Zirconium (Zr) standard solution at 1000 µg/mL in 1.0 mol/L HNO₃ with trace HF, used for preparing calibration curves in analytical techniques such as inductively coupled plasma mass spectrometry (ICP-MS), ICP optical emission spectroscopy (ICP-OES), and atomic absorption spectroscopy (AAS) to accurately quantify zirconium concentrations in environmental, geological, metallurgical, and industrial samples.