Detecting Peroxides in Pharmaceutical Grade Solvents

Pharmaceutical production demands solvents free from reactive impurities to avoid unwanted side-products. Organic peroxides are a key concern, as they can form easily when solvents come into contact with oxygen during storage or handling. 

Titration methods often lack the sensitivity, selectivity, and reproducibility required for reliable solvent purity control—leaving a risk of undetected contamination and reduced product quality. To address this, Da Vinci Laboratory Solutions (DVLS) developed a fast, accurate, and repeatable alternative based on a flow injection system: the Fast Peroxide Analyzer (FPA). A new application note describes the analysis of peroxide content in pharmaceutical-grade solvents using the DVLS FPA system, 

Flow Injection System Configuration

The DVLS Fast Peroxide Analyzer is a flow injection system that uses an Agilent 1260 Infinity III HPLC system configured with a pump, an autosampler, a DVLS reaction module, and a UV-VIS detector. 

The sample is injected into the reagent stream of acidified Iodide and transferred to the Reaction Module. Peroxides present will react with the Iodide to Iodine and form a brownish color. The DVLS Reaction Module is designed to optimize the conversion to Iodine – similar to the iodometric titration reaction. After the reaction the formed Iodine is detected using UV-VIS spectroscopy.

Analysis of Peroxide Content

The FPA is calibrated using Dibenzoyl Peroxide standards in 1-Propanol (NPA). To test whether the detector response is not affected by the solvent matrix, standards of Dibenzoyl Peroxide in selected solvents are prepared. These standards have a concentration range of 0 up to 100 ppm active Oxygen. 

A test of several organic solvents shows that within a total analysis time of 5 minutes, the peroxide content is determined with a detection limit below 0.1 mg/kg, and a precision of RSD < 5%.

Interested in this peroxide analysis? Download the application note.