Figure 6: A comparison GC chromatogram of class 1 residual solvents by spiking trichlormethiazide; a) 800 mg/mL trichlormethiazide in DMSO as background; b) class 1 residual solvents standard solution containing 1,1-dichloroethene, 1,1,1-trichloroethane, carbon tetrachloride, and 1,2-dichloroethane only; c) class 1 residual solvents standard solution spiked with 800 mg/mL trichlormethiazide.