The validation of rapid, low-cost spectrophotometric procedures for the quantification three main groups bioactive substances (flavones and flavonols, flavanones dihydroflavonols, total phenolics) in poplar-type propolis has been performed. A assay based on formation an aluminium chloride complex was applied flavones flavonols using galangin as standard. Because high amount dihydroflavonols "poplar type" propolis, introduction a distinct procedure their considered special significance DAB9...

Abstract The compositions of positions sn ‐1, 2 and 3 triacylglycerols can be determined by partial hydrolysis with ethyl magnesium bromide, derivatization the total products (S)‐(+)‐1‐(1‐naphthyl)ethyl isocyanate isolation diacyl‐ ‐glycerol urethane derivatives chromatography on solid‐phase extraction columns containing an octadecylsilyl phase. diastereomeric ‐1,2‐and 2,3‐diacylglycerol are separated high‐performance liquid silica for determination their fatty acids gas chromatography. Each...

Abstract Procedures for the preparation of stationary phases several silver ion chromatographic techniques have been surveyed. Thin‐layer chromatography (TLC), conventional (normal pressure) column chromatography, solid phase extraction (SPE), high‐performance liquid (HPLC), and supercritical fluid (SFC) in mode considered. The utilization these analysis fatty acids triacylglycerols has demonstrated.

Complete regioselective separation of five pairs isomeric dipalmitoyl polyalkenoyl glycerols with two to six double bonds in the unsaturated acyl residues has been achieved by RP-HPLC on a single ODS column. Four columns stationary phases containing different percentages free silanol groups have tested. Binary mobile ACN admixed dichloromethane, tetrahydrofuran, 1-propanol, 2-propanol, ethanol, or acetone examined. The choice modifier depended nature phase. more polar solvents were better...

Biosurfactant activity and naphthalene degradation by a new strain identified as Bacillus cereus 28BN were studied. The grew well produced effective biosurfactants in the presence of n-alkanes, naphthalene, crude oil vegetable oils. detected surface tension lowering medium, thin layer chromatography infrared spectra analysis. With (2%) sole carbon source, high levels rhamnolipids at concentration 2.3 g l -1 determined stationary growth. After 20 d incubation 72 ± 4% initial was degraded....

Abstract The ability of reversed‐phase high‐performance liquid chromatography (RP‐HPLC) to separate some positionally isomeric disaturated and monounsaturated triacylglycerols (TAGs) as intact species is demonstrated for the first time. Mobile phases acetonitrile modified with methanol, ethanol, 2‐propanol, 1‐propanol, 1‐butanol, acetone, or dichloromethane were tested separation POP‐PPO, PLP‐PPL, PEP‐PPE, PDP‐PPD (P – palmitic, O oleic, L linoleic, E eicosapentaenoic, D docosahexaenoic acid...

The triacylglycerols of meadowfoam oil have been resolved by HPLC in the silver ion and reversed‐phase modes, two techniques used a complementary fashion. fractions obtained were collected quantified gas chromatography their methyl esters presence an internal standard. Silver gave distinctive resolution which differing solely position chain‐length single monoenoic fatty acyl group resolved, order elution being 11−20∶1, 5−20∶1, 13−22∶1, 5−18∶1 9−18∶1. Reversed‐phase also containing positional...

Abstract The lipid composition of the seed oil three varieties (L‐74, VIR‐11 and BGR‐455) Lallemantia iberica Fisch. & Mey. (Lamiaceae) harvested in Bulgaria was examined detail. Triacylglycerols (TAG >90%), phospholipids (<3%), sterol esters (~0.2%), accompanying compounds—sterols (~0.3%) tocopherols (336–499 mg/kg)—were determined for first time. In addition, specific distribution fatty acids between classes elucidated. Nineteen TAG species were unambiguously identified...

A silver ion HPLC procedure is described that suitable to determine the fatty acid composition of plant seed oils. After conversion acids p-methoxyphenacyl derivatives, it was possible achieve baseline resolution all components with 0 3 double bonds, including positionally isomeric 18:1 oleic (cis 9-18:1), petroselinic 6-18:1), and cis-vaccenic 11-18:1), in aniseed oil (Pimpinella anisum, Apiaceae) by a single gradient run on cation exchange column laboratory converted form. The UV detector...

Soya bean and linseed oils were analysed by successive application of silver-ion reversed-phase thin-layer chromatography densitometry. Direct quantitative determination all the 20 possible triacylglycerol (TAG) classes including critical pairs (SD2+S2T; M2T+D3; SDT+MDT; ST2+MT2) was performed. TAG molecular species down to 0·1% (32 in soya oil 26 oil) identified quantified. The detection limit 0·2 μg standard deviation between 1·0% for silver ion (TLC) 0.1% 3.9% TLC determinations. accuracy...

The efforts to reveal, in detail, the molecular and intramolecular structures of one main lipid classes, namely, triacyl-sn-glycerols, which are now known affect their specific important role all living organisms, briefly overviewed. Some milestones significance gradual but continuous development improvement analytical methodology identify triacylglycerol regio- stereoisomers complex samples traced throughout years: use chromatography based on different separation principles; improvements...

Abstract Analytical and preparative thin‐layer chromatography (TLC) on intact silica gel layers modified with either silver nitrate (Ag‐TLC) or dimethyldichlorosilane (RP‐TLC), combined densitometric quantification gas (GC), have been used to elucidate the lipid classes, their fatty acid profiles, triacylglycerol, sterol compositions of raw microwaved roasted walnuts, hazelnuts almond kernels harvested in Bulgaria. The results triacylglycerol are good agreement those reported for other...