Analysis of Polymer Additives - Shim-pack GPC 805 + GPC 801

Significance of Polymer Additive Analysis

The stability and performance of polymer-based products depend critically on the presence and effectiveness of additives such as antioxidants and UV stabilizers. Accurate quantification and identification of these components ensure product quality, regulatory compliance and long-term durability in applications ranging from packaging to automotive parts.

Objectives and Scope of the Study

This application note demonstrates a rapid and reliable approach for separating and quantifying three common polymer additives—Tinuvin 144, Tinuvin 120 and Irganox 1010—within a polystyrene matrix using size‐exclusion chromatography (SEC) coupled with a photodiode array detector (PDA) and refractive index detector (RID). The study aims to resolve overlapping peaks and deliver clear analytical results within a single run.

Methodology and Instrumentation

The analysis employed a Nexera™ GPC system fitted with two Shim-pack™ GPC columns (805 and 801, 300 mm × 8 mm I.D. each) in series.

• Mobile phase: tetrahydrofuran (THF)
• Flow rate: 0.8 mL/min
• Column temperature: 40 °C
• Injection volume: 10 µL
• Detection: RID plus PDA scanning from 220 to 400 nm
• Sample: 0.5 % polystyrene spiked with three additives
• Run time: 31 min (overlap time 15.5 min)

Data deconvolution was performed with i-PDeA II software to separate coeluting signals and obtain pure additive profiles.

Main Results and Discussion

The chromatogram at 240 nm displayed distinct peaks corresponding to each additive and the polystyrene matrix.

• Tinuvin 144 eluted earliest due to its lower molecular weight.
• Irganox 1010 and Tinuvin 120 showed partially overlapping signals, successfully resolved by deconvolution.
• The polymer backbone peak appeared separately, confirming minimal interference with additive signals.

Deconvolution enhanced quantification accuracy by isolating absorbance contributions of closely eluting species. The method achieved baseline separation within a 31 min cycle, suitable for routine QC workflows.

Practical Benefits and Applications

This SEC–PDA/RID approach enables analytical laboratories to:

• Monitor additive levels in polymer formulations with minimal sample preparation.
• Support R&D in optimizing stabilizer blends for extended product life.
• Ensure compliance with regulatory standards on additive migration and residual content.

Future Trends and Potential Applications

Advances in multidetector SEC, including light scattering and mass spectrometry, will further improve molecular characterization of additives. Integration of automated deconvolution workflows and data analytics will accelerate decision-making in polymer quality control and materials development.

Conclusion

The described method offers a robust, high-resolution technique for simultaneous analysis of multiple polymer additives in a single run. Its combination of SEC separation, dual detection and software deconvolution delivers precise results, making it well suited for industrial and research laboratories.

Reference

• Application News L.537 (JP, ENG). Shimadzu Corporation, 2021.