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The Kinetics of Oxytetracycline Degradation in Deionized Water under Varying Temperature, pH, Light, Substrate, and Organic Matter
Author(s) -
Doi Adriana M.,
Stoskopf Michael K.
Publication year - 2000
Publication title -
journal of aquatic animal health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 52
eISSN - 1548-8667
pISSN - 0899-7659
DOI - 10.1577/1548-8667(2000)012<0246:tkoodi>2.0.co;2
Subject(s) - oxytetracycline , degradation (telecommunications) , aqueous solution , kinetics , substrate (aquarium) , organic matter , bentonite , nuclear chemistry , chemistry , chromatography , environmental chemistry , chemical engineering , biochemistry , biology , organic chemistry , antibiotics , ecology , telecommunications , physics , quantum mechanics , computer science , engineering
The kinetics of oxytetracycline (OTC) degradation in deionized water was studied under the influence of various environmental factors. The experiment was conducted with a solution of 10 μg aqueous OTC /mL in 600‐mL glass beakers under controlled laboratory conditions. The aqueous concentration of OTC was determined by high‐performance liquid chromatography. Low temperatures (4°C) favored high drug stability, and high temperatures (43°C) speeded OTC degradation, resulting in a very short half‐life of 0.26 ± 0.11 d. Light exposure caused photodecomposition, reflecting degradation rates threefold higher than those under dark conditions. Acidic conditions (pH 3.0) favored drug stability (half‐life = 46.36 ± 4.92 d), and alkaline conditions (pH 10.0) increased the degradation rate (half‐life = 9.08 ± 4.22 d). The presence of a substrate (bentonite clay) resulted in an approximate 17% decrease in OTC concentration within 5 min of contact. Addition of organic matter (fish feed) along with the substrate resulted in a 41% decrease in OTC concentrations within 5 min of contact.