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Table 1 Comparative overview of four extraction methods parameters

From: Assessment of antibiotic residues in commercial and farm milk collected in the region of Guelma (Algeria)

Extraction steps Method 1 Method 2 Method 3 Method 4
(Martins et al. (2014))
1) Sample amount 3g 10g 10g 0.5g
2) Type of container 50mL Falcon tube 2mL Eppendorf tube
3) Mixed internal standard solution, 1MRL (EU2377/90) 150μL 150μL 500μL 12.5μL
4) EDTA, 0.1M 200μL 200μL 667μL 30μL
5) Mixture methanol/acetonitrile 7mL 7mL 23mL /
6) Sodium sulfate anhydride 3g 3g 3g /
7) Mixed standard solution* 75μL 75μL 250μL 12.5μL
8) Vortexing 1min 10sec and equilibration for 10min from light
9) Centrifugation 10000rpm, 10min at 4°C  
10) Deprotonization     0.6mL
Ethanol/acetic acid (96/4)
Followed by short vortexing and 30min at -18°C incubation
11) Supernatant 5mL evaporated to dryness at 40°C followed by addition of 300 μL of water MilliQ /
12) Vortex and centrifugation Few seconds
12000rpm during 30min
13) Supernatant All supernatant 0.75mL with addition of 0.25mL
Formic acid 0.1% in water/ formic acid in acetonitrile (98:2)
14) Filtration 0.2μm filter /
  1. *mixed standard solution contained: Sulfonamides (sulfapyridine, sulfamethoxypyridazine, sulfadoxine, sulfadimidine, sulfamonomethoxine, sulfaquinoxaline, sulfaquinoxaline, sulfamoxole, sulfachlorpyridazine, sulfadimethoxine, sulfaquinoxaline, sulfathiazole, sulfaguanidine, trimethoprim, sulfamerazine, sulfamethoxazole, Sulfadiazine, sulfacetamide, sulfisoxazole), penicillins (amoxicillin, ampicillin, penicillin V, penicillin G, dicloxacillin, cloxacillin, oxacillin, nafcillin) quinolones (flumequine, difloxacin, sarafloxacin, ciprofloxacin, enrofloxacin, danofloxacin, nalidixic acid, marbofloxacin, norfloxacin, ofloxacin , oxolinic acid), macrolides (erythromycin, spiramycin, josamycin, clindamycin, lincomycin, neospyramycin, tilmicosin, tylosin, tylvalosin, tulatrhomycin), tetracyclines (doxycycline , oxytetracycline ,4-epi- chlortetracycline, 4-epi-oxytetracycline, 4-epi- tetracycline, tetracycline, chlortetracycline)