245.7z.001 <iOS FULL>

: Moisture and water vapor must be removed using drying tubes to prevent "quenching," which weakens the fluorescence signal. Application and Precision

: Stannous chloride is added to reduce these ions into elemental mercury vapor ( Hg0cap H g to the 0 power 245.7z.001

The method relies on . Unlike traditional absorption methods, CVAFS measures the light emitted by excited mercury atoms. : Moisture and water vapor must be removed

: The use of high-purity argon (99.998%) is mandatory; using nitrogen or air significantly reduces sensitivity. : The use of high-purity argon (99

However, based on the specific number , this often refers to EPA Method 245.7 , a high-precision protocol for measuring mercury levels in water. Below is a structured overview (essay) of this technical method. Overview of EPA Method 245.7: Mercury Detection

: High-purity argon gas carries the vapor into the CVAFS analyzer , where it is exposed to UV light (253.7 nm), causing fluorescence that is then measured. Critical Interferences

: Samples are first treated with a brominating digestion (potassium bromate/bromide) to convert all mercury forms into mercuric ions ( Hg2+cap H g raised to the 2 plus power