Ingus Perkons

Determination of pharmaceutical residues in wastewater using high performance liquid chromatography coupled to quadrupole-Orbitrap mass spectrometry

HIGHLIGHTSA method for the determination of 24 emerging pharmaceuticals has been developed.The analysis of 21 samples revealed the occurrence of 20 selected pharmaceuticals.The highest concentration was found for caffeine and acetaminophen. ABSTRACT A multi‐class method for the determination of 24 emerging pharmaceutical residues has been developed and validated. The method is based on solid‐phase extraction of wastewater samples using Strata‐X cartridges followed by high performance liquid chromatography coupled to hybrid quadrupole − Orbitrap high resolution mass spectrometry (HPLC‐Q‐Orbitrap‐HRMS). A single‐laboratory validation procedure showed satisfactory analytical performance. The analysis of 21 samples collected at the wastewater treatment plant in Riga revealed the occurrence of 20 compounds of different therapeutic classes. The highest concentration was found for the central nervous system stimulator caffeine − up to 12 &mgr;g L−1, the analgesic acetaminophen up to 4.2 &mgr;g L−1, the antibiotic ciprofloxacin in the concentration range of 250–400 ng L−1, and the non‐steroidal anti‐inflammatory drug (NSAID) ibuprofen at 100–325 ng L−1.

The application of phospholipid removal columns and ultra-high performance liquid chromatography—tandem quadrupole mass spectrometry for quantification of multi-class antibiotics in aquaculture samples

In this study a robust and sensitive method based on a proposed sample purification procedure, using zirconia-coated Phree™ columns and analysis by ultra-high performance liquid chromatography with triple quadrupole tandem mass spectrometry are presented for the assessment of multi-class antibiotics in farmed fish species. The sample preparation procedure benefited from combined precipitation of proteins and selective removal of phospholipids by Phree™ columns, resulting in a high sensitivity of the method (LOQ 0.3-9mgkg(-1)). The in-house validation results (precision, repeatability, decision limit CCα, detection capability CCβ, etc.) indicate that the elaborated method is fully suitable for the analysis of the main classes of antibiotics in accordance with the European Union (EU) Commission Decision 2002/657/EC. The method was applied to the analysis of antibiotics in trout and sturgeon samples obtained from the local inland aquacultures in Latvia. The results revealed the presence of two antibiotics (enrofloxacin and trimethoprim) in 12 out of the 20 analysed fish samples at concentrations (0.33-12.2μgkg(-1)) below the MRLs, thus causing no acute risks to consumers.

A comparison of gas chromatography coupled to tandem quadrupole mass spectrometry and high-resolution sector mass spectrometry for sensitive determination of polycyclic aromatic hydrocarbons (PAHs) in cereal products

Due to the high consumption level, cereals represent one of the major sources of human exposure to PAHs. Taking into account the low maximum permitted level (ML) established in the European Union (EU) for the sum of four priority PAHs (PAH4) in processed cereal-based foods, sensitive and selective analysis for very low concentrations of these carcinogenic compounds was developed and compared by applying two different analytical techniques. Elaborated methods demonstrated appropriate performance in PAHs analysis even at low contamination levels. Limits of detection (LOD) for the PAH4 varied between 0.002μgkg-1 and 0.006μgkg-1, recoveries were in the range of 92-103% for GC-MS/MS and 108-117% for GC-HRMS. Elaborated methods were applied for the analysis of 35 Latvian cereals and bread samples. The concentrations of PAH4 were in a range of 0.22-1.62μgkg-1 with 14% of samples exceeding the current EU maximum permitted levels.

Determination of pharmaceutical residues and assessment of their removal efficiency at the Daugavgriva municipal wastewater treatment plant in Riga, Latvia

Pharmaceutical products (PPs) belong to emerging contaminants that may accumulate along with other chemical pollutants in wastewaters (WWs) entering industrial and/or urban wastewater treatment plants (WWTPs). In the present study, the technique of ultra-high-performance liquid chromatography coupled to Orbitrap high-resolution mass spectrometry (Orbitrap-HRMS) was applied for the analysis of 24 multi-class PPs in WW samples collected at different technological stages of Daugavgriva WWTP located in Riga, Latvia. Caffeine and acetaminophen levels in the range of 7,570-11,403 ng/L and 810-1,883 ng/L, respectively, were the predominant compounds among 19 PPs determined in the WW. The results indicate that aerobic digestion in biological ponds was insufficiently effective to degrade most of the PPs (reduction efficiency <0-50.0%) with the exception of four PPs that showed degradation efficiency varying from 55.0 to 99.9%. Tests of short-term chemical and enzymatic hydrolysis for PP degradation in WW samples were performed, and the results reflected the complexity of different degradation mechanisms and physicochemical transformations of PPs. The toxicological studies of WW impact on Daphnia magna indicated gradual reduction of the total toxicity through the treatment stages at the WWTP.