Tomasz Chmiel

Comprehensive two-dimensional gas chromatography for determination of the terpenes profile of blue honeysuckle berries.

Terpenes are the main group of secondary metabolites, which play essential role in human. The establishment of the terpenes profile of berries of different blue honeysuckle cultivars was achieved by headspace solid-phase microextraction coupled with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (HS-SPME/GC×GC-TOFMS). The berries were found to contain 44 terpenes identified by GC×GC-TOFMS. From these, 10 were previously reported in blueberries. According to their chemical structure, the compounds were organised in different groups: monoterpene hydrocarbons and monoterpene oxygen-containing compounds (oxides, alcohols, aldehydes, and ketones). Positive identification of some of the compounds was performed using authentic standards, while tentative identification of the compounds was based on deconvoluted mass spectra and comparison of linear retention indices (LRI) with literature values. The major components of volatile fraction were monoterpenes, such as eucalyptol, linalool and p-cymene. Furthermore, quantitative analysis showed that eucalyptol was the most abundant bioactive terpene in analysed berries (12.4-418.2 μg/L).

Botanical and Geographical Origin Characterization of Polish Honeys by Headspace SPME-GC× GC-TOFMS

Volatile organic compounds (VOCs) composition of Polish honeys obtained from various geographical regions was studied. Headspace solid phase microextraction (HS-SPME) using Divinylbenzene/Carboxen/Polydimethylsiloxane-coated fibers was used in combination with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GCGC-TOFMS) because of the complexity of the samples. Acacia, linden, rapeseed, buckwheat and honeydew honeys were studied in this project. A total of 329 compounds were identified during the investigations. Positive identification of 82 compounds was achieved using analytical standards, while tentative identification of 247 compounds was based on comparison of deconvoluted mass spectra and linear temperature programmed retention indices (LTPRI) with NIST 2005 library and literature values, respectively. Many VOCs identified in Polish honey samples were commonly present in honeys from other geographical regions of Europe (e.g. Italy, Corsica). They included certain acyclic and cyclic alkanes, acyclic and cyclic alkenes, aromatic hydrocarbons, oxygenated aromatic compounds, alcohols, aldehydes, ketones, es- ters, ethers, nitriles, organic sulphides, phenolic compounds and terpenes. GCGC-TOFMS profiles for the same types of honey samples were remarkably similar. Eight botanic discriminants were selected among all compounds. Their identity was confirmed by comparison with authentic standards. Furthermore, possible geographical discriminants for Polish honeys were identified, including 19 for acacia, 3 for linden, 3 for rapeseed and buckwheat and 6 for honeydew honeys.

Application of response surface methodology to optimize solid-phase microextraction procedure for chromatographic determination of aroma-active monoterpenes in berries

Most of scientific papers concern the qualitative or semi-quantitative analysis of aroma-active terpenes in liquid food matrices. Therefore, the procedure based on solid-phase microextraction and two-dimensional gas chromatography-time-of-flight mass spectrometry for determination of monoterpenes in fresh berries was developed. The optimal extraction conditions using divinylbenzene-carboxen-polydimethylsiloxane fiber were: temperature of 50°C, extraction time of 26min, equilibrium time of 29min. The developed procedure provides a high recovery (70.8-99.2%), good repeatability (CV<10.4%), high linearity (r>0.9915) and offers practical advantages over currently used methods: reliability of compounds identification, simplicity of extraction and at least one order of magnitude lower detection limits (0.10-0.011μg/L). The method was successfully applied to determine monoterpenes in 27 berry samples of different varieties and 4 berry products. Tukeys test revealed that monoterpenes content is a reliable indicator of fruit maturity and origin. It suggests that the method may be of interest to researchers and food industry.

Nondestructive Optical Sensing of Flavonols and Chlorophyll in White Head Cabbage (Brassica oleracea L. var. capitata subvar. alba) Grown under Different Nitrogen Regimens

A multiparametric optical sensor was used to nondestructively estimate phytochemical compounds in white cabbage leaves directly in the field. An experimental site of 1980 white cabbages (Brassica oleracea L. var. capitata subvar. alba), under different nitrogen (N) treatments, was mapped by measuring leaf transmittance and chlorophyll fluorescence screening in one leaf/cabbage head. The provided indices of flavonols (FLAV) and chlorophyll (CHL) displayed the opposite response to applied N rates, decreasing and increasing, respectively. The combined nitrogen balance index (NBI = CHL/FLAV) calculated was able to discriminate all of the plots under four N regimens (0, 100, 200, and 400 kg/ha) and was correlated with the leaf N content determined destructively. CHL and FLAV were properly calibrated against chlorophyll (R(2) = 0.945) and flavonol (R(2) = 0.932) leaf contents, respectively, by using a homographic fit function. The proposed optical sensing of cabbage crops can be used to estimate the N status of plants and perform precision fertilization to maintain acceptable crop yield levels and, additionally, to rapidly detect health-promoting flavonol antioxidants in Brassica plants.

Solid phase microextraction–comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry: a new tool for determining PAHs in airport runoff water samples

A fundamental aspect of airport operations is the pollution caused by airport runoff waters. Polycyclic aromatic hydrocarbons (PAHs) are one of the most important groups of xenobiotics which are commonly found in runoff water originating from airports. Only very limited data on the analysis of airport runoff water have been published until now. Therefore, a reliable and accurate analytical method based on headspace solid-phase microextraction (HS-SPME) coupled with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC-TOF-MS) for simultaneous determination of 16 PAHs in airport runoff water was developed. The optimization of the HS-SPME procedure resulted in the following extraction conditions: extraction time of 45 min, temperature of 70 °C, salt addition of 3.0 g, and desorption time of 10 min at 270 °C. The recovery values obtained using this method (63–108%) mostly fell within the acceptable range for the analytical procedures. This indicates that HS-SPME is a suitable and efficient tool for the extraction of PAHs from airport wastewater, the latter being characterized by a very complex matrix composition. In addition, the developed procedure exhibited satisfactory selectivity, accuracy and a low MDL (0.22–2.20 ng L−1). It should be emphasized that the presented procedure is new with respect to the determination of toxic, mutagenic and carcinogenic analytes in the original environmental samples, elaboration of the detailed metrological characteristics, and the diversity of places from which runoff water samples are collected. The validated analytical protocol was successfully applied to determine the aforementioned organic pollutants in real samples collected from different international airports. Regardless of the airport location, chrysene, phenanthrene and pyrene were the most abundant PAH compounds detected in all analyzed samples (1.8–26.3 μg L−1). The presented methodology can be used for tracking the environmental fate of PAHs and assessing the impact of airports on the environment.

Gas chromatography-olfactometry (GC-O), electronic noses (e-noses) and electronic tongues (e-tongues) for in vivo food flavour measurement

Abstract: The flavour of food products is undoubtedly one of the most important parameters influencing acceptance of particular products by consumers. Therefore, evaluation of taste and smell of food products is important in different areas of food industry. This chapter reviews two types of artificial olfaction instrumentation, i.e. gas chromatography-olfactory (GC-O) and chemical sensor technologies (electronic nose and tongue – e-nose and e-tongue), combined with multivariate data processing methods as promising approaches for rapid analysis of food. The chapter first discusses the working principles of each system and gives a brief description of instrumentation. Further discussion concerns comparison of the GC-O system with sensor technologies, especially by considering the advantages and disadvantages of both type of instrumentation. The chapter also includes examples of specific applications for the detection of food flavour and volatile components.

Simultaneous determination of individual isothiocyanates in plant samples by HPLC-DAD-MS following SPE and derivatization with N-acetyl-l-cysteine.

The procedure for the isothiocyanates (ITCs) determination that involves derivatization with N-acetyl-l-cysteine (NAC) and separation by HPLC was developed. Prior to derivatization, plant ITCs were isolated and purified using solid-phase extraction (SPE). The optimum conditions of derivatization are: 500μL of isopropanolic eluate obtained by SPE combined with 500μL of derivatizing reagent (0.2M NAC and 0.2M NaHCO3 in water) and reaction time of 1h at 50°C. The formed dithiocarbamates are directly analyzed by HPLC coupled with diode array detector and mass spectrometer if required. The method was validated for nine common natural ITCs. Calibration curves were linear (R(2)⩾0.991) within a wide range of concentrations and limits of detection were below 4.9nmol/mL. The recoveries were in the range of 83.3-103.7%, with relative standard deviations <5.4%. The developed method has been successfully applied to determine ITCs in broccoli, white cabbage, garden cress, radish, horseradish and papaya.