Katarzyna Bielicka-Daszkiewicz

Theoretical and experimental methods of determination of the breakthrough volume of SPE sorbents.

Solid-phase extraction is one of the most popular sample preparation methods. The selection of the appropriate extraction system is an important stage in the elaboration of analytical procedure. In this case, the knowledge of the interactions between isolated compounds, sorbent and elution solvents seems to be important. The extraction ability of sorbents in the SPE bed depends also on: (i) the bed capacity; (ii) the volume of sample loaded, (iii) the nature and volumes of conditioning solvents and eluents. One of the important parameters is the breakthrough volume, which determines the maximum volume of water sample which can be introduced into the sorbent. In this work two methods of determination of the breakthrough volumes are presented: experimental method with frontal analysis, and theoretical method with computational applications. Both procedures were used for the characterization of nine polymeric sorbents based on divinylbenzene copolymers. Comparison of results allows to choose the computational procedure of breakthrough volume determination as the easier one and less time consuming.

Role of Hansen solubility parameters in solid phase extraction.

The sorbent-eluent systems combined from eight polymeric sorbents and seven solvents as eluents were used for the extraction of phenol and its oxidation products from water samples. The individual interactions between sorbents, eluents and analytes were characterized by Hansen solubility parameters. Principal components analysis (PCA) was used for revealing the dominant interactions (dispersive, polar, and hydrogen bonding type) in sorbent-analyte-eluent systems. The importance of solubility parameters was also determined by a novel procedure based on sum of ranking differences (SRD). Although PCA and ranking by SRD are based on different principles and calculations, they have provided very similar results. The recovery in a given system has been predicted from the magnitudes of mutual interactions (sorbent-analyte, sorbent-eluent, analyte-eluent) by multiple linear regression.

Preparation and examination of monolithic in-needle extraction (MINE) device for the direct analysis of liquid samples.

Combination of extraction and chromatographic techniques opens NEW possibilities in sample preparation area. Macroporous poly(styrene-divinylbenzene) (PS-DVB) monoliths were prepared by in situ polymerization in stainless steel needles. The surface of stainless steel needle was modified earlier by the silane coupling agent. Monolithic materials located inside needles were used as the in-needle extraction device. Scanning electron microscope (SEM) images were obtained for nine monoliths. Spectra of prepared materials were also performed with the use of two techniques: Attenuated Total Reflectance (ATR) and Fourier Transform Infrared Spectroscopy (FTIR). The new monolithic in-needle extraction (MINE) devices were used in the preparation of a series of test water samples for chromatographic analysis. The extraction of phenolic compounds from water samples was carried out by pumping liquid samples through the MINE device. Obtained results indicate a high efficiency of in-needle extraction systems based on monolithic materials. Breakthrough volume and the sorption efficiency of prepared monolithic in-needle extraction devices were determined experimentally. The achieved recovery was close to 90%, and determined LOQ values varied between 0.4 and 6 μg.

Estimation of the breakthrough volume of selected steroids for C‐18 solid‐phase extraction sorbent using retention data from micro‐thin layer chromatography

SPE method is a very popular technique, and is commonly used for the prepurification, concentration, and isolation of different organic compounds from variable matrices. In this work, the optimization of SPE process was carried out. The breakthrough volume of solid sorbents based on octadecylsilane was determined and three methods were compared: (1) calculation one - the breakthrough volume was calculated using retention factor k determined with micro-TLC method, frontal analysis - (2) breakthrough volume was determined as volume of whole elution peak, and (3) breakthrough volume was determined as the center of peak gravity. For calculation method, the k values of key estrogens and progestogens were derived from the micro-TLC experiment reported previously. By combining these three methods, we can point the start of elution, the maximum concentration of analyte in eluate, and the whole eluent volume, which is necessary to achieve an appropriate selectivity and high extraction recovery. Proposed calculation method allows to estimate the beginning of the steroid peak, when the analyte appears in the eluate flowing from the sorbent. Such observation advances the SPE optimization protocol that was described before and was based on the correlation between raw k(SPE) and k(micro-TLC) data.

Optimization of SPE/GC/HPLC Analytical Procedure for Determination of Phenol, Quinones, and Carboxylic Acids in Water Samples

Chromatographic techniques are among the most useful analytical methods. Gas and liquid chromatography were used in the analysis of some organic compounds: phenol, hydroquinone, benzoquinone, and maleic and fumaric acids. The analytical way for the determination of these compounds in water samples was investigated. Solid-phase extraction (SPE) technique was used on the sample preparation step, different divinylbenzene-based sorbents were applied. Calibration curves of given compounds were linear over the ranges: 50–500 μg/mL for phenol and its acetic derivatives, 50–1500 μg/mL for benzoquinone in GC analysis, and 50–250 μg/mL for phenol, 40–1000 μg/mL for hydroquinone, and 4–4500 μg/mL for carboxylic acids in HPLC analysis. The LOD and LOQ of proposed analytical procedure were in the ranges of LOD: 0.042–23.83 μg/mL; LOQ: 0.138–78.64 μg/mL.

Best conditions for biodegradation of diesel oil by chemometric tools

Diesel oil biodegradation by different bacteria-yeast-rhamnolipids consortia was tested. Chromatographic analysis of post-biodegradation residue was completed with chemometric tools (ANOVA, and a novel ranking procedure based on the sum of ranking differences). These tools were used in the selection of the most effective systems. The best results of aliphatic fractions of diesel oil biodegradation were observed for a yeast consortia with Aeromonas hydrophila KR4. For these systems the positive effect of rhamnolipids on hydrocarbon biodegradation was observed. However, rhamnolipids addition did not always have a positive influence on the biodegradation process (e.g. in case of yeast consortia with Stenotrophomonas maltophila KR7). Moreover, particular differences in the degradation pattern were observed for lower and higher alkanes than in the case with C22. Normally, the best conditions for “lower” alkanes are Aeromonas hydrophila KR4 + emulsifier independently from yeasts and e.g. Pseudomonas stutzeri KR7 for C24 alkane.

Assessment of the adsorption strength of fragrances on zeolites via solid-phase extraction

ABSTRACT Zeolites are porous materials, which have very interesting properties, very useful in physicochemistry, analytical, and industrial chemistry. In these works, solid-phase extraction technique was used for the description of adsorption/desorption properties of zeolite-like materials. Some natural and synthetic molecular sieves were tested. Three fragrance compounds: geraniol, menthol, and thymol were used as adsorbates. The obtained results indicate that the adsorption efficiency was higher for modified natural zeolites than for other materials. Chain compounds are strongly adsorbed by aromatic rings, so this property can be used in the preparation of fragrance materials. GRAPHICAL ABSTRACT

Extraction techniques based on solid state and connected with liquid chromatography

ABSTRACT Extraction methods applied in analysis of water samples can be named as liquid chromatography. Very often, these techniques are used as sample preparation method before another analytical method such gas chromatography or high performance liquid chromatography. The subject of this review is to compare the extraction techniques of liquid samples and discuss their characteristics in comparison with liquid chromatography. Some new extraction techniques are described, and some characteristic parameters are compared. GRAPHICAL ABSTRACT

New Mesoporous Aluminosilicates Used for Solid-phase Extraction of Hydrocarbons and Fragrance Compounds

ABSTRACT The extraction efficiency of three newly synthesized mesoporous aluminosilicate materials with different Si/Al ratios was evaluated. The surface morphology and pore sizes of new mesoporous materials were determined, and the adsorption properties were examined. Scanning electron microscopy–energy dispersive spectroscopy was used to characterize the Al content in the material. The Brunauer, Emmett, Teller Isotherm method was used for determining the surface area and the pore size of synthesized materials. The adsorption properties of examined materials were evaluated by solid-phase extraction in classical form and using microsolid-phase extraction. In addition, the use of the examined aluminosilicates was investigated as sorbents for hydrocarbons and fragrance compounds.

Application of micro-solid-phase extraction for determination of released dental fillings components in artificial saliva solution

In this work, the microextraction devices in form of sachets were prepared and used for isolation of released dental fillings components from artificial saliva solutions As sorbents mesoporous aluminosilicate and C18-bonded silica were used. Gas chromatography was used for indication of analytes in samples. The dependence of adsorption on variable factors were determined. The effect of adsorbent mass, the membrane type for μ-SPE device and time of adsorption on the efficiency of the process were examined. The dependence between the extraction recovery and the desorption solvent was also indicated. Based on calculated adsorption capacities in time of adsorption and equilibrium state the kinetic study was prepared. The validation of determination method by using of membrane-protected microextraction for sample preparation was conducted. The developed method proved to be convenient and offers good reproducibility. The detection limits of the method under optimized conditions were in the range of 0,117 μg mL-1 for camphor to 1407 μg mL-1 for 4-methoxyphenol. Two examined membrane protected sorbent were successfully applied for extraction of eluted dental ingredients.