Trimethoprim d9

Based on the marketing data of pharmaceuticals, 57 types of pharmaceuticals were initially selected as target compounds in our preliminary study. Out of the 57 compounds, we selected 27 compounds as the targets in this study based on their influent concentrations and detection frequencies. In total 27 types of pharmaceuticals, including 11 antibiotics, 6 anti-inflammatory/NSAIDs, 2 antiarrhythmic drugs, and 1 stimulant were selected as the target substances. Table 1 shows the physicochemical properties of the substances. For the standard substances and reagents used in the analysis, 10 mg/L of a standard solution of 98% or higher purity purchased from Sigma-Aldrich (Saint Louis, MO, USA) and Fluka (Seelze, Germany) was prepared and stored in a freezer at −20 °C or below. It was diluted and used on the day of the analysis. Twenty types of isotopically labeled standards (acetaminophen-d4, salicylic acid-d4, atenolol-d7, caffeine-13C3, carbamazepine-d10, cimetidine-d3, ciprofloxacin-d8, diclofenac-13C6, diphenhydramine-d3, erythromycin-d6, gemfibrozil-d6, ibuprofen-d3, iopromide-d3, ketoprofen-d3, naproxen-d3, ofloxacin-d3, propranolol-d7, sulfadimethoxine-13C6, testosterone-d3, and trimethoprim-d9) were purchased from Sigma-Aldrich and Toronto Research Chemicals (Toronto, ON, Canada).