Determination of chemical oxygen demand in aqueous samples with non-electrochemical methods

Water contamination is a globally important environmental concern, with chemical oxygen demand (COD) being a criteria in water quality assessment, providing information on the availability of chemically degradable fractions of organic pollutants. However, the standard method for COD analysis is time-consuming and results may vary between laboratories. Efforts to resolve these problems have mostly focussed on improvements to both digestion and detection techniques and this review addresses recent trends in the determination of COD in aqueous samples, based on published literature since 2000. The features of principal methods are critically reviewed, focusing on their practical applicability. This review includes an overview of: 1) standard methods; 2) novel digestion techniques; 3) varying detection methods, such as chemiluminescence, spectrophotometry and others; 4) and future trends in COD measurements. Electrochemical techniques are excluded, as despite their importance as an environmental friendly alternative for COD measurement, these methods have only recently been developed and require a full and separate review.