Abstract: The paper introduced a simple and rapid method of determining the phosphorus and arsenic in food. At first thesample was combusted by the technology of oxygen bomb ashing combustion in high pressure and pure oxygen. Then, the ashingproducts were absorbed by the thick and strong base NaOH. Under the acid condition, the Arsenic concentration was determinedby As-Bi-Mo -blue spectrophotometry method after the As3+ was transferred into As5+ oxidized by the KMnO4 and thephosphorus could be analyzed by As-Bi-Mo -blue spectrophotometry method after the phosphorus in food was transformedto the phosphoric anhydride. These samples such as powder shrimp skin, flour and tea were analyzed by the method. The resultsshowed that the method was simple, fast and highly pure. The percent recovery of phosphorus was 96.8%～103% and arsenic96.3%～103%. The results showed that the method was practical and satisfactory and could be used in assaying the quantityof phosphorus and arsenic in food directly.

Key words: oxygen bomb, combustion, ashing, spectrophotometric method, food, phosphorus, arsenic