Dissolved Oxygen, Total & Reactive Phosphorus, Chromium VI Testing
Dissolved Oxygen, Total & Reactive Phosphorus, Chromium VI Testing
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Dissolved Oxygen (DO) is the amount of oxygen that dissolves in the water, which depends on many factors, such as the water temperature, the air pressure, the salt content of the water, the water quality and so on. DO is an indicator of self-purification ability of a water body and the value is most commonly expressed in mg/L. Generally, a higher dissolved oxygen level indicates better water quality. If dissolved oxygen is depleted by the organic pollutants, some organisms may not be able to survive because of the low conversion of DO in water. Hence, the measurement of the amount of dissolved oxygen in water is of great importance for the protection of water source.
Phosphorus (P) is an essential element of food and biofuel production, which cannot be substituted by any other chemical element, and is a non-renewable geological resource [1]. Phosphorus occurs in water as inorganic phosphate (i.e., orthophosphate and condensed phosphate) and organic phosphates in both dissolved and particulate forms [2], which is accepted that the DRP (dissolved reactive phosphorus) fraction approximates the most available form of phosphorus in aquatic ecosystems. Inefficiencies in Phosphorus P use are not only of concern for long-term Phosphorus security, but have profound negative downstream impacts through eutrophication, which impairs water quality, undermines aquatic ecosystem function and threatens water security. The determination of the total dissolved phosphorus (TDP) and dissolved reactive phosphorus (DRP) in waters is therefore important to evaluate water quality.
Chromium (Cr) is widely used in many industrial processes and products, including in metallurgy (as a corrosion inhibitor), paint pigments, antifouling agents, fungicides, leather tanning, and electroplating, and is released as industrial waste into aquatic environments [3,4]. In aquatic environments, Cr is presented in several oxidation states, although only hexavalent [Cr(VI)] and trivalent [Cr(III)] chromium are biologically important [5]. Cr(VI), which is more mobile and toxic than Cr(III), is a strong oxidizing agent and potential carcinogen. Therefore, there is a need to determine Cr(VI) in water.
Alfa Chemistry is fully accredited at local and international level on testing the quality of water, and we aim to be the world leader in the technology of water detection. We can provide a broad range of methods and instruments to solve the problem that you are facing.
Dissolved Oxygen Measurement Methods
There are many methods available for measuring dissolved oxygen concentrations. The traditional method is the Winkler titration. While this method was considered the most accurate and precise for many years, it is also subject to human error and is more difficult to execute than the other methods. For now, Membrane oxygen electrodes is the most widely used and accepted method for real-time measurement of oxygen in water.
Cr(VI) Measurement Methods
There are mainly three methods available for measuring Cr(VI) concentrations in water samples, such as spectrophotometry method (the diphenyl carbamide spectrophotometry, the chromium-phenotype spectrophotometry, hexadecyl trimethyl bromide spectrophotometry), titration method and graphite furnace atomic absorption spectrophotometry (GFAAS) method.
Total & Reactive Phosphorus Measurement Methods
Determination of phosphorus depends on the complete conversion of phosphorus compounds presented into orthophosphate, which can be directly reacted with molybdate to produce phosphomolybdenum blue after reducing the phosphomolybdic acid with a suitable reducing agent. while the DRP or TDP determinations require the application of various digestion methods, such as wet chemical digestion, high temperature combustion, or fusion, microwave digestion, or UV photo-oxidation.
Alfa Chemistry is professional in detection of dissolved oxygen, total & reactive phosphorus and chromium VI. We can provide accurate and reliable tests results within the time constraint. Please feel free to contact us if you have any concerns. Check our instruments list to see our capabilities.
References
Elser JJ, Bennett E. A broken biogeochemical cycle [J]. Nature, 2011, 478:29–31.
L.M.L. Nollet, Handbook of Water Analysis [S], Marcel Dekker, New York, 1999, p. 273.
A.R. Pratt, D.W. Blowes, C.J. Ptacek, Products of chromate reduction on proposed subsurface remediation material [J], Environ. Sci. Technol. 31 (1997) 2492–2498.
D. Baron, C.D. Palmer, J.T. Stanley, Identification of two iron-chromate precipitates in a Cr(VI)-contaminated soil [J], Environ. Sci. Technol. 30 (1996) 964–968.
D.C. Lee, C.J. Park, J.E. Yang, Y.H. Jeong, H.I. Rhee, Screening of hexavalent chromium biosorbent from marine algae [J], Appl. Microbiol. Biotechnol. 54 (2000) 597–600.