Various methods were developed and validated for the analysis of Polycyclic Aromatic Hydrocarbons (PAHs), in the environmental samples. However, their analysis in relevant concentrations in environmental samples can be a challenging task. The aim of this study was to estimate the performance of a modified standard procedure for the determination of polycyclic aromatic hydrocarbons in environmental water samples using liquid-liquid extraction as a preparation step followed by gas chromatography/mass spectrometry. Implementation of long term quality control procedures after validation of the analytical procedures enables acquisition of accurate and reliable results. Three year monitoring of the quality control samples (containing 10-40 ng/L of PAHs) showed that method main characteristics, such as accuracy, precision and measurement uncertainty have constant stability and with no statistically significant changes during this period.

The past decade has seen a large global interest in the development of renewable energy sources, and bio-products based on plant biomass. This is owing to the abundance of lignocellulosic material on the planet and due to their high sugar content. However plant biomass is a complex matrix of hemicellulose and aromatic lignin interacting with core cellulose making it remarkably resistant towards enzymatic saccharification

Agomelatine is a melatonergic antidepressant approved for marketing in the European Union in February 2009; several methods are published for its determination in human specimens so far based mainly on mass spectrometric detection. Aim of this study is the development and validation of the first method based on UV detection of agomelatine after purification from human plasma / serum with a conventional SPE (onto a Bond Elut Certify cartridge) and separation by a UHPLC system (on a Hypersil GOLD analytical column by a mixture of eluents used in gradient mode). The wavelengths of 230 nm and 245 nm were used for the determination of agomelatine and the internal standard (harmine), respectively. The method was validated according to FDA guidelines. Linearity ranges from 50-800 ng/mL, covering therapeutic and supra-therapeutic levels. Extraction recoveries were 91 and 83% for plasma and serum respectively (R2> 0.9946). The intra-day and inter-days precisions ranged from 4.52-7.63 and 5.25-8.01% and, 9.27-10.15 and 9.53-11.05% for plasma and serum, respectively. LODs and LOQs were 15 and 50 ng/mL for both matrices. Overall, the method is specific for agomelatine, selective towards several antipsychotics, other antidepressants and sedative-hypnotics. Validation studies demonstrated that the proposed UHPLC method meets satisfactory validation criteria, is simple, rapid, reliable, reproducible and easily applicable for routine clinical casework.

An improved, Liquid-liquid Extraction (LLE) procedure, without derivatisation, using large volume injection, followed by separation with Gas Chromatography (GC), and mass spectrometric detection, in Selected Ion Monitoring (SIM), has been fully validated and applied in the quantitation of three priority female steroid estrogens (natural estrogens: 17-β-estradiol (E2), estrone (E1) and the synthetic estrogen:17-α-ethinylestradiol (EE2)), in water and in raw influent wastewater matrix. The method has been validated, over the range 10-100 µg/L, showing, for all target analytes, good linearity (mean r2 = 0.997), recovery (mean = ± 99%), and precision (mean RSD = ± 5.5%) in both water and wastewater matrix. The Method Detection Level (MDL) was: 5 ng/L for E1, 2 ng/L for E2 and 5 ng/L for EE2. The LOQ was 10 ng/L for E1, E2 and EE2. The signal/ Noise (S/ N) ratio method gave an LOD and LOQ of 1 ng/L (S/ N = 17-61) for all three estrogens. The method was successfully applied to the determination of the target estrogens in raw wastewater, treated wastewater and river water. The estrogen levels, in all tested matrices, obtained by the GC-MS method compared fairly well with the previously used Enzyme-Linked Immunosorbent Assay (ELISA). The method showed to be a viable option to ELISA and Liquid Chromatography- tandem Mass Spectrometry (LC-MS/MS).

This study shows a method for the detection and quantification of six volatile nitrosamines, dimethyl nitrosamine, diethylnitrosamine, N-nitrosopyrrolidine, N-nitrosopiperidine, N-nitrosomorpholine, N-nitrosoibuthylnitrosamine in meat products. The procedure based on: (a) Isolation of the compounds by vacuum steam distillation, (b) extraction in solid phase - SPE - from aqueous distillates using activated carbon and (c) analysis by gas chromatography-mass spectrometry. The recovery of the compounds from fortified samples (sausages and their preserved liquid) with 200 µg.Kg-1 ranged between 10.9 - 61.7% to solid sample and 20.9 - 80.4% to liquid sample. The direct application of this method to samples of canned sausages allowed the separation, identification and quantification of the nitrosamines at the µg.Kg-1 level with detection limit varying between 0.2 to 1.0 µg.Kg-1.