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

Food Safety and Risk

Table 1 Comparative overview of four extraction methods parameters

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			/

*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)

ISSN: 2731-9245