WS Residual Free Chlorine Back Catalog number: 55023 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 83509 EPA Method 8315 Calibration Mix #1 Price on request BB-15 4,4'-Dibromobiphenyl, 1.2ml x 50ug/ml, nonane Price on request 0918.14-500-IO 2,4-Dimethyldibenzothiophene, 500µg/mL, Solvent-isooctane, Unit 1mL, # of units-1, Cas.no. 31317-18-7 Price on request