ERROR RECOGNITION AND PROGRAM OPTIMIZATION IN ET-AAS BY TIME-RESOLVED SIGNALS (DIRECT DETERMINATION OF ELEMENT TRACES IN URINE - CD, CO, CR, NI, TI, PB)

The direct determination of trace elements in urines with ET-AA-spectrometry leads to numerous systematic errors. Part of these errors can be discovered by time-resolved signals and can thereby be avoided. Contrary to the assumption that optimal results can be obtained via the signal area, it is often the measurement of the signal height, which is to be given preference (better ratio of atomic absorption signal/background signal). Phosphate-containing matrix modifiers cause systematic interferences; their use should therefore be avoided. The determination of cobalt traces with the ET-AA-spectrometry and with D2-background correction will always yield wrong values, if samples contain at the same time phosphorous oxygen compounds as well as alkali compounds. Previous Co-determinations which were carried out with this method should therefore be controlled in a number of biotic matrices. When "Zeeman"-correction is used, such errors will not occur.