GB/T 33285.2-2024 "Leather and fur, determination of alkylphenols and alkylphenol polyoxyethylene ethers, Part 2: Indirect method" specifies the use of High performance liquid chroma-tography, HPLC (HPLC) and gas chromatograph - Mass spectrometry (GC-MS) method for the determination of alkylphenols (nonylphenol and octyphenol) and alkylphenol polyoxyethylene ethers (nonylphenol polyoxyethylene ethers and octyphenol polyoxyethylene ethers) in leather and fur. This document applies to the determination of these compounds in leather, fur and their products and processing aids. The content of alkyl phenols and alkyl phenol polyoxyethylene ethers is determined by detecting their degradation products after cracking, which provides an important basis for the quality control of leather and fur products.