Chlorine is one of the most widely used disinfectants in water treatment due to its strong oxidizing and biocidal properties. It is commonly used in drinking water treatment, municipal wastewater treatment, cooling systems, and swimming pools to control bacteria and other microorganisms.

In potable water applications, chlorine also helps reduce the effects of iron, manganese, ammonia, and sulfide. Routine chlorine testing is essential for maintaining proper disinfection levels, optimizing treatment processes, and ensuring regulatory compliance.

CHEMetrics Chlorine Test Kits measure free chlorine, total chlorine, and hypochlorite using either DPD or DDPD test methods. Both visual and instrumental test kits are available to support field testing, process monitoring, and laboratory analysis.

Chlorine Test Methods

DPD Method

The DPD Method is USEPA-accepted procedure for measuring chlorine in water. Free chlorine reacts with DPD reagent to produce a pink-colored complex. When ammonia or amines are present, a portion of the chlorine may exist as combined chlorine. Combined chlorine does not interfere with free chlorine measurements provided readings are taken within one minute. To determine total chlorine (free chlorine plus combined chlorine), use the included A-2500 Activator Solution (potassium iodide). Results are reported as ppm (mg/L) Cl₂.

The DPD method may also be used to determine hypochlorite concentrations in cleaning solutions and disinfectants prior to dilution. In these applications, results are reported as percent (%) NaOCl.

DDPD Method

The DDPD Method is derived from the DPD method and is particularly useful in systems where chlorine biocides and chromate corrosion inhibitors are used simultaneously. Free chlorine reacts with DDPD reagent to form a purple-colored complex. When ammonia or amines are present, combined chlorine may also be present in the sample. Total chlorine can be determined using the included A-2500 Activator Solution (potassium iodide). Results are reported as ppm (mg/L) Cl₂.

CHEMets vs Vacu-Vials: Which Testing System is Right for You?

CHEMetrics offers two ampoule-based testing systems for chlorine analysis: CHEMets® Visual Kits and Vacu-Vials® Instrumental Kits. Both systems utilize CHEMetrics self-filling ampoule technology, which automatically draws the correct sample volume into the ampoule for fast, convenient testing.

CHEMets Visual Kits use visual color comparison to determine chlorine concentration and require no instrumentation. CHEMets Kits are idea for routine field testing, quick screening applications, cost-effective monitoring, and users who do not require electronic data collection.

Vacu-Vials Instrumental Kits use a photometer or spectrophotometer (sold separately) to measure color intensity and calculate chlorine concentration. Vacu-Vials Kits are ideal for process monitoring and control, laboratory testing, regulatory and compliance applications, higher accuracy and repeatability requirements, and electronic recordkeeping and reporting.

Choose the Right Kit

Single Analyte Meter (SAM) Kit: Complete kit with photometer included

Vacu-Vials Kit: Test kit for use with a compatible photometer or spectrophotometer (sold separately).

CHEMets Visual Kit: Visual color-comparison kit with no instrument required. Visual Kits include everything needed to perform 30 tests: 30 self-filling CHEMets ampoules, low-and high-range concentrators, accessory solutions (when required), 25mL sample cup, instructions, plastic carrying case.