Abstract
Pharmaceutical and illicit drugs are emerging contaminants found in the environment globally. Many are chiral and stereochemistry plays an important role on their environmental fate and effects. However, investigations at the enantiomeric level are limited, particularly for complex particulate matrices such as sediments. This is due to further sample processing requirements and a lack of suitable analytical methods. Therefore, here a new enantioselective methodology is proposed for 15 drugs in sediment. Sample treatment by accelerated solvent extraction and solid phase extraction was critical for subsequent enantioselective separations. Using liquid chromatography–tandem mass spectrometry, a Chiral-V enantioselective column enabled multi-residue separations of anti-depressants, beta-blockers, beta-agonist, anti-histamine and stimulants. Method trueness for all enantiomers was 86–121% and method quantitation limits were below 3 ng g−1 dry weight. Application of the method revealed the enantiomeric composition of fluoxetine, amphetamine, propranolol, venlafaxine and citalopram in sediment for the first time. All drugs except venlafaxine were present in non-racemic form, i.e. unequal enantiomer concentrations. This is significant considering drug toxicity towards benthic organisms could be enantiospecific.
Highlights
Pharmaceutical and illicit drugs are emerging contaminants as their fate and effects in the environment are not fully understood (Cizmas et al 2015; Wilkinson et al 2017)
The objectives of the study were (i) to establish a new methodology for multi-residue enantioselective profiling of chiral drugs in sediments, and (ii) to determine the enantiomeric composition of chiral drugs present in sediments impacted by wastewater treatment plants and septic tanks
The inclusion of R/S( ±)-desmethylcitalopram required a run time of 40 min (Fig. 1). This remains shorter than previous enantioselective methods for R/S( ±)-desmethylcitalopram which require ≥ 80 min (Evans et al 2015)
Summary
Pharmaceutical and illicit drugs are emerging contaminants as their fate and effects in the environment are not fully understood (Cizmas et al 2015; Wilkinson et al 2017). The main source of drugs in the environment is the discharge of effluent from centralised wastewater treatment plants. Septic tanks can play a significant role with 20% of United States households served by a septic tank or similar system (Schaider et al 2017). In Scotland, 7% of the population is estimated to use a septic tank (Ramage et al 2019). Little attention has been given to the impact of septic tanks to surrounding aquatic systems with respect to drugs.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
