The GB/T 18873-2008 standard specifies the technical requirements and specifications for the quantitative analysis of biofilm specimens using a transmitted Electron Microscope (EM) (TEM) in combination with an X-ray energy spectrometer. The standard is applicable to the analysis of the content of non-ultralight elements in biofilm specimens. The biofilm specimen is irradiated by a high-energy electron beam to excite the production of characteristic X-Rays, and its intensity is analyzed by an energy spectrometer to determine the concentration of elements in the sample. The standard provides a scientific method for the composition analysis of biological materials, which helps to understand the chemical composition of biological specimens more accurately.