Determination of Metals and Trace Elements in Water and Wastes by Inductively Coupled Plasma-Atomic Emission Spectrometry. Covers 31 elements with specified method detection limits suitable for drinking water, wastewater, and solid waste extracts.
According to EPA 200.7, samples intended for dissolved metals determination must be filtered (0.45 µm) and preserved to pH < 2 with nitric acid.
Total-recoverable samples (with particulates) must be acidified to pH < 2 upon collection. Preservation may occur in the lab if performed within two weeks and held at pH < 2 for at least 16 hours.
Dissolved metals: analyze acidified filtrate directly.
Total recoverable metals: acid pretreatment with HNO₃ + HCl, followed by gentle refluxing.
For boron and silica: only plastic, PTFE, or quartz labware is permitted.
Analysis is carried out by ICP-AES after nebulization into the plasma.
The EPA method requires:
