Regression equation, correlation coefficients, linearity ranges, and LLOQs for five analytes.

Peak no.	Analytes	Calibration curves	Correlation coefficient, R2	Linear range (ng mL−1)	LLOQs (ng mL−1)
1	ATP	y = 0.0130x − 0.8114	0.9990	10.5–1080.5	10.5
2	ADP	y = 0.0270x − 2.4892	0.9991	9.5–1180.5	9.5
3	AMP	y = 0.0101x − 0.7401	0.9990	10.6–2070.0	10.6
4	CATR	y = 0.0006x − 0.0271	0.9992	9.5–1450.5	9.5
5	ATR	y = 0.0048x − 0.1623	0.9996	10.8–1480.0	10.8