Daniela Heimler

Polyphenols in greenhouse and open-air-grown lettuce

Abstract Lactuca sativa L. plants (cv. Audran) developed in greenhouse or in open air, were analysed for their polyphenol compounds (caffeic acid derivatives, quercetin and kaempferol glycosides) to verify whether these two different growing environments affected both the qualitative and quantitative phenol patterns. The lettuce extracts from greenhouse and open-air samples were compared and directly analysed by HPLC/DAD, HPLC/MS and HPTLC. All open-air samples had higher flavonol contents than the greenhouse ones. The applied rapid and sensitive HPTLC method could be routinely employed to determine the leaf flavonol content of a large number of lettuce samples.

Soap thin-layer chromatography of some primary aliphatic amines

Abstract The chromatographic characteristics of nine primary aliphatic amines have been studied using soap thin-layer chromatography. The influence of the type of detergent and its concentration, of the organic solvent and of the acid concentration on the chromatographic behaviour of these amines was investigated. Many separations that cannot be effected with either ion-exchange or reversed-phase chromatography have been effected.

Concentration, separation and determination of hydrocarbons in sea water

Abstract A method for determining the hydrocarbons dissolved in sea water, including their concentration and separation into homogeneous classes, is described. Extraction with organic solvents, determination of the optimum volumes for n-hexane and carbon tetrachloride and concentration procedures for the extracts were investigated. Separation of hydrocarbons from polar compounds and their fractionation into five classes (aliphatic, monoaromatic and polynuclear with 2, 3–4 and 5–6 rings) were achieved using adsorption chromatography on a two-step microcolumn of silica gel and aluminium oxide. The overall recovery efficiency of the procedures and the detection limits of several hydrocarbons in 11 of sea water are reported.

Determination of flavonoids, flavonoid glycosides and biflavonoids inOlea europaea L. Leaves

SummaryThe flavonoid content of olive leaves was studied by a method based on thin-layer chromatography and recording UV spectra directly on the layer. Three flavonoid glycosides, quercitrin, rutin and luteolin-7-glycoside, one flavonoid aglycone, luteolin, and chlorogenic acid were found in olive leaves. Three compounds with a biflavonoid-type sructure have been characterized. Ten cultivars were investigated in order to indicate qualitative and quantitative differences.

Reversed-phase and soap thin-layer chromatography of peptides.

Abstract The chromatographic behaviour of 38 peptides on layers of silanized silica gel alone and impregnated with anionic and cationic detergents has been investigated. On the basis of the comparison with the amino acid constituents, it has been possible to predict the sequence of the affinities of the peptides with the different solvents. Many separations have been carried out on layers impregnated with 4% dodecylbenzenesulphonic acid solution.

Soap thin-layer chromatography of sulphonamides and aromatic amines

Abstract Using soap thin-layer chromatography, we investigated the behaviour of sulphonamides and many primary aromatic amines. The influence on the chromatographic behaviour of the kind of detergent, the organic solvent percentage in the eluent in the presence and absence of acids, and the apparent pH of the eluent has been widely investigated. Many separations that cannot be effected on ion exchangers have been carried out.

PTR-TOF-MS and HPLC analysis in the characterization of saffron (Crocus sativus L.) from Italy and Iran

Saffron samples from Italy and Iran were analyzed for their content in aroma and bioactive compounds with different analytical techniques. HPLC was used for the identification and quantification of crocins, picrocrocin, safranal and flavonoids content, while the novel proton transfer reaction time-of-flight mass spectrometer was employed for the aroma compounds analysis. Italian saffron turned out to be richer in total crocins and safranal contents. Sample characterization was performed with an unsupervised statistical approach; tests involving different numbers of parameters deriving from the two analytical techniques were performed. The results achieved showed that the best samples classification was obtained by joining the information acquired from both techniques; following such an approach, a sharper separation between Iranian and Italian samples was achieved. Finally, among the variables that most contribute to the description of variability, isophorone, safranal and picrocrocin were identified to be the most significant.

Conventional, organic and biodynamic farming: differences in polyphenol content and antioxidant activity of Batavia lettuce

BACKGROUND Lactuca sativa L. ssp. acephala L., cv. Batavia red Mohican plants were cultivated under intensive conventional, organic and biodynamic farming and were analyzed for their polyphenol content and antiradical activity in order to demonstrate the influence of farming on yield, polyphenol content and antiradical activity. RESULTS The yield of plants from conventional farming was the highest (2.89 kg m⁻²), while polyphenol content, measured by spectrophotometry, of these plants was lower at P < 0.05 (1.36 mg g⁻¹) than the content of plants from organic and biodynamic farming (1.74 and 1.85 mg g⁻¹, respectively). The antiradical activity, measured by DPPH · assay, was positively correlated to flavonoid and hydroxycinnamic acid contents. CONCLUSION Flavonoid, hydroxycinnamic acid and anthocyan patterns were not affected by the type of cultivation, while quantitative differences were demonstrated and some differences were found between conventional farming and organic or biodynamic farming. The yield of conventionally grown salads was the highest.

PTR‐TOF‐MS analysis of volatile compounds in olive fruits

BACKGROUND Volatile compounds of Cellina di Nardò and Ogliarola Barese, two typical Italian olive varieties, have been characterised at different ripening stages. Proton transfer reaction-time-of-flight-mass spectrometry (PTR-TOF-MS) was used for the first time on these fruits with the aim of characterising the volatile profile and, in the case of Ogliarola, the changes which may occur during the maturation process. RESULTS PTR-TOF-MS does not involve any sample pre-treatment, and allows high-resolution measurements, large spectra and small fragmentation of the volatiles. Therefore it allows both compound identification and data statistical treatments. In the present work, about 40 compounds that contribute to the discrimination between samples of the two varieties have been identified. CONCLUSIONS Three groups of compounds were identified: (1) compounds that are typical of mature fruits of Ogliarola, (2) compounds that tend to decrease during the change from green to mature fruits, and (3) compounds that increase during the maturation process.

Reversed-phase and soap thin-layer chromatography of amino acids

The chromatographic characteristics of 33 amino acids have been studied using soap thin-layer chromatography (TLC). The influence of the type of detergent, the organic solvent and the acid concentration in the eluent on the chromatographic behaviour of the amino acids was investigated. Many interesting separations that cannot be effected by ion-exchange TLC have been performed.