ASTM D5799 alternative for the trace analysis of Peroxides in 1,3-Butadiene

As Butadiene is a reactive compound, it may form Peroxides upon exposure to air or during processing. To prevent auto polymerization in storage tanks and to avoid potential safety hazards an accurate determination of Peroxide traces in Butadiene is required. Da Vinci Laboratory Solutions has developed the Fast Peroxide Analyser as a safe and accurate alternative for the iodometric titration method ASTM D5799. A new application note provides an insight into the Fast Peroxide analysis compared to the ASTM D5799 method.

Flow Injection System

To eliminate any safety hazard and to provide accurate results Da Vinci Laboratory Solutions has introduced the Fast Peroxide Analyser (FPA) based upon a flow injection. The FPA system (Figure One) uses an Agilent 1260 Infinity II HPLC system configured with a pump, an autosampler, a DVLS reaction module and a variable wavelength detector. A Pressure Station is used for safe handling of liquid Butadiene in LPG contained in a cylinder.

The analysis of Peroxide, as active Oxygen, is based on the oxidation of Iodide by Peroxides. The sample is injected into a reagent stream of acidified Iodide and transferred to the Reaction Module. The Peroxides present in the sample will react with the Iodide to Iodine and will form a brownish color. The DVLS Reaction Module is designed to optimise the conversion. This is the same reaction that takes place in an iodometric titration as seen in Equation One.

ROOR + 2 I^- + 2 H⁺ → I₂ + 2 ROH

Equation One: Redox reaction of Iodide with Peroxide

After the reaction, the formed Iodine is detected using UV-Vis spectroscopy at the optimal wavelength for Iodine. Figure Two displays the calibration curve of the standard Dibenzoyl Peroxide (DBP) in 1-Propanol including the estimated level of detection (LOD) and level of quantification (LOQ).

Comparison of FPA with ASTM D5799

The application note shows the analysis results of a Pentane standard and two 1,3-Butadiene samples. Both Butadiene samples are analysed in tenfold to measure the repeatability. Figure Three shows the chromatogram of a 1,3-Butadiene sample containing 0.0629 mg/kg Active Oxygen and embedded the comparison table.

This table exhibits that the iodometric titration D5799 method suffers from poor repeatability and reproducibility for the intended range. The DVLS FPA analysis results demonstrate that the DVLS Fast Peroxide Analyser greatly improves the repeatability and estimated reproducibility. As it also significantly reduces the analysis time, the DVLS Fast Peroxide Analyser is a fast, safe and accurate alternative for the analysis of Peroxide traces in 1,3-Butadiene.

The key benefits of the FPA system are:

• Fast analysis in less than 5 minutes;
• Wide application range;
• Excellent performance down to ppb level;
• Automated alternative to traditional wet chemistry analysis methods;
• Closed analysis system prevents air interference issues;
• Configuration based on the standard Agilent HPLC modules saves bench space.

Download the new application note of the trace Peroxide analysis of 1,3-Butadiene for more information.