Wyniki wyszukiwania - BazTech

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Determination of benzene, toluene, ethylbenzene and xylene in field and laboratory by means of cold fiber SPME equipped with thermoelectric cooler and GC/FID method

Tajik L., Bahrami A., Ghiasvand A., Shahna F. G.

Polish Journal of Chemical Technology

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2017

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Vol. 19, nr 3

9--15

EN

A simple and effective cooling device based on a thermoelectric cooler was applied to cool the SPME fiber. The device was used for quantitative extraction of aromatic hydrocarbons in the air. Several factors such as coating temperature, extraction temperature and relative humidity in the laboratory setting were optimized. Comparison of the results between the cold fiber SPME (CF-SPME) and NIOSH 1501 method on standard test atmosphere indicated a satisfactory agreement. The CF-SPME and SPME method were also compared. The results revealed that CF-SPME has the most appropriate outcome for the extraction of aromatic hydrocarbons from the ambient air. The cold fiber SPME technique showed good results for several validation parameters. Under the optimized conditions, the limits of detection (LOD) and the limits of quantification (LOQ) ranged from 0.00019 to 0.00033 and 0.0006 to 0.001 ng ml−1 , respectively. The intra-day relative standard deviation (RSD) showed ranging from 4.8 to 10.5%.

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Analysis of the volatile compounds in Nepeta crispa willd. Using improved HS-SPME-GC-MS and comparison with conventional methods

Azar P. A, Porgham-Daryasari A, Saber-Tehrani M, Soleimani M.

Acta Chromatographica

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2012

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Vol. 24, no. 1

75--84

EN

In this study, gas chromatography-mass spectrometry (GC-MS) following microwave distillation and solid-phase microextraction (MD-SPME) was developed for the analysis of essential oil compounds in Nepeta crispa. To improve the headspace (HS) method, microwave powers, irradiation times, and SPME fiber coatings were studied. The optimal experiment parameters obtained were 65-μm PDMS/DVB SPME fiber, a microwave power of 400 W, and an irradiation time of 3 min. MD-SPME was compared with headspace solid-phase microextraction (HS-SPME) and conventional hydrodistillation (HD) for the extraction of essential oil compounds in N. crispa. A comparative qualitative and quantitative study on the composition of the oils was carried out. For this, 26 compounds, constituting 98.2% of the oil, were identified in the essential oil by MD-SPME, and 23 compounds, representing 91.3% of the oil, were characterized in the SPME and HD methods; 25 compounds, constituting 94.6% of the oil, were separated and identified. The main compounds identified by all methods were 1,8-cineol, β-bourbonene, α-terpineol, and β-pinene. The relative standard deviation (RSD) values of less than 8% show that the MD-SPME method has good repeatability.It has been shown that the extraction of essential oils from N. crispa with MD-SPME was better in terms of energy saving, extraction time, plant material, oxygenated fractions, and product quality.

3

Wykorzystanie techniki SPME GC MS w analizie autentyczności geograficznego pochodzenia kawy Coffea arabica i Coffea canephora var. Robusta

Bryła M., Berezińska A., Obiedziński M.

Analityka : nauka i praktyka

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2010

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nr 3

52-58

PL

Wspólnotowe prawo żywnościowe wysoko stawia kwestię ochrony konsumentów żywności przed próbami fałszowania produktów spożywczych. W pracy zbadano możliwość wykorzystania analizy składu frakcji lotnej ziarna kawowego z lokalnej palarnio-kawiarni do różnicowania kaw o różnym pochodzeniu geograficznym.

4

Application of gas chromatography, mass spectrometry and olfactometry for quality assessment of selected food products

Wardencki W., Chmiel T., Dymerski T., Biernacka P., Plutowska B.

Ecological Chemistry and Engineering. S

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2009

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Vol. 16, nr 3

287-300

EN

The volatile compounds in spirits and honeys were determined by headspace solid-phase microextraction as sample preparation technique and gas chromatography (GC) with mass spectrometry (MS) and olfactometry (O) detection. Identification of spirits and honey volatiles was made by comparison mass spectra with data in NIST Mass Spectral Database. Additionally, flavour compounds detected by sensory-panel were registered in the form of olfactograms by fmgerspan method. Analysis of raw spirits indicated the presence of over 200 compounds, of which a significant number were identified (including esters, higher alcohols, aldehydes, acetals, as well as furanes, sulphur compounds, terpenoids and benzene derivatives). Among them over 50 were identified whose presence or high content can decrease the quality of distillates. In the result of performed analysis of honeys, 163 volatile and semi-volatile compounds were identified (aliphatic and aromatic acids, aldehydes, ketones, alcohols and phenols, terpenoids, furane and pyrane derivatives). In the midst of them markers of each type of honeys were indicated. Formed determinant lists can be useful for distinguish and quality control (for example finding adulterations) of Polish honeys. Besides, application of GC-MS technique coupled with olfactometry make possible creating aroma profiles of investigated honeys. Employed techniques were characterized by high sensitivity and repeatability, furthermore they are less time-consuming.

PL

Stosując mikroekstrakcję do fazy stacjonarnej z fazy nadpowierzchniowej jako metodę przygotowania próbek i chromatografię gazową (GC) ze spektrometrią mas (MS) i olfaktometrią (O) jako metodę oznaczeń końcowych, oznaczono lotne związki w spirytusach i miodach. Identyfikację przeprowadzono przez porównanie widm masowych z widmami z biblioteki NIST. Dodatkowo, wykrywane przez panel oceniający związki zapachowe rejestrowano w formie olfaktogramów, stosując metodę "odcisku palca". Analiza surowych spirytusów wykazała obecność ponad 200 związków, z których większość została zidentyfikowana (estry, wyższe alkohole, aldehydy, acetale, a także furany, związki siarki, terpenoidy i pochodne benzenu). Stwierdzono, że ponad 50 związków z tej grupy to związki odpowiedzialne za pogorszenie jakości destylatów. W rezultacie przeprowadzonej analizy miodów zidentyfikowano 163 lotne i średniolotne związki (alifatyczne i aromatyczne kwasy, aldehydy, ketony, aldehydy i fenole, terpenoidy, pochodne furanu i piranu). Spośród tych związków wskazano markery każdego typu miodu. Lista markerów pozwala rozróżniać i kontrolować jakość (np. stwierdzić zafałszowanie) polskich miodów. Zastosowanie dodatkowo metody GC-MS połączonej z olfaktometrią pozwoliło stworzyć profile związków zapachowych badanych miodów. Zastosowane metody charakteryzują się duża czułością i powtarzalnością, a ponadto są względnie szybkie.