Development and Validation of Near-Infrared Methods for the Quantitation of Caffeine, Epigallocatechin-3-gallate, and Moisture in Green Tea Production

Table 5

Validation results of the method.

Project	Describe	Caffeine	Moisture content	EGCG
Linearity	NIR prediction = a  reference value + b	Training set	Training set	Training set
		Y = 0.9957X + 0.0223	Y = 0.9812X − 1.7039	Y = 0.9885X + 0.0944
		R^2 = 0.9957	R^2 = 0.9812	R^2 = 0.9885
Accuracy	The paired t-test between the NIR predicted value and the reference value of the sample in the validation set	Prediction set	Prediction set	Prediction set
		t = −1.441	t = −0.663	t = 0.505
		p = 0.162 (α = 0.05)	p = 0.513 (α = 0.05)	p = 0.618 (α = 0.05)
Repeatability	The same sample was measured 6 times on the same day by the same operator	Sample reference 3.45%	Sample reference 6.05%	Sample reference 7.15%
		SD = 0.095	SD = 0.202	SD = 0.107
		RSD = 2.699%	RSD = 3.654%	RSD = 1.459%
Intermediate precision	The same sample was measured by two operators for three consecutive days	Sample reference 3.45%	Sample reference 6.05%	Sample reference 7.15%
		SD = 0.029	SD = 0.179	SD = 0.039
		RSD = 0.835%	RSD = 2.968%	RSD = 0.554%

SD: standard deviation; RSD: relative standard deviation.