XPS Detection Limits in XPS
Detection Limits depend on Noise and Baseline Endpoint Averaging
XPS Detection Limits
by M. Biesinger (UWO)
In general, detection limits for XPS range from 0.1 to 1 atomic percent. However there are cases where limits could be much better or much worse. An article from Alexander Shard  gives an excellent look at detection limits in over 6000 binary systems for both Al and Mg X-ray sources. In such systems a heavy element, such as gold, in a light element matrix, say carbon, would have detection limits closer to 0.01 atomic percent. For the opposite situation, carbon in a gold matrix, detection limits for carbon would be around 3 atomic percent. Spectral overlaps can also degrade detection limits significantly and are incorporated into the tables presented. Overlaps with Auger peaks can be overcome by changing X-ray sources used (i.e. using Mg K instead of Al K). One can also work with advanced curve-fitting techniques to overcome some of these overlap issues.
 A.G. Shard, Surf. Interface Anal. 46 (2014) 175-185.