Internal Standard Solution, 1.2ml, nonane

Ba, 1000 µg/mL in 2% HNO3, 100ml

Sulfur Calibration Mixtures: Di-n-butyl sulfide in Heavy White Oil (less than 20mg/kg S) Unit : 10mL screw-capped bottle Light White Mineral Oil Heavy White Mineral Oil (20 cSt at 40°C) (70 cSt at 40°C)

D4-Sulfamethoxazole, 10mg