. 2023 May 12;12(5):1092. doi: 10.3390/antiox12051092

Table 3.

Prepared targeted individual standards for individual and compound quantification.

Compound	Class	Purity	Mass, mg	Volume, mL	Stock Solution, mg mL⁻¹	Calibration Range
Leucine	Amino acids	99%	9.8	10 mL water	0.98	1–50 μg mL⁻¹ R² = 0.996
Ferulic acid	Phenolic acids	98%	10.1	10 mL methanol	1.01	1–100 μg mL⁻¹ R² = 0.9999
Apigenin	Flavonoids	99.08%	9.0	100 mL ethanol	0.09	100–100,000 ng mL⁻¹ R² = 0.9997
Coumarin	Hydroxycoumarins	98%	9.8	10 mL methanol	0.98	100–100,000 ng mL⁻¹ R² = 0.997