The composition of a brass alloy is determined through target factor a
nalysis (TFA) of Auger data. In spite of spectral interference between
Cu and Zn transitions, quantitative information is derived from both
the low-energy and the high-energy part of the brass spectrum. From th
e less surface-sensitive high-energy region, the nominal composition o
f the alloy is recovered, whereas from the more surface-sensitive low-
energy region a definitely higher Zn/Cu ratio is found. This is interp
reted in terms of surface segregation of Zn brought about by in situ s
cribing for surface cleaning.