Table 1. Regression equation, correlation coefficient (R²), limit of detection (LOD) and limit of quantification (LOQ) of GPH

Standard	Concentration range (μg/mL)	Regression equation	R2	LOD (μg/mL)	LOQ (μg/mL)
GPH	1-50	y = 45086.3x + 986.8	0.9999	0.07	0.22