Used as a reference standard in environmental testing laboratories to calibrate instruments and validate analytical methods for copper detection in water. Ensures accuracy and reliability in monitoring copper levels in drinking water, wastewater, and natural water bodies. Supports compliance with regulatory standards by providing a known concentration for quality control and proficiency testing. Commonly used in atomic absorption spectroscopy (AAS), inductively coupled plasma (ICP) analysis, and colorimetric testing. Helps maintain consistency across multiple tests and laboratories, especially in environmental monitoring, industrial discharge control, and public health assessments.