Trace Elements in Water standard reference material (SRM) is intended primarily for use in evaluating methods used to determine trace elements in fresh water.

• Accompanied with certificate documenting NIST-certified values, expanded uncertainties, and coverage factor (k) for elements in SRM 1643F
• Values are traceable to the International System of Units (SI) and SI-derived units of mass fraction and mass concentration
• The NIST certificate is provided with storage and use instructions

Each unit of SRM 1643F consists of a polyethylene bottle containing ~250 ml of acidified water, sealed within an aluminised plastic bag to maintain stability. The SRM simulates the elemental composition of fresh water. The solution contains nitric acid at a volume fraction of ~2%, equivalent to an amount of substance concentration (molarity) of nearly 0,32 mol/l.

The certified mass fraction values are consensus estimates that blend the results of the gravimetric preparation value and a value determined by either inductively coupled plasma mass spectrometry (ICP-MS) or inductively coupled plasma optical emission spectrometry (ICP-OES).