Table 1.

Detection in tetracycline, doxycycline, and minocycline of catechol-phenolate-like and hydroxamate-like groups

Antibiotic^a	A₅₁₀in Arnow assay for catechol-phenolate	A₅₂₆ in Csaky assay for hydroxamate
Tetracycline	0.07 ± 0.02	0.54 ± 0.09
Doxycycline	0.04 ± 0.03	0.25 ± 0.04
Minocycline	1.23 ± 0.09	1.44 ± 0.11
Positive control^b	2.82 ± 0.14	2.71 ± 0.09
Negative control^c	0	0.04 ± 0.02

↵a Antibiotics were used at 1 mg/ml.
↵b 2,3-Dihydroxybenzoic acid (1 mg/ml) for the Arnow assay and hydroxylamine hydrochloride (1 mg/ml) for the Csaky assay.
↵c Distilled water.