Objective Analyze and evaluate the measurement uncertainty of phenylethanolamine A residue in beef using liquid chromatography tandem mass spectrometry. Methods By analyzing the detection process and mathematical model, the main sources of uncertainty in the residual amount of phenylethanolamine A are determined: uncertainty caused by detection equipment, uncertainty caused by standard and sample weighing, uncertainty caused by laboratory temperature, uncertainty caused by transfer and constant volume, uncertainty caused by sample pretreatment, and uncertainty caused by experimental repeatability. Results The measurement uncertainty of each component was calculated and the relative standard uncertainty $\left({{u}_{\mathrm{{rel}}}={0.11}}\right)$ was synthesized for the detection of phenylethanolamine A residue in beef by liquid chromatography-tandem mass spectrometry. The expanded uncertainty of the determination results was $\mathrm{U}\left( X\right)={0.11}\mathrm{{g}}/\mathrm{{kg}}$ . The detection result of measuring phenylethanolamine A in beef by liquid chromatography tandem mass spectrometry was: $X=\left({{0.51}\pm {0.11}}\right)\mathrm{{\mu g}}/\mathrm{{kg}}, k =2$ . Conclusion The detection equipment had the greatest impact on the measurement uncertainty of phenylethanolamine A residue, followed by sample pre-treatment, experimental repeatability, and transfer and constant volume. In daily testing, attention should be paid to the condition of the instruments and equipment, timely verification and calibration should be carried out, the experimental process, transfer and constant volume operation should be standardized, so that to minimize the impact of the above factors on measurement uncertainty as much as possible.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |