Table 2. Calibration curves of sphingolipids.

Compounds	Calibration range (ng mL−1)	Equations	Coefficient correlation (r)
Sph	1.0–100	Y=0.0105+0.000463X	>0.999
dhSph	0.1–100	Y=0.000340+0.000148X	>0.997
S1P	0.05–100	Y=0.0000184+0.000155X	>0.999
dhS1P	0.5–100	Y=0.000120+0.000279X	>0.998
Cer d18 : 1/16 : 0	5.0–100	Y=0.0161+0.000172X	>0.989
Cer d18 : 1/18 : 1	1.0–100	Y=0.000635+0.000150X	>0.999
Cer d18 : 1/18 : 0	1.0–100	Y=0.00245+0.0000950X	>0.998
Cer d18 : 1/20 : 0	5.0–100	Y=0.000959+0.0000868X	>0.994
Cer d18 : 1/22 : 0	5.0–100	Y=0.00544+0.0000765X	>0.987
Cer d18 : 1/24 : 0	5.0–100	Y=0.0100+0.0000816X	>0.979