Electrothermal atomic absorption determination of chromium in sediments

An electrothermal atomic absorption spectrometric method has been developed to determine total chromium concentration in natural sediment samples. Sam ples were mineralized by dry ashing at 550 degrees C and fused at 1100 degr ees C for 30 min with lithium metaborate. Dissolved samples were injected i n graphite tubes, mineralized at 1100 degrees C, and atomized at 2600 degre es C. Standard addition calibration made unnecessary the use of chemical mo difiers. The method provided a limit of detection from 23 to 45 ng liter(-1 ). The relative standard deviation for chromium determination was between 3 and 14%. Results obtained for a standard reference material agree well wit h the certified valuer A series of natural samples were analyzed by the dev eloped procedure and also directly by neutron activation analysis without a ny pretreatment and comparable results were obtained by both procedures. (C ) 1999 Academic Press.