Dissolved Oxygen

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Visual Kits

Range MDL Method Type Kit Cat. No. Refill Cat. No.
0-20 ppb 2 ppb Rhodazine D ULR CHEMets K-7511 R-7511
0-40 ppb 2.5 ppb Rhodazine D CHEMets K-7540 R-7540
0-100 ppb 5 ppb Rhodazine D CHEMets K-7599 R-7540
5-180 ppb 5 ppb Rhodazine D CHEMets K-7518 R-7518
0-1 ppm 0.025 ppm Rhodazine D CHEMets K-7501 R-7501
1-12 ppm 1 ppm Indigo Carmine CHEMets K-7512 R-7512

Instrumental Kits

Range Method Type Kit Cat. No.
0-1.000 ppm Rhodazine D Vacu-vials K-7553
0-2.00 ppm Indigo Carmine Vacu-vials K-7503
0-15.0 ppm Indigo Carmine Vacu-vials K-7513
0-15.0 ppm Indigo Carmine SAM Photometer + Vacu-vials I-2002

The CHEMetrics test kits for the determination of Dissolved Oxygen in aqueous solutions are based on patented Self-Filling Reagent Ampoule technology, and employ the rhodazine D & indigo carmine methods, delivering sensitivity and accuracy within two minutes or less. Premixed. Premeasured. Precise. Each kit contains 30 tests. Suitable for environmental testing as well as high-pressure boiler and deep well oil recovery equipment applications.

The Indigo Carmine Method




Test kits for environmental and drinking water applications (ppm range) employ the indigo carmine method. The reduced form of indigo carmine reacts with D.O. to form a blue product. The indigo carmine methodology is not subject to interferences from temperature, salinity, or dissolved gases such as sulfide, which plague users of D.O. meters. Results are expressed as ppm (mg/l) O2.

References:
ASTM D 888-87, Dissolved Oxygen in Water, Test Method A.
Gilbert, T. W., Behymer, T. D., Castañeda, H. B., "Determination of Dissolved Oxygen in Natural and Wastewaters," American Laboratory, March 1982, pp. 119-134.

The Rhodazine D™ Method

Test kits for boiler waters and applications requiring trace levels of D.O. (ppb range) employ the Rhodazine D methodology. Developed by CHEMetrics, Inc., and approved by ASTM as the reference method for ppb D.O. determination, the Rhodazine D compound in reduced form reacts with dissolved oxygen to form a bright pink reaction product. The method is not subject to salinity or dissolved gas interferences. Oxidising agents, including benzoquinone, can cause high results. Reducing agents such as hydrazine and sulphite do not interfere. Results are expressed as ppm (mg/l) or ppb (ug/l) O2.

Low-range dissolved oxygen test kits include a special sampling tube for use with boiler feedwater. This device allows the user to break the tip of the ampoule in a flowing sample stream in order to preclude error from contamination by atmospheric oxygen.

Click here for more information on CHEMetrics ppb Dissolved Oxygen test kits.

References:
Developed by CHEMetrics, Inc. ASTM Power Plant Manual, 1st. ed. p. 169 (1984).
ASTM D 5543-09, Low Level Dissolved Oxygen in Water.
Department of the Navy, Final Report of NAVSECPHILADIV Project A - 1598, Evaluation of CHEMetrics Feedwater Dissolved Oxygen Test Kit (1975).

Applications

The level of dissolved oxygen in natural waters is often a direct indication of quality, since aquatic plants produce oxygen, while microorganisms generally consume it as they feed on pollutants. At low temperatures the solubility of oxygen is increased; during summer, saturation levels can be as low as 4 ppm. Dissolved oxygen (D.O.) is essential for the support of fish and other aquatic life and aids in the natural decomposition of organic matter. Waste treatment plants that employ aerobic digestion must maintain a level of at least 2 ppm dissolved oxygen.

At elevated temperatures, oxygen is highly corrosive to metals, causing pitting in ferrous systems such as high-pressure boilers and deep well oil recovery equipment. To prevent costly corrosion damage, the liquids in contact with the metal surfaces must be treated, usually by a combination of physical and chemical means. Deaeration can reduce the dissolved oxygen concentration of boiler feedwater from several ppm to a few ppb. Chemical reducing agents such as hydrazine, DEHA, or sodium sulphite, may be used instead of or in conjunction with deaeration.


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