Agata Kot-Wasik

Fate and Analysis of Pharmaceutical Residues in the Aquatic Environment

The presence of pharmaceuticals in different compartments of the environment is a new challenge not only for technologists of water and wastewater treatment but also for analytical chemists involved in development of new analytical methods. Many drugs are not completely degraded in the human body. They are often excreted after only slight transformation or in unchanged form, mainly as polar molecules (clofibric acid, primidone). It has been proved in many studies that substances of pharmaceutical origin are not eliminated in the process of water treatment; their biodegradation in the environment is also difficult (1). Detailed chemical analysis of water is necessary for the safe use of water resources. It is important to identify all pollutants present in water and, hence, to fully evaluate water quality and predict effect on humans. The continuous improvement of analytical techniques makes it possible to identify a wider spectrum of components and improve detection limits. A brief review of input by different sources, and fate and analysis of pharmaceuticals, parapharmaceuticals, and their metabolites in environment is presented.

Development of a liquid chromatography-tandem mass spectrometry procedure for determination of endocrine disrupting compounds in fish from Mediterranean rivers.

A new, sensitive and rapid method based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) approach followed by ultra high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) was developed for the determination of nineteen endocrine disruptors (EDCs) and related compounds belonging to different classes in various fish species. Matrix effect on the analytical performance was evaluated, and thus, internal sample calibration was chosen as the most appropriate approach when analyzing such complex matrices as biota. The procedure provided adequate recoveries in the range from 40% to 103% for most of the compounds, low method detection limits (MDLs) in the range from 0.002 to 3.09ng/g for fish homogenates and high accuracy <20%. The developed method was applied for the analysis of target compounds in homogenates of different fish species from four impacted Mediterranean rivers: Ebro, Llobregat, Júcar and Guadalquivir. Eleven out of the nineteen target EDCs were found at least once in fish homogenates. Llobregat was identified as the most polluted river, where high concentrations were measured in fish homogenates especially for bisphenol A (223.91±11.51ng/g). Tris (2-butoxyethyl) phosphate (TBEP), caffeine, and methyl and benzyl paraben were found in fish from the four river basins.

Isoprostanes-Biomarkers of Lipid Peroxidation: Their Utility in Evaluating Oxidative Stress and Analysis

Isoprostanes (IsoPs) are key biomarkers for investigating the role of free radical generation in the pathogenesis of human disorders. To solve IsoPs-related problems with regard to isoprostanes, analytical tools are required. This paper reviews the problems and trends in this field focusing on the methodology for assaying biomarkers in exhaled breath condensate (EBC) samples. A large amount of work has been done in the qualitative and quantitative analysis of IsoPs, but a standardized method has yet to emerge. The methodologies described differ, either in the sample preparation steps or in the detection techniques, or both. Requiring a number of chromatographic steps, the relevant extraction and purification procedures are often critical and time-consuming, and they lead to a substantial loss of target compounds. Recent data show that EBC is a promising non-invasive tool for the evaluation of different diseases. Two main analytical approaches have been adopted for IsoPs measurement: immunological methods and mass spectrometry. The methodologies for the extraction, purification and analysis of IsoPs in EBC samples are presented.

The lipophilicity of artificial and natural sweeteners estimated by reversed-phase thin-layer chromatography and computed by various methods

The chromatographic behavior of some artificial and natural sweeteners was established by reverse phase high performance thin-layer chromatography (RP-HPTLC) on RP-18, RP-18W, RP-8, CN and NH(2) stationary phases. The mobile phases were mixtures of acetonitrile-water in different proportions of volume, chosen to create a suitable migration during the chromatographic process. The lipophilicity was described through different chromatographic descriptors such as R(M0), mean of R(M) (mR(M)), and scores of R(M) values corresponding to the first principal component (PC1/R(M)). In addition, scores and loadings resulting from covariance matrix of retention data enable new information about similarity and differences of investigated compounds and between both the stationary and mobile phases. The experimental lipophilicity indices estimated from retention data are directly correlated with the computed values, via computer software and internet module, at a high significant statistical level.

Preservation and storage of water samples

Starting from the sampling up to the time of analysis, the content of water sample can be altered due to the chemical, physical, and biological reactions it undergoes. This article deals with the processes occurring in the water samples during their storage and with reasons of their occurrence. Special attention has been paid to the chemical and physicochemical reactions as well as to microbiological and photochemical degradation of the component of the sample. Techniques for the water sample preservation are also reviewed.

The lipophilicity indices of flavonoids estimated by reversed‐phase liquid chromatography using different computation methods

The chromatographic behavior of some flavonoids was established by RP-HPLC on RP-18 (LiChroCART, LiChrosphere RP-18e), RP-8 (Zorbax, Eclipse XDB-C8), CN (Säulentechnik, LiChrosphere CN100) columns. The mobile phases were mixtures of methanol-water in different volume proportions from 70 to 80% v/v for RP-18 and RP-8, while for the CN column the proportions were between 66 and 70% v/v. The lipophilicity was expressed through different lipophilicity descriptors such as mean of k (mk), mean of log k (mlog k), log k(W), S, f() and scores of k and log k corresponding to the first principal component. The experimental lipophilicity indices are directly correlated with the computed values, via computer software and internet module, at a high analytical level. Furthermore, the results obtained applying principal component analysis to k and/or log k values allow the prediction and explanation of the interaction involved in the retention mechanism which takes place between the compounds and the employed stationary phases during the development.

Modern approach for determination of lactulose, mannitol and sucrose in human urine using HPLC–MS/MS for the studies of intestinal and upper digestive tract permeability

A new analytical procedure was described for the simultaneous determination of lactulose, mannitol and sucrose in urine, in which HILIC chromatography and tandem mass spectrometry detection are used. Sugars are orally administered for the estimation of intestinal permeability in children digestive tract. Samples were purified by dispersive solid phase extraction (d-SPE) using Amberlite MB150 resin. Raffinose was selected as an internal standard. The chosen chromatographic separation was carried out on ZIC(®)-HILIC column in 10 min at a flow rate of 0.3 mL/min, using mixture of acetonitrile (ACN) and ammonium acetate (NH(4)Ac) in water (H(2)O) as the mobile phase. Within-run precision (CV) measured at three concentrations was 1.08%, 0.32% and 0.49% for lactulose; 1.88%, 0.47% and 0.75% for mannitol, 2.95%, 1.31% and 0.6% for sucrose. Between-run CVs were 0.75%, 1.1% and 1.2% for lactulose; 1.1%, 1.02% and 1.01% for mannitol; 1.17%, 1.4% and 1.05% for sucrose. Analytical recovery of all three sugar probes was 95.06-99.92%. The detection limits were: 15.94 ng/mL for lactulose, 17.10 ng/mL for sucrose and 11.48 ng/mL for mannitol. The proposed method is rapid, simple, sensitive and suitable for the determination of intestinal permeability of the sugar derivatives in children.

The Current State-of-the-Art in the Determination of Pharmaceutical Residues in Environmental Matrices Using Hyphenated Techniques

Several thousand tons of pharmaceuticals and their transformation products (metabolites and degradation products) are introduced into the environment each year. They affect both human health and the environment, therefore, analytical procedures enabling the determination of a wide range of pharmaceuticals at trace levels with minimal effort, time, and energy are required. Nowadays, hyphenated techniques are commonly applied in pharmaceutical analysis. This article provides a brief overview of the state-of-the-art and future trends in the determination of pharmaceutical residues and their transformation products with a focus on the most popular techniques in the field, such as ultra or high-performance liquid chromatography (UHPLC or HPLC) coupled with tandem mass spectrometry (MS/MS), quadrupole time-of-flight (QTOF), and a hybrid quadrupole/linear ion trap (QqLIT) in different environmental matrices (water, soil/sediment). Attention is paid to different aspects, benefits, and limitations of the application of UPLC and mass spectrometry–based techniques.

Elucidation of transformation pathway of ketoprofen, ibuprofen, and furosemide in surface water and their occurrence in the aqueous environment using UHPLC-QTOF-MS

AbstractThe identification and determination of transformation products (TPs) of pharmaceuticals is essential nowadays, in order to track their fate in the aqueous environment and, thus, to estimate the actual pollution. However, this is a challenging task due to the necessity to apply high-resolution instruments enable to detect known and unknown compounds. This work presents the use of liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) as a powerful tool for the identification of three selected pharmaceuticals, furosemide (FUR), ibuprofen (IBP), and ketoprofen (KET), and their TPs in various water samples. Laboratory degradation experiments were performed using xenon lamp as a source of the irradiation in order to simulate phototransformation processes which may occur in the environment. Furthermore, the photodegradation kinetics of three selected compounds were assessed in a reactor equipped with xenon lamp in river water samples. Five TPs of IBP, seven of KET, and five of FUR were identified; some of them are presented here for the first time. Accurate mass measurements and fragmentation pattern obtained during an LC-QTOF-MS analysis allowed for structure elucidation of TPs followed by the creation of transformation pathway of selected pharmaceuticals. Finally, different water samples (wastewater influent and effluent, river water, untreated and treated water) were analyzed in order to estimate the presence of parent and transformed compounds. Only KET was detected in untransformed form in considered samples. Most of the TPs of selected drugs were found at least once in all water samples. Although IBP and FUR were not present in water samples as parent compounds, their different TPs occur. A great potential of LC-QTOF-MS in the identification and structural elucidation of TPs in the environment, allowing the recognition of the fate of pharmaceuticals in the environment through the determination of transformation pathway, has been presented. Phototransformation of three selected pharmaceuticals

Chromatographic lipophilicity determination using large volume injections of the solvents non-miscible with the mobile phase

A new perspective in the lipophilicity evaluation through RP-HPLC is permitted by analysis of the retention factor (k) obtained by injecting large volumes of test samples prepared in solvents immiscible with mobile phase. The experiment is carried out on representative groups of compounds with increased toxicity (mycotoxins and alkaloids) and amines with important biological activity (naturally occurring monoamine compounds and related drugs), which are covering a large interval of lipophilicity. The stock solution of each compound was prepared in hexane and the used mobile phases were mixtures of methanol or acetonitrile and water, in suited volume ratio. The injected volume was between 10 and 100 μL, while the used stationary phases were RP-18 and RP-8. On both reverse stationary phases the retention factors were linearly decreasing while the injection volume was increasing. In all cases, the linear models were highly statistically significant. On the basis of the obtained results new lipophilicity indices were purposed and discussed. The developed lipophilicity indices and the computationally expressed ones are correlated at a high level of statistical significance.