Table 2.

Descriptive statistics of features, formulas, and A1α compounds between negative and positive modes.

Ionization mode	Negative	Positive	Total
Number of features	4,317	10,606	14,923
Average (SD) features per sample	480 (207)	1,178 (542)	1,658 (724)
Geometric mean peak area	420,000	230,000	270,000
Features assigned a formula	181	249	430
Unique formulas	166	231	270
Percent of features assigned a formula	4.2%	2.3%	2.9%
Percent peak area assigned a formula	12.8%	19.2%	16.9%
Features with A1α designation	74	74	148
Percent peak area of A1α compounds	8.2%	7.0%	7.4%