Jeno Fekete

Nonylphenol, octylphenol, and bisphenol-A in the aquatic environment: A review on occurrence, fate, and treatment

The aim of this study was to assess the performance of a method of analyzing pesticides in rice by using pressurized liquid extraction (PLE) and to perform a preliminary monitoring by using that method. The instrumental quantification limit, instrumental detection limit, method quantification limit, and method detection limit were determined. PLE temperature was also optimized for 6 target pesticides. Mean recoveries of spiked rice with target pesticides (4 ng/g and 40 ng/g) were 83%-109% with the repeatability of the analysis, represented as relative standard deviations, ranged from 1.3% to 11% (n = 5) for PLE at 130 degrees C. These results were satisfactory according to the method of positive list in Japan. In a preliminary analysis of 10 target pesticides in 54 commercial rice samples, ferimzone was detected in only one unpolished rice sample.This paper reviews the current knowledge on the occurrence, biodegradation, and photooxidation of nonylphenol (NP), octylphenol (OP), and bisphenol-A (BPA) in aquatic environment. Generally, the concentrations determined were 0.006–32.8, < 0.001–1.44, and 0.0005–4.0 μ g L−1 for NP, OP, and BPA respectively in river waters worldwide. Anthropogenic activities that can lead to run-off and storm water discharge may contribute to such concentrations in rivers. Pathways for biodegradation of NP and BPA appear to be similar. The influence of ferric ions, oxalate, hydrogen peroxide, and dissolved organic matter (DOM) on the photooxidation of NP and BPA in natural water is presented. Several techniques including nanofiltration, adsorption, sonochemical, photocatalytic, chlorination, ozonation, and ferrate(VI) oxidation for removals of NP, OP, and BPA are also reviewed.

Simultaneous determination of corticosteroids, androgens, and progesterone in river water by liquid chromatography-tandem mass spectrometry

The assessment of steroidal hormones in the environment requires sensitive and selective analytical techniques suitable for sample matrices. This paper reports a simple method to analyze simultaneously six corticosteroids (triamcinolone, cortisol, dexamethasone, flumethasone, prednisolone, triamcinolone acetonide), four androgens (boldenone, epitestosterone, methyltestosterone, nortestosterone), and progesterone in river and drinking water sources. The developed method is based on a single solid-phase extraction (SPE) followed by liquid chromatography/tandem mass spectrometry (LC-MS/MS) with atmospheric pressure chemical ionization (APCI). The main advantage of this method over other methods includes the use of a single SPE with a low volume cartridge for sample preparation, separation of steroids on alkyl-amide stationary phase with no matrix interferences by LC-MS/MS analysis, and simultaneous analysis of more than two groups of steroids. The method was characterized by generally good performance, analyzing three groups of steroids using 100 and 1000mL samples with average recovery ranges of 80-109% and 68-126%, respectively at a level of 1ngL(-1). The limit of detection (LOD) ranged from 0.06 to 0.2 and 0.01-0.21ngL(-1) for 100mL and 1000mL samples volumes, respectively. Sixty samples of Danube River and drinking water sources from different regions of Hungary were collected to analyze target steroids in two sampling periods in 2008 and 2009. Steroids, except cortisol, dexamethasone, flumethasone, prednisolone, epitestosterone and progesterone were below detection limits. Endogenous steroids (cortisol, epitestosterone, progesterone) were present in the concentration range of 0.08-2.67ngL(-1) while synthetic corticosteroids (dexamethasone, flumethasone, and prednisolone) varied from 0.064 to 1.43ngL(-1). Steroids were present in river water, except progesterone, which was present only in ground water. Levels of steroids are compared with other rivers in the world and were briefly discussed.

Evaluation of a new wide pore core–shell material (Aeris™ WIDEPORE) and comparison with other existing stationary phases for the analysis of intact proteins

The separation of large biomolecules such as proteins or monoclonal antibodies (mAbs) by RPLC can be drastically enhanced thanks to the use of columns packed with wide-pore porous sub-2 μm particles or shell particles. In this context, a new wide-pore core-shell material has been recently released under the trademark Aeris WIDEPORE. It is made of a 3.2 μm solid inner core surrounded by a 0.2 μm porous layer (total particle size of 3.6 μm). The aim of this study was to evaluate the performance of this new material, compare it to other recently developed and older conventional wide-pore columns and demonstrate its applicability to real-life separations of proteins and mAbs. At first, the traditional h(min) values of the Aeris WIDEPORE column were determined for small model compounds. The h(min) values were equal to 1.7-1.8 and 1.4 for the 2.1 and 4.6 mm I.D. columns, respectively, which are in agreement with the values reported for other core-shell materials. In the case of a small protein Insulin (5.7 kDa), the achievable lowest h value was below 2 and this impressive result confirms that the Aeris WIDEPORE material should be dedicated to protein analysis. This column was then compared with five other commercially available wide-pore and medium-pore stationary phases, in the gradient elution mode, using various flow rates, gradient steepness and model proteins of MW=5.7-66.8 kDa. The Aeris WIDEPORE material often provided the best performance, in terms of peak capacity, peak capacity per time and pressure unit (PPT) and also based on the gradient kinetic plot representation. Finally, real separations of filgrastim (18.8 kDa) and its oxidized and reduced forms were performed on the different columns and the Aeris WIDEPORE material provided the most impressive performance (peak capacity>100 for t(grad)<6 min). Last but not least, this new material was also evaluated on digested and reduced mAb and powerful, high-throughput separations were also attained.

Evaluation of recent very efficient wide-pore stationary phases for the reversed-phase separation of proteins.

In the present contribution, columns packed with fully porous widepore 1.7μm particles (Acquity BEH300) and widepore core-shell 3.6μm particles (Aeris WP) were evaluated for the separation of model and therapeutic proteins of varying sizes, hydrophobicity and isoelectric points. Two types of bonding were compared, namely C4 and C18 in a systematic way. The kinetic performance of these stationary phases was evaluated in a previous paper hence this new work focuses on their retention behaviour, loading capacity and selectivity. Using the Tanaka tests, model proteins, and other confirmatory experiments, it is highly probable that with proteins, strong interaction mechanisms were predominant on the Aeris WP while the hydrophobic interaction was the driving force of the retention on the Acquity BEH300 material. This explained why, despite the lower pore volume of the Aeris WP material, the apparent retention factors of proteins possessing both hydrophobic and charged amino acids residues were very close on the four investigated columns. In terms of peak widths, values for proteins were similar for all the tested stationary phases, despite the probable strong ion exchange mechanisms of Aeris WP column. This could be explained by the excellent mass transfer characteristics afforded by the thin porous layer (∼0.2μm) at the surface of the particle which probably compensates for the slow secondary ionic interaction kinetics. The loading capacity was also evaluated on all the four widepore columns, using model proteins. On average, approximately 2-4 times higher amount of proteins can be injected on the fully porous BEH300 compared to the core-shell Aeris WP columns when avoiding 10% change in peak width or in tailing. However, this result could be strongly influenced by the nature and shape of the protein, its hydrophobicity, folding, size and number of charges. Finally, all of these columns were employed for the highly efficient separation of a therapeutic protein (interferon-α-2A) and some closely related proteins and showed excellent performance and selectivity. This result confirms that RPLC gained interest in the biopharmaceutical field as it provides significantly better peak widths than size-exclusion or ion-exchange and inherent compatibility with MS.

Monitoring of selected metabolites and biotransformation products from fermentation broths by high-performance liquid chromatography

Abstract Reversed-phase high-performance liquid chromatographic methods with UV-photodiode array or multiwavelength detection were developed for the analysis of secondary fungal metabolites mevinolin (also known as monacolin K, lovastatin or Mevacor) and fumagillin in fermentation broths. Samples obtained from screening experiments of Aspergillus fumigatus and Aspergillus terreus strains were analyzed for fumagillin and mevinolin, respectively. Isocratic and gradient elution was used with acetonitrile-aqueous phosphoric acid or acetonitrile-phosphate buffer eluents. Sample preparation was accomplished by extraction of the whole fermentation broth with an acid-organic solvent mixture. Similarly, bacterial degradation products of 2,4,6-trichlorophenol obtained from microbial remediation processes were analyzed by reversed-phase HPLC with UV-photodiode array detection. Extraction of the analyte from solid samples was done by solvent extraction and solid-phase extraction clean-up using octadecyl-modified silica sample preparation cartridges.

ANALYSIS OF SULFONAMIDE RESIDUES IN REAL HONEY SAMPLES USING LIQUID CHROMATOGRAPHY WITH FLUORESCENCE AND TANDEM MASS SPECTROMETRY DETECTION

This paper presents new reversed phase liquid chromatographic methods (HPLC-FLD and LC-MS/MS) for the quantification of sulfonamides in spiked and incurred honey samples. The sample preparation was optimized using Oasis HLB (hydrophilic–lipophilic balance) solid-phase extraction (SPE) cartridge. Elutions of sulfonamides were carried out under acidic, neutral, and basic conditions using methanol. Recoveries under acid condition were in the range from 66.8–90%, which were approximately 10% higher than those obtained under other conditions. The sample clean-up was also tested using Strata-XL cartridges. The HPLC-FLD separation was performed using a Varian C18 column and a ternary (methanol-acetonitrile-phosphate buffer, pH 5) mobile phase resulting good selectivity for the determination. The robustness of the ternary gradient method was evaluated by computer simulation (DryLab). LC-MS/MS separation was carried out on a Kinetex XB core-shell type HPLC column that enabled a low limit of detection (0.01–0.5 µg/kg) and faster separation (6 min). The developed methods were validated in accordance with the European Union Commission Decision 2002/657/EC and were applied successfully for more than four hundred honey samples (under a national monitoring program). The concentrations of sulfadimethoxine, sulfachloropyridazine, and trimethoprim residues in samples were found in a concentration range from 0.03 up to 686 µg/kg.

Polycyclic aromatic hydrocarbons (PAHs) in surface waters of Ráckevei-Soroksári Danube Branch, Hungary

Concentrations of polycyclic aromatic hydrocarbons (PAHs) in the surface waters of Ráckevei-Soroksári Danube (RSD) branch, Hungary were determined at ten sites during eight sampling events from October 2002–April 2004. Low and medium molecular weight PAHs (2–4 rings) varied from a few ng/L to hundreds of ng/L while high molecular weight PAHs (5–6 rings) were present at much lower concentrations (< 0.5–31 ng/L). Generally, concentrations of most of the individual PAHs were not significantly different (p > 0.05) during the different seasons. Concentrations of anthracene, fluoranthene, and pyrene were significantly lower (p < 0.005) in the winter month whereas concentrations of benzo(a) anthracene, chrysne, and benzo(b)fluoranthene were significantly lower (p < 0.05) in the fall season. Possible causes of such distribution in the surface waters of RSD include nature of the inputs of organic matter and different systems of winds or rains of the seasons. Of the total PAHs, the 2–3-ring PAHs contributed to about 78% while 4–6-ring PAHs accounted for 22%. This suggests that the incomplete combustion of fossil hydrocarbons may be the predomainate source of PAHs in surface water of RSD. Seasonally, petroleum and heavy fuel combustion were main sources of PAHs in summer and winter seasons, respectively. However, both sources contribute to PAHs in the spring season. The levels of PAHs in our study were compared with other regions of the world. Concentrations of PAHs in our study were higher than most of the surface waters of Europe, North America, and Australia, but similar to some parts of European and Asian regions.

Analysis of Sub µg/kg Lincomycin in Honey, Muscle, Milk, and Eggs Using Fast Liquid Chromatography–Tandem Mass Spectrometry

A fast liquid chromatography-tandem mass spectrometry (LC-MS-MS) method is developed to determine lincomycin (LM) in honey, muscle, milk, and egg. Samples are cleaned-up at pH 4.7 using Strata-X-C mixed-mode polymeric strong cation exchange solid-phase extraction (SPE) cartridges, which could selectively adsorb the lincomycin from matrices under the acidic condition. LM is separated on the recently introduced Kinetex XB core-shell type HPLC column using isocratic elution mode with a mobile phase containing 0.1% formic acid in water/acetonitrile (93/7, v/v, pH 2.6) at a flow rate of 0.7 mL/min. The subsequent MS/MS detection has decreased ion effect, which allows the limit of detection (LOD) of LM for honey to be 0.05 µg/kg for honey and 0.5 µg/kg for muscle, milk, and egg. These LODs are much lower than those reported previously. The other main advantage of the developed method is the analysis time of only 3.5 min, which is about three times shorter than other reported LC-MS-MS methods. Recoveries varies between 94.2% and 125.2% and in-house reproducibility ranges from 3.7% to 28.7%. The developed method is validated according to European Union (EU) Commission Decision 2002/657/EC using a matrix-comprehensive validation strategy. All studied analytical parameters fulfills the EU guidelines.

Octylphenol and Nonylphenol in Surface Water of Ráckevei-Soroksári Danube Branch, Hungary

Concentrations of 4-octylphenol (OP) and 4-nonylphenol (NP) in surface water samples were determined at 10 sites during eight samplings (October 2002 to April 2004) at Ráckevei-Soroksári Danube (RSD) branch, Hungary. OP levels in surface waters ranged from < 0.0016 to 0.0907 μ g L− 1, whereas NP concentrations varied from < 0.008 to 0.428 μ g L− 1. The highest concentrations were found at a specific site, which receives input from an industry. A seasonal trend with higher concentrations of OP and NP was observed in waters during the warmer months. Concentrations of OP and NP in surface water were compared with other reported concentrations around the world. The concentrations of NP in RSD were found to be below the reported toxic concentrations for marine and freshwater species.

Determination of glyphosphate and some related compounds by ion-exchange high performance liquid chromatography

Anion exchange liquid chromatographic methods are described for the determination of N-phosphonomethyl-glycine (PMG), which is known also as glyphosate, its monomethylester (PMG-Met), N,N-bis(phosphonomethyl)-glycine (bis-PMG), N-methyl, N-phosphonomethyl-glycine (PMG-NMet) and glycine (Gly). Five different anion exchange columns were tested for the separation of the above mentioned compounds. Effects of the eluent pH, ionic strength and organic solvent composition were studied. It was found that only some of the tested columns were applicable for the separation of the PMG and PMG-NMet critical pair, which may be due to the different structure, the ratio of the hydrophobic and hydrophilic surface area of the ion exchanger. Analytical performance of the methods was investigated. Some examples are also shown for the application of these described methods.