Page 202 - Materials Chemistry, Second Edition

Determination of Pharmaceutical Compounds in Sewage Sludge 183

with OASIS MCX cartridges (Waters, UK) was applied. Analytical determination
was carried out by LC-MS/MS. Recoveries were in the range from 49% to 180%, but
for the majority of compounds, they were in the range from 90% to 110%. Langford
et al. (2011) applied MAE to the extraction of the 30 most dispensed pharmaceuticals
in Scotland in 2007. Extraction was carried out with pure MeOH or MeOH:formic
acid (100:0.1, v/v). Extracts were evaporated to 8–9 mL and centrifuged at 21,000
g, forming three layers. The middle layer was injected into the LC-MS/MS system
without clean-up.

9.2.1.4 Quick, Easy, Cheap, Effective, Rugged and
Safe Extraction (QuEChERS)
This method was developed by Anastassiades et al. (2003) for the determination
of pesticides in fruits and vegetables. QuEChERS is based on sample extraction
with acetonitrile, liquid-liquid partition by salting out with sodium chloride and
magnesium sulfate, and simultaneous removal of residual water and clean-up by
dispersive solid-phase extraction (d-SPE) with anhydrous magnesium sulfate and
a disperser sorbent. The variables to optimize are the type and amount of salts, the
presence and type of ligand (EDTA, citrate, etc.), the sample pH, acidification or not
of acetonitrile (commonly with acetic acid), and the type and amount of the disperser
sorbent (primary and secondary amine [PSA], C18, graphitized carbon, and their
mixtures are most commonly used). The method is simple and rapid and does not
require expensive equipment or large solvent volumes. Peysson and Vulliet (2013)
reported a multiresidue method based on QuEChERS extraction and liquid chroma-
tography/time-of-flight/mass spectrometry (LC-TOF-MS), which allowed the deter-
mination of 117 pharmaceuticals and hormone residues in sewage sludge. PSA, C18,
graphitized carbon, and their mixtures were tested as disperser sorbents. The best
recoveries were obtained with PSA. The major drawback of the method was the low
recoveries of complexed molecules, tetracyclines, and fluoroquinolones. Bourdat-
Deschamps et al. (2014) applied QuEChERS to the determination of 13 pharmaceu-
ticals, including eight antibiotics (fluoroquinolones, tetracyclines, sulfonamides, and
macrolide), an anti-epileptic (carbamazepine), anti-inflammatories (diclofenac and
ibuprofen), and a lipid regulator (gemfibrozil) in sewage sludge supernatant from an
urban municipal WWTP based on activated sludge. Sludge supernatant (5 mL) was
extracted with acidified acetonitrile (1% acetic acid) after addition of sodium sulfate,
sodium acetate, and Na EDTA. Clean-up was carried out with PSA. They reported
2
that sodium sulfate, as QuEChERS salt, and Na EDTA are necessary for fluoroqui-
2
nolone and tetracycline extraction. Recoveries were in the range from 78% to 120%;
inter-day precision, expressed as RSD%, was 6%–30%; and LOQs were in the range
of 10–200 ng L .
−1
9.2.1.5 Matrix Solid-Phase Dispersion (MSPD)
MSPD was developed in 1989 by Baker et al. (Baker et al., 1989) for the isolation of
drug residues from tissues. Solid and semi-solid samples are mixed with an appro-
priate solid sorbent, introduced into an empty column, and eluted with the appropri-
ate solvent. Extraction and clean-up are simultaneously carried out with low solvent
consumption and without expensive instrumentation. The variables to optimize are