10 μg/mL of each analyte in n-Hexane2,2',4,4'-Cl4-3-Me(No.21) 2,3',4,4'-Cl4-5-Me(No.52)2,2',4,4'-Cl4-5-Me(No.22) 2',3,4,4'-Cl4-6-Me(No.74)2,2',4,5'-Cl4-5-Me(No.25) 2',3,4,6'-Cl4-6-Me(No.80)2,2',4,6'-Cl4-3-Me(No.27) 3,3',4,4'-Cl4-2-Me(No.87)2,2',5,5'-Cl4-4