Research Article
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 | R2 = 0.9957 | R2 = 0.9812 | R2 = 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% |
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SD: standard deviation; RSD: relative standard deviation.
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