OPTIMIZATION OF BERYLLIUM DETERMINATION I N BIOLOGICAL-MATERIALS BY GRAPHITE-FURNACE AAS

A method was optimized to enhance the sensitivity of graphite furnace atomic absorption spectrometry for the determination of beryllium in b iological materials. Magnesium nitrate was added to the acid-digested sample solution, and a low-noise photomultiplier was utilized. The amp lifier was operated at 10 times the ordinary amplification. Best resul ts were obtained with a magnesium concentration of 10(-3) M when 50 mu l of the solution was injected and ashed at 1250-degrees-C for 30 s. U nder these conditions, the matrix alkali salts are diminished to such an extent that background correction can be readily made, without impa iring the beryllium sensitivity. The detection limit is 0.005 ppb (Be 0.25 pg). By this method a beryllium content of 0.50 ng/g (SD 0.04, n = 12) was found in NIST Bovine Liver (SMR 1577)