This study developed a novel method for the detection of 22 antibiotics in marine sediments by integrating online solid-phase extraction(SPE) with ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS). The method was subsequently applied to the analytical determination of antibiotics in offshore bay sediments. Optimal experimental conditions were established through systematic optimization of sample extraction and online SPE parameters. Sediment samples were extracted using an acetonitrile-EDTA/McIlvaine buffer solution(1∶1, v/v), diluted with ultrapure water, and then purified and enriched using a large-pore styrene/divinylbenzene-packed PLRP-S online SPE column. The processed samples were separated on a Poroshell EC-C18 column(50 mm×2.1 mm, 1.9 µm) and detected in electrospray ionization(ESI) positive ion mode with multiple reaction monitoring(MRM) acquisition. The entire analytical process was completed within 14 min. The results showed that the 22 antibiotics showed good linearity in their respective mass concentration ranges with the correlation coefficients(R2)≥0.990 0, the limits of detection(LODs, S/N=3) were 0.001‒0.08 ng/g, and the limits of quantification(LOQs, S/N=10) were 0.004‒0.4 ng/g. The spiked recoveries of the 22 antibiotics under three spiked levels(low, medium and high) were 45.1%‒145.6% with the relative standard deviations(RSDs)<14%. The method was used to detect antibiotics in winter and summer sediment samples from Shandong Sishili Bay offshore. The results showed that a total of 19 antibiotics from five classes were detected in nine summer sediment samples, with the contents ranging from 0.01 to 34.64 ng/g; and oxytetracycline exhibited the highest detection level. A total of 20 antibiotics from five classes were detected in 10 winter sediment samples, with the contents ranging from 0.004-19.11 ng/g; and ofloxacin showed the highest detection level. Compared with the commonly used offline SPE method, this method greatly simplifies the sample purification process and provides a simple and effective method for the routine detection of common antibiotics in marine sediments.
| 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 |