Abstract
Atomic absorption spectrophotometry was applied to the determination of zinc in foods.
(1) Absorbancy at 213.9mμ was measured to determine zinc.
(2) A linear relationship between an absorbancy and a concentration was found within the range of 0-5 p. p. m. zinc.
(3) Samples were burnt to ashes in an electric muffle furnace at 550°C, the ashes were dissolved with 5ml of 6N hydrochloric acid and made up to 100ml with water. One ml of the acid solution was pipetted and added 5ml of 6N hydrochloric acid, 5ml of calcium chloride (2500p. p. m. Ca) and 20ml of ethylalcohol, and then made up to 100ml with water. This solution was submitted to the analysis of zinc.
(4) Silicon, tin, copper, chromium, magnesium and potassium interfered with the determination of zinc considerably, but the interferences were eliminated by adding 2500p. p. m. of calcium.
(5) Recoveries of zinc added to the sample solution were found to be satisfactory.
(6) The reproducibility of analytical values was also satisfactory, that is, the coefficient of variation for zinc was 4.83% for oyster.
(7) Contents of zinc in marine products examined were about 0.5-3mg% with the exception of oyster and crab, contents of it were50-70mg% for the former and 16mg% for the latter, respectively.
