Mustafa Z. Özel

Determination of volatile nitrosamines in various meat products using comprehensive gas chromatography-nitrogen chemiluminescence detection.

An optimized method was developed for the extraction, pre-concentration and analysis of nitrosamines (NAs) in various meat products. Values of reproducibility, linearity, limit of detection (LOD) and limit of quantitation (LOQ) for six NA standards (N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodi-n-propylamine, N-nitrosopyrrolidine, N-nitrosopiperidine, N-nitrosodi-n-butylamine) were determined. The LODs using this method were between 1.66-3.86 and LOQs between 6.96-16.71 μg L(-1). The screening of four different types of meat samples (sausage, salami, sucuk and doner kebab) showed that all samples contained levels of various NAs, identified with high confidence using comprehensive gas chromatography (GCxGC) and a fast responding element specific nitrogen chemiluminescence detector (NCD). The sum of the six NAs were highest in the doner kebab samples, being between 0.51-16.63 μg kg(-1) and were lowest in the sausage samples at 0.45-2.93 μg kg(-1). The described method is simple, rapid, selective and sensitive.

New Sensitive and Quantitative Analysis Method for Organic Nitrogen Compounds in Urban Aerosol Samples

Atmospheric aerosols contain a highly complex mixture of organic and inorganic compounds; however, as a chemical class relatively little is known about organic nitrogen (ON) content, with few satisfactory methods for speciated analysis. In this paper we report a sensitive and quantitative method for the speciation of ON within ambient atmospheric aerosol. Aerosol samples, collected on quartz microfiber filters, were extracted in water followed by solid phase extraction, elution, and concentration before analysis by comprehensive gas chromatography with a nitrogen chemiluminescence detection system (GCxGC-NCD). The NCD detection method was optimized using liquid standards. The GCxGC-NCD method showed high selectivity, sensitivity, and equimolarity in its response to individual organic compounds. Limits of detection (LOD) and limits of quantitation (LOQ) for four ON standards (1-nitropentane, o-toluidine, nonanenitrile, and quinoline) were determined to be in the range 0.16-0.27 pgN and 0.71-1.19 pgN, respectively. Between 21 and 57 different ON compounds were found in urban aerosol, (including 10 nitriles, 9 alkyl nitro compounds, 4 nitro-phenols, 4 amides, 3 nitrosamines, and 2 nitro-PAHs) on different dates from a city center location. Pyrrole (8.26-39.21 ngN m(-3) air) and N-butyl-benzenesulfonamide (6.23-20.87 ngN m(-3) air) were the most abundant ON compounds observed in all samples analyzed. The average mass loading of the total identified ON was 532.51 ngON m(-3) air. The sensitivity, selectivity, and relative ease of quantitation of unknown ON components makes the technique a significant improvement over previous laboratory methods.

Analysis of Organic Nitrogen Compounds in Urban Aerosol Samples Using GCxGC-TOF/MS

Despite the fact that a significant number of organic and inorganic compounds have been measured in aerosol samples, relatively little is known about the organic nitrogen (ON) content. The ON components of 23 urban aerosol samples were characterized using a direct thermal desorption technique (DTD) together with comprehensive two-dimensional gas chromatography-time of flight mass spectrometry (GCxGC-TOF/MS). Between 17 and 57 various ON compounds mainly nitriles, amides, amines, and nitro compounds were found in individual samples collected on different dates from the same location. In total identifications were made for over 100 ON different compounds in urban aerosol. Aminomethanesulfonic acid, o-cyanobenzoic acid and hexadecanenitrile were found in all samples. 4-[2-(methylamino)ethyl]-phenol, pyridine, 4,4a,5,7a-tetrahydro-8,8-dimethyl-(1à,4à, 4aà,7aà)-1,4-methano-1H-cyclopenta[d]pyridazine, caprolactam, tetradecanitrile, penoxaline, tetradecanamide, and eicosanenitrile were detected in many of the samples. ON compounds contained 1–4 N atoms and ranged in MW from 59–302 Da. DTD proved an efficient tool for the analysis of volatile organic nitrogen components in ambient aerosol, avoiding more costly and time consuming off-line extraction techniques. Desorption of ON standards on filter papers showed efficient transfer to the GC.

Determination of volatile nitrosamines in grilled lamb and vegetables using comprehensive gas chromatography – Nitrogen chemiluminescence detection

The grilling of meat may generate dangerous levels of mutagenic and carcinogenic nitrosamines (NAs). Meat and vegetable samples underwent a two-step solid-phase extraction before analysis by comprehensive gas chromatography with a nitrogen chemiluminescence detection system (GCxGC-NCD). The GCxGC-NCD method showed high selectivity, sensitivity and equimolarity in its response to six specific NAs. NA contamination of charcoal-grilled lamb at various stages of cooking and with various fat contents and also charcoal-grilled vegetables were investigated. The grilling of lamb on unready charcoal resulted in the formation of considerable quantities of NAs. Grilling lamb on properly prepared, ready charcoal resulted in an increase in total concentrations of six NAs from 0 to 4.51 μg kg(-1) over a period of 16 min. Increasing the fat content of the grilled lamb from 5% to 20% caused a modest increase in total concentrations of the six investigated NAs from 4.51 to 5.30 μg kg(-1).

Analysis of roasted and unroasted Pistacia terebinthus volatiles using direct thermal desorption-GCxGC-TOF/MS.

The objective of this study was to determine the effects of roasting time on volatile components of Pistacia terebinthus L., a fruit growing wild in Turkey. The whole fruit samples were pan roasted for 0, 5, 10, 15, 20 and 25min at 200°C. Volatile compounds were isolated and identified using the direct thermal desorption (DTD) method coupled with comprehensive gas chromatography - time of flight mass spectrometry (GCxGC-TOF/MS). The major components of the fresh hull of P. terebinthus were α-pinene (10.37%), limonene (8.93%), β-pinene (5.53%), 2-carene (4.47%) and γ-muurolene (4.29%). Eighty-three constituents were characterised from the volatiles of fresh whole P. terebinthus fruits obtained by direct thermal desorption with α-pinene (9.62%), limonene (5.54%), γ-cadinane (5.48%), β-pinene (5.46%), β-caryophyllene (5.24%) being the major constituents. The type and the number of constituents characterised were observed to change with differing roasting times. Limonene (5.56%), α-pinene (4.84%), 5-methylfurfural (4.78%), 5-hydroxymethylfurfural (5-HMF, 3.89%), dimethylmetoxyfuranone (3.67%) and 3-methyl-2(5H)furanone (3.12%) were identified as the major components among the 104 compounds characterised in the volatiles of P. terebinthus, roasted for 25min. In addition, volatiles of fully roasted P. terebinthus fruits contained furans and furanones (15.42%), pyridines (4.45%) and benzene derivatives (3.81%) as the major groups.

Genotoxic, cytotoxic, and apoptotic effects of Hypogymnia physodes (L.) Nyl. on breast cancer cells

The aim of this study is to determine the chemical composition, and evaluate the genotoxic, and anti‐growth potency of the methanol extracts of lichen species Hypogymnia physodes (L.) Nyl. (HPE). Anti‐growth effect was tested in two different human breast cancer cell lines (MCF‐7 and MDA‐MB‐231) by the MTT and ATP viability assays and apoptosis was assayed by the caspase‐cleaved cytokeratin 18 (M30‐antigen). Genotoxic activity of HPE was studied using chromosome aberration and micronuclei tests in human lymphocytes culture in vitro. The chemical composition of H. physodes was analyzed by using direct thermal desorption method coupled with comprehensive gas chromatography–time of flight mass spectrometry (GCXGC‐TOF/MS). Our results indicate that HPE has an anti‐growth effect at relatively lower concentrations, while relatively higher concentrations are required for genotoxic activity. HPE, therefore, seems to represent a therapeutic potential and poses new challenges for medicinal chemistry.

The effect of various drying techniques on apricot volatiles analysed using direct thermal desorption-GC-TOF/MS.

The volatile constituents obtained from dried Sekerpare-type apricots by direct thermal desorption were examined using gas chromatography (GC) coupled with time of flight mass spectrometry (TOF/MS). Various commercially used drying techniques (sun, hot air and microwaves) were employed to dry the apricot samples before desorption. Some apricots were dried using only a desiccator and the volatile desorbed from these was used as a standard. Limonene (16.33%); (E)-2-hexenal (9.32%); gamma-decalactone (7.89%); butyl acetate (6.94%); beta-ionone (5.96%); acetic acid (4.83%) and isobutanal were found to be the major components in the desiccator-dried samples. This is the first study to report the detection of isobutanal, tridecanol and 1-pentadecanol as dried apricot constituents. The profiles of the volatiles desorbed changed when other drying techniques (sun, hot air, and microwaves) were used. The major components found in samples dried by these three methods were 5-hydroxymethylfurfural (5-HMF), 2,3-dihydro-4-H-pyran-4-one and furfural.

Analysis of Black Mulberry Volatiles Using GCxGC-TOF/MS

Volatile constituents of black mulberry (Morus nigra) dried with various commercially used techniques (sun, hot air, and microwaves) were obtained by direct thermal desorption and analysed using comprehensive GCxGC coupled with time of flight mass spectrometry (TOF/MS). Some mulberries were dried using only a desiccator and the volatile desorbed from these was used for comparison. The number of components of volatile fractions obtained for the desiccator, sun, microwave and hot air dried samples were 45, 43, 41, and 40, respectively. Acetic acid (8.18%), ethyl linolenate (7.43%), hexanol (5.42%), 3-methylbutanal (5.01%), 2,3-butanediol (4.93%), 3-hydroxy-2-butanone (4.82%), and 2,3-pentanedione (4.18%) were found to be the major components in the desiccator-dried samples. The profiles of the volatiles desorbed changed when other drying techniques (sun, hot air, and microwaves) were used. Isobutanal, pentanal, 1,2-propanediol, octane, and linalool acetate were found only in the desiccator-dried mulberry samples.

Analysis of essential oils of Origanum onites by superheated water extraction using GCxGC-TOF/MS.

Abstract Superheated water extraction was used to extract essential oils from leaves and grains of Origanum onites. The effect of different sample collection dates on the amount and composition of extracted essential oils was investigated. C-18 solid phase extraction was used to elute the essential oils from the aqueous extract. The volatile components were characterized by comprehensive (two dimensional) gas chromatography with time of flight mass spectrometry (TOF/ MS). The O. onites samples were collected on three different dates (15 June 2006, 25 June 2006, 05 July 2006). The extraction yields from O. onites leaves were 2.88 %, 3.06 %and 3.97 %; and from O. onites grains 3.63 %, 4.22 %and 4.57 %, respectively from each collection date. The main component found in all samples was carvacrol. The later collection dates gave better essential oil recovery from both leaves and grains.

Volatiles of Fresh and Commercial Sweet Red Pepper Pastes: Processing Methods and Microwave Assisted Extraction

Microwave-assisted hexane or water extraction was used to extract flavor compounds from fresh red pepper fruit and also from traditionally and industrially made pepper pastes. The composition of the volatile components from each extract was analyzed using comprehensive two-dimensional gas chromatography with time of flight mass spectrometry. In total, 79 compounds were determined including 15 alcohols, 14 terpenes, 13 aldehydes, 12 ketones, 7 fatty acids, 6 fatty acid esters, and 6 browning reaction products. The major common compounds of fresh pepper and the pastes were 2-pentanone, 3-hexanol, acetic acid, oleic acid, and linoleic acid. The compounds (E)-2-undecenal, farnesol, 2-pentadecyn-1-ol, linolenic acid, and squalene were found only in the fresh pepper samples. Browning reaction products were observed in both of the pastes. However, their concentration was much higher in the industrially made one. Microwave-assisted hexane extraction from the traditionally made pepper paste gave the highest number of volatiles. Many volatiles considered to possess pleasant aroma characteristics were observed only in the traditionally made paste.