Where in SW-846 can I find a method for total organic carbon (TOC) in soil and other solid matrices?
There is no SW-846 method for TOC in soils. The Office of Resource Conservation and Recovery (ORCR) does not have any regulatory requirements that govern the total organic carbon content of soils or solid matrices. Therefore, without a regulatory driver, there is no need for a method for TOC in soil in SW-846. Scientists in Europe and North America have developed a variety of methods for TOC over the years. Some of them are based on titration of "easily oxidizable organic carbon," while others involve the high temperature combustion of any organic carbon in the soil and measurement of the resulting carbon dioxide. If you need a method for TOC in soil, you can google to find available test procedures and consult with your regulator or data user to see which procedure(s) is more appropriate for your intended application.