5.3 Calibration
• A calibration range must be set for the project. A blank plus three standards bracketing the applicable range will typically be run.
• Calibration standards are produced as dilutions from purchased stock standards, and standard information recorded in the appropriate field notebook. All standards must be produced from NIST traceable material using Hg free water. Dilute the 1000 ng/l stock standard to 0.5 ng/l by adding 0.5l stock to 1 ml mercury free water. Serial dilutions can be made from the 0. 5 ng/l stock standard as follows: