. 2019 Apr 29;20:217. doi: 10.1186/s12859-019-2803-8

Table 1.

Comparison of the coefficient of variation (CV) of normalized lipid levels in three replicate injections calculated using different methods or ions

Test	CV (Avg)	CV (# >)^a	Sign Test
[M + H/NH4]⁺	5 ± 3%	31	p = 0.057
[M + Na]⁺	10 ± 10%	49	p = 0.057
Pos	4 ± 5%	10	p < 0.0001
Neg	12 ± 15%	42	p < 0.0001
Height	7 ± 5%	126	p < 0.0001
Area	6 ± 7%	59	p < 0.0001
Smoothed	7 ± 6%	103	p < 0.0001
Not Smoothed	6 ± 5%	82	p < 0.0001

^aThe number of species with CVs greater in the respective method or ion

Note that comparison for ions were made using peak areas, while those for smooth versus not smoothed utilized peak heights. Note that negative ion mode had an injection with a different volume than the remaining injections, and hence this could be the reason for increased CV as compared to positive ion mode