ISO 15680 Stock Calibration Standard Solution 1 14 Analytes to be used with Internal standard S1, each 2000µg/mL in methanol; unit: 1x5mL 3944.1 Dichlorodifluoromethane [75-71-8] 3945.1 Monochloromethane [74-87-3] 3946.1Monobromomethane [74-83-9] 3