Residual printing solvents in packaging materials,” Chimia, vol. 56, pp. 295–297, 2002.