Abstract: A new speictrophotometric method for rapiddetermination of calcium based on its purple color reaction with 3.3 ’-Dimethy Lphenolphthalein in the presence of basic medium of ethanoamine -boric acid as buffer solution has been nivestigated.The optimum pH is 11.the λmax 570um the linear range of determination 0 ~ 10 μg/6ml and the molar absorbance coefficient ε =1 .8 x 10~4 .The percentage of recovery with standard addition is about 97.6% to 101 .6% and the coefficient of Variation of determination is about 3. 16% .This method has been found satistadory for the rapid determination of calcium in food.

Key words: Food； Calcium 3.3&rsquo, -Dimethyphenolphthalein；