Simultaneous Determination of Four Tetracycline Antibiotics Residues in Chicken by Solid Phase Extraction Coupled with High Performance Liquid Chromatography
Bibliographic record
Abstract
Objective: To establish a simple and rapid method for simultaneous determination of Tetracycline, Oxytetracycline, Chlortetracycline and Doxycycline in chicken. Methods: After optimized sample pretreatment and chromatographic conditions, tetracycline antibiotics in spiked chicken were extracted by ultrasonic extraction with Na2EDTA-Mcllvaine buffer solution (pH=4.0), purified and enriched by HLB solid phase extraction column, separated by Shim-pack GIST C18 column (4.6×150 mm, 3 μm), methanol-acetonitrile-oxalic acid (1:2:7, V: V: V) as the mobile phase, the flow rate was 0.9 mL/min, the UV detection wavelength was 350 nm, and the peak area was quantified by external standard method. Results: The linearity of the four tetracycline antibiotics was good in the range of 0.05-1 mg/kg (r＞0.997), and the detection limits were 2.53 μg/kg ~ 5.94 μg/kg according to the S/N ratio (S/N) of 3. The relative standard deviations (RSD, n=6) of precision were 1.51%-4.80%. The recoveries were from 76.81% to 96.34%. Conclusion: The method has good selectivity, high accuracy and reproducibility, and is suitable for simultaneous determination of four tetracycline antibiotics in chicken.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".