An analytical method for the simultaneous extraction and determination of four different groups of pharmaceuticals in compost from the biodegradation of biological infectious hazardous wastes (BIHW) was developed and successfully validated. Compost samples were spiked with known concentrations of the pharmaceuticals of interest. Ultrasonic extraction with an ethyl acetate and methanol solution (1:1) resulted to be effective for the extraction of eight target compounds. All the compounds were separated in a single gradient run by UHPLC using a Zorbax SB C18 Agilent (2.1×50mm, 1.8μm) column. Analytes were detected and quantified via multiple reaction monitoring (MRM) using an AB SCIEX API-5000TM triple quadrupole with electrospray ionization (ESI) in positive mode. The optimum mobile phase consisted of ammonium formate (2mM, pH 3): MeOH (50:50). Recovery values of the ultrasonic extraction for all compounds were on the order of 87% to 113% with absolute deviations lower than 11%. The limits of detection and quantification for the eight pharmaceuticals were on the order of 0.66ngg(-1) and 2ngg(-1) respectively for all the pharmaceuticals analyzed. These values are lower than those values reported in the literature. Suitable level of linearity, acceptable limits of detection and quantification, good repeatability and inter-day precision, non-ion interference, and low matrix effect resulted from the validation of the analytical method. Implementation of the analytical procedure proposed in this research will contribute in having shorter analysis time and lower costs when working with complex matrices such as compost.
Keywords: Compost; Pharmaceuticals; UHPLC–MS/MS; Ultrasonic extraction (USE).
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