Reaction of β-blockers and β-agonist pharmaceuticals with aqueous chlorine. Investigation of kinetics and by-products by liquid chromatography quadrupole time-of-flight mass spectrometry.
The degradation of two β-blockers (atenolol and propranolol) and one β-receptor agonist (salbutamol) during water chlorination was investigated by liquid chromatography-mass spectrometry (LC-MS). An accurate-mass quadrupole time-of-flight system (QTOF) was used to follow the time course of the pharmaceuticals and also used in the identification of the by-products. The degradation kinetics of these drugs was investigated at different concentrations of chlorine, bromide and sample pH by means of a Box-Behnken experimental design. Depending on these factors, dissipation half-lives varied in the ranges 68-145 h for atenolol, 1.3-33 min for salbutamol and 42-8362 min for propranolol. Normally, an increase in chlorine dosage and pH resulted in faster degradation of these pharmaceuticals. Moreover, the presence of bromide in water samples also resulted in a faster transformation of atenolol at low chlorine doses. The use of an accurate-mass high-resolution LC-QTOF-MS system permitted the identification of a total of 14 by-products. The transformation pathway of β-blockers/agonists consisted mainly of halogenations, hydroxylations and dealkylations. Also, many of these by-products are stable, depending on the chlorination operational parameters employed.
Department of Analytical Chemistry, Nutrition and Food Science, IIAA-Institute for Food Analysis and Research, University of Santiago de Compostela, Santiago de Compostela, Spain. jb.quintana@usc.es
José Benito
JB
Quintana
Rosario
R
Rodil
Rafael
R
Cela
D000318:Adrenergic beta-Agonists / Q000737:chemistry* / Q000302:isolation & purification; D000319:Adrenergic beta-Antagonists / Q000737:chemistry* / Q000302:isolation & purification; D000420:Albuterol / Q000737:chemistry* / Q000302:isolation & purification; D001262:Atenolol / Q000737:chemistry* / Q000302:isolation & purification; D002713:Chlorine / Q000737:chemistry*; D002853:Chromatography, Liquid; D054879:Halogenation; D007700:Kinetics; D013058:Mass Spectrometry; D011433:Propranolol / Q000737:chemistry* / Q000302:isolation & purification; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification; D018508:Water Purification
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D014874:Water Pollutants, Chemical; D014867:Water; D002713:Chlorine; D001262:Atenolol; D011433:Propranolol; D000420:Albuterol