Table 3.
Different conventional methods used for the detection of colistin in animal-based food.
| Country | Sample | Method Used | Chromatography Conditions Used | Detection Limit | Reference | |||
|---|---|---|---|---|---|---|---|---|
| Model | Column | Solvent | Flow Rate | |||||
| China | Spiked bovine milk | HPLC–MS/MS | An HPLC (Hewlett-Packard HP 1100 series, Rockville, MD, USA) integrated system consisting of a 100-well auto-sampler, a 100 µL sample loop, a degasser, a quaternary pump and a thermostated column oven set at 25 °C was used | Chromatographic separation was performed in a 250 mm × 2.1 mm, 5 µm Alltima C18 separation column (Alltech, Deerfield, MA, USA) and a corresponding C18 guard column (7.5 mm × 4.6 mm) | Mobile phase A: 0.1% formic acid in acetonitrile and mobile phase B: saturated ammonium formate:formic acid:acetonitrile:water (1:5:50:950, v/v/v/v) | Flow rate of 0.2 mL min−1 under a gradient elution program comprised of two mobile phases | 50 µg/Kg | [85] |
| China | Spiked fishery products | UPLC–MS/MS | A UPLC–MS/MS system comprised an Acquity UPLC system connected online with a Quattro Premier tandem mass spectrometer (Waters, Milford, MA, USA) | The column used was an ACQUITYTM BEH C18 reversed phase column (2.1 mm × 100 mm, 1.7 µm particle size) maintained at 40 °C | Mobile phase was 0.2% formic acid in acetonitrile and 0.2% formic acid in water | Flow rate and temperature of the drying gas (N2) were 750 L h−1 and 350 °C, respectively. The cone gas flow (N2) was 50 L h−1 | 10 µg/Kg (colistin A), 40 µg/Kg (colistin B) | [86] |
| Hungary | Spiked pig feeds | HPLC–fluorescence detector | JASCO PU-980 high pressure pump (JASCO, Kyoto, Japan) | A TSK ODS 120T column (150 × 4.6 mmID, 5 µm) was used with an injection volume of 25 µL | Mobile phase was 22:78 v/v acetonitrile–50 mM sodium sulfate, 20 mM orthophosphoric acid, 25 mM triethylamine | Flow rate of the mobile phase and post-column reagent were 1.5 and 1.0 mL min−1, respectively | 20 mg/Kg | [87] |
| Spain | Spiked animal feeds | HPLC–fluorescence detector | Thermo HPLC system equipped with a P200 gradient pump | Analytical column (150 × 4.6 mm i.d.) used was packed with Ultracarb 5 µm ODS 30%C. Guard columns (50 × 4.6 mm i.d.) were packed with dry 40 µm Pelliguard LC-18 | Mobile phases with methanol and acetonitile | Flow of 1.5 mL | 5 mg/Kg | [88] |
| France | Spiked bovine milk and tissues (muscle, liver, kidney, fat) | HPLC–MS | The HPLC system consisted of a solvent delivery pump (model P2000, Thermo Separation Products, Les Ulis, France), an injection valve (model 7725i, Rheodyne, Cotati, CA, USA) | An analytical column (125 × 4 mm i.d.) pre-packed with 5 μmNucleosil C18 (Macherey-Nagel, Düren, Germany) | Mobile phase was acetonitrile and a 0.035 M triethylamine solution adjusted to pH 2.5 with phosphoric acid and mixed in 17:83 (v/v) proportions | The flow rate was 1.5 mL/min | 25 µg/L (milk), 100 µg/Kg (tissues) | [89] |
| China | Swine liver, chicken eggs, feed, swine muscles, chicken muscles, bovine muscles, sheep muscles, bovine raw milk | UHPLC–MS/MS | An Acquity ultra-performance liquid chromatography system (Waters, Milford, MA, USA) | An Acquity BEH C18 column (50 mm × 2.1 mm i.d., 1.7 μm particle size) (Waters, Milford, MA, USA) | Mobile phases comprised of 0.5% formic acid in water (solvent A) and 0.5% formic acid in acetonitrile (solvent B) | Flow rate was 0.4 mL/min with the following gradient program: 0–0.5 min, 95% A; 0.5–3.0 min, 95–50% A; 3.0–4.0 min, 50–5% A; 4.0–4.1 min, 5–95% A; 4.1–5.5 min, 95% A | 5–30 µg/Kg | [90] |
| Belgium | Spiked swine manure | UHPLC–MS/MS | An Acquity UPLC H-class system (Waters, Milford, MA, USA) | Reversed-phase Kinetex C18 column (100 mm × 2.1 mm i.d., 1.7 µm) with a SecurityGuard Ultra guard cartridge system (Phenomenex, Utrecht, The Netherlands) | The elution was performed gradually with changing amounts of H2O/MeCN (95/5) + 0.5% FA + 0.1% ammonium formate (solvent A) and MeCN + 0.1% FA (solvent B). The gradient (15 min) was initiated with 95% of solvent A (0–1 min), followed by a linear decrease of A to 75% (1–3 min). From min 3–5, there was a linear decrease of solvent A to 0% and this was held until min 7. Re-equilibration of the gradient at 95% A was held from min 7–15 | Flow at 400 µL/min | 20.2 µg/Kg (colistin A), 15 µg/Kg (colistin B) | [91] |
| China | Spiked swine and poultry feeds | UHPLC–MS/MS | LC–MS/MS system (Thermo Electron Corp., Wyman, Waltham, MA, USA) consisting of a Finnigan Surveyor Plus system with an online degasser, a Surveyor autosampler and a TSQ Quantum triple quadrupole mass spectrometer equipped with an electrospray interface operating in the positive mode (ESI+) | Separation was performed on 150 mm × 2.1 mm, 5 μm Hypersil Gold C18 analytical columns (Thermo Electron Corporation, Waltham, MA, USA) | Mobile phase A consist formic acid in water and mobile phase B formic acid in ACN | Flow-rate of 0.2 mL min−1 | 27.5 µg/Kg (colistin A), 25.7 µg/Kg (colistin B) | [92] |
| China | Spiked piglet premix, pig feed additive, poultry complete feed, pig complete feed and fattening pig premix | UHPLC–MS/MS | Shimadzu liquid chromatography system (Shimadzu, Kyoto, Japan) | Separations were carried out on a Phenomenex Kinetex Biphenyl column (50 mm × 2.1 mm i.d., 2.6 µm particle size, Phenomenex, Torrance, CA, USA) | Mobile phase consisted of 0.1% FA in ACN solution (A) and 0.1% FA in water solution (B) with the following gradient elution program: 0 min, 6% A; 2 min, 6% A; 5 min, 40% A; 14 min, 70% A; 14.1 min, 6% A; 18 min, 6% A | Flow rate of 0.2 mL/min. | 5–20 µg/Kg (colistin A), and (colistin B) | [93] |
| Canada | Spiked chicken muscle | UPLC–MS/MS | Waters Acquity UPLC interfaced to a Waters Micromass triple quadrupole Premier mass spectrometer equipped with an ESI source and controlled by MassLynx 4.1 software(Waters, Milford, MA, USA) | Poroshell 120, 100 × 2.1 mm id, 2.7 μm (Agilent Technologies, Mississauga, ON Canada) | Mobile phase A (0.1% formic acid in water)and mobile phase B (methanol) | Flow rate of 0.40 mL/min | 39 µg/Kg (colistin A), 50 µg/Kg (colistin B) | [94] |
| Italy | Spiked bovine milk, meat | HPLC–MS | Thermo Ultimate 3000 High Performance Liquid Chromatography system (Thermo Scientific, San Jose, CA, USA) | InfinityLab Poroshell 120 HILIC column (100 × 2.1 mm; 2.7 μm, Agilent Technologies, Santa Clara, CA, USA) connected with the InfinityLab Poroshell 120 HILIC guard column (5 × 2.1 mm, 2.7 μm) | Eluent A was an aqueous solution containing 1% (v/v) formic acid (FA) and 1 mM ammonium formate (AF), eluent B was acetonitrile. The gradient was initiated with 20% eluent A for 2 min, continued with linear increase to 35% A in 5 min. In 1 min eluent A increased to 95% and this condition was maintained for 7 min. The system returned to 20% B in 0.1 min and was re-equilibrated for 4 min (run time: 17 min) | Flow rate was 0.25 mL min−1 | 33 µg/Kg | [95] |
| Hong Kong | Spiked bovine milk and tissues | HPLC–MS/MS | An integrated HPLC system (Hewlett–Packard HP 1100series, Rockville, MD, USA) consisting of a 100-well autosampler, a degasser, two-channel binary pump, and atemperature control oven (set at 25 °C), and interfaced with a TSQ Quantum Discovery mass spectrometer (Thermo-Finnigan, San Jose, CA, USA) | 150 mm×2.1 mm, 5 μm Phenomenex Luna C18 analytical column (Torrance, CA, USA) connected to a 7.5 mm × 4.6 mm Alltech Alltima C18 guard column (Deerfield, IL, USA) | Mobile phases, which were comprised of a mixture of (A) 0.1% formic acid in water and (B) 0.1% formic acid in acetonitrile, were delivered under a gradient elution program (0–4 min: 95% A, 5% B; 4–8 min: 30% A, 70% B and held for 4 min; 12 min: 95% A, 5% B and held for 3 min to restore initial conditions before the next injection | Flow-rate of 0.25 mL min−1 | 1–16 µg/Kg (colistin A), 6–14 µg/Kg (colistin B) | [96] |
| Switzerland | Spiked bovine liver, kidney, muscle, egg, milk | UHPLC–MS/MS | Acquity system (sample and solvent manager) from Waters (Millford, MA, USA) | Kinetex C18, 2.1 × 150 mm × 2.6 µm column with an installed pre-filter (Krud-katcher), both from Phenomenex (Torrance CA, USA) | Mobile phase A: 50 mL acetonitrile, 3 mL of formic acid and 0.1 mL of trifluoroacetic acid were transferred into a 1000 mL volumetricflask and diluted to volume with purified water; Mobile phase B: 50 mL of purified water, 3 mL of formic acidand 0.1 mL of trifluoroacetic acid were transferred into a 1000-mLvolumetric flask and diluted to volume with ACN | Linear gradient was used: 0–2 min with 8% B and flow0.4 mL min−1, 2–7 min with 8–20% B, 7–8 min with 20–30% B, 8–11 min with 30–100% B, 11–11.1 min with 100% B and flow 0.4–0.8 mL min−1, 11.1–12.5 min with 100%, 12.5–12.51 min with 100–8% B and flow 0.8–0.4 mL min−1. 12.51–14 min with 8% B and flow 0.4 mL min−1 | Muscle 15 µg/Kg (colistin A), 30 µg/Kg (colistin B); kidney 30 µg/Kg (colistin A), 30 µg/Kg (colistin B); liver 30 µg/Kg (colistin A), 30 µg/Kg (colistin B); egg 20 µg/Kg (colistin A), 30 µg/Kg (colistin B); milk 20 µg/Kg (colistin A), 40 µg/Kg (colistin B); | [97] |
| France | Spiked milk | Disc diffusion method (STAR protocol) | NA | NA | NA | NA | 1 mg/L | [98] |
NA—not applicable.