Table 5.

Performance and conditions of several chromatographic methods developed for tetracycline analysis.

Sample clean-up	Summary chromatographic conditions	Column	Wavelength(s) (nm)	Limit of detection	Reproducibility (RSD, %)	Recovery (%)	Detection system	Reference
Spectrophotometry
Liquid-liquid extraction/CH3CN/CH2Cl2 petroleum ether	0.02 mol L−1 H3PO4/0.01 mol L−1 sodium 1-decanesulphonate and CH3CN	PLRP-S, 5 μm, 150 × 4.6 mm	355	2.2–28.6 ng g−1	<15.5	54–88	Ion pair-diode array detector (DAD)	[50]
SPE/Strata-X® (33 μm, 100 mg, 6 mL)	CH3CN, oxalic acid, CH3OH	C18, 3 μm, 250 × 4.6 mm	355	9.8–27.2 μg kg−1	<12.6	55.4–86.3	UV	[51]
SPE/Oasis® HLB (100 mg, 3 mL)	CH3CN, oxalic acid, CH3OH	C18, 5 μm, 250 × 4.6 mm	350/360/370	1.64–4.08 μg L−1	<9.6	83.5–108.6	DAD	[52]
SPE/Oasis HLB (100 mg, 3 mL)/Bond Elut® (500 mg, 3 mL)	Trifluoroacetic acid (TFA), CH3CN, CH3OH	XDB C18, 150 × 4.6 mm, 5 μm	330	3.5–6.5 μg L−1	<14.4	82.1–114.7	DAD	[53]
Fluorescence
SPE/Oasis HLB (60 and 200 mg)	CH3CN and oxalic acid 0.01 M (pH 2.0).	C8 (100 × 3 mm, 5 μm)	λ ex 385/λem 500	50 μg kg−1	<7.2	85.0–92.8	Fluorescence detector (FLD)	[54]
SPE/Oasis HLB (30 mg)	oxalic acid, CH3CN	PLRP-S 5 μm, 150 × 4.6 mm	λ ex 374/λem 499 nm	0.6–1.2 μg L−1	<9.0	84.0–110.0	FLD	[55]
Trace enrichment cartridge	CH3CN and oxalic acid	Supersphere RP-8 250 × 4.0 mm, 3 μm	λ ex 350/λem 420 nm	11–15 μg kg−1	<5.8	90.0–97.0	UV/FLD/MS	[56]
SPE/Oasis HLB (200 mg)	CH3CN and oxalic acid	Nucleosil C18 column (5 μm, 250 × 4 mm)	λ ex 385/λem 500	50 μg kg−1	<8.0	86.0–95.0	FLD	[57]
SPE/Oasis HLB (60 mg)/Sep-Pak® C18 (500 mg)/Bond Elut Certify®	CH3CN and 0.01 mol L−1 oxalic acid	Symmetry Shield™ RP8, 150 × 4.6 mm	λ ex 385/λem 500	5.1–34.7	<12.7	61.0–115.0	FLD	[58]
SPE/Oasis HLB (30 mg)	20 mmol L−1 TFA, CH3CN	Zorbax SB C18 column (3 μm, 250 × 4.6 mm)	λ ex 399/λem 473	0.2–500 μg kg−1	<5.0	59.0–97.0%	FLD/UV	[59]
SPE/Oasis HLB (60 mg)	CH3OH/CH3CN/50 mmol L−1 oxalic acid	Luna 5 μ C18, 250 × 4.6 mm	λ ex 255/λem 365	2.2 ng g−1	<5.0	75.3–82.5	FLD	[60]