RESUMEN
ve To compare the advantage and disadvantages of spectrophotometry assay, microwave di-gestion and standard circumfluence method for determination of chemical oxygen demand (COD) in various water samples. Methods The levels of COD of the water samples were determined by spectro-photometry, microwave di-gestion and standard circumfluence method respectively. Results The relative standard variations were 4.3% ~ 9.59% for spectrophotometry, 3.58% ~5.61% for microwave digestion method and 4.03% ~ 4.27% for standard circumfluence method. The recovery rates of adding standard material were 90% -95% , 90% ~96% and 90% ~98% respectively. Conclusion The microwave digestion method showed easy, rapid and accurate. It presented good practical prospect in monitoring environmental samples.