鄰苯二甲酸二異壬酯為複雜混合物，因製程差異有不同產品，對應之標準品有2種，CAS No 28553-12-0及CAS No 68515-48-0。依據IUPAC命名，CAS No 28553-12-0 為di-isononyl phthalate，其2個酯烷基主要均為C9；而CAS No 68515-48-0為 1,2-benzenedicarboxylic acid, di-C8-10 branched alkylesters, C9 rich，其2個酯烷基以C9為主要組成，C8或C10排列組合亦佔相當比例，另工業生產應用及暴露風險評估以CAS No 28553-12-0 項目為主，綜上，DINP標準品採用CAS No 28553-12-0。
參考文獻：
European Chemicals Bureau. 2003. 1,2-Benzenedicarboxylic acid, di-C8-10 branched alkyl esters, C9-rich and di-isononyl phthalate (DINP) risk assessment. European Union Risk Assessment Report. The Ministry of the Environment and the Ministry of Employment and Solidarity. France. (https://echa.europa.eu/documents/10162/83a55967-64a9-43cd-a0fa-d3f2d3c4938d)