Used in calibration and quality control processes within petroleum testing laboratories to ensure accurate and consistent analysis of crude oil and refined products. These standard samples help validate the performance of analytical instruments such as gas chromatographs, mass spectrometers, and sulfur analyzers. They are essential for verifying test methods like distillation, flash point, viscosity, and hydrocarbon composition in accordance with international standards (e.g., ASTM, ISO). By providing a known reference, they support reliable measurement in refining, fuel production, and environmental compliance testing.