Determination of Eight Kinds of Catechins in Bottled Green-tea Drinks by HPLC on a Cholesteryl Group Staionary Phase Column
Bibliographic record
Abstract
Eight kinds of catechins are well known because of their antioxidant activity and chemopreventive effects against cancers. The determination of eight kinds of catechins {GC: (−)-gallocatechin; EGC: (−)-epigallocatechin; C: (+)-catechin; EC: (−)-epicatechin; EGCg: (−)-epigallocatechin gallate; GCg: (−)-gallocatechin gallate; ECg: (−)-epicatechin gallate; CG: (−)-catechin gallate} in bottled green tea drinks by high-performance liquid chromatography (HPLC) with an ultraviolet detector (UV) on a cholesteryl group stationary phase column has been developed. This analytical method provides high linearity of the calibration curve as well as both repeatability and reproducibility. The correlation coefficient of the working curve of calibration were estimated to be from 0.9998 to 0.9987 for eight kinds of catechins in the concentration range from 5 mg L−1 to 150 mg L−1. The limits of detection (LOD) calculated on 3σ at 10 mg L−1 were 0.39 mg L−1 for GC, 0.74 mg L−1 for EGC, 0.07 mg L−1 for C, 0.33 mg L−1 for EC, 0.28 mg L−1 for EGCg, 0.35 mg L−1 for GCg, 0.18 mg L−1 for ECg, and 0.19 mg L−1 for CG. The limits of quantification (LOQ) calculated on 10σ at 10 mg L−1 were 1.29 mg L−1 for GC, 2.48 mg L−1 for EGC, 0.24 mg L−1 for C, 1.09 mg L−1 for EC, 0.94 mg L−1 for EGCg, 1.17 mg L−1 for GCg, 0.62 mg L−1 for ECg, and 0.65 mg L−1 for CG. Good results (the recoveries were 85.5–109.6% and the relative standard deviations were 2.5–4.9%) were obtained in recovery tests by using bottled green tea drinks. This proposed method could be successfully applied to the determination of eight kinds of catechins in bottled green tea drinks.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".