Digestion with nitric, perchloric and sulfuric acids

Digestion with nitric, perchloric and sulfuric acids 

Transfer to a 100 ml Kjeldahl flask 2 g of an accurately weighed sample and add 5 ml of HN03. After vigorous initial reaction subsides, heat gently until further reaction ceases, cool, slowly add 8 ml of H2S04 and heat until 

---

A hair sample (1 g) is washed with water, acetone, ether, and detergents followed by a successive rinse with water, acetone, and ether. After washing and drying the hair sample, it is digested with nitric, perchloric, and sulfuric acids. After digestion, the hydrochloric acid concentration of the sample solution is adjusted to 4 M, and it is boiled for 5 min. The tellurium content in the sample solution is determined by the hydride generation atomic absorption spectrometry described above. The lower detection limit is 1 ng/g and the levels of unexposed subjects are below the detection limit [13]. 

---