Table 1. Number of confident peptide identifications^a.

	gradient type
gradient length	linear	in silico-optimized	MS1-optimized
4 h	17 433	18 079	17 759
	17 228	17 843	17 449
	17 363	17 978	17 804
	17 210	17 590	17 576
average	17 308.5	17 872.5	17 647.0
2 h	6176	6478	6700
	6030	6298	6583
	5980	6239	6713
	5965	6412	6578
average	6037.8	6356.8	6643.5

^aWe give the number of peptides identified at 1% FDR for all the data sets investigated throughout the study.