719
Anal. Chem. 1985, 57, 719-723
sured; the AES results were supported by LEED measurements on the Cu (110) surface (12).Therefore, the estimated accuracy is about &lo%. In general, the systematic error for quantification of the surface coverage by the decrease in the matrix signal (5) is higher and depends mainly on the knowledge of the mean escape depth of the Auger electrons, which may be wrong by f30% (17). With conventional trace analysis techniques, e.g., acid digestion in combination with microtitrimetric or spectrophotometric determination of sulfur in metals, a detection limit of 0.2 ppm, an accuracy of typical *IO% at 2 ppm and I f l o % precision can be achieved with about 0.5 g of a sample consumed (18).As compared to these figures, the segregation/ sputtering and AES method shows comparable accuracy, better precision, lower detection limit, and negligible sample consumption (
