Polystyrene is one of the most commonly manufactured polymers today. Pure polystyrene is highly crystalline and rigid, making it brittle. One method of increasing the flexibility and reducing the brittle nature of the material is to blend the polymer with mineral oil. Precise control of the amount of mineral oil used is necessary to ensure the correct performance properties are obtained reproducibly. MQC+ provides a fast, simple and accurate method of measuring the content of mineral oil in crystalline polystyrene.