This test method is an official method for the quantitative determination of multiple metals and elements in plant materials and pet foods using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) post-open block digestion. This method provides reliable analysis of essential nutrients and potential contaminants in complex biological matrices. This test method quantifies calcium, copper, iron, magnesium, manganese, phosphorus, potassium, sodium, sulfur, and zinc.