Extraction of tetracycline antimicrobials from river water and sediment: a comparative study of three solid phase extraction methods

Abstract

Tetracyclines are ubiquitous pollutants in the aquatic environment so it is necessary to determine their levels in river water and sediment. Many extraction techniques have been suggested in previous studies. However there is lack of comparisons among them. This work compared three extraction methods Ultrasonic Assisted Tandem Solid Phase Extraction (UA-TSPE), Ultrasonic Assisted Dispersive Solid Phase Extraction (UA-DSPE) and Ultrasonic Assisted Matrix Solid Phase Dispersion (UA-MSPD) in conjunction with a complexing agent to complex metal cations, for the extraction of tetracycline antibacterials from fortified ultra-pure water, river water and sediment samples under acid conditions. Samples were analyzed on a RP-HPLC coupled to UV detection. The linear dynamic range for calibration curves of all techniques were 0.01 to 1 µgml-1 (water) and 0.01 to 1 µgg-1 (sediment) with R 2 values ranging from 0.995 to 0.999. The overall recovery was in the range 92.13 to 99.62%. UA-DSPE yielded the best recoveries (at p > 0.05), range 97.23 to 99.62%. UA-TSPE was second at 94.99 to 97.75%, while UA-MSPD was third at 92.13 to 97.84% recovery. Limit of detection (LOD) (at signal to noise ratio = 3) and Limit of quantification (LOQ) (at signal to noise ratio = 10) for spiked river water and sediment were in the range 11.53 to 22.75 ngml-1 and 30.12 to 56.22 ngml-1 , respectively.