Determination of chemical oxygen demand

Discussion. One very important application of potassium dichromate is in a back-titration for the environmental determination16 of the amount of oxygen required to oxidise all the organic material in a sample of impure water, such as sewage effluent. This is known as the chemical oxygen demand (C.O.D.) and is expressed in terms of milligrams of oxygen required per litre of water, mg L l. The analysis of the impure water sample is carried out in parallel with a blank determination on pure, double-distilled water. 

(1) This solution is prepared by dissolving 5g of silver sulphate in 500 mL of concentrated sulphuric acid. 

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Silver sulfate is used as a catalyst to oxidize long chain aliphatic hydrocarbons in the determination of chemical oxygen demand (COD). 

Examples of redox indicators are Indigo Carmine (C.I. 73015 [ 860-22-0] 8), which is frequently employed, and ferroin, an iron(n) complex with three 1,10-phenanthroline ligands (14), which is widely used in water and wastewater analysis in the determination of chemical oxygen demand (COD) in an internationally standardized procedure. For the structure of the organic ligand, see p. 539. 

Li, J., L. Zheng, L. Li, G. Shi, Y. Xian, and L. Jin. 2007. Photoelectro-synergistic catalysis combined with a FLA system application on determination of chemical oxygen demand. Talanta 72 1752-1756. 

Zhao, H., D. Jiang, S. Zhang, K. Catterall, and R. John. 2004. Development of a direct photoelectrochemical method for determination of chemical oxygen demand. Anal. Chem. 76 155-160. 

Chen, Y., Y. Wu, L. Zhu, et al. 2006. Rapid determination of chemical oxygen demand using a nano-Ti02-KMn04 photocatalytic oxidation system. Fenxi Huaxue 34 1595-1598. 

Ramon, R., Valero, R, and del Valle, M. 2003. Rapid determination of chemical oxygen demand using a focused microwave heating system featuring temperature control. 

T. Korenaga, H.Y. Ikatsu, The determination of chemical oxygen demand in waste-waters with dichromate by flow injection analysis, Anal. Chim. Acta 141 (1982) 301. 

D.-Z. Dan, R.C. Sandford, P.J. Worsfold, Determination of chemical oxygen demand in fresh waters using flow injection with on-line UV-photocatalytic oxidation and spectrophotometric detection, Analyst 130 (2006) 227. 

Fig. 7.2 (a) Scheme of a completely continuous flow analyser for uninterrupted determination of chemical oxygen demand, (b) Results obtained in the monitoring of laboratory waste throughout an afternoon. (Reproduced from [1] with permission of the Royal Society of Chemistry). 

T. Korenaga and H. Ikatsu, Effect of Silver Salt on the Determination of Chemical Oxygen Demand by Flow Injection Analysis [in Japanese]. Mp-pon Kagaku Kaishi, 4 (1981) 618. 

T. Korenaga, H. Ikatsu, and T. Mori wake. The Oxidation Behaviour of Various Organic Compounds on the Determination of Chemical-Oxygen Demand by Means of Flow Injection Analysis with Acidic Permanganate. Bull. Chem. Soc. Jpn., 55 (1982) 2622. 

J. M. H. Appleton, J. F. Tyson, and R. P. Mounce, The Rapid Determination of Chemical Oxygen Demand in Waste Waters and Effluents by Flow Injection Analysis. Anal. Chim. Acta, 179 (1986) 269. 

T. Korenaga, T. Moriwake, and T. Takahashi, Evaluation of Three Flow Injection Analysis Methods for the Determination of Chemical Oxygen Demand. Mem. Sch. Eng., Okayama Univ., 19 (1984) 53. 

Silvestre, C.I.C., Frigerio, C., Santos, J.L.M., and Lima, J.LF.C (2011) Quantum dots assisted photocatalysis for the chemiluminometric determination of chemical oxygen demand using a single interface flow system. Anal. Chim. Acta, 699, 193-197. 

Determination of chemical oxygen demand by a flow injection method using cerium(lV) sulfate as oxidizing agent. Analytica Chimica Acta T71-. 237-244. 

FI A manifold with on-line UV-photocata lytic oxidation used for the determination of chemical oxygen demand. Detector spectrophotometer (Amax = 524 nm) IV injection valve RC reaction coil. 

M. Zenki, S. Fujiwara, T. Yokoyama, Repetitive determination of chemical oxygen demand by cyclic flow injection analysis using on-hne regeneration of consumed permanganate. Anal. Sci. 22 (2006) 77-80. 

A. Cuesta, J.L. Todoli, J. Mora, A. Canals, Rapid determination of chemical oxygen demand by a semi-automated method based on microwave sample digestion, chromium(vi) organic solvent extraction and flame atomic absorption spectrometry. Anal. Chim. Acta 372 (1998) 399-409. 

Z.Q. Zhang, H.T. Yan, Y. Lin, Rapid determination of chemical oxygen demand by flame AAS based on flow injection on-line ultrasound-assisted digestion and manganese speciation separation. Atom. Spectrosc. 25 (2004) 191-196. 

W. Liu, Z. Zhang, Y. Zhang, Chemiluminescence micro-flow system for rapid determination of chemical oxygen demand in water, Microchim. Acta 160 (2008) 141-146. 

Y. Hu and Z. Yang. A simple chemiluminescence method for determination of chemical oxygen demand values in water. Talanta, 63 521-526, 2004. 

S. Ai, M. Gao, Y. Yang, J. Li, and L. Jin. Electrocatalytic sensor for the determination of chemical oxygen demand using a lead dioxide modified electrode. Electroanalysis, 16 404-409, 2004. 

S. Zhang, H. Zhao, D. Jiang, and R. John. Photoelectrochemical determination of chemical oxygen demand based on an exhaustive degradation model in a thin-layer cell. Anal. Chim. Acta, 514 89-97, 2004. 

C.E. Domini, M. Hidalgo, F. Marken, and A. Canals. Comparison of three optimized digestion methods for rapid determination of chemical oxygen demand dosed microwaves, open microwaves, and ultrasoimd irradiation. Anal. Chim. Acta, 561 210-217, 2006. 

B. Li, Z. Zhang, J. Wang, and C. Xu. Qrernilurninescence system for automatic determination of chemical oxygen demand using flow injection analysis. Talanla, 61 651-658,2003. 

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