Volatile Matter Testing of Packaging Materials: Standards, Methods, and Applications

Volatile matter testing of packaging materials identifies and quantifies residual solvents, monomers, and other volatile organic compounds (VOCs) that can migrate from films, laminates, and printed packaging into food, pharmaceuticals, and consumer products. Using headspace gas chromatography and gravimetric techniques in accordance with GB, EN, ASTM, and ISO standards, accredited third-party laboratories help manufacturers verify regulatory compliance, prevent odor issues, and safeguard product quality. This article explains the scope of testing, target compounds, analytical methods, and practical answers to frequently asked questions.

Technical Overview

Volatile matter in packaging materials refers to the fraction of substances that can evaporate from the material under normal or moderately elevated temperature conditions. In flexible packaging and printed materials, the primary sources are residual solvents from gravure and flexographic printing inks, laminating adhesives, and coating processes. Additional contributors include unreacted monomers, low-molecular-weight additives, processing aids, and moisture retained within paper or polymer substrates.

Excessive volatile content creates significant quality and safety risks. Volatile compounds can migrate through packaging layers into food, pharmaceuticals, and cosmetics, causing off-odors, taste transfer, and potential consumer exposure to hazardous substances such as benzene and toluene. In electronics packaging, volatile outgassing may contaminate sensitive components. For these reasons, volatile matter content is tightly controlled by food-contact regulations such as the GB 4806 series and GB 9685, by product standards such as GB/T 10004 for laminated plastic films, and by international test standards including EN 13628 and ASTM F1884.

Results are typically expressed as total residual solvents in milligrams per square meter (mg/m²) of material, or as concentrations of individual compounds in mg/kg. Detection is performed at trace levels, and accredited third-party laboratories operating under ISO/IEC 17025 quality systems provide the independent verification required for regulatory submissions and customer audits.

Testing Samples

Flexible Plastic Films and Laminates

Single-layer films such as BOPP, PET, PE, CPP, and PA, as well as multi-layer laminates produced by dry lamination or extrusion lamination, are the most frequently tested sample types. These structures commonly carry residual ethyl acetate, toluene, or ketone solvents from adhesive and ink systems.

Printed and Coated Packaging

Surface-printed and reverse-printed films, varnished papers, and coated boards are tested to verify that solvent retention from the printing process meets specification before conversion into finished packaging.

Paper, Paperboard, and Aluminum Foil Structures

Paper-based materials and foil laminates used for food service, cartons, and pharmaceutical blister packaging are evaluated for both solvent residues and general volatile loss on heating.

Raw Materials and Auxiliary Chemicals

Inks, laminating adhesives, primers, and polymer resins can be tested at the incoming inspection stage to control volatile content at the source and support supplier qualification programs.

Testing Items

Testing programs are tailored to the material, process, and end use, and commonly cover the following items:

• Total residual solvents (total VOC content) expressed in mg/m²
• Esters: ethyl acetate, n-butyl acetate, isopropyl acetate
• Ketones: acetone, methyl ethyl ketone (MEK), cyclohexanone
• Aromatic hydrocarbons: benzene, toluene, ethylbenzene, xylene
• Alcohols: ethanol, isopropanol, n-butanol
• Residual monomers: styrene, vinyl chloride, acrylate and methacrylate monomers
• Total volatile matter by gravimetric oven method (loss on heating)
• Low-molecular-weight siloxanes in silicone-coated release liners

Testing Methods

Static Headspace Gas Chromatography (HS-GC)

Static headspace GC is the reference technique for residual solvent determination. A specimen of known area, typically 100 cm², is cut from the sample and sealed in a headspace vial. The vial is equilibrated in a heated oven, generally between 80°C and 150°C, so that volatile compounds partition into the headspace gas phase. An aliquot of the headspace is injected into a gas chromatograph equipped with a flame ionization detector (FID), and individual solvents are quantified against external calibration standards. This approach is standardized in EN 13628-1 for flexible packaging and in ASTM F1884 for packaging materials in general.

GC-MS Identification and Confirmation

Where unknown odors are investigated or non-target compounds are suspected, headspace or solvent-extraction GC coupled with mass spectrometric detection (GC-MS) is used to identify the full volatile profile of the material, including monomers and degradation products.

Gravimetric Oven Method

For total volatile content, weighed specimens are heated in a ventilated oven at a specified temperature, commonly 105°C, for a defined period. The percentage mass loss after conditioning in a desiccator is reported as volatile matter. Comparable principles are applied in ISO 1269 for vinyl chloride resins and in related GB and JIS procedures for polymeric raw materials.

Thermogravimetric Analysis (TGA)

TGA provides rapid screening by monitoring sample mass while temperature is ramped under a controlled atmosphere. Mass loss occurring below approximately 150°C is attributed to volatiles, making the technique useful for development work and comparative studies between material batches.

In migration-oriented studies for food-contact compliance, GC and GC-MS analysis of food simulants may be added following the GB/T 23296 series to assess transfer of volatile substances under intended use conditions.

Applications

Volatile matter testing supports packaging manufacturers, brand owners, and converters across multiple industries:

• Food packaging compliance: demonstrating that films, laminates, and printed materials meet the GB 4806 series, GB 9685, and customer specifications for residual solvents
• Pharmaceutical packaging: verifying low volatile levels in blister foils, laminated films, and printed leaflet materials to protect drug product integrity
• Cosmetics and personal care: preventing odor and ingredient contamination in flexible pouches and sachets
• Electronics packaging: controlling volatile outgassing from bags, trays, and films used for sensitive components
• Export compliance: meeting EN and ASTM-based requirements for international markets
• Quality control and troubleshooting: incoming material inspection, batch release testing, and root-cause analysis of odor complaints

FAQ

What is the difference between residual solvents and total volatile matter?

Residual solvents are specific process solvents, such as ethyl acetate or toluene, retained from inks and adhesives, and are quantified individually by headspace GC. Total volatile matter is a broader gravimetric measure of all mass lost on heating, which may also include moisture and other low-boiling substances.

What are typical acceptance limits for residual solvents?

Under GB/T 10004, total residual solvents in laminated films are limited to 5 mg/m² or less, with benzene-class solvents effectively prohibited. Many converters and brand owners apply stricter internal specifications of 2 to 3 mg/m² total solvents, with tighter individual limits on toluene, particularly for food and pharmaceutical applications.

How should samples be submitted for testing?

Samples should be cut from representative production material, kept flat and uncreased, and sealed immediately in inert barrier bags to prevent solvent loss. A minimum area of several hundred square centimeters per sample is recommended, and testing should be performed promptly, since volatile content declines over time.

How long does volatile matter testing take?

Standard headspace GC and gravimetric tests are typically completed within five to ten working days. Investigations involving unknown compound identification by GC-MS may require additional time for method development and spectral confirmation.

Why is headspace GC the preferred method?

Headspace GC directly measures the volatile fraction that can escape from packaging under realistic conditions, offers high sensitivity and selectivity for individual solvents, and requires minimal sample preparation, making it the basis of the EN 13628 and ASTM F1884 test methods.

Can testing identify the source of an odor problem?

Yes. A combined HS-GC and GC-MS approach identifies the specific compounds responsible, and comparison of printed versus unprinted or laminated versus unlaminated sections of the material usually allows the source, whether ink, adhesive, or substrate, to be pinpointed.