This article introduces a liquid chromatography-atmospheric pressure photoionization-mass spectrometry method (LC-APPI-MS) for the determination of chloramphenicol antibiotics in fish meat. The method involves extraction of the samples with ethyl acetate, followed by liquid-liquid distribution with acetonitrile and n-hexane for cleanup. Recoveries of chloramphenicol from young yellowtail meat and flatfish meat spiked at 0.1-2 ng/g were 89.3%-102.5% and 87.4%-94.8%, respectively. The limit of detection (signal-to-noise = 3) of the young yellowtail meat and the flatfish meat were 0.27 and 0.10 ng/g.
The document details a method developed for determining chloramphenicol antibiotics in fish meats using liquid chromatography-atmospheric pressure photoionization-mass spectrometry (LC-APPI-MS). The study focuses on optimizing ion source parameters to achieve simple mass spectra and strong signals corresponding to the [M-H] ion.
The experimental procedure involves extracting samples with ethylacetate, followed by a clean-up step using liquid-liquid distribution. Key optimization results include setting the capillary voltage at 3500 V when acetone is used as a dopant, the vaporizer temperature at 350 °C to prevent thermal degradation, and the fragmentor voltage at 120 V for optimal signal-to-noise ratio.
| Column | Zorbax Eclipse XDB C18 (150 mm x 3 mm, 5 um) |
|---|---|
| Ionization Mode | APPI (Negative) |
| SIM Ion Target | m/z 321; (M-H} |
| Drying Gas Flow | 7 L/min at 360 °C |
| Nebulizer Pressure | 50 psi |
| Fragmentor Voltage | 120V |
| Capillary Voltage (with dopant) | 3500 V |
The optimum capillary voltage is 3500 V, which yields higher intensity than without the dopant.
The vaporizer temperature should be set at 350 °C, as higher temperatures cause thermal degradation.
The optimum fragmentor voltage is found at 120 V, where the best S/N ratio was observed.