Retention and lipophilicity of newly synthesized 3-benzyloxy steroid derivatives in normal- and reversed-phase HPLC

The retention behaviour and separation ability of nine newly synthesized 3-benzyloxy estrone derivatives were studied by FIPLC on silica and C-18 commercially available columns. The mobile phases used were: benzene-ethyl acetate, benzene-tetrahydrofuran, benzene-acetonitrile, methanolwaler and acetonitrilc-water in various proportions. The results are discussed in terms of nature of the solute, eluent and stationary phase. The correlation between the retention constants of nine 3- benzyloxy estrone derivatives obtained on C-18 column and calculated log P was examined too

Gas Chromatography in Food Authentication

Authentication of food products and food fraud detection are of great importance in the modern society. The application of sophisticated instrumentation, such as gas chromatography (GC), with this aim helps to improve the protection of consumers. Gas chromatography mostly combined with the most powerful detector, a mass spectrometer (MS), and various multivariate data processing tools is in the last few decades being increasingly applied in authenticity and traceability of a wide spectra of food products. These include animal and plant products, beverages and honey. This chapter gives an overview of the most recent applications of gas chromatography technique in determining food authenticity, described in scientific literature

Povezanost disaharidnih profila odredenih GC/EI-qMS sistemom sa genomima sorti pšenice, raži i tritikalea

Cultivars of small grain species: wheat (Triticum aestivum), rye (Secale cereale) and triticale (Triticosecale) were selected because of their specific biochemical composition of carbohydrates for gas chromatographic analysis. Samples were grounded to flour and extracted with 96% ethanol solution. Extracted mono- and disaccharides were first derivatized into corresponding trimethylsilyl-oximes (TMSO) and analyzed on a GC/EI-qMS device. Four eluting peaks at specific retention times (18.57 min, 18.80 min, 20.85 min, and 21.39 min), were identified as trimethylsilyl-oximes of turanose, melibiose and two peaks of sucrose using Wiley 275 and NIST 14 mass spectra libraries, and were further selected as discrimination factors. Their presence/absence in certain small grain cultivar was labeled with 1/0 thus creating binary numerical matrices, introduced into multivariate analysis. Exploratory data analysis techniques were applied, thus providing a successful background for wheat, rye and triticale species differentiation, regardless of the specific cultivar they belong to, avoiding quantitative determinations of defined discrimination markers. Higher similarities between wheat and triticale cultivars, in comparison with rye species, may be due to the fact that most of the triticale genome structure originates from wheat species.Sorte strnih žita: pšenice (Triticum aestivum), raži (Secale cereale) i tritikalea (Triticosecale), analizirane su primenom sistema gasne hromatografije sa maseno-spektrometrijskom detekcijom zbog specifičnog biohemijskog sastava ugljenih hidrata. Uzorci su prvo samleveni u brašno, a potom ekstrahovani 96%-tnim rastvorom etanola. Ekstrahovani disaharidi su zatim derivatizovani u odgovarajuće trimetilsilil-oksime i analizirani pomoću GC/EI-qMS uređaja. Bibliotečkim pretraživanjem Wiley 275 i NIST 14 baza masenih spektara četiri eluirajuća pika, sa specifičnim vremenima retencije (18,57 min, 18,80 min, 20,85 min, i 21,39 min), identifikovana su kao trimetilsilil-oksimi turanoze, melibioze i saharoze, i odabrana kao diskriminirajući faktori. Njihovo prisustvo, odnosno, odsustvo u određenim sortama strnih žita označeno je sa '1', odnosno, '0', kreirajući pritom binarne numeričke matrice, koje su podvrgnute multivarijantnoj analizi. Primenjene istraživačke tehnike analize podataka pružile su dobru osnovu za diferencijaciju pšenice, raži i tritikalea, bez obzira na specifičnu sortu kojoj pripadaju, izbegavajući pritom kvantitativnu analizu definisanih markera diskriminacije. Pretpostavlja se da uočena izraženija sličnost između sorti pšenice i tritikalea, u odnosu na raž, može biti rezultat činjenice da najveći deo strukture genoma sorti tritikalea vodi poreklo upravo od sorti pšenice

Normal and reversed phase high performance liquid chromatography of some new 1, 2, 4-triazole derivatives

The retention behaviour and separation ability of normal and reversed phase HPLC with one non-polar and two polar mobile phases, have been studied by measuring the retention constants of a series of newly synthesized 1,2,4-triazole derivatives. The results are discussed in terms of the nature of the solute, eluent and stationary phase

Lipidni i šećerni profili različitih sorti ječma (Hordeum vulgare)

The lipid components and soluble sugars in flour samples of different cultivars of barley (Hordeum vulgare), involving winter malting barley, winter forage barley, spring barley, and hulless barley, were identified). Fatty acids were extracted from flour samples with n-hexane, and derivatized into volatile methyl esters, using TMSH (trimethylsulfonium hydroxide) in methanol. Soluble sugars were extracted from defatted and dried samples of barley flour with 96% ethanol, and further derivatized into the corresponding trimethylsilyl (TMS) oximes, using hydroxylamine hydrochloride solution and BSTFA (N,O-bis-(trimethylsilyl)-trifluoroacetamide). The hexane and alcoholic extracts of barley cultivars were analyzed by GC-MS system. Lipid and sugar compositions were very similar in all barley cultivars. Therefore, multivariate analysis was applied to numerical values of automatically integrated areas of the identified fatty acid methyl esters and TMS oximes of soluble sugars. The application of hierarchical cluster analysis showed a great similarity between the investigated flour samples of barley cultivars, according to their fatty acid content (0.96). Also, significant, but somewhat less similarity was observed regarding the content of soluble sugars (0.70). These preliminary results indicate the possibility of distinguishing flour made of barley, regardless of the variety, from flours made of other cereal species, just by the analysis of the contents of fatty acids and soluble sugars.U ovom radu identifikovane su lipidne komponente i rastvorljivi šećeri u uzorcima brašna različitih sorti ječma (Hordeum vulgare). Ispitane su sledeće sorte ječma: 3 uzorka sorte ozimog pivskog ječma, 3 uzorka sorte ozimog stočnog ječma, i po jedan uzorak sorti jarog i golozimog ječma. Iz uzorka brašna ječma prvo su heksanom ekstrahovane masne kiseline, koje su zatim derivatizovane u odgovarajuće, isparljive metil-estre, primenom reagensa za derivatizaciju TMSH (trimetilsulfonijum-hidroksid u metanolu). Nakon toga, obezmašćeni i osušeni uzorci ječmenog brašna podvrgnuti su ekstrakciji 96%-tnim etanolom, čime su izdvojeni rastvorljivi šećeri, koji su dalje derivatizovani u odgovarajuće TMS- oksime, primenom rastvora hidroksilamin-hidrohlorida i BSTFA (N, O-bis- (trimetilsilil)-trifluoroacetamid). Heksanski i alkoholni ekstrakti sorti ječma analizirani su primenom gasne hromatografije - masene spektrometrije (GCMS). Sastav lipidnih, kao i šećernih komponenata je bio vrlo sličan kod svih sorti. Stoga je za dalju obradu podataka primenjena multivarijantna analiza numeričkih vrednosti integrisanih površina identifikovanih metil-estara masnih kiselina i trimetilsilil-oksima rastvorljivih šećera. Primena hijerarhijske klaster analize pokazuje veoma velike sličnosti između ispitanih uzoraka brašna sorti ječma, po sadržaju masnih kiselina (0.96). Takođe značajna, ali nešto manja sličnost ustanovljena je kod sadržaja rastvorljivih šećera (0,70). Ovi preliminarni rezultati ukazuju na mogućnost razlikovanja ječmenog brašna, bez obzira na sortu, od brašna drugih žitarica analizom sadržaja masnih kiselina i rastvorljivih šećera

Gas chromatography-mass spectrometry system applied to determine botanical origin of various types of edible vegetable oils

This study represents a new strategy for discrimination of 59 samples of various cold-pressed, virgin and refined edible vegetable oils according to the corresponding botanical origin. Samples were produced from 17 plant species: olive, sunflower, safflower, flax, pumpkin, sesame, hemp, walnut, hazelnut, almond, grape, black cumin, apricot, plum, soybean, wheat and rapeseed. A GC/MS device performing in a ion current (IC) mode, combined with multivariate clustering, was employed in the analysis. Derivatization reaction occurred in the injector of a gas chromatograph. The discriminations between species were based on marker-peaks of 9 molecular ions of dominant fatty acid methyl esters (FAMEs), which were chosen as descriptors: m/z 268, 270, 292, 294, 296, 298, 324, 326 and 354. Dendrogram obtained after performing cluster analysis shows clear discriminations of the analyzed samples, based on the belonging botanical origin. These results demonstrate that IC-GC/MS approach with cluster analysis could be a useful tool in rapid screening for botanical origin of commercial samples of various edible vegetable oils

Characterisation of colloidal gold systems by photometry, spectrophotometry and chronopotentiometric stripping analysis

Colloidal systems of different metals attract lot of attention in scientific research due to their specific physico-chemical properties and possible application routes. In this respect particularly interesting is colloidal gold that has very broad application in different fields, including catalysis, biological and cancer research, electronics etc. Colloidal gold was generated by electric arc discharge method in a home-made generator. The generator consisted of a control system which maintained a constant distance between the electrodes (2 mm), a power supply system and amperometer which controlled the arc discharge parameters, halogen bulbs used as resistors, a glass container with deionized water and a magnetic stirrer. Generation technique consisted in adding 10 l of 35% hydrochloric acid to 500 ml of distilled water, submerging gold (99.9999%) electrodes (d=1 mm) in the solution and initiating electric arc discharge. Initial voltage was set to 20-70 V and the current was maintained at 205 A during entire generation process (30 min) by adjusting electrode distance. The influence of the initial voltage on optical characteristic of colloidal systems was examined by photometry and spectrophotometry, whereas the concentration of free gold ions was determined by chronopotentiometric stripping analysis at glassy carbon electrode. Photometric and spectrophotometric analyses were performed to characterise indirectly particle size distribution, since light absorption, reflection and transmission are highly affected by particle size. The size of gold nanoparticles, in return, affects strongly their properties and behavior in biological systems. By using both yellow-green and blue optical filters in photometric analysis, absorption increased almost linearly in the entire voltage range. Spectrophotometric analysis revealed absorption maximum in the range of 470-590 nm, depending on the initial voltage. Absorption maximum increased with initial voltage, indicating increase in the concentration of colloidal gold. Initial voltage also affected dominant particle size. Particle size distribution was determined by Zetasiyer Nano ZS90. Dominant particle size was in the range from 5 nm (at 50 V) to 19 nm (at 30 V). The influence of generation potential on the concentration of free gold was evaluated by chronopotentiometric stripping analysis at glassy carbon electrode. As a supporting electrolyte 0.1 HCl was used. Electrolysis potential was -0.6 V. After 600 s of electrolysis dissolution current of 8.3 A was applied to reach final potential of +1.25V. The concentration of free gold increased linearly with initial voltage (y=0.0 1x+0.73; r2=0.9849) from 0.95 mg/l (at 20 V) to 1.3 mg/l (at 70 V)

Thermo-Acid pretreatment of starch based kitchen waste for ethanol production

Recently, research on the alcoholic fermentation of kitchen waste has been accelerating for both ecological and economical reasons, primarily for ethanol use as renewable biofuel. Present work deals with the fermentative production of ethanol from different starch based kitchen waste. Kitchen waste from local students restaurant was separated by basic component as: peas, green beans, beans, rice, potato, wheat bread and corn. Thermo-acidic pretreatment of these raw materials was conducted by the addition of HCl up to pH of 1, and by autoclaving at 120 oC for 30 min. From the experimental result, maximum ethanol yield was obtained from wheat bread (0.11 g/g). The highest ethanol yield per starch of 0.36 g/g, which equals to 64% of the theoretical value, was obtained for peas. From the overall analysis, the examined thermo-acid pretreatment was the most efficient for hydrolysis of wheat bread, while it was least efficient for green beans. In order to enhance the efficiency of conversion of starch from kitchen waste into ethanol, pH lower than 1 is highly recommended. The results demonstrated the potential of different food waste as a promising biomass resource for the production of ethanol

Novi metod procene sastava smeša jestivih ulja: ulje suncokreta i uljane repice

Food authentication is the process by which a food product is verified as complying with its label description. The characterization and authentication of oils and fats is a subject of great importance for market and health aspects. The aim of this paper was to determine the possibility of applying a gas chromatography device with a mass spectrometric detector (GC-MS) coupled to a newly developed mathematical model to determine the proportion of individual oils in simulated blended oil samples.Autentifikacija hrane je postupak kojim se potvrđuje usaglašenost prehrambenog proizvoda sa njegovim opisom na etiketi. Karakterizacija i autentifikacija ulja i masti je tema od velike važnosti sa tržišnog i zdravstvenog aspekta. Cilj ovog rada bio je da se utvrdi mogućnost primene uređaja za gasnu hromatografiju sa masenim spektrometrom kao detektorom (GC-MS) i novorazvijenog matematičkog modela za određivanje udela pojedinačnih ulja u simuliranim uzorcima smeša ulja

Thermo-acid pretreatment of starch based kitchen waste for ethanol production

Recently, research on the alcoholic fermentation of kitchen waste has been accelerating for both ecological and economical reasons, primarily for ethanol use as renewable biofuel. Present work deals with the fermentative production of ethanol from different starch based kitchen waste. Kitchen waste from local students restaurant was separated by basic component as: peas, green beans, beans, rice, potato, wheat bread and corn. Thermo-acidic pretreatment of these raw materials was conducted by the addition of HCl up to pH of 1, and by autoclaving at 120oC for 30 min. From the experimental result, maximum ethanol yield was obtained from wheat bread (0.11 g/g). The highest ethanol yield per starch of 0.36 g/g, which equals to 64% of the theoretical value, was obtained for peas. From the overall analysis, the examined thermo-acid pretreatment was the most efficient for hydrolysis of wheat bread, while it was least efficient for green beans. In order to enhance the efficiency of conversion of starch from kitchen waste into ethanol, pH lower than 1 is highly recommended. The results demonstrated the potential of different food waste as a promising biomass resource for the production of ethanol