The Effect of pretreatment and time of Storage on the determination of selenium by AAS in tissues of patients with breast tumors.


AbstractThis study involves an investigation on the effect of pretreatment using many acids or their mixtures on the determination of selenium in a standard reference material of tissue. The mixture (HClO4: H2O2) (1:1) gave the best accuracy in the determination of selenium concentration in the standard sample, the optimum conditions for the other parameters (Temperature & time of storage of the tissue in solutions (formalin & normal saline) were also evaluated. The standard calibration curve revealed a straight line and high sensitivity indicated by detection limit (DL=0.3 X 10-3 ug / ml. ) and % recovery = 96.2 . Selenium can be measured in tissue samples which kept in formalin up to 6 days for both Benign & malignant tissues . But, in normal saline up to 4 days in both benign & malignant tissues can be tolerated . Higher values for selenium concentration in malignant tissue compared with benign tissue are found . In the other hand lower values for selenium concentration in sera samples of patients with breast cancer are noticed