GB/T 27860-2011 specifies the estimation of the adsorption coefficient (Koc) for a test chemical substance on soil and on sewage sludge by means of high performance liquid chromatography (HPCL). This standard covers important sections as the following，e.g. Koc terms and definitions, information on the test substance, test descriptions, experiment preparations/processes/quality control, and the test data and report.

GB/T 27860-2011 is identical in technical content with the OECD Test Guideline 121, published in 2001.

The standard is applicable to chemical substances which are sufficiently stable during the duration of the experiment. It may be particularly useful for chemicals which are difficult to study in other experimental systems (i.e. volatile substances; substances which are not soluble in water at a concentration which can be measured analytically; substances with a high affinity to the surface of incubation systems). The method can be used for mixtures, which give unresolved elution bands. In such a case, upper and lower limits of the log Koc values of the compounds of the test should be stated.

The method is not applicable for substances which react with the eluent or the stationary phase. It is also not applicable for substances that interact in a specific way with inorganic components (e.g. formation of cluster complexes with clay minerals). The method may not work for surface active substances, inorganic compounds and moderate or strong organic acids and bases. Log Koc values ranging from 1.5 to 5.0 can be determined.