Miniaturized QuEChERS based sample preparation method combined with gas chromatography-tandem mass spectrometry for the determination of selected polycyclic aromatic hydrocarbons in crustacean gammarids

The study presents a new miniaturized and low-cost sample preparation method combined with gas chromatography-triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS) analysis developed to determine selected polycyclic aromatic hydrocarbons (PAHs: (naphthalene - Nap, acenaphthene - Ace, anthracene - Ant, fluoranthene - Flu, and benzo [a]pyrene - BaP) in dried gammarid samples. The sample preparation involved modification of the so-called QuEChERS (stands for quick, easy, cheap, effective, rugged, and safe) method followed by use of a novel combination of dispersive liquid-liquid micmextraction (DLLME) and treatment with H2SO4 solution, which allowed further purification and concentration of the extract and solvent exchange without the need for solvent evaporation. The QqQ-MS/MS detector operating in the pseudo-MRM mode was used to detect PAHs with increased sensitivity compared to the classical quadrupole MRM technique. The method was validated in terms of linearity and range, detection and quantification limits (LOD and LOQ), matrix effect, recovery and precision for the analysis of 200 mg samples of dried freshwater shrimps Gammarus pulex. The LOQs for the target PAHs ranged from 4.7 to 6.3 ng g(-1) dw (dry weight) or after applying the conversion factor of 0.2 (dw/ww) from 0.94 to 1.3 ng g(-1) ww (wet weight). The recovery for all the analytes was in the range 72-104% and repeatability (precision) expressed by relative standard deviation in the range 1-10%. The developed method has been shown to be suitable for the purpose of monitoring and controlling compliance with environmental quality standards (EQS, set by the EU) for Flu and BaP in surface water biota.