Xiaoqin Wei et al.
Analytical and bioanalytical chemistry, 385(6), 1039-1044 (2006-06-01)
Tetracycline antibiotics (TCs) such as doxycycline (DOTC), chlortetracycline (CTC), oxytetracycline (OTC), and tetracycline (TC) react with Cu(II) in pH 3.5 BR buffer medium to form 1:1 cationic chelates, which further react with titan yellow to form 2:1 ion association complexes.